Organic Foods Pdf Essay Example for Free

Organic Foods Pdf Essay Abstract: During the last decade, consumers’ trust in food quality has decreased drastically, mainly because of growing ecological awareness and several food scandals (e. g. BSE, dioxins, bacterial contamination). It has been found that intensive conventional agriculture can introduce contaminants into the food chain. Consumers have started to look for safer and better controlled foods produced in more environmentally friendly, authentic and local systems. Organically produced foods are widely believed to satisfy the above demands, leading to lower environmental impacts and higher nutritive values. So far, studies have partly con? rmed this opinion. Organic crops contain fewer nitrates, nitrites and pesticide residues but, as a rule, more dry matter, vitamin C, phenolic compounds, essential amino acids and total sugars than conventional crops. Organic crops also contain statistically more mineral compounds and usually have better sensory and long-term storage qualities. However, there are also some negatives: plants cultivated in organic systems generally have 20% lower yields than conventionally produced crops. Several important problems need to be addressed in the coming years: environmental, bacterial and fungal contamination of organic crops and, the most essential issue, the impact of organic food consumption on animal and human health.  © 2007 Society of Chemical Industry Keywords: organic plant crops; quality; yield; composition; nutrition; vitamins; phenolics; sugars; nitrates; nitrites; pesticides; dry matter; health; sensory qualities. FACTORS INFLUENCING THE QUALITY OF ORGANIC PLANT FOOD PRODUCTS There are several important factors in?uencing the quality of food products that also are relevant to organically produced plant products. As illustrated in Fig. 1, the basic factors are the quality of the environment (abiotic factors) and the levels of pest and pathogen damage (biotic factors) to which plants are subjected. The main components of the environment (air, water, soil) have to be unpolluted if the crops obtained are expected to be of high nutritive quality. Many environmental contaminants enter the food production chain (soil–plant–animal–human organism), causing signi? cant problems in human health. 1 These contaminants include heavy metals, pesticide residues, nitrogen compounds, mycotoxins, chlorinated biphenyls (PCBs), aromatic hydrocarbons (e. g. benzo[a]pyrene), plant growth stimulators (e. g. choline chloride), antibiotics, hormones, radioactive isotopes and plastic substances (monomers). Climate and weather are also important factors, as well as soil type and pH, soil cultivation, fertilisation and conditions of crop storage after harvest. ? Biotic factors can have also a signi? cant impact on crop quality. The main biotic factors are cultivar choice, bacterial and fungal contamination (disease) and pest damage. Cultivars of the same crop species can differ signi? cantly in nutritive quality. For example, the content of ? carotene in carrots (Daucus carota L. ) can vary between 7. 19 and 13. 84 mg g? 1 depending on the cultivar. 2 The main potential source of bacterial contamination in plant crops is animal manure used in organic farming. Contamination can take place via the roots or by water splashing onto the leaf surfaces. The most important organisms are several species of facultative anaerobic bacteria (Salmonella enterica, Escherichia coli O157:H7, Campylobacter spp., Listeria monocytogenes, Clostridium botulinum, Mycobacterium paratuberculosis), protozoa (Toxoplasma gondii), tapeworms, viruses and prions. The results obtained so far are contradictory. Some studies indicate higher bacterial contamination in organic crops, while others show the opposite. 3 Mycotoxins (produced by fungi) originate mostly in the ? eld but can also develop during storage. Owing to the fact that fungicides are not used Correspondence to: Ewa Rembialkowska, Organic Foodstuffs Division, Faculty of Human Nutrition and Consumer Sciences, Warsaw Agricultural University, Nowoursynowska 159 C, PL-02-776 Warszawa, Poland E-mail: ewa [emailprotected] pl (Received 24 October 2006; revised version received 29 January 2007; accepted 8 February 2007). Figure 1. Factors in? uencing the quality of organic food products. in organic agriculture, some authors believe that organically produced foods will contain higher concentrations of mycotoxins. However, literature reviews show that mycotoxin concentrations are usually similar or reduced in organic compared with conventional products. 4 The most notorious mycotoxins are those produced by Fusarium species on cereal crops and maize. One of the reasons for lower Fusarium infections in organic grains could be the lower nitrogen concentrations in the tissues. 5 Insect pests also exert an in? uence on crop quality. Because of the ban on synthetic pesticides in organic agriculture, insects often damage fruits and vegetables, thereby diminishing their yield and harming their appearance. However, it is not clear whether they also reduce their nutritive quality. In contrast, there is evidence that organically grown plants contain more phytochemicals (which are natural insecticides) and are therefore more resistant to insect damage. 6 They can also play a positive role in human health, because several phytochemicals, being plant defence compounds, are connected with possible health bene? ts (Brandt K, oral presentation at QLIF Congress, Newcastle, 2005). Regulations on organic plant production allow actions that avoid many negative features of crop quality if they are consistently performed by producers. In order to ful? l these demands and to offer highquality products to consumers, an ef? cient and airtight certi? cation and control system must be implemented. In most countries such systems are quite ef?cient, though a rapid increase in the number of organic farms could lead to problems with a subsequent loosening of regulatory control. Therefore the main rule should be ‘trust is good, but control is better’. Moreover, the ? nal quality of organic food products is in? uenced by the effective implementation of 2758 the regulations on animal production and organic food processing. Only precise ful? lment of all these regulations can guarantee the best organic food quality (Fig. 1). IMPACT OF REGULATION ON ORGANIC PLANT PRODUCTION The regulations for organic plant production are clear and detailed. 7 The European Union (EU) regulation published in 19918 contains parts that relate directly to the composition of organic plant products. The most important aspects of this regulation include:7 †¢ a ban on genetic engineering and genetically modi? ed organisms (GMOs); †¢ lower nitrogen levels – a maximum limit for manure application of 170 kg N ha? 1 year? 1 ; †¢ a ban on synthetic pesticides; †¢ a ban on synthetic mineral fertilisers; †¢ a ban on growth promoters. Organic farmers must follow the above regulations if they want to pass the inspection procedure every year and receive a certi? cation document. If all requirements are complied with, several qualitative results can be expected. The most important conclusions from scienti? c comparisons are given below. CONTAMINANTS Nitrates and nitrites A large amount of data shows that the content of nitrates and nitrites is distinctly higher in conventionally cultivated than in organic crops. This is important, because nitrates can easily be converted into nitrites, which can cause a dangerous illness called methaemoglobinaemia in babies, infants and elderly people. 9 J Sci Food Agric 87:2757–2762 (2007) DOI: 10. 1002/jsfa Quality of organic plant products. Moreover, nitrites can react with amines to create nitrosamines, which are carcinogenic and mutagenic substances causing cancer of the digestive tract and leukaemia. 10 This process is dangerous not only for young children but also for adults of any age. Based on a large amount of data, the nitrate content of organic and conventional crops has been compared. On average, the nitrate content of organic crops was 49% that of conventional crops. 11 These and other data provide a basis for stating that organic methods lead to an approximately 50% reduction in the intake of nitrates and nitrites by humans. Pesticides Governments place legal limits, known as the Maximum Residue Level (MRL), on the level of pesticides that can be present in food. The MRL is usually estimated by testing individual pesticides on rats. Governments maintain that consumption of pesticides below the MRL is not a health risk. However, at lower levels, pesticides are known or suspected to cause many diseases and health problems, including cancer. 12 The main problem is that the MRL for pesticides is usually estimated by testing individual pesticides on rats for a relatively short period. Virtually nothing is known about the effects of consuming combinations of potentially hundreds of different pesticides over the course of a lifetime. We do not and cannot know explicitly what is causing what, so precaution is the main tool available to us (Howard V, oral presentation at QLIF Congress, Newcastle, 2005). The levels of pesticide residues found in organic crops are de? nitely lower than those present in conventional crops (Howard V, oral presentation at QLIF Congress, Newcastle, 2005). It can be expected that eating organic foods will result in lower pesticide levels in human milk and body tissues. There is some evidence con? rming this hypothesis. Researchers in France found that the level of pesticide residues in the milk of breast-feeding women decreased signi? cantly with an increase in the proportion of organic food in the daily diet (from 25 to 80%). 13 All available results show that the content of pesticide residues is signi? cantly lower in organic crops, which creates safer health conditions for consumers eating organically. Heavy metals Heavy metals such as cadmium, lead, arsenic, mercury and zinc are introduced into the food chain from various sources, including industry, transportation, communal wastes and agriculture. For example, mineral phosphoric fertilisers used in conventional agriculture can introduce cadmium into crops, but the metal industry and transportation also cause cadmium contamination of soils and crops. Therefore there are no clear results in studies comparing the levels of J Sci Food Agric 87:2757–2762 (2007) DOI: 10. 1002/jsfa heavy metals in organic and conventional crops. Some data point to higher levels in conventional crops, while others show the opposite. 11 A problem to be solved is whether organic farming (composting, increasing the organic matter in soil, pH, etc. ) can diminish the intake of heavy metals by cultivated plants. DESIRABLE COMPOUNDS IN PLANTS Vitamins, phenolic compounds and mineral compounds The nutritive value of foods depends mainly on them having the appropriate content of compounds indispensable for proper functioning of the human organism. The content of phyto-compounds in plant foods is a topic of great interest in food science nowadays. A growing body of evidence indicates that secondary plant metabolites (phytochemicals) play a critical role in human health and may be nutritionally important. 14 There are two main theories explaining the factors in? uencing the levels of compounds in plants. 15 The carbon/nitrogen (C/N) balance theory states that, when nitrogen is easily available, the plant will ? rst make compounds with high nitrogen content, e. g. proteins for growth and nitrogen-containing secondary metabolites such as alkaloids, glucosinolates and non-protein amino acids such as the Allium ? avour precursors. When nitrogen availability is limiting for growth, the metabolism changes more towards carboncontaining compounds, e. g. starch, cellulose and non-nitrogen-containing secondary metabolites such as phenolics and terpenoids. The second, newer theory is the growth/ differentiation balance hypothesis (GDBH). 15 It states that the plant will always assess the resources available to it and optimise its investment in processes directed towards growth or differentiation. The term ‘differentiation’ encompasseses increased formation of defence compounds as well as accelerated maturation and seed development. The C/N balance theory is a special and typical case of the GBDH theory, since low nitrogen availability is the most common growth-limiting condition in natural ecosystems. 15 To verify the above theories, several authors investigated the content of some vitamins and phyto-compounds in organically and conventionally produced crops. In order to summarise different data, for each organic–conventional comparison a % difference was calculated: [(organic ? conventional)/conventional] ? 100 The collected data for several desirable components are presented in Table 1. The role of vitamin C (ascorbic acid) in the human organism is basic for several metabolic functions, mainly because it is one of the major cellular direct antioxidants (along with glutathione) and is a 2759 E Rembialkowska Table 1. Contents of desirable components in organic crops relative to those in conventional crops Component Vitamin C Phenolic compounds Iron Magnesium Phosphorus Mean % difference +28. 