Efficacy of a community-based dietary intervention to enhance micronutrient adequacy of high-phytate maize-based diets of rural Malawian children

Objective: To evaluate the efficacy of a community-based dietary intervention to reduce risk of micronutrient inadequacies in high-phytate maize-based Malawian diets. Design: Quasi-experimental post-test design with a non-equivalent control group. Setting: Four villages in Mangochi District, Southern Malawi. Participants: Households with children aged 3-7 years in two intervention (n=200) and two control (n=81) villages participated in a 6-month intervention employing dietary diversification, changes in food selection patterns, and modifications to food processing to reduce the phytate content of maize-based diets. Baseline comparability between the groups was confirmed via assessment of sociodemographic characteristics, anthropometry, knowledge and practices, morbidity, haemoglobin and hair zinc. After 12 months, knowledge and practices and dietary intakes were assessed by interactive 24-hour recalls, one during the food plenty and a second during the food shortage season. Nutrient adequacy for the two groups was compared via dietary quality indicators and predicted prevalence of inadequate intakes using the probability approach. Results: Intervention children had diets that were significantly more diverse and of a higher quality than those of controls. Median daily intakes of protein, calcium, zinc (total and available), haem iron, vitamin B-12 and animal foods (grams; % of total energy) were higher (P < 0.05) whereas phytate intakes, phytate/zinc and phytate/iron molar ratios were lower (P < 0.01) in the intervention group; some spread of knowledge and practices to controls occurred. Conclusions: Our community-based dietary strategies reduced the predicted prevalence of inadequate intakes of protein, calcium, zinc and vitamin B-12, but not iron, in children from Malawian households with very limited resources.