[Simple obesity in children. A study on the role of nutritional factors]

Excessive amount of adipose tissue in children and adolescents and simple obesity in particular constitute a growing health problem throughout the world. Adverse health effects of obesity of children justify the need to look for efficient treatments, among them the dietary treatment. THE AIM OF THE STUDY was to examine the effectiveness of dietary treatment in children with simple obesity on the basis of thorough analysis of their state of nutrition, method of nutrition and eating habits and the impact of other environmental factors. Four research hypotheses were formulated: 1. simple obesity of children is influenced by selected environmental factors such as parents' level of education, familial inclination to obesity and health habits, 2. chosen and accepted by the child and/or its mother/parents programme of dietary treatment in the form of low-energy diet with elements of low glycemic index results in the loss of body mass in children, 3. implemented dietary treatment translates into the modification of basic anthropometric features--body mass, body height, thickness of skin and adipose folds on arm, below shoulder blade (scapula), on abdomen as well as arm circumference and anthropometric parameters of examined children--body mass index BMI, waste-hip ratio, body fat content, 4. implemented dietary treatment has an impact on modification of certain biochemical indicators--lipid profile of children with increased indicators of lipid metabolism.

The research concerned 236 children living in the Mazowsze region with diagnosed simple obesity (relative body mass index rel BMI =20%), directed to Gastroenterological and Endocrinological Unit of the Institute of Mother and Child, after the children and/or their mothers/parents had accepted participating in a ten-week long research programme. The state of nutrition was evaluated on the basis of the examination of 8 basic features and 5 anthropometric parameters and basic biochemical indicators of metabolism of carbohydrates and fats, before and after the beginning of dietary treatment. The assessments of the method of nutrition, including eating habits, proportions of food products in the food ration and nutritional value of daily food rations was conducted on the basis of 10-14-day records of the child's diet before the implementation of dietary treatment and on the basis of randomly selected 3-day records of the child's diet from the diet book after the dietary treatment was introduced. The environmental data were collected on the basis of a questionnaire, constructed for this study.

The main risk factors for simple obesity in examined children (n=236) aged 3-15 yrs were familial and environmental conditions. A significant correlation was found between the children's obesity expressed by a normalized body mass index BMI z-score, unrelated to age and sex, and mother's level of education and father's obesity (Chi(2) test, p<0.05). A positive correlation was demonstrated between the normalized relative body mass index (BMI z-score) and children's anthropometrical parameters--thickness of skin and adipose folds on the arm, below the shoulder blade (scapula), on the abdomen and their sum, arm circumference, waste-hip ratio and body fat content and the children's parents body mass index (father's BMI, mother's BMI). In boys with simple obesity the tendency to central obesity was observed since early childhood. In the examined group of children no distortions of metabolism of carbohydrates were observed (correct fasting levels of glucose), while in children with obesity the irregularities of metabolism of fats were noted. The implemented dietary treatment (low energy diet with elements of low glycemic index) had a significant impact on improvement of lipid metabolism in all children in whom the irregularities of metabolism of fats were noted. Modification of the diet of children aged 3-6 by implementing dietary recommendations, including the increased frequency of meals and the choice of products with low glycemic index, did not have a significant impact on the decrease of the body mass index in 95% of examined children. A considerable number of children aged 3-6 (n=12) continued to eat only three meals a day and their model of nutrition, including the selection of products, was not significantly modified. The introduced low energy diet with elements of low glycemic index in children of school age (7-15 years) with simple obesity positively influenced the decrease of analyzed features and parameters (p<0.0001). During dietary treatment statistically significant decrease of the children's body mass was observed as well as a decrease of the thickness of skin and adipose folds on the arm, below the shoulder blade (scapula), on the abdomen and a decrease of arm circumference and body fat content. The change of the energy content of a daily food ration, the amount of consumed carbohydrates and products from the group of sugar and sweets, cereal foodstuffs and fat and products from the group of other fats was positively correlated with body mass loss expressed as the difference between z-score BMI before and after the dietary treatment. The modification of the eating habits--increased frequency of meals and reduction or elimination of eating between the meals during the nutrition intervention were not significantly linked to the change of normalized body mass index in the examined children. Only the frequency of eating sweets was related to the change of z-score BMI (p<0.05). The implemented dietary treatment in obese children aged 7-15 yrs significantly influenced the body mass loss. In children (n=38/236) with lipid metabolism abnormalities, the low energy diet with elements of low glycemic index had a favorable impact on the lipid profile. The increased levels of total cholesterol, LDL cholesterol and triglycerides returned to normal.

1. Simple obesity in children aged 3-15 yrs is connected with familial and environmental factors, including incorrect eating habits. 2. Dietary treatment consisting in the lowering of energetic value of the diet through the reduction of fat consumption and quantity and quality changes with respect to carbohydrates consumption decreased the children's obesity, and was more effective in the older age group (7-15 yrs). Dietary treatment normalizes the lipid profile in children. 3. Significant body mass loss has been observed in children in whose diet the amount of proteins and their share in the total energy value only slightly differs from the level before the dietary treatment. The amount of proteins in the children's diet was within the range of physiological recommendations.