7 +119. 3 +21. 1 +29. 3 +13. 6 Range (%) ? 38 to +135. 5 ? 56. 6 to +734. 2 ? 73 to +240 ? 35 to +1206 ? 44 to +240 Number of studies 21 15 16 17 18 production and reduces carbohydrate production. Moreover, the increased protein produced in response to high nitrogen levels contains lower amounts of certain essential amino acids such as lysine and therefore has a lower quality with respect to human nutrition. Source: Ref. 17 and author’s own calculations. cofactor for certain enzymes. Vitamin C also supports detoxication and resistance of the human organism. The higher content of vitamin C in organic crops is bene? cial to health, because vitamin C inhibits the in situ formation of carcinogenic nitrosamines, thus diminishing the negative impact of nitrates on the human organism. 10 Therefore organic vegetables can play an important anticarcinogenic role. Plant-based phenolic metabolites are particularly interesting because of their potential antioxidant activity and medical properties, including anticarcinogenic activity. 15 According to Benbrook,16 organic farming has elevated antioxidant levels in about 85% of the cases studied to date and, on average, levels are about 30% higher compared with foods grown conventionally. Mineral compounds containing iron, magnesium and phosphorus are fundamental for human health. According to Worthington,17 the higher mineral content in organic crops may be connected with the higher abundance of micro-organisms in organically managed soil. These micro-organisms produce many compounds that help plants to combine with soil minerals and make them more available to plant roots. Unfortunately, there have been only a few studies on other vitamins such as ? -carotene, B1 and B2 and the results are contradictory. Therefore no general conclusions can be drawn about these compounds. Total sugars A higher total sugar content in plant crops not only improves their taste but is also an important component of their technological quality, e. g. in the case of sugar beet. Studies clearly indicate a higher content of total sugars, mainly sucrose, in organically produced vegetables and fruits such as carrots, sugar beet, red beetroot, potatoes, spinach, Savoy cabbage, cherries, redcurrants and apples. 11,18 Proteins Several studies analysed in review papers11 show that the quantity of crude protein is lower in organic than in conventional crops but that the quality is better as measured by essential amino acid content. According to Worthington,17 nitrogen from any kind of fertiliser affects the quantity and quality of protein produced by plants. Provision of a large amount of nitrogen to a plant increases protein 2760 SENSORY QUALITY OF ORGANIC FOODS Many studies have proved quite unequivocally that vegetables and fruits from organic farms have a better taste and smell. This was found for carrots and potatoes, celery and red beetroot, head cabbage and tomatoes as well as for apples, cherries and redcurrants. 11 Organic fruits contained more total sugars, which probably in?uenced the better taste perception by consumers. Better taste and smell have also been found for bread made from organic grain, which also had better crumb elasticity. 6 Interesting studies have been conducted on animal food preference in which animals were given organic or conventional fodder. Most studies have proved a clear animal preference for foods produced organically; such studies have been conducted on rats, mice, hens and rabbits. 19 Preference for organic fodder was also observed in cases where, according to chemical analyses, both organic and conventional fodder ful? lled all physiological needs of the animals tested. 20 The reason for this was probably the difference in taste between organic and conventional fodder. STORAGE QUALITY OF ORGANIC PLANT CROPS Transpiration losses and decay processes, as well as changes in nutritive value, normally take place during the storage period of potatoes and other vegetables. However, these changes can proceed at different rates and to differing degrees. Most of the available data indicate that the decay process is slower in organic crops, which therefore show better storage quality after the winter period. A review study based on many sources21 concluded that the storage quality of vegetables and fruits was better in the case of plants grown on organic farms (Table 2). The better storage quality of organic crops Table 2. Storage losses of carrots, potatoes and various fruits and vegetables from organic (ORG) and conventional (CONV) farmsa Carrots Potatoes Fruits and vegetables ORG CONV ORG CONV ORG CONV Number of quoted studies Storage loss (% of initial mass) a 15 33 15 40 22 22 22 30 53 28 53 38 Average data based on literature review. 21 J Sci Food Agric 87:2757–2762 (2007) DOI: 10. 1002/jsfa Quality of organic plant products Table 3. Positive nutritive attributes of organic plant products No. 1 2 3 4 5 Attribute Organic crops contain fewer nitrates, nitrites and pesticide residues than conventional crops. There is no clear difference in the content of heavy metals between organic and conventional crops Organic plant products contain, as a rule, more dry matter, vitamin C, phenolic compounds, essential amino acids and total sugars. However, the level of ? -carotene is often higher in conventional plant products Organic plant products contain statistically more iron, magnesium and phosphorus. They also tend to contain more chromium, iodine, molybdenum, selenium, calcium, boron, manganese, copper, potassium, sodium, vanadium and zinc Organic plant products usually have better sensory quality. They have a clearer smell and taste and are sweeter and more compact because of their higher dry matter content Preference for organic products is typical not only for humans but also for animals such as rats, rabbits and hens. This preference was also observed in cases where, according to chemical analyses, both organic and conventional fodder ful? lled all physiological needs of the animals tested Vegetables and fruits from organic production maintain better quality during winter storage, showing lower mass losses due to transpiration, decay and decomposition processes. A possible reason for this is their higher content of dry matter, minerals, sugars and other bioactive compounds 6 Table 4. Negative and unclear aspects of organic plant products No. 1 Negative aspect Plants cultivated in organic systems have, as a rule, signi?cantly (on average 20%) lower yields than conventionally produced crops. This increases their price and creates for many consumers a barrier to buying organic foods Unclear aspect Environmental contamination (heavy metals, PCBs, dioxins, aromatic hydrocarbons) can be similar in organic and conventional crops, because the impact of industrial, transport and communal sources is similar on organic and conventional farms located in the same area Bacterial (mainly Salmonella and Campylobacter) Contamination can sometimes be higher in organic produce, but scienti?c evidence of this is still not clear Mycotoxins can contaminate both organic and conventional foods, but scienti? c data are contradictory The impact of organic food consumption on human health and wellbeing remains essentially unknown in spite of some positive indications, so the subject needs further study 2 3 4 was probably associated with a higher content of dry matter in their ? esh, resulting in less extensive decay and decomposition. Lower losses in organic production have not only nutritive but also economic bene? ts. In conventional systems, high yields are produced but signi?cant losses during storage reduce the economic bene? ts. CONCLUSIONS Recent food crises (BSE, foot and mouth disease, food contamination by dioxins, toxic fungi, Salmonella and Campylobacter bacteria) have caused consumers to look for more authentic and safer foods. Organic food production is widely recognised as being more friendly to the environment, more controlled and better for animal welfare. On the other hand, many data indicate that a lot of food contaminants have their source in conventional methods of agriculture, animal production and food processing. The negative effect of the continuing enthusiastic use of chemical fertilisers and pesticides in agriculture is potentially huge. Therefore safer methods of agricultural production, mostly organic methods, are very important. Studies conducted in various countries have indicated several positive attributes of organic plant J Sci Food Agric 87:2757–2762 (2007) DOI: 10. 1002/jsfa products (Table 3) but also a few negative and unclear aspects (Table 4). To summarise the positives, organic food should be recommended for all, but especially for young babies, pregnant and breast-feeding women, elderly and chronically ill people and vegetarians. The last group obviously consumes a lot of vegetables, which can contain too high levels of carcinogenic substances when produced conventionally. The lower content of nitrates and higher content of phenolic compounds and vitamin C in organic crops are especially important for health. Nitrates are easily converted in the digestive tract into poisonous nitrites, which are the precursors of carcinogenic nitrosamines. This process is hampered by vitamin C, and carcinogenesis is retarded by phenolic compounds and other dietary phytochemicals present at higher levels in organically produced crops. Therefore organic vegetables can play an important anticarcinogenic role. REFERENCES 1 Rembialkowska E, Organic agriculture and food quality, in Ecological Agriculture and Rural Development in Central and Eastern European Countries, Vol. 44 of NATO Science Series, ed. by Filho WL. IOS Press, Amsterdam, pp. 185–204 (2004). 2761 E Rembialkowska ? ? 2 Schuphan W, Biochemische Sortenprufung an Gartenmohren ? ? als neuzeitliche Grundlage fur planvolle Zuchtungsarbeit. Z? chter 2:25–43 (1942). U 3 Franz E, van Bruggen AHC and Semenov AM, Risk-analysis of human pathogen spread in the vegetable industry: a comparison between organic and conventional production chains, in Bayesian Statistics and Quality Modelling in the AgroFood Production Chain, ed. by van Boekel MAJS, Stein A and van Bruggen AHC. Kluwer Academic, Dordrecht, pp. 81–94 (2004). 4 FAO, Food Safety as Affected by Organic Farming (Twentysecond FAO Regional Conference for Europe). [Online]. (2000). Available: www. fao. org/docrep/meeting/x4983. htm. 5 Van Bruggen AHC and Termorshuizen AJ, Integrated approaches to root disease management in organic farming systems. Aust Plant Pathol 32:141–156 (2003). 6 Bjorn G and Fruekilde AM, Cepa onions (Allium cepa L) grown conventionally and organically – similarities and differences. Gron Viden 153:1–6 (2003). (in Danish). 7 Hansen B, Alroe HF, Kristensen ES and Wier M, Assessment of food safety in organic farming. DARCOF Working Paper 52 (2002). 8 EU, Council Regulation No. 2092/91 of 24 June 1991 on organic production of agricultural products and indications referring thereto on agricultural products and foodstuffs. OJL 198, 22. 7 P. 1 (1991). ? 9 Szponar L and Kierzkowska E, Azotany i azotyny w srodowisku oraz ich wplyw na zdrowie czlowieka. Post Hig Med Do? w s 44:327–350 (1990). 10 Mirvish SS, Vitamin C inhibition of N-nitroso compounds formation. Am J Clin Nutr 57:598–599 (1993). 11 Rembialkowska E, Wholesomeness and Sensory Quality of Potatoes and Selected Vegetables from the Organic Farms. Fundacja ? Rozwoj SGGW, Warszawa (2000). 12 BMA, The BMA Guide to Pesticides, Chemicals and Health. Report of Science and Education. British Medical Association, London (1992). 13 Aubert C, Pollution du lait maternel, une enquete de terre vivante. Quatre Saisons Jardinage 42:33–39 (1987). 14 Lundeg? rdh B and M?rtensson A, Organically produced plant a a foods – evidence of health bene? ts. Acta Agric Scand B 53:3–15 (2003). 15 Brandt K and Molgaard JP, Organic agriculture: does it enhance or reduce the nutritional value of plant foods? J Sci Food Agric 81:924–931 (2001). 16 Benbrook CM, Elevating Antioxidant Levels in Food through Organic Farming and Food Processing. An Organic Center of Science Review. Organic Center for Education and Promotion (2005). 17 Worthington V, Nutritional quality of organic versus conventional fruits, vegetables, and grains. J Alternative Compl Med 7:161–173 (2001). 18 Zadoks JC, Development of Farming Systems. Pudoc, Wageningen (1989). 19 Williams CM, Nutritional quality of organic food: shades of grey or shades of green? Proc Nutr Soc 61:19–24 (2002). ? 20 Woese K, Lange D, Boess Ch and Bogl KW, A comparison of organically and conventionally grown foods – results of a review of the relevant literature. J Sci Food Agric 74:281–293 (1997). 21 Bulling W, Qualit? tsvergleich von ‘biologisch’ und ‘konventionell’ a erzeugten Feldfruchten. Regierungsprasidium, Stuttgart (1987). 2762 J Sci Food Agric 87:2757–2762 (2007) DOI: 10. 1002/jsfa.

