The effect of zinc fortification of a therapeutic complementary food on the growth and immune function of severely malnourished children in Malawi

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Authors

MacDonald, Audrey Carolyn

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University of Guelph

Abstract

The objective of this study was to improve the content and bioavailability of zinc in Malawi's national therapeutic food (Likuni Phala) and to assess its impact on the immune and growth recovery of malnourished children. The study was a randomised controlled trial with a stratified block design of 121 hospitalised, malnourished children, with mean (±SD) age, length for age (LAZ) and weight for length (WLZ) of 24 ± 11 months, -3.4 ± 1.5 and -2.3 ± 1.0 z-scores, respectively. Fifty six percent of the children were oedematous; the remaining 44% were non-oedematous. Children were severely immune suppressed; 52% were anergic. Three variations of the therapeutic Likuni Phala (LP) were assessed over a four week period; (1) fortified with micronutrients plus zinc (50 mg Zn/100 g dry weight) and with reduced phytate (ZF), (2) fortified with micronutrients without zinc and with reduced phytate (F), and (3) unfortified and without reduced phytate (UF). Following the intervention, both non-oedematous and oedematous children in the F group were 1.80 and 1.75 times more likely to respond positively to the delayed hypersensitivity skin test than the children in the ZF group (p < 0.05), when controlling for age, gender, initial DHS response, HIV and nutritional status and site of test. Nevertheless, among non-oedematous children, final WLZ scores were higher in the ZF (-1.36) than in the F (-1.99) treatments, as was the rate of weight gain in the ZF (4.6 g/kg/d) than the F (1.4 g/kg/d). In contrast, among oedematous children, final WLZ scores were lower in the ZF (-1.71) than the F (-1.19) treatments, and those in the ZF group had a lower rate of weight gain (2.4 g/kg/d) than those in the F (4.8 g/kg/d) group. Our study suggests that levels of zinc (10 mg/kg/day) in combination with the micronutrient fortification of LP resulted in a suppression of the immune system over that of children receiving the LP fortified with micronutrients without zinc (0.7 mg zinc/kg/day), in both non-oedematous and oedematous children. Nevertheless, there were significant increases in weight and rate of weight gain in these non-oedematous children, while the oedematous children decreased in ponderal growth and body composition indices.

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content, bioavailability, zinc, Malawi, national therapeutic food, Likuni Phala, immune recovery, growth recovery, malnourished children

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