Impact of Animal Source Foods on Growth, Morbidity and Iron Bioavailability in Kenyan School Children

• Main Author: Grillenberger, Monika
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2006
• Subjects: Agronomy; Fruits; Insulin-like growth factors; Meals; Mortality; Pharmaceutical sciences
• ISBN: 9798516028595

Simultaneous multiple micronutrient deficiencies that are highly prevalent in developing countries can impair growth and immunity with an increased risk of morbidity, mortality, and poor psychomotor development. Animal source foods can provide highly bioavailable micronutrients and improve the absorption of micronutrients from plant foods that are less bioavailable. The research presented in this thesis is part of a randomised controlled feeding intervention study that was carried out in order to examine the efficacy of animal source foods in improving cognitive function, growth, and morbidity in rural Kenyan children. Food supplements were provided for two years as a mid-morning snack to children aged 6-9 years from twelve primary schools (n 554). The habitual diet mainly consists of maize and beans with little or no animal source foods and children suffer from stunting and micronutrient deficiencies. Schools were randomly assigned to four study groups: 1) Control: no food supplement provided; 2) Energy supplement: a food supplement based on a local dish of maize, beans and vegetables (githeri); 3) Milk supplement: githeri plus a glass of milk (200 mL); and 4) Meat supplement: githeri with 60 g minced beef. The food supplements were approximately isoenergetic and contained an estimated energy content of ~250 kcal/serving (1050 kJ) during the first three months of the intervention and were then modified to obtain a total energy content of ~300 kcal/serving (1255 kJ). The supplements would supply ~20% of the daily energy requirement, yet the meat supplement would provide highest proportions of recommended amounts of micronutrients, particularly vitamin B12, bioavailable iron and bioavailable zinc, and the milk supplement would provide highest proportions of recommended amounts of vitamin A, riboflavin, calcium and phosphorus. Thus dietary quality would be improved for children receiving the meat or milk supplement compared with children receiving the energy supplement, and dietary quantity would be improved for all supplemented children compared with children in the control group. Weight gain was significantly higher (~10%) in the children receiving any type of food supplement compared with the control group. However, it remains unsolved if it was the energy and/or nutrients provided by the food supplements that resulted in the observed improvement in weight. No overall effect of the food supplementation was found on height. Children receiving the milk supplement who were more stunted gained 1.3 cm (15%) more height than children in the control group. Children receiving the meat supplement gained ~80% more mid-upper-arm muscle area (MMA) than those in the control group and ~30% more than those receiving the milk or energy supplement. Children receiving the milk supplement gained ~40% more MMA than those in the control group. No effects of the food supplements were found on measures of body fat. Analyses of the total diet of the children, i.e., their home diet and the food supplements, revealed that energy from animal source foods, but not total energy, was predictive of gain in height, weight, MMA, and mid-upper-arm fat area. Further, haem iron, preformed vitamin A, calcium and vitamin B12 positively predicted height and weight gain. In contrast, nutrients predominantly found in plant foods and dietary components that inhibit micronutrient absorption, such as fibre and phytate, negatively predicted the children’s growth. No effect of any of the food supplements was found on common childhood diseases or indicators of illness severity, but there was the trend that predicted risks were lowest for children receiving the milk supplement for most of the morbidity outcomes. The amount of absorbed iron in the habitual diet of the children was very low (0.56 ± 0.47 mg/d) due to the high amount of iron absorption inhibitors in the diet. Simulations of different household dietary strategies revealed that the combined addition of meat and ascorbic acid to a meal was the most efficacious approach to reduce the prevalence of inadequate iron intake, which was estimated to be 77% in the habitual diet. The findings of the study indicate that animal source foods can improve iron bioavailability and are beneficial for growth. An increase in the consumption of animal source foods should therefore be part of any program aiming at alleviating micronutrient malnutrition in children in developing countries