Biochemical and Hormonal Changes in Childhood Obesity

Biochemical and Hormonal Changes in Childhood Obesity The prevalence of chronic or non communicable disease is escalating much more rapidly in developing countries than in industrialized countries. According to World Health Organization (WHO) estimates, by the 2020, non communicable diseases will account for approximately three quarter of all deaths in the developing countries (WHO. Global Strategy for non communicable disease prevention, 1997). In this regard, a potential emerging public health issue for the developing countries may be increasing incidence of childhood obesity with associated complications, which in turn is likely to create public health burden for poorer nations in the near future (Freedman et al, 2001). Lower to middle income nations face the double burden of having both malnourished and over nourished population, with most overweight and obese children being concentrated in urban areas. Rapid urbanization is associated with unhealthy lifestyle or New World Syndrome. In addition, in such communities, childhood obesit y is still considered a sign of healthiness and high social class. There is no universal consensus on a cut off points for defining overweight and obesity in children and adolescents, usually, for clinical practice and epidemiological studies, child overweight and obesity are assessed by means of indicators based on weight and height measurements, such as weight for height measures or body mass index (weight (kg)/height (m2))(WHO. Report series no.847, 1995).The US Centers for Disease Control and Prevention (CDC) defines obese as being at or above 95th percentile of body mass index for age (Kuczmarsk RJ et al, 2000). History of obesity is both interesting and gives details of its progression. Obesity is an age-old health condition. Through out the history of obesity, its reputation varies from appreciation and opposite among cultures and in time. Ancient Egyptians are said to consider obesity as disease. Perhaps the most famous and earliest evidence of obesity is the Venus figurines, Statuettes of an obese female torso that probably had a major role in rituals. Ancient China has also been aware of obesity and dangers that come with it. They always were a believer of prevention as a key to longevity. The Aztecs believed that obesity was supernatural, an affliction of the gods. Hippocrates, the father of medicines was aware of sudden deaths being more common among obese men than lean ones as stated in his writings. In certain cultures and areas where food is scarce and poverty is prevalent, is viewed as symbol of wealth and social status. To date, an African tribe purposely plumps up a bride to pre pare her for child bearing. Before a wedding can be set, a slim bride is pampered to gain weight until she reaches the suitable weight. Through out the history of obesity, the publics view and status of obesity changed considerably in the 1900s. It was regarded as unfashionable by the French designer, Paul Poi ret who designed skin-revealing clothes for women. About the same time, the incidence of obesity began to increase and become wide spread. Later in 1940s, Metropolitan life insurance published a chart of ideal weight for various heights. They also advocated that weight gain parallel to age is unhealthy. The government and medical society become more hands-on with obesity by imitating campaign against it. This was preceded by a study of risk factors for cardiovascular disease revealing obesity in the high ranks. Since then various diets and exercise programs have emerged. In 1996, the Body Mass Index (BMI) was published. This statistical calculation and index determined that a person is obese or not. At this time ,obesity incidence have soared, led by children and adolescent obesity, tripling in just a few short years, greater than any number in the history of obesity. This increase in the incidence of childhood obesity with associated cardiovascular risks, type 2 diabetes mellitus and stroke is supported by a considerable body of evidence. The prevalence of overweight and obesity in childhood and adolescents has been increasing throughout much of the developed and developing world for the past few decades. It has become increasingly clear that excess adiposity in childhood predisposes individual not only to increased risk of adiposity and its sequaele as adults (Freedman et al, 2001), but also to increased risk of multiple chronic diseases in childhood and adolescence (Rosen bloom et al, 1999). Though mechanism not clearly delineated, excess body weight and adiposity is associated with type 2 diabetes mellitus and its complications, cardiovascular disease risk factors, non alcoholic fatty liver disease and asthma in youth. Childhood Obesity 1930 1972 Risk factors for coronary heart disease (CHD) such as hypertension, dyslipidemia, impaired glucose tolerance and vascular abnormalities were present in overweight children. CHD is likely to be increased in overweight children when they become adults as a result of established risk factors. This study investigated whether excess weight in childhood was associated with CHD in adulthood among a very large cohort of persons born in Denmark in 1930 through 1972. They underwent mandatory annual health examination at public or private schools in Copenhagen. Each child was examined by school doctors or nurses and was assigned a health card bearing childs name, date of birth, birth weight reported by parents. 10,235 men and 4,318 women, for whom childhood BMI data were available, received a diagnosis of CHD or died of CHD as adults. The risk of CHD event, a non fatal event, and a fatal event among adults was positively associated with BMI at 7-13 years of age for boys and 10 to 13 years of ag e as girls. The associations were linear for each age and risk increased across the entire BMI distribution. Childhood Obesity 1930 1972 Risk factors for coronary heart disease (CHD) such as hypertension, dyslipidemia, impaired glucose tolerance and vascular abnormalities were present in overweight children. CHD is likely to be increased in overweight children when they become adults as a result of established risk factors. This study investigated whether excess weight in childhood was associated with CHD in adulthood among a very large cohort of persons born in Denmark in 1930 through 1972. They underwent mandatory annual health examination at public or private schools in Copenhagen. Each child was examined by school doctors or nurses and was assigned a health card bearing childs name, date of birth, birth weight reported by parents. 10,235 men and 4,318 women, for whom childhood BMI data were available, received a diagnosis of CHD or died of CHD as adults. The risk of CHD event, a non fatal event, and a fatal event among adults was positively associated with BMI at 7-13 years of age for boys and 10 to 13 years of ag e as girls. The associations were linear for each age and risk increased across the entire BMI distribution. Childhood Obesity and Economic Growth 1930-1983 Childhood obesity was related to the economic growth during the 50 years of economic growth in the industrialized world especially in Denmark. Annual measurements of height and weight were available for all children born between 1930 and 1983 attending primary schools in Copenhagen Municipality. 165,389 boys and 163,609 girls from the age of 7 through 13 years were included in this study. After computerization SBMI (kg/m2) were calculated and the prevalence of overweight and obesity according to international age and gender–specific criteria. Economics growth was indicated by the Gross National Product and the overall consumption per capita, adjusted for inflation. Prevalence of overweight and obesity among Danish children rose in phases, which were not paralleled by trends in economic growth. The microeconomics growth indicators seem inappropriate as proxies for the environmental exposures that have elicited the obesity epidemic. Childhood obesity and television viewing Children spend a substantial portion of their lives watching television (TV). Investigators have hypothesized that TV viewing causes obesity by one or more than three mechanisms: Displacement of physical activity. Increased calorie consumption while watching or caused by the effects of advertising. Reduced resting metabolism. The relationship between TV viewing and obesity has been examined in a relatively large number of cross sectional epidemiological but few longitudinal studies. Many of them have found relatively weak, positive association or mixed results. Many experimental studies have found that reducing TV viewing may help to reduce the risk of obesity. One school based experimental study was designed specifically to test directly the casual relationship between TV viewing behaviors and body fatness. The results of this randomized controlled trial provide evidence that TV viewing is a cause of increased body fatness and that reducing the TV viewing is a promising strategy for preventing childhood obesity (Robinson; 2001). The objective of another study (Utter J et al, 2006), was to explore how time spent watching television (TV) is associated with the dietary behavior of New Zealand children and young adolescents. Total number of participants was 3275 children aged 5-17 years. The findings suggest that longer duration of TV watching (thus more frequent exposure to advertising) influences the frequency of consumption of soft drinks, some sweets and snacks and some fast foods among children and young adolescents. Efforts to control the time spent watching TV may result in better dietary habits and weight control for children and adolescents. Childhood Obesity US- A decade of progress, 1990-1999 Current data suggest that 20% of US children are overweight .An analysis of the secular trends suggest that 20% of US children are overweight, and a clear up ward trend in body weight in children of 0.2 Kg between 1973 and 1994. In addition, childhood obesity is more prevalent among minority sub groups such as African Americans. Obesity that begins early in life persists into adulthood and increases the risk of obesity related conditions later in life. There has been tremendous increase in the number of studies examining the etiology and health effects of obesity in children (Goran MI, 1990-1999).1980 (boys 0.2% girls 0.5%) and 1997 (boys 1.2%, girls 2.0%). Ten years trends of childhood obesity in Israel 1990-2000 Cross sectional data was collected from 13284 second and fifth class school; children between 1990-2000. Prevalence of obesity was determined using Israeli and US reference values. BMI values at 95th percentile increased overtime in all ages and sex categories. Between 1990 and 2000, 95th centile values were increased by 12.7%and 11.8% among second grade boys and girls respectively. Among fifth graders in 2000, 10.7% of boys and 11.1% of girls exceeded the 1990 BMI reference values. The proportion of obese children increased over time using both Israeli and US reference values (Huerta Michael et al, 2008). Netherlands. Overweight, Obesity in 2003: V.1980-97. Data on 90,071 children, aged 4-16 years were routinely collected by 11 Community Heath Services during 2002-2004. International cut -off points for BMI to determine overweight and obesity. On average, 14.5% of boys and 17.5% of the girls were overweight (including obesity), which is a substantial increase since 1980 (boys 3.9% and girls 6.9%) and 1997 (boys 9.7% and girls 13%). Similarly 2.6% of the boys and 3.3% 0f the girls aged 4-16 years were obese, which is much higher than in 1980 (boys 0.2% and girls 0.5%) and 1997 (boys 1.2% and girls 2.0%), (KatjaVan Den Husk, 2007). Obesity trends in US. 2003-2006 Height and weight measurements were obtained from 8164 children and adolescents as apart of the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey (NHANES). Because no statistically significant differences in the prevalence of high BMI for age were found between the estimates for 2003-2004 and 2005-2006, data for four years were combined to provide more stable estimates for the most recent time period. Over all, in 2003-2006, 11.3% of children and adolescents aged 2 through years were at or above 97th percentile of the 2000 BMI- for- age growth charts, 16.3% were at or above 95th percentile. Prevalence estimates vary by age and by racial/ethnic group. Analysis of the trends in high BMI for age showed no statistically significant trend over the four time periods (1999-2000, 2001-2002, 2003-2004, and 2005-2006) for either boys or girls (Cynthia l.Ogden et al, 2008). 