A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences and Engineering of the Nelson Mandela African Institution of Science and Technology
Infant and young child feeding practices rank among the most effective interventions to promote child growth and development. Improving the quality of complementary food has been observed as an important strategy for promoting child growth in resource-poor settings. Therefore, the objective of this study was to design a safe and nutritious model formula that meets nutritional requirement for infants and young children aged 6 – 23 months. The objective was achieved by conducting a cross-sectional study aimed to assess the nutritional status of 394 children and identify factors associated to under-nutrition. Then, complementary flours were collected randomly from selected households and analyzed for macro- and micro-nutrients, phytate content and presence of aflatoxins. Exposure assessment was done to evaluate the contribution of aflatoxins exposure on nutritional status of children. Finally, the model formula was designed using commonly consumed foods to meet the nutritional requirements for children. Data analysis was performed by using SPSS (IBM version 21), ENA for smart, Microsoft Excel and LINDO (version 6.1). The results showed that prevalence of stunting was 40.4% (95% CI; 29.8% - 50.9%). Children aged between 12 - 23 months were more stunted compared to those aged between 6 – 11 months (p ≤ 0.001). The age of introducing complementary foods (AOR = 13.3, 95%CI, 2.6 – 67.6), maternal education (AOR = 5.5, 95% CI, 1.0 – 9.8) and residence in Chamwino district (AOR = 3.2, 95%, 1.3 – 5.9) were identified as factors associated with stunting. Analysis of cereal-based complementary foods indicated that protein and fat content ranged from 1.17 - 11.17 g/100 g and 0.61 - 11.19 g/100 g respectively. A significant difference in protein content between composite cereals and other types of complementary foods was observed (p ≤ 0.001). Sorghum had the highest iron and phytate content of 8.37 mg/100 g and 1176.8 mg respectively. Aflatoxins contamination was detected in 42.5% of home-made complementary flours at the levels ranging from 0.3 μg/kg to 2,128 μg/kg. There was a significant association between stunting and infants dietary exposure to aflatoxin B1 (p = 0.05, 95% CI; 0.019 - 0.028). Cereal-based complementary foods consumed by the studied children were observed to have dual burdens in a sense that they contained high level of phytate and being contaminated with aflatoxins to the levels of health concern that may contribute to impairment of growth. Developed optimized model formula serves as a basis for ensuring adequate nutrient intake, minimized intake of phytate and reduced dietary exposure of infants