Micronutrient Deficiencies Among Vulnerable Populations in Tanzania: Evidence for Interventions and Programmatic Implications

Abstract

Multiple micronutrient deficiencies are highly prevalent in sub-Saharan Africa primarily due to inadequate dietary intake and limited diversity of fruits, vegetables, animal protein, and fortified foods. Women of reproductive age (WRA), pregnant and lactating women, children and the chronically ill have been noted to be at particularly high risk for micronutrient deficiencies and these deficiencies have been linked to a range of poor health outcomes. This thesis expands the epidemiologic evidence on the role of micronutrient deficiencies in health and the effect of supplementation and fortification interventions in these vulnerable populations in Tanzania. Chapter 1 assesses the effectiveness of a national food fortification program among WRA in urban Tanzania. Using data obtained from a cohort of 600 WRA, we document that implementation of a wheat flour folic acid fortification program resulted in significant increases in serum folate concentrations and a large reduction in the prevalence of folate deficiency. Chapter 2 examines the effect of prenatal zinc and vitamin A supplementation on maternal iron status and risk of anemia and the effect of prenatal iron supplementation on maternal zinc status. We analyzed data from two randomized controlled trials of zinc, vitamin A, and iron supplementation among Tanzanian HIV-negative pregnant women. We found no beneficial effect of zinc or vitamin A supplementation on hematological or micronutrient status. However, we found that iron supplementation significantly reduced the risk of iron-deficiency but did not affect zinc status. Chapter 3 assesses the association of impaired hematological status at antiretroviral therapy (ART) initiation with mortality and HIV-related morbidities among HIV-infected adults in Tanzania. Using data from a trial of multivitamins (vitamin B-complex, C and E), we found that impaired hematological status at ART initiation was associated with increased risk of mortality and post treatment weight loss, and make the case for further investigation of the role of iron in HIV disease progression. Conclusions: Scaling up optimal micronutrient interventions among vulnerable populations are likely to improve health and significantly contribute to the attainment of sustainable development in Tanzania and in countries of similar burden of malnutrition and disease in Africa.