11-March 2005. Public Release Date: Consensus on Childhood Obesity, Recommends classification as disease A common statement on childhood obesity was published to day in the journal of Chemical Endocrinology and Metabolism (one of the journals of Endocrine Society). The consensus statement reflects the conclusions from an international summit held in Israel last year (2004) and includes a controversial recommendation to classify obesity as a disease. This decision was based upon the available research on the diagnosis, prevalence, causes (including endocrine disorders), risks, prevention and treatment of childhood obesity. Pediatric obesity is now recognized as a major health problem all over the world. Researcher have found that children who are obese have a higher risks adult obesity, which is strongly associated with many serious medical complications that impair quality of life and lead to additional increased risks. The statement also noted the prevalence of overweight/obesity among children 6-11 years (in the US) doubled between the years 1980-2000. By classifying obesity as legiti mate disease, public funding and in user sreimbursement for obesity treatment becomes legalized (consensus on childhood obesity, 2005). Serious health risks will likely to begin to appear in obese children and adolescents as they grow older. These may include diabetes mellitus, metabolic syndrome, hyperandrogenism, heart disease, hypertension, respiratory factors, and sleep disorders. Obese children are also at greater risk of anxiety and depression. It also recommended a number of measures that can be implemented by parents; schools, health providers and government and regulatory agencies to help to prevent the onset of childhood obesity Endocrine Regulation of Energy Metabolism Adipocytokines and Obesity The mechanism underlying obesity was further explained by the discovery of adipocytokines, the role of peripheral thyroid hormones (T4, T3), thyroid stimulating hormone and insulin the regulation of energy metabolism. The levels of some of the adipocytokines were shown to be related to visceral obesity, type 2 diabetes mellitus and coronary artery disease. Plasma levels of all the adipocytokines increase with the obesity except adiponectin (Yuji Matsuzawa et al, 2003). Recent studies point out to the adipose tissue as a highly active organ secreting a range of hormones, Leptin, Adiponectin, and Resistin. They are considered to take part in the regulation of energy metabolism. Leptin, Adiponectin and Resistin are produced by the adipose tissue. Leptin and Adiponectin are insulin sensitizing while Resistin increase the insulin resistance. Leptin The notion that genetic abnormalities contribute to obesity gained important support with the identification of the Ob gene and its protein product in 1994 (Zhangy et al, 1996). The Ob gene termed Leptin from the Greek Leptos, meaning thin, is produced in adipose tissue and is thought to act as an afferent satiety signal in a feed back loop that affects the appetite and satiety centre in the hypothalamus of brain. The ultimate effect of this loop is to regulate body-fat mass. In human, as noted by Considine et al, 1996; caloric restriction reduces leptin concentrations and Ob mRNA levels in adipose tissue, and refeeding increases these levels. One fundamental mechanism of obesity is insensitivity to the action of Leptin, presumably in the hypothalamus. The Leptins primary physiological function is to provide a signal to suppress body fat by decreasing food intake or increasing energy expenditure. Serum leptin concentrations change more during weight loss than during weight gain (Rose nbaum M et al, 1997). Adiponectin Adiponectin or Adipo Q, an adipocyte specific secreted protein with roles in glucose and lipid homeostasis (Insulin stimulates the secretion of adiponectin). Circulating adiponectin concentrations are high 500-30,000 Â µg/l (5-30mg/ml) accounting for 0.01% of total plasma proteins (Berget et al, 2002). Adiponectin was discovered in the mid 1990s by four different groups of researchers (Hu E et al, 1996). Adiponectin has various biological functions including insulin sensitizing (Hotta K et al, 2000), antiatherogenic (Yamauchi T et al, 2003), anti-inflammatory (Ouchi N et al, 2003), antiangiogenic and anti tumor functions (Brakenhielm E et al, 2004). Adiponectin acts through Adiponectin receptors, Adipo R1 and Adipo R2. Adipo R1 is mostly expressed in skeletal muscles and Adipo R2 is abundant in liver. These receptors are also expressed by the pancreatic ß cells (Kharroubi et al, 2003), macrophages and atherosclerotic lesions (Chinetti et al, 2004) as well as in brain (Yamauchi et al, 2003). Circulating Adiponectin levels display diurnal variation with a nocturnal decline and maximum levels in the late morning (Gavrila et al, 2003). Adiponectin is also found in breast milk, which in turn is implicated in childhood obesity prevention (Savino et al, 2008). Among the various adipocytokines, adiponectin, which is an abundant circulating protein (247 amino acids) synthesized purely in adipose tissue, appears to play a very important role in carbohydrates, lipid metabolism and vascular biology. Adiponectin appears to be a major modulator of insulin action and its levels are reduced in type 2 diabetes mellitus, which could contribute to peripheral insulin resistance in this condition. It has significant insulin sensitizing as well as anti inflammatory properties that include suppression of macrophage phagocytosis and TNF-a secretion and blockage of monocytes adhesion to endothelial cells in vitro. Although further investigations are required, Adiponectin administration, as well as regulation of the pathway controlling its production, represents a promising target for managing obesity, hyperlipidemia, insulin resistance, type 2 diabetes mellitus, and vascular inflammation (Manju Chandran et al, 2003). Resistin Human resistin is 108 amino acids prepeptide and is cleaved before its secretion from the Adipose tissue. Resistin circulates in the blood as dimeric protein consisting of 92 amino acids polypeptides that are linked by a disulfide bridge. Holcomb et al, 2000 first described the gene family and its tissue specific distribution. Originally described as lung specific, is also produced by the adipose tissue and peripheral blood monocytes. It is also present in dividing epithelia of the intestine. Resistin increase blood glucose and insulin concentration in the mice and impairs hypoglycemic response to insulin infusion. In addition, anti resistin antibodies decrease blood glucose and insulin sensitivity in obese mice (Ukkalo O, 2002). The physiological role of resistin in human remains controversial. There more resistin protein in obese than lean individuals, with a significant positive correlation between resistin and BMI. BMI is a significant predictor of insulin resistance, but resisti n adjusted for BMI is not. These data demonstrate that resistin protein is present in human adipose tissue and blood and that there is significantly more resistin in serum of obese individuals. Serum resistin is not a significant predictor of insulin resistance in human (Youn et al, 2003, Rear R and Donnelly R, 2004). Tumor Necrosis Factor-a It will be unreasonable not to mention the Tumor Necrosis Factor a and its role in vascular inflammation related to atherosclerosis especially in obesity. It is a cytokine involved in systemic inflammation and is a member of a group of cytokines that stimulate the acute phase reaction. The primary role of TNF is in the regulation of immune cells. TNF is able to induce apoptotic cell death, to induce inflammation and to inhibit tumourgenesis and viral replication. Dysregulation and, in particular, over production of TNF have been implicated in a variety of human diseases, as well as cancer (Locksley et al, 2001). The theory of antitumoural response of the immune system in vivo was recognized by the physician William B in 1968. Dr A Granger reported a cytotoxic factor produced by lymphocytes and named it Lymphotoxin (Kalli WB and Granger GA, 1968). Dr L Loyal old, in 1975 reported another cytotoxic factor produced by macrophages and named it Tumor Necrosis Factor (TNF) (Cars well et al, 1975). Interleukin – 6 (IL-6) Chronic inflammation is linked to endothelial dysfunction, atherosclerosis, and insulin resistance (Fernandez-Real JM and Ricart W, 2003 and Fernandez-Real JM, Ricart W, 2005). Plasma concentrations of proinflammatory cytokines, such as interleukin (IL) 18, IL-6, and tumor necrosis factor (TNF)-a, and of several other inflammatory markers are increased in patients with ischemic heart disease (Fernandez-Real JM and Ricart W, 2003, Ridker PM et al, 2002, Engstrom G et al, 2004, Ridker PM et al, 1997, Pradham AD et al, 2002). Circulating cytokines also are elevated in type 2 diabetes, obesity, and insulin resistance syndrome and play a central role in the pathogenesis of these disorders (Fernandez-Real JM and Ricart W, 2003). IL-6 is a mediator of the inflammatory response, and it is linked to dyslipidemia, type 2 diabetes, and risk of myocardial infarction (Fernandez-Real JM and Ricart W, 2003, Ridker PM et al, 2000, Esteve E et al, 2005, Yudkin JS et al, 2000). IL-6 is secreted by a variety of different cell types, including lymphoid and endothelial cells, fibroblasts, skeletal muscle, and adipose tissue. Circulating IL-6 levels correlate with obesity and insulin resistance and may predict the development of type 2 diabetes mellitus (Yudkin JS et al, 2000, Pradhan AD et al, 2001, Akira S et al, 1993, Mohamed-Ali V et al, 1997). Endothelial dysfunction is regarded as a causal factor in the development of atherosclerosis (Hansson GK, 2005). It is one of the earliest abnormalities that can be detected in people at risk for cardiovascular events, and it is linked to insulin resistance and type 2 diabetes (Steinberg HO and Baron AD, 2002, Natali A et al, 2006). Cytokines have an important role in the endothelial injury induced by inflammation. The vascular endothelium is involved in the inflammatory response to atherosclerosis (Hansson GK, 2005, Steinberg HO and Baron AD, 2002, Natali A et al, 2006, Widlansky ME et al, 2003), and changes in endothelium function could underlie the association between cardiovascular disease and inflammation. Obesity Related Insulin Resistance: Definition and Pathogenesis Insulin resistance is a state in which a given amount of insulin produces a subnormal biological response (Kahn CR, 1978). In particular, it is characterized by a decrease in the ability of insulin to stimulate the use of glucose by muscles and adipose tissue and to suppress hepatic glucose production and output (Matthaei et al, 2000). Furthermore, it accounts a resistance to insulin action on protein and lipid metabolism and on vascular endothelial function and genes expression (Bajaj M and Defronzo RA, 2003). Several defects in the insulin signaling cascade have been implicated in the pathogenesis of insulin resistance, Insulin resistance is believed to have both genetic and environmental factors implicated in its etiology (Matthaei et al, 2000 and Liu et al, 2004). The genetic component seems to be polygenic in nature, and several genes have been suggested as potential candidates (Matthaei et al, 2000). However, several other factors can influence insulin sensitivity, such as obesity, ethnicity, gender, perinatal factors, puberty, sedentary lifestyle and diet (Liu et al, 2004). The Role of Fatty Acids and Adipocytokines Obesity represents the major risk factor for the development of insulin resistance in children and adolescents (Caprio S, 2002), and insulin resistance/hyperinsulinemia is believed to be an important link between obesity and the associated metabolic abnormalities and cardiovascular risk (Weiss R and Kaufman FR, 2008). Approximately, 55% of the variance in insulin sensitivity in children can be explained by total adiposity, after adjusting for other confounders, such as age, gender, ethnicity and pubertal stage (Caprio S, 2002). Obese children have hyperinsulinemia and peripheral insulin resistance with an ~40% lower insulin-stimulated glucose metabolism than non-obese children (Caprio S et al, 19996). Adipose tissue seems to play a key role in the pathogenesis of insulin resistance through several released metabolites, hormones and adipocytokines that can affect different steps in insulin action (Matsuzawa Y, 2005) (Fig. 1). Adipocytes produce non-esterified fatty acids, which inhibit carbohydrate metabolism via substrate competition and impaired intracellular insulin signaling (Matsuzawa Y, 2005, Griffin ME et al 1999 and Randle PJ, 1998). In children, as in adults, several adipocytokines have been related to adiposity indexes as well as to insulin resistance. Adiponectin is one of the most common cytokines produced by adipose tissue, with an important insulin sensitizing effect associated with anti-atherogenetic properties (Despres JP, 2006 and Gil-Campos M et al, 2004). Whereas obesity is generally associated with an increased release of metabolites by adipose tissue, levels of Adiponectin are inversely related to adiposity (Matsuzawa Y, 2005). Therefore, reduced levels of this adipocytokine have been implicated in the pathogenesis of insulin resistance and metabolic syndrome (Matsuzawa Y, 2005). Decreased levels of Adiponectin have been detected across tertiles of insulin resistance in children and adolescents (Weiss R et al, 2004), where it is a good predictor of insulin sensitivity, independently of adiposity (Lee S et al, 2006). Adipose tissue also produces tumour necrosis factor-a, an inflammatory factor, which can alter insulin action at different levels in the intracellular pathway (Matsuzawa Y, 2005). Interleukin-6 (IL-6) is ano ther inflammatory cytokine released by adipose tissue and its levels are increased in obesity (Matsuzawa Y, 2005). IL-6 stimulates the hepatic production of C-reactive protein and this can explain the state of inflammation associated with obesity, and could mediate, at least partially, obesity-related insulin resistance (Matsuzawa Y, 2005). Data based mainly on animal studies also suggest that increased levels of resistin, another molecule produced by adipose tissue, could impair insulin sensitivity (Matsuzawa Y, 2005). The