Zinc Absorption From SQ-LNS With and Without Phytase

Background: Community based-intervention trials conducted among infants and young children in low- and middle-income countries have found that zinc supplementation of young children (in the form of liquid supplements or dispersible tablets) increases linear growth and weight gain, and reduces the prevalence of diarrhea and respiratory infections, and lowers all-cause mortality. Aside from supplements, additional dietary zinc can also be provided through "home-fortification" of complementary foods with small-quantity lipid-based nutrient supplements (SQ-LNS; 20g/d), which are typically formulated as a peanut-based paste enriched with a vitamin and mineral complex containing 8 mg elemental zinc (as ZnSO4). However, the efficacy of LNS as a delivery vehicle for preventive zinc supplementation remains uncertain. Two recent studies, which provided LNS containing 4-10 mg Zn daily for 6-9 months found no significant differences in plasma zinc concentrations at the end of the intervention period compared to placebo. This lack of response may be due to the reduced absorption of zinc when it is part of a complex food matrix and provided with cereal-based meals; both SQ-LNS and cereal grains contain moderate to high concentrations of phytate, the main dietary factor known to substantially reduce zinc absorption. The addition of exogenous phytases is an efficacious strategy to reduce the phytate content of foods, and increase the bioavailability of dietary zinc; however, the efficacy of this approach has not yet been demonstrated for SQ-LNS. Objective: The overall objective of the study is to assess the efficacy of adding exogenous phytase to SQ-LNS by investigating intra-individual differences in the fractional absorption of zinc (FAZ) among children who receive additional dietary zinc (8 mg/d) from SQ-LNS with or without phytase. Trial approach: The study will be a double-blind randomized controlled clinical trial, designed to permit within-child comparisons of zinc absorp