Physiological requirements (PR) for zinc (Zn) are met with a Zn supplement but not with phytate reduction of maize‐based diets in poor indigenous Guatemalan infants aged 9 mo

Abstract

Plant‐based, low diversity complementary feeds are inevitably low in Zn. The objective of this study was to evaluate two strategies or a combination of the two to augment the absorption of Zn.The study was a 2×2 design of low phytate (80% reduction)/control maize and a 5 mg Zn/placebo (given as ZnS047H20) supplement administered separately from meals. The subjects were indigenous Guatemalan infants aged 9 mo. The interventions were commenced at age 6 mo. On the test day, fractional absorption of Zn (FAZ) from meals and from the supplement were measured by a dual isotope tracer ratio method with food and supplement extrinsically labeled with 67Zn & 70Zn, respectively. Zn intake (ZI) was measured in duplicate meals and from the supplement/placebo. Absorbed Zn (AZ) was calculated from ZI × FAZ.FAZ, ZI, and AZ did not vary between dietary (phytate) intervention groups; therefore, data were combined in the table (mean (SD)). Data for the group randomized to receive the Zn supplement are also included:Conclusions1) The lack of any detectable benefit of the low phytate maize has to be interpreted with caution because of the low intake of maize at this age. 2) Zn absorption from complementary foods (breast milk Zn not included) was ≤ 50% of the estimated physiological requirement (PR, 0.84 mg/d, Institute of Medicine). 3) Mean AZ of supplement alone provided a comfortable margin above the estimated PR.Supported by Eunice Kennedy Shriver NICHD/NIH #HD040657.