close relationship between Leptin levels and insulin resistance in children has also been suggested by the data (Chu NF et al, 2000). Serum levels of retinol-binding protein 4 (RBP4) correlate with insulin resistance in subjects with obesity as well as in those with impaired glucose tolerance (IGT) or type 2 diabetes mellitus, therefore suggesting that it could be useful in assessing insulin resistance and the associated risk for complications (Graham TE et al, 2006). Serum RBP4 is independently related to obesity as well as to components of the metabolic syndrome in normal weight and overweight children (Aeberli I et al, 2007). Diet composition in obese children might be an additional factor promoting and/or worsening insulin resistance. Animal and human studies suggest that a high energy intake as well as a diet rich in fat and carbohydrates and low in fiber could increase the risk of developing insulin resistance (Canete R et al, 2007). The Role of Fat Distribution An altered partitioning of fat between subcutaneous and visceral or ectopic sites has been associated with insulin resistance (Weiss R and Kaufman FR, 2008). Visceral fat has a better correlation with insulin sensitivity than subcutaneous or total body fat (Caprio S et al, 1995), in both obese adults and children. Visceral fat has higher lipolytic activity compared with subcutaneous fat, therefore a greater amount of free fatty acids and glycerol gain entry or carried out to the liver (Matthaei et al, 2000). Visceral fat in girls is directly correlated to the glucose-stimulated insulin levels and inversely correlated with insulin sensitivity and the rate of glucose uptake. No correlation was found between abdominal subcutaneous fat (Caprio S et al, 1995). Ectopic deposition of fat in the liver or muscle can also be responsible for insulin resistance in obese subjects, as the accumulation of fat in these sites impairs insulin signaling, with a reduced glucose uptake in the muscle and a decreased insulin-mediated suppression of hepatic glucose production (Weiss R and Kaufman FR, 2008). Intramyocellular lipid (IMCL) accumulation has been shown as a factor related to decreased insulin sensitivity (Jacob S et al, 1999 and Thamer C et al, 2003). Obese insulin sensitive children and adolescents present lower levels of visceral fat and IMCL when compared with obese insulin resistant children (Weiss R et al, 2005). Accumulation of fat in the liver has also been associated with insulin resistance, independently of adiposity (Kelley DE et al, 2003). It has also been suggested that deposits of fat around blood vessels can produce several cytokines and therefore contribute to the development of insulin resistance, through a so-called vasocrine effect (Yudkin JS et al, 2005). Insulin Resistance and Associated Complications Insulin resistance in obesity is strictly related to the development of hypertension (Marcovecchio ML et al, 2006 and Cruz ML et al, 2002), dyslipidemia (Howard BV and Howard WJ, 1994), impaired glucose tolerance (IGT) (Sinha R et al, 2002), hepatic steatosis (DAdamo E et al, 2008), as well as to the combination of these factors, also known as metabolic syndrome (Eckel RH et al, 2005). Furthermore, insulin resistance is associated with systemic inflammation, endothelial dysfunction, early atherosclerosis and disordered fibrinolysis (Dan Dona P et al, 2002). It is alarming that these metabolic and cardiovascular complications are already found in obese children and adolescents (Dietz WH, 2004). The presence of these alterations in prepubertal children is then particularly worrying, as insulin resistance and related complications might be further exacerbated by the influence of puberty, due to the physiological decrease in insulin sensitivity associated with normal pubertal development (Caprio S et al, 1989). Insulin resistance in childhood can track in adult life (Sinaiko AR et al, 2006). Insulin resistance at the age of 13 years predicts insulin resistance at age 19 years, independently of BMI, and is also associated with cardiovascular risk in adulthood (Sinaiko AR et al, 2006). The fundamental role of insulin resistance in human disease was already recognized in 1988 by Reaven (Reaven GM, 1988) who emphasized its role in the development of a grouping of metabolic abnormalities, which he defined as syndrome X. Later studies strengthened the concept of insulin resistance as a key component of the metabolic syndrome, a cluster of impaired glucose tolerance (IGT), dyslipidemia, hypertension, hyperinsulinemia, associated with an increased risk of type 2 diabetes mellitus and cardiovascular disease (Eckel RH et al, 2005). Insulin resistance represents a serious and common complication of obesity during childhood and adolescence. A timely diagnosis and an appropriated prevention and treatment of obesity and insulin resistance are required in order to reduce the Biochemical and Hormonal Changes in Childhood Obesity Biochemical and Hormonal Changes in Childhood Obesity The prevalence of chronic or non communicable disease is escalating much more rapidly in developing countries than in industrialized countries. According to World Health Organization (WHO) estimates, by the 2020, non communicable diseases will account for approximately three quarter of all deaths in the developing countries (WHO. Global Strategy for non communicable disease prevention, 1997). In this regard, a potential emerging public health issue for the developing countries may be increasing incidence of childhood obesity with associated complications, which in turn is likely to create public health burden for poorer nations in the near future (Freedman et al, 2001). Lower to middle income nations face the double burden of having both malnourished and over nourished population, with most overweight and obese children being concentrated in urban areas. Rapid urbanization is associated with unhealthy lifestyle or New World Syndrome. In addition, in such communities, childhood obesit y is still considered a sign of healthiness and high social class. There is no universal consensus on a cut off points for defining overweight and obesity in children and adolescents, usually, for clinical practice and epidemiological studies, child overweight and obesity are assessed by means of indicators based on weight and height measurements, such as weight for height measures or body mass index (weight (kg)/height (m2))(WHO. Report series no.847, 1995).The US Centers for Disease Control and Prevention (CDC) defines obese as being at or above 95th percentile of body mass index for age (Kuczmarsk RJ et al, 2000). History of obesity is both interesting and gives details of its progression. Obesity is an age-old health condition. Through out the history of obesity, its reputation varies from appreciation and opposite among cultures and in time. Ancient Egyptians are said to consider obesity as disease. Perhaps the most famous and earliest evidence of obesity is the Venus figurines, Statuettes of an obese female torso that probably had a major role in rituals. Ancient China has also been aware of obesity and dangers that come with it. They always were a believer of prevention as a key to longevity. The Aztecs believed that obesity was supernatural, an affliction of the gods. Hippocrates, the father of medicines was aware of sudden deaths being more common among obese men than lean ones as stated in his writings. In certain cultures and areas where food is scarce and poverty is prevalent, is viewed as symbol of wealth and social status. To date, an African tribe purposely plumps up a bride to pre pare her for child bearing. Before a wedding can be set, a slim bride is pampered to gain weight until she reaches the suitable weight. Through out the history of obesity, the publics view and status of obesity changed considerably in the 1900s. It was regarded as unfashionable by the French designer, Paul Poi ret who designed skin-revealing clothes for women. About the same time, the incidence of obesity began to increase and become wide spread. Later in 1940s, Metropolitan life insurance published a chart of ideal weight for various heights. They also advocated that weight gain parallel to age is unhealthy. The government and medical society become more hands-on with obesity by imitating campaign against it. This was preceded by a study of risk factors for cardiovascular disease revealing obesity in the high ranks. Since then various diets and exercise programs have emerged. In 1996, the Body Mass Index (BMI) was published. This statistical calculation and index determined that a person is obese or not. At this time ,obesity incidence have soared, led by children and adolescent obesity, tripling in just a few short years, greater than any number in the history of obesity. This increase in the incidence of childhood obesity with associated cardiovascular risks, type 2 diabetes mellitus and stroke is supported by a considerable body of evidence. The prevalence of overweight and obesity in childhood and adolescents has been increasing throughout much of the developed and developing world for the past few decades. It has become increasingly clear that excess adiposity in childhood predisposes individual not only to increased risk of adiposity and its sequaele as adults (Freedman et al, 2001), but also to increased risk of multiple chronic diseases in childhood and adolescence (Rosen bloom et al, 1999). Though mechanism not clearly delineated, excess body weight and adiposity is associated with type 2 diabetes mellitus and its complications, cardiovascular disease risk factors, non alcoholic fatty liver disease and asthma in youth. Childhood Obesity 1930 1972 Risk factors for coronary heart disease (CHD) such as hypertension, dyslipidemia, impaired glucose tolerance and vascular abnormalities were present in overweight children. CHD is likely to be increased in overweight children when they become adults as a result of established risk factors. This study investigated whether excess weight in childhood was associated with CHD in adulthood among a very large cohort of persons born in Denmark in 1930 through 1972. They underwent mandatory annual health examination at public or private schools in Copenhagen. Each child was examined by school doctors or nurses and was assigned a health card bearing childs name, date of birth, birth weight reported by parents. 10,235 men and 4,318 women, for whom childhood BMI data were available, received a diagnosis of CHD or died of CHD as adults. The risk of CHD event, a non fatal event, and a fatal event among adults was positively associated with BMI at 7-13 years of age for boys and 10 to 13 years of ag e as girls. The associations were linear for each age and risk increased across the entire BMI distribution. Childhood Obesity 1930 1972 Risk factors for coronary heart disease (CHD) such as hypertension, dyslipidemia, impaired glucose tolerance and vascular abnormalities were present in overweight children. CHD is likely to be increased in overweight children when they become adults as a result of established risk factors. This study investigated whether excess weight in childhood was associated with CHD in adulthood among a very large cohort of persons born in Denmark in 1930 through 1972. They underwent mandatory annual health examination at public or private schools in Copenhagen. Each child was examined by school doctors or nurses and was assigned a health card bearing childs name, date of birth, birth weight reported by parents. 10,235 men and 4,318 women, for whom childhood BMI data were available, received a diagnosis of CHD or died of CHD as adults. The risk of CHD event, a non fatal event, and a fatal event among adults was positively associated with BMI at 7-13 years of age for boys and 10 to 13 years of ag e as girls. The associations were linear for each age and risk increased across the entire BMI distribution. Childhood Obesity and Economic Growth 1930-1983 Childhood obesity was related to the economic growth during the 50 years of economic growth in the industrialized world especially in Denmark. Annual measurements of height and weight were available for all children born between 1930 and 1983 attending primary schools in Copenhagen Municipality. 