A previous longitudinal three-country study in Egypt, Kenya and Mexico found significant positive associations between intake of animal source foods (ASF) and growth, cognitive development and physical activity. To test for a causal relationship, a controlled school feeding intervention study was designed to test the hypotheses that ASF would improve micronutrient status, growth and cognitive function in Kenyan primary school children. Twelve rural Kenyan schools with 554 children were randomized to four feeding interventions using a local vegetable stew as the vehicle. The groups were designated as Meat, Milk, Energy and Control, who received no feedings. Feeding was carried out on school days for seven terms during 21 mo. Preintervention baseline measures included nutritional status, home food intake, anthropometry, biochemical measures of micronutrient status, malaria, intestinal parasites, health status and cognitive and behavioral measures. The measurements of each child were repeated at intervals over 2 y. Baseline data revealed stunting and underweight in approximately 30% of children and widespread inadequate intakes and/or biochemical evidence of micronutrient deficiencies, particularly of iron, zinc, vitamins A and B-12, riboflavin and calcium. Little or no ASF were eaten and fat intake was low. Malaria was present in 31% of children, and hookworm, amebiasis and giardia were widely prevalent. The outcomes measured were rates of change or increase during the intervention in cognitive function, growth, physical activity and behavior and micronutrient status. Hierarchical linear random effects modeling was used for analysis of outcomes.

A randomized, controlled school feeding study was conducted in rural Embu District, Kenya to test for a causal link between animal-source food intake and changes in micronutrient nutrition and growth, cognitive, and behavioral outcomes. Twelve primary schools were randomly assigned to 1 of 4 groups. Children in Standard I classes received the local plant-based dish githeri as a midmorning school snack supplemented with meat, milk, or fat added to equalize energy content in all feedings. The Control children received no feedings but participated in data collection. Main outcome measures assessed at baseline and longitudinally were 24-h food intake recall, anthropometry, cognitive function, physical activity, and behaviors during school free play. For cognitive function, the Meat group showed the steepest rate of increase on Raven's Progressive Matrices scores and in zone-wide school end-term total and arithmetic test scores. The Plain githeri and Meat groups performed better over time than the Milk and Control groups (P < 0.02-0.03) on arithmetic tests. The Meat group showed the greatest increase in percentage time in high levels of physical activity and in initiative and leadership behaviors compared with all other groups. For growth, in the Milk group only younger and stunted children showed a greater rate of gain in height. The Meat group showed near doubling of upper midarm muscle area, and the Milk group a smaller degree of increase. This is the first randomized, controlled feeding study to examine the effect of meat- vs. milk- vs. plant-based snacks on functional outcomes in children.

Observational studies of dietary patterns and growth and studies with milk supplementation have shown that children consuming diets containing animal source foods grow better. This study evaluates the growth of 544 Kenyan schoolchildren (median age 7.1 y) after 23 mo of food supplementation with a meat, milk or energy supplement (approximately 1255 kJ) compared to a control group without a supplement. Multivariate analyses controlled for covariates compared gain in weight, height, weight-for-height Z-score (WHZ), height-for-age Z-score (HAZ), mid-upper-arm circumference, triceps and subscapular skinfolds, mid-upper-arm muscle and mid-upper-arm fat area. Children in each of the supplementation groups gained approximately 0.4 kg (10%) more weight than children in the Control group. Children in the Meat, Milk and Energy groups gained 0.33, 0.19 and 0.27 cm more, respectively, in mid-upper-arm circumference than children in the Control group. Children who received the Meat supplement gained 30-80% more mid-upper-arm muscle area than children in the other groups, and children who received the milk supplement gained 40% more mid-upper-arm muscle area than children who did not receive a supplement. No statistically significant overall effects of supplementation were found on height, HAZ, WHZ or measures of body fat. A positive effect of the milk supplement on height gain could be seen in the subgroup of children with a lower baseline HAZ (< or = -1.4). The results indicate that food supplements had a positive impact on weight gain in the study children and that the addition of meat increased their lean body mass.

Previous observational studies in developing countries have suggested that diet quality, particularly increased animal source food (ASF) consumption, is positively associated with child cognitive development. This report presents findings from a study in rural Kenya, designed to test the impact of three different diets on the cognitive development of school children. Twelve schools with a total of 555 Standard 1 children (equivalent to U.S. Grade 1) were randomized to one of four feeding interventions: Meat, Milk, Energy or Control (no feeding). Feeding continued for seven school terms (21 mo), and cognitive tests were administered before the commencement of feeding and during every other term of feeding. Hierarchical linear random effects models and associated methods were used to examine the effects of treatment group on changes in cognitive performance over time. Analyses revealed that children receiving supplemental food with meat significantly outperformed all other children on the Raven's Progressive Matrices. Children supplemented with meat, and children supplemented with energy, outperformed children in the Control group on tests of arithmetic ability. There were no group differences on tests of verbal comprehension. Results suggest that supplementation with animal source food has positive effects on Kenyan children's cognitive performance. However, these effects are not equivalent across all domains of cognitive functioning, nor did different forms of animal source foods produce the same beneficial effects. Implications of these findings for supplementation programs in developing countries are discussed.

Animal source foods (ASF) can provide micronutrients in greater amounts and more bioavailable forms compared to plant source foods, but their intake is low in many poor populations. However, the impact of ASF on micronutrient status of undernourished populations has not been assessed. Supplemental meat (60-85 g/d), milk (200-250 mL/d) or energy (isocaloric with the meat and milk, 240-300 kcal/d) were randomly assigned to 555 undernourished school children aged 5-14 y in a rural malaria-endemic area of Kenya, at one school meal daily for one school year. Blood and stool samples were collected at baseline and after 1 y to assess stool parasites, malaria, hemoglobin, serum or plasma C-reactive protein, ferritin, iron, zinc, copper, vitamin B-12, folate and retinol, and erythrocyte riboflavin. At baseline, there was a high prevalence of micronutrient deficiencies (iron, zinc, vitamins A and B-12 and riboflavin), yet plasma ferritin was low in few children, and none had low serum copper. At the end of the year of supplementation, plasma vitamin B-12 concentrations were significantly increased in children fed the Meat or Milk meal; prevalence of severe plus moderate deficiency fell from 80.7% at baseline to 64.1% in the Meat group and from 71.6 to 45.1% in the Milk group, respectively. No significant improvement was observed in the status of other micronutrients compared to the Energy and Control groups, although malaria and other infections may have obscured effects. Supplementation with small amounts of meat or milk reduced the high prevalence of vitamin B-12 deficiency in these children.