165,389 boys and 163,609 girls from the age of 7 through 13 years were included in this study. After computerization SBMI (kg/m2) were calculated and the prevalence of overweight and obesity according to international age and gender–specific criteria. Economics growth was indicated by the Gross National Product and the overall consumption per capita, adjusted for inflation. Prevalence of overweight and obesity among Danish children rose in phases, which were not paralleled by trends in economic growth. The microeconomics growth indicators seem inappropriate as proxies for the environmental exposures that have elicited the obesity epidemic. Childhood obesity and television viewing Children spend a substantial portion of their lives watching television (TV). Investigators have hypothesized that TV viewing causes obesity by one or more than three mechanisms: Displacement of physical activity. Increased calorie consumption while watching or caused by the effects of advertising. Reduced resting metabolism. The relationship between TV viewing and obesity has been examined in a relatively large number of cross sectional epidemiological but few longitudinal studies. Many of them have found relatively weak, positive association or mixed results. Many experimental studies have found that reducing TV viewing may help to reduce the risk of obesity. One school based experimental study was designed specifically to test directly the casual relationship between TV viewing behaviors and body fatness. The results of this randomized controlled trial provide evidence that TV viewing is a cause of increased body fatness and that reducing the TV viewing is a promising strategy for preventing childhood obesity (Robinson; 2001). The objective of another study (Utter J et al, 2006), was to explore how time spent watching television (TV) is associated with the dietary behavior of New Zealand children and young adolescents. Total number of participants was 3275 children aged 5-17 years. The findings suggest that longer duration of TV watching (thus more frequent exposure to advertising) influences the frequency of consumption of soft drinks, some sweets and snacks and some fast foods among children and young adolescents. Efforts to control the time spent watching TV may result in better dietary habits and weight control for children and adolescents. Childhood Obesity US- A decade of progress, 1990-1999 Current data suggest that 20% of US children are overweight .An analysis of the secular trends suggest that 20% of US children are overweight, and a clear up ward trend in body weight in children of 0.2 Kg between 1973 and 1994. In addition, childhood obesity is more prevalent among minority sub groups such as African Americans. Obesity that begins early in life persists into adulthood and increases the risk of obesity related conditions later in life. There has been tremendous increase in the number of studies examining the etiology and health effects of obesity in children (Goran MI, 1990-1999).1980 (boys 0.2% girls 0.5%) and 1997 (boys 1.2%, girls 2.0%). Ten years trends of childhood obesity in Israel 1990-2000 Cross sectional data was collected from 13284 second and fifth class school; children between 1990-2000. Prevalence of obesity was determined using Israeli and US reference values. BMI values at 95th percentile increased overtime in all ages and sex categories. Between 1990 and 2000, 95th centile values were increased by 12.7%and 11.8% among second grade boys and girls respectively. Among fifth graders in 2000, 10.7% of boys and 11.1% of girls exceeded the 1990 BMI reference values. The proportion of obese children increased over time using both Israeli and US reference values (Huerta Michael et al, 2008). Netherlands. Overweight, Obesity in 2003: V.1980-97. Data on 90,071 children, aged 4-16 years were routinely collected by 11 Community Heath Services during 2002-2004. International cut -off points for BMI to determine overweight and obesity. On average, 14.5% of boys and 17.5% of the girls were overweight (including obesity), which is a substantial increase since 1980 (boys 3.9% and girls 6.9%) and 1997 (boys 9.7% and girls 13%). Similarly 2.6% of the boys and 3.3% 0f the girls aged 4-16 years were obese, which is much higher than in 1980 (boys 0.2% and girls 0.5%) and 1997 (boys 1.2% and girls 2.0%), (KatjaVan Den Husk, 2007). Obesity trends in US. 2003-2006 Height and weight measurements were obtained from 8164 children and adolescents as apart of the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey (NHANES). Because no statistically significant differences in the prevalence of high BMI for age were found between the estimates for 2003-2004 and 2005-2006, data for four years were combined to provide more stable estimates for the most recent time period. Over all, in 2003-2006, 11.3% of children and adolescents aged 2 through years were at or above 97th percentile of the 2000 BMI- for- age growth charts, 16.3% were at or above 95th percentile. Prevalence estimates vary by age and by racial/ethnic group. Analysis of the trends in high BMI for age showed no statistically significant trend over the four time periods (1999-2000, 2001-2002, 2003-2004, and 2005-2006) for either boys or girls (Cynthia l.Ogden et al, 2008). 11-March 2005. Public Release Date: Consensus on Childhood Obesity, Recommends classification as disease A common statement on childhood obesity was published to day in the journal of Chemical Endocrinology and Metabolism (one of the journals of Endocrine Society). The consensus statement reflects the conclusions from an international summit held in Israel last year (2004) and includes a controversial recommendation to classify obesity as a disease. This decision was based upon the available research on the diagnosis, prevalence, causes (including endocrine disorders), risks, prevention and treatment of childhood obesity. Pediatric obesity is now recognized as a major health problem all over the world. Researcher have found that children who are obese have a higher risks adult obesity, which is strongly associated with many serious medical complications that impair quality of life and lead to additional increased risks. The statement also noted the prevalence of overweight/obesity among children 6-11 years (in the US) doubled between the years 1980-2000. By classifying obesity as legiti mate disease, public funding and in user sreimbursement for obesity treatment becomes legalized (consensus on childhood obesity, 2005). Serious health risks will likely to begin to appear in obese children and adolescents as they grow older. These may include diabetes mellitus, metabolic syndrome, hyperandrogenism, heart disease, hypertension, respiratory factors, and sleep disorders. Obese children are also at greater risk of anxiety and depression. It also recommended a number of measures that can be implemented by parents; schools, health providers and government and regulatory agencies to help to prevent the onset of childhood obesity Endocrine Regulation of Energy Metabolism Adipocytokines and Obesity The mechanism underlying obesity was further explained by the discovery of adipocytokines, the role of peripheral thyroid hormones (T4, T3), thyroid stimulating hormone and insulin the regulation of energy metabolism. The levels of some of the adipocytokines were shown to be related to visceral obesity, type 2 diabetes mellitus and coronary artery disease. Plasma levels of all the adipocytokines increase with the obesity except adiponectin (Yuji Matsuzawa et al, 2003). Recent studies point out to the adipose tissue as a highly active organ secreting a range of hormones, Leptin, Adiponectin, and Resistin. They are considered to take part in the regulation of energy metabolism. Leptin, Adiponectin and Resistin are produced by the adipose tissue. Leptin and Adiponectin are insulin sensitizing while Resistin increase the insulin resistance. Leptin The notion that genetic abnormalities contribute to obesity gained important support with the identification of the Ob gene and its protein product in 1994 (Zhangy et al, 1996). The Ob gene termed Leptin from the Greek Leptos, meaning thin, is produced in adipose tissue and is thought to act as an afferent satiety signal in a feed back loop that affects the appetite and satiety centre in the hypothalamus of brain. The ultimate effect of this loop is to regulate body-fat mass. In human, as noted by Considine et al, 1996; caloric restriction reduces leptin concentrations and Ob mRNA levels in adipose tissue, and refeeding increases these levels. One fundamental mechanism of obesity is insensitivity to the action of Leptin, presumably in the hypothalamus. The Leptins primary physiological function is to provide a signal to suppress body fat by decreasing food intake or increasing energy expenditure. Serum leptin concentrations change more during weight loss than during weight gain (Rose nbaum M et al, 1997). Adiponectin Adiponectin or Adipo Q, an adipocyte specific secreted protein with roles in glucose and lipid homeostasis (Insulin stimulates the secretion of adiponectin). Circulating adiponectin concentrations are high 500-30,000 Â µg/l (5-30mg/ml) accounting for 0.01% of total plasma proteins (Berget et al, 2002). Adiponectin was discovered in the mid 1990s by four different groups of researchers (Hu E et al, 1996). Adiponectin has various biological functions including insulin sensitizing (Hotta K et al, 2000), antiatherogenic (Yamauchi T et al, 2003), anti-inflammatory (Ouchi N et al, 2003), antiangiogenic and anti tumor functions (Brakenhielm E et al, 2004). Adiponectin acts through Adiponectin receptors, Adipo R1 and Adipo R2. Adipo R1 is mostly expressed in skeletal muscles and Adipo R2 is abundant in liver. These receptors are also expressed by the pancreatic ß cells (Kharroubi et al, 2003), macrophages and atherosclerotic lesions (Chinetti et al, 2004) as well as in brain (Yamauchi et al, 2003). Circulating Adiponectin levels display diurnal variation with a nocturnal decline and maximum levels in the late morning (Gavrila et al, 2003). Adiponectin is also found in breast milk, which in turn is implicated in childhood obesity prevention (Savino et al, 2008). Among the various adipocytokines, adiponectin, which is an abundant circulating protein (247 amino acids) synthesized purely in adipose tissue, appears to play a very important role in carbohydrates, lipid metabolism and vascular biology. Adiponectin appears to be a major modulator of insulin action and its levels are reduced in type 2 diabetes mellitus, which could contribute to peripheral insulin resistance in this condition. It has significant insulin sensitizing as well as anti inflammatory properties that include suppression of macrophage phagocytosis and TNF-a secretion and blockage of monocytes adhesion to endothelial cells in vitro. Although further investigations are required, Adiponectin administration, as well as regulation of the pathway controlling its production, represents a promising target for managing obesity, hyperlipidemia, insulin resistance, type 2 diabetes mellitus, and vascular inflammation (Manju Chandran et al, 2003). Resistin Human resistin is 108 amino acids prepeptide and is cleaved before its secretion from the Adipose tissue. Resistin circulates in the blood as dimeric protein consisting of 92 amino acids polypeptides that are linked by a disulfide bridge. Holcomb et al, 2000 first described the gene family and its tissue specific distribution. Originally described as lung specific, is also produced by the adipose tissue and peripheral blood monocytes. It is also present in dividing epithelia of the intestine. Resistin increase blood glucose and insulin concentration in the mice and impairs hypoglycemic response to insulin infusion. In addition, anti resistin antibodies decrease blood glucose and insulin sensitivity in obese mice (Ukkalo O, 2002). The physiological role of resistin in human remains controversial. There more resistin protein in obese than lean individuals, with a significant positive correlation between resistin and BMI. BMI is a significant predictor of insulin resistance, but resisti n adjusted for BMI is not. These data demonstrate that resistin protein is present in human adipose tissue and blood and that there is significantly more resistin in serum of obese individuals. Serum resistin is not a significant predictor of insulin resistance in human (Youn et al, 2003, Rear R and Donnelly R, 2004). Tumor Necrosis Factor-a It will be unreasonable not to mention the Tumor Necrosis Factor a and its role in vascular inflammation related to atherosclerosis especially in obesity. It is a cytokine involved in systemic inflammation and is a member of a group of cytokines that stimulate the acute phase reaction. The primary role of TNF is in the regulation of immune cells. TNF is able to induce apoptotic cell death, to induce inflammation and to inhibit tumourgenesis and viral replication. Dysregulation and, in particular, over production of TNF have been implicated in a variety of human diseases, as well as cancer (Locksley et al, 2001). The theory of antitumoural response of the immune system in vivo was recognized by the physician William B in 1968. Dr A Granger reported a cytotoxic factor produced by lymphocytes and named it Lymphotoxin (Kalli WB and Granger GA, 1968). Dr L Loyal old, in 1975 reported another cytotoxic factor produced by macrophages and named it Tumor Necrosis Factor (TNF) (Cars well et al, 1975). Interleukin – 6 (IL-6) Chronic inflammation is linked to endothelial dysfunction, atherosclerosis, and insulin resistance (Fernandez-Real JM and Ricart W, 2003 and Fernandez-Real JM, Ricart W, 2005). Plasma concentrations of proinflammatory cytokines, such as interleukin (IL) 18, IL-6, and tumor necrosis factor (TNF)-a, and of several other inflammatory markers are increased in patients with ischemic heart disease (Fernandez-Real JM and Ricart W, 2003, Ridker PM et al, 2002, Engstrom G et al, 2004, Ridker PM et al, 1997, Pradham AD et al, 2002). Circulating cytokines also are elevated in type 2 diabetes, obesity, and insulin resistance syndrome and play a central role in the pathogenesis of these disorders (Fernandez-Real JM and Ricart W, 2003). IL-6 is a mediator of the inflammatory response, and it is linked to dyslipidemia, type 2 diabetes, and risk of myocardial infarction (Fernandez-Real JM and Ricart W, 2003, Ridker PM et al, 2000, Esteve E et al, 2005, Yudkin JS et al, 2000). IL-6 is secreted by a variety of different cell types, including lymphoid and endothelial cells, fibroblasts, skeletal muscle, and adipose tissue. Circulating IL-6 levels correlate with obesity and insulin resistance and may predict the development of type 2 diabetes mellitus (Yudkin JS et al, 2000, Pradhan AD et al, 2001, Akira S et al, 1993, Mohamed-Ali V et al, 1997). Endothelial dysfunction is regarded as a causal factor in the development of atherosclerosis (Hansson GK, 2005). It is one of the earliest abnormalities that can be detected in people at risk for cardiovascular events, and it is linked to insulin resistance and type 2 diabetes (Steinberg HO and Baron AD, 2002, Natali A et al, 2006). Cytokines have an important role in the endothelial injury induced by inflammation. The vascular endothelium is involved in the inflammatory response to atherosclerosis (Hansson GK, 2005, Steinberg HO and Baron AD, 2002, Natali A et al, 2006, Widlansky ME et al, 2003), and changes in endothelium function could underlie the association between cardiovascular disease and inflammation. Obesity Related Insulin Resistance: Definition and Pathogenesis Insulin resistance is a state in which a given amount of insulin produces a subnormal biological response (Kahn CR, 1978). In particular, it is characterized by a decrease in the ability of insulin to stimulate the use of glucose by muscles and adipose tissue and to suppress hepatic glucose production and output (Matthaei et al, 2000). Furthermore, it accounts a resistance to insulin action on protein and lipid metabolism and on vascular endothelial function and genes expression (Bajaj M and Defronzo RA, 2003). Several defects in the insulin signaling cascade have been implicated in the pathogenesis of insulin resistance, Insulin resistance is believed to have both genetic and environmental factors implicated in its etiology (Matthaei et al, 2000 and Liu et al, 2004). The genetic component seems to be polygenic in nature, and several genes have been suggested as potential candidates (Matthaei et al, 2000). However, several other factors can influence insulin sensitivity, such as obesity, ethnicity, gender, perinatal factors, puberty, sedentary lifestyle and diet (Liu et al, 2004). The Role of Fatty Acids and Adipocytokines Obesity represents the major risk factor for the development of insulin resistance in children and adolescents (Caprio S, 2002), and insulin resistance/hyperinsulinemia is believed to be an important link between obesity and the associated metabolic abnormalities and cardiovascular risk (Weiss R and Kaufman FR, 2008). Approximately, 55% of the variance in insulin sensitivity in children can be explained by total adiposity, after adjusting for other confounders, such as age, gender, ethnicity and pubertal stage (Caprio S, 2002). Obese children have hyperinsulinemia and peripheral insulin resistance with an ~40% lower insulin-stimulated glucose metabolism than non-obese children (Caprio S et al, 19996). Adipose tissue seems to play a key role in the pathogenesis of insulin resistance through several released metabolites, hormones and adipocytokines that can affect different steps in insulin action (Matsuzawa Y, 2005) (Fig. 1). Adipocytes produce non-esterified fatty acids, which inhibit carbohydrate metabolism via substrate competition and impaired intracellular insulin signaling (Matsuzawa Y, 2005, Griffin ME et al 1999 and Randle PJ, 1998). In children, as in adults, several adipocytokines have been related to adiposity indexes as well as to insulin resistance. Adiponectin is one of the most common cytokines produced by adipose tissue, with an important insulin sensitizing effect associated with anti-atherogenetic properties (Despres JP, 2006 and Gil-Campos M et al, 2004). Whereas obesity is generally associated with an increased release of metabolites by adipose tissue, levels of Adiponectin are inversely related to adiposity (Matsuzawa Y, 2005). Therefore, reduced levels of this adipocytokine have been implicated in the pathogenesis of insulin resistance and metabolic syndrome (Matsuzawa Y, 2005). Decreased levels of Adiponectin have been detected across tertiles of insulin resistance in children and adolescents (Weiss R et al, 2004), where it is a good predictor of insulin sensitivity, independently of adiposity (Lee S et al, 2006). Adipose tissue also produces tumour necrosis factor-a, an inflammatory factor, which can alter insulin action at different levels in the intracellular pathway (Matsuzawa Y, 2005). Interleukin-6 (IL-6) is ano ther inflammatory cytokine released by adipose tissue and its levels are increased in obesity (Matsuzawa Y, 2005). IL-6 stimulates the hepatic production of C-reactive protein and this can explain the state of inflammation associated with obesity, and could mediate, at least partially, obesity-related insulin resistance (Matsuzawa Y, 2005). Data based mainly on animal studies also suggest that increased levels of resistin, another molecule produced by adipose tissue, could impair insulin sensitivity (Matsuzawa Y, 2005). The close relationship between Leptin levels and insulin resistance in children has also been suggested by the data (Chu NF et al, 2000). Serum levels of retinol-binding protein 4 (RBP4) correlate with insulin resistance in subjects with obesity as well as in those with impaired glucose tolerance (IGT) or type 2 diabetes mellitus, therefore suggesting that it could be useful in assessing insulin resistance and the associated risk for complications (Graham TE et al, 2006). Serum RBP4 is independently related to obesity as well as to components of the metabolic syndrome in normal weight and overweight children (Aeberli I et al, 2007). Diet composition in obese children might be an additional factor promoting and/or worsening insulin resistance. Animal and human studies suggest that a high energy intake as well as a diet rich in fat and carbohydrates and low in fiber could increase the risk of developing insulin resistance (Canete R et al, 2007). The Role of Fat Distribution An altered partitioning of fat between subcutaneous and visceral or ectopic sites has been associated with insulin resistance (Weiss R and Kaufman FR, 2008). Visceral fat has a better correlation with insulin sensitivity than subcutaneous or total body fat (Caprio S et al, 1995), in both obese adults and children. Visceral fat has higher lipolytic activity compared with subcutaneous fat, therefore a greater amount of free fatty acids and glycerol gain entry or carried out to the liver (Matthaei et al, 2000). Visceral fat in girls is directly correlated to the glucose-stimulated insulin levels and inversely correlated with insulin sensitivity and the rate of glucose uptake. No correlation was found between abdominal subcutaneous fat (Caprio S et al, 1995). Ectopic deposition of fat in the liver or muscle can also be responsible for insulin resistance in obese subjects, as the accumulation of fat in these sites impairs insulin signaling, with a reduced glucose uptake in the muscle and a decreased insulin-mediated suppression of hepatic glucose production (Weiss R and Kaufman FR, 2008). Intramyocellular lipid (IMCL) accumulation has been shown as a factor related to decreased insulin sensitivity (Jacob S et al, 1999 and Thamer C et al, 2003). Obese insulin sensitive children and adolescents present lower levels of visceral fat and IMCL when compared with obese insulin resistant children (Weiss R et al, 2005). Accumulation of fat in the liver has also been associated with insulin resistance, independently of adiposity (Kelley DE et al, 2003). It has also been suggested that deposits of fat around blood vessels can produce several cytokines and therefore contribute to the development of insulin resistance, through a so-called vasocrine effect (Yudkin JS et al, 2005). Insulin Resistance and Associated Complications Insulin resistance in obesity is strictly related to the development of hypertension (Marcovecchio ML et al, 2006 and Cruz ML et al, 2002), dyslipidemia (Howard BV and Howard WJ, 1994), impaired glucose tolerance (IGT) (Sinha R et al, 2002), hepatic steatosis (DAdamo E et al, 2008), as well as to the combination of these factors, also known as metabolic syndrome (Eckel RH et al, 2005). Furthermore, insulin resistance is associated with systemic inflammation, endothelial dysfunction, early atherosclerosis and disordered fibrinolysis (Dan Dona P et al, 2002). It is alarming that these metabolic and cardiovascular complications are already found in obese children and adolescents (Dietz WH, 2004). The presence of these alterations in prepubertal children is then particularly worrying, as insulin resistance and related complications might be further exacerbated by the influence of puberty, due to the physiological decrease in insulin sensitivity associated with normal pubertal development (Caprio S et al, 1989). Insulin resistance in childhood can track in adult life (Sinaiko AR et al, 2006). Insulin resistance at the age of 13 years predicts insulin resistance at age 19 years, independently of BMI, and is also associated with cardiovascular risk in adulthood (Sinaiko AR et al, 2006). The fundamental role of insulin resistance in human disease was already recognized in 1988 by Reaven (Reaven GM, 1988) who emphasized its role in the development of a grouping of metabolic abnormalities, which he defined as syndrome X. Later studies strengthened the concept of insulin resistance as a key component of the metabolic syndrome, a cluster of impaired glucose tolerance (IGT), dyslipidemia, hypertension, hyperinsulinemia, associated with an increased risk of type 2 diabetes mellitus and cardiovascular disease (Eckel RH et al, 2005). Insulin resistance represents a serious and common complication of obesity during childhood and adolescence. A timely diagnosis and an appropriated prevention and treatment of obesity and insulin resistance are required in order to reduce the

Artificial Fish: AUVs Designed to Model Animals :: Autonomous Undersea Vehicles Fish Essays

Artificial Fish: AUVs Designed to Model Animals Humans venture beneath the ocean's surface to collect resources, conduct research, engage in warfare, and perform countless other tasks. The need for increasingly specialized technology to accomplish these tasks has prompted the development of many different designs of submersibles, varying from manned nuclear submarines to Remotely Operated Vehicles (ROVs) dragged behind surface ships, to untethered Autonomous Undersea Vehicles (AUVs) (Blidberg 1). This last design, the AUV, has received special attention in recent years as humans explore greater and greater depths. As its name suggests, the AUV functions independently, without intervention from a human operator. It carries its own power source (traditionally a battery), and receives all its commands from an onboard computer, thus involving some degree of artificial intelligence. This computer serves to direct the robotic submersible in performing a pre-defined task. Because its movement is not restricted by a cable connec ting it to a mother ship, the AUV is ideal for operating in hazardous areas and at great depths. Current and proposed activities for AUVs include undersea exploration, scientific sampling of physical oceanic conditions (such as salinity level and temperature), laying and inspection of gas lines and cables, searching for downed aircraft, and mine reconnaissance (Canfield, Hylands). A key aspect of common AUV design, however, prevents this list of activities from expanding and limit the current potential of AUV performance. Due to the inefficiency of propulsion and power systems, AUVs are highly unstable in any turbulent water, are limited to short missions, can carry only small payloads, and have little maneuvering control at low speeds (MIT, Canfield). In the most unfavorable of conditions, AUVs may not even be able to reach their intended destinations while traveling at slow speeds, despite the use of slow speed guidance systems (Healey 335). Small rotary propellers plagued with low efficiency and lagged response times typically power AUVs (MIT). Furthermore, batteries often require 70% of the hull space (MIT). Closely tied to efficiency of propulsion systems is the hydrodynamic shape of the submersible's hull. While hull designs have improved over time, they do not compare to the hydrodynamic efficiency of fish and aquatic mammal shapes. As Jeff Walker, a biology professor at the University of Southern Maine, stated, "It's a lofty goal for a human-made vehicle to achieve the performance of a fish" (qtd.

Essay: Analysis of Sonnet 33 -- Sonnet essays

Analysis of Sonnet 33 Full many a glorious morning I have seen Flatter the mountaintops with sovereign eye, Kissing with golden face the meadows green, Gilding pale streams with heavenly alchemy, Anon permit the basest clouds to ride With ugly rock on his celestial face And from the forlorn world his visage hide, Stealing unseen to west with this disgrace. Even so my sun one early morn did shine With all-triumphant splendor on my brow. But out, alack! he was but one hour mine, The region cloud hath masked him from me now Yet him for this my love no whit disdaineth, Suns of the world may stain when heaven's sun staineth. This sonnet houses nature imagery, personifying certain elements of nature. 1-2: 'Ý have seen a large amount of glorious mornings' "flatter the mountaintops with (a) soverign eye." The sun here is the eye of the morning, making the latter in semblance of a person. Using "sovreign" to describe the "eye" gives the reader the impression of the sun as, perhaps, the ruler of natur...

Comparing Truth in The Education of Children, Paradise Lost and Hamlet

Nature of Truth in The Education of Children, Paradise Lost and Hamlet      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   To some, truth is something that is absolute and unchanging. To others, truth is volatile and inconstant. In the 16th and 17th century, the foundations of civilization itself had been shaken. Many of the ideas which were thought to be absolutely true had been plunged into the depths of uncertainty. The cosmological, geographical, and religious revolutions called into question the nature of truth itself. It is no wonder, then, that some of the great writers at the time included within their works a treatise on the ways in which truth is constructed. Because of the major ideological revolutions that shaped their world, Milton, Montaigne, and Shakespeare all used characters and theatrical devices to create their own ideas on the construction of truth.    As a result of Milton's failed political aspirations, he believes that individuals do not construct truth, or decide for themselves what the truth is; instead, individuals receive the truth directly or indirectly from God. Conversely, deception comes from Satan. In Paradise Lost, Milton sets up this idea by forcing good to result only from obedience to God's will and evil to result whenever God is disobeyed. Dr. Evans' argument that Milton's ultimate point in all this is to express a moral position that is very extreme, that no quality or action can be innately good or evil, is firmly rooted in this model. What determines the morality of anything we do is in whose service we do it. Since Raphael was sent from God, his warning is true and divine. Since Satan disobeyed God, his ideas are all false lies. Part of Milton's ideology may have come from his own life experiences. After the restorat... ...FCS, 2000.    Brentano, Franz, The Origin of our Knowledge of Right and Wrong, trans. Cecil Hague (London: Constable, 1902).    Fish, Stanley Eugene. Surprised by Sin: The Reader in Paradise Lost. New York: St. Martin's Press, 1967.    Milton, John. Paradise Lost. Ed. Roy Flannagan. New York: Macmillan, 1993.    Patrides, C.A. Milton and The Christian Tradition. (Oxford: Clarendon Press, 1966)    Montaigne, Michel de. The Complete Essays of Montaigne. Trans. DonaldM. Frame. Stanford: Stanford UP, 1958.    Moore, G. E., Review of The Origin of our Knowledge of Right and Wrong by Fritz Brentano, International Journal of Ethics, vol. 14 (1903), pp. 123-8. -----, 'Nature of Truth', Mind, vol. 16 ns, no. 62 (April 1907), pp. 229-35.    Shakespeare, William. Hamlet. 1600? Ed. Sylvan Barnet. New York: Signet Classic, 1998.

One Flew over the Cuckoos Nest: the Power of Laughter Essay

Jimmy Buffet once said â€Å"If we couldn’t laugh, we would all go insane. † When an individual is no longer capable of laughing, he is also no longer capable of being in control of himself. This happens when a greater authority has the power to deny a person of their laughter; which, inevitably, denies him of his freedom. Ken Kesey conveys the idea that laughter and freedom go hand in hand throughout his novel One Flew Over The Cuckoo’s Nest. Kesey portrays laughter as a parallel to freedom through various literary symbols and imagery in order to illustrate how the power of laughter can free a man who is under the control of an unjust authority. Through the characterization of Nurse Ratched and McMurphy, Kesey illustrates how the manipulation of others and the challenge of authority is a key component in the ability to laugh. Through the characterization of Nurse Ratched, Kesey illustrates how one person can manipulate others for her own specific intentions. Throughout the story, it is clear that Nurse Ratched (Bug Nurse) manipulates the patients and faculty to control them so she has all the power. As the book starts, we are immediately brought into this mental ward in the eyes of Chief Bromden. As he walks down the hall, and the aids insult him because he is dumb and deaf. However, little do they know that Chief is the exact opposite. As they continue to speak as if he weren’t there and hand him the broom, â€Å"They laugh†¦[it is a] Hum of black machinery, humming the hate and death and other hospital secrets† (10). The laughter of the black aids is not clear and freeflowing like laughter should be. Instead, it is described as a â€Å"hum† which illustrates that even the aids do not have the freedom to laugh. They are â€Å"black machinery† or descendents of the combine which demonstrates that the faculty on this ward is under the control of Nurse Ratched and the combine. It is also evident that they are all working together because when machines are working correctly, they hum in synchronization, just like these men are doing with their empty laughter. Along with the machine-like laughs, the men also know what is going on in the ward because chief implies that their humming contains all of the mysteries. Kesey uses machine-like references and imagery in order to illustrate Nurse Ratched’s influence on her employee’s; she is the reason there is no laughter on the ward. Another cene that expresses Big Nurses power is when Chief is describing how Big Nurse hates when things are out of order. Chief explains that even her uniform has to be crisp and clean at all times, and when its not, she still smiles and pretends not to care, but inside it bothers her to no extent. He makes it clear that he sees, â€Å"her sit in the center of this web of wires like a watchful robot, tend her network with mechanical insect skill, know every second which wire runs where and just what current to send up to get the results she wants† (30). Big Nurse is portrayed as a mechanical spider who has the knowledge and ability to control whatever is in her â€Å"web. † Kesey references her as machine-like figure due to her constant necessity to be in control. Everything she does must be in a certain order and flow a certain way. When Chief says she knows how to â€Å"get the results she wants† it makes it clear that she is able to manipulate everyone. This demonstrates that her manipulation takes away all of the patients power to do anything; it even takes away their freedom and laughter. Another example that portrays this idea is in the article Salvation Through Laugher. The author, Stephen L. Tanner, is analyzing Kesey’s work, and as he discusses the first chapter of One Flew Over the Cuckoo’s Nest, he notes how, â€Å"Miss Ratched is pleased when a ‘completed product’ goes back into society as a ‘functioning, adjusted component'† (Tanner 57). Tanner’s analysis expresses how Big Nurses intentions are to create these robots that do not have the ability to think for themselves. A â€Å"completed product† or success, will be think and act like the faculty, just another part of the machine. The pleasure Nurse Ratched gets out of these success’ illustrates that she loves gaining power and taking away people’s freedoms. Nurse Ratched manipulates the men on the ward and the faculty in order to gain power and take away all of their freedoms, even their freedom to laugh. Kesey conveys that the challenge of authority is the key to finding true identity. The protagonist, McMurphy immediately is introduced as this man with a huge, impenetrable ego. From the moment he steps on the ward, Chief notices that he’s different. Upon McMurphys arrival, Chief is awakening from the fog he is in. He’s in the day room with his inmates and is listening in on their conversations. Suddenly he hears Nurse Ratched announce that there is a new arrival. McMurphy enters the ward and is laughing. Chief notes that, â€Å".. it’s free and loud†¦[it] sounds real†¦it’s the first [real] laugh I’ve heard in years† (16). This illustrates how McMurphy, even from the beginning, has the intentions to challenge the rules. Before him, no one laughed on the ward, or even spoke above an indoor voice. However, as soon as he arrives, his laughter is â€Å"loud and free† which demonstrates that he is boisterous and independent. The combine will not succeed in taking away his freedom, nor will Nurse Ratched take away his ability to laugh. A second example is the scene in which McMurphy and his inmates disregard Big Nurses orders that they cannot watch the world series and watch it anyway because they had the majority in the second vote. As they all stop cleaning and sit down in front a blank TV screen, Nurse Ratched’s anger builds. Finally, she loses it and screams at McMurphy that he is , â€Å"‘supposed to be working during these hours! ‘ Her voice†¦a tight whine†¦a saw ripping through pine† (127) â€Å"her voice sounds like it hit a nail†(128). McMurphy’s breaking of the rules and influence on his inmates drives Nurse Ratched to the edge. Her voice hitting â€Å"a nail† illustrates authority running into a large bump and stopping it right in its tracks. The whining in her voice demonstrates that McMurphy is frustrating her, he is testing her power and this worries her, because she does not want to lose her power, and McMurphy is threatening her. However, no matter what Nurse Ratched does, she cannot seem to stop McMurphy and his free laugh. One of the most vital scenes is when McMurphy breaks the glass in the nurses station just after Cheswick commits suicide. He walks up to the nurse’s station, â€Å"†¦as big as a house! †¦[and says] in his slowest , deepest drawl how he figured he could use one of the smokes he bought†¦then he ran his hand through the glass†¦[it came] apart like water splashing†(172). McMurphy, haven been gone for a short while, challenges Big Nurses power and shows her that he’s back and is not losing this war. Him being â€Å"as big as a house† gives a visual that his power is radiating off of him. When he asks for his cigarettes, its in a slow and deep voice, and he does not wait for a response, just runs â€Å"his hand through the glass† it illustrates that he is not asking permission for anything. He will go against all of her rules because she cannot control him. The imagery Kesey uses to illustrate the glass shattering because when water splashes, there are many droplets and its not just one massive drop. McMurphy did not just break the glass or scratch Big Nurses power, he shattered it. He made his point that he has the power, not her, and he will always be free. Throughout the story, Kesey continues to have McMurphy constantly breaking the rules and challenging conformity in order to put across the idea that challenging authority can bring individuality. Ken Kesey, the author of One Flew Over The Cuckoo’s Nest, conveys the idea that laughter and freedom go hand in hand when it comes to a person being an individual. Through the characterization of Nurse Ratched and McMurphy, Kesey suggests that manipulating others and challenging authority is an essential part of laughing and freedom. I have come to learn that freedom can be achieved by laughing and it’s a necessity to laugh, therefore it’s a necessity to be free. After reading this novel, it is clear that laughter is crucial part of individuality and without it, we would all be mechanical robots because as Kesey once said â€Å"if you lose your laugh, you lose your footing. â€Å"

Management of Bipolar (Manic Depression)

Forgotten Kids are children that have disabilities that are barely visible. They have their arms and legs, can see and hear, run, play, etc. , but most have never been invited to a birthday party or to a sleep over. They are the last to be chosen to play and the first to be blamed. Their illnesses aren†t fatal, but a small part of their hearts and souls die with every rejection. Their behaviors seem odd or unpredictable to themselves as much as to society. They are misunderstood and overlooked, thus the name â€Å"Forgotten Kids. Maybe I can bring understanding by showing and providing insight into the life of a child struck with mental illness and hopefully people will realize that my child is just as special as the next. An estimated 7,000,000 children in Missouri that suffers from these â€Å"invisible disabilities. † Mental illness not only affects the life of the child but the whole community. I live with this fact every day because my son suffers from Bipolar, better known as Manic Depression. Bipolar children long to be free of the strange feelings of sadness or euphoria and the voices that torment them. They wish for a good nights sleep and hope for a day when they can put their words on paper. They dream of friends who don†t abandon them when their moods change; and look for a miracle in the eyes of doctors who don†t always believe that bipolar can happen to a child. Until society becomes more aware and accepting of these illnesses, our future children with these disabilities stand no chance. My son,was diagnosed at age nine after his third stay in a child†s psychiatric unit. He was admitted following a period of behaviors I could not understand nor control. I remember him being â€Å"different† (I now know he was Manic) as far back as three years old, leaving me with raging emotions of guilt, shame, loss and grief. By age nine, he had begun lying, stealing, destroying property, setting fires, and hurting himself (these are called rages. ) He had no friends at school, though he would say that wasn†t true. He was filled with an anger I could not comprehend. Most people who knew us said it was my fault as a parent that if I would just â€Å"control† him, he would be fine. Not only was my son stigmatized but so was I. Not until we located the right doctor and started the proper medications that he needed was he â€Å"fine. † Through the years as the medication began working its wonders a new child began to emerge. He laughs, he plays, but most of all he talks about what he feels. He would say that we cannot conceive his isolation, and the depth of it at times. He would apologize for the fact that he couldn†t offer me better understanding. I realized then that what he gives is so much more valuable. He gives me an opportunity to discover the depth of my character, my love, my commitment, my patience, my ability to cope, and the opportunity to explore my spirit more deeply than I ever imagined. I told him that because of him, I am driven to go further than I would have ever gone on my own, working harder, seeking answers to the many questions that seemed to have no answers. He describes a world that seems to pass him by. How he longs to run and play like other children. How sometimes it is a challenge just to crawl from his bed in the morning. Hearing this it becomes obvious how much â€Å"normal† people take for granted and how we forget how precious life is. We†re not burdened with the strifes and conflicts of a much more complicated life. I only wish he could enjoy the freedom of just being a child. He cries from the loneliness that tears his world apart wondering if he is bad or evil and why he isn†t like everyone else. I can†t answer, except to say there is a reason we just don†t understand it. His ability to live through the nightmare of his life is amazing. It†s not easy raising a child with a mental illness but what is even harder is not being accepted by your community because of ignorance and fear. To let a physical, neurological, biochemical or mental handicap stand in the way of these children†s future would be a major tragedy.