Zinc absorption during late pregnancy in rural southern Ethiopia

Abstract

Little is yet known about zinc absorption in late pregnancy, and no information on absorption from the total diet is available. The objective was to measure the fractional absorption of zinc (FAZ) and to estimate the total quantity of absorbed zinc (TAZ) each day during the third trimester of pregnancy in poor rural southern Ethiopian women. The participants (n = 17) were a convenience sample from a larger study population. The third stage of pregnancy was estimated from fundal height by the Bushulo Health Center prenatal outreach program. FAZ was determined with a dual-isotope tracer ratio technique that uses measurements of urine enrichment with zinc stable isotopes administered intravenously and orally, as an extrinsic label, with all meals in 1 d. Total dietary zinc (TDZ) was calculated from weighed diet records and Ethiopian food-composition tables supported by zinc and phytate analyses of major food items for individual meals. Plasma zinc and exchangeable zinc pool size were also estimated. Mean (+/-SD) FAZ was 0.35 +/- 0.11, TDZ was 6.0 +/- 3.2 mg/d, TAZ was 2.1 +/- 1.0 mg/d, phytate intake was 1033 +/- 843 mg/d, plasma zinc was 44.1 +/- 6.0 microg/dL, and the exchangeable zinc pool size was 142 +/- 39 mg. The molar ratio of phytate to zinc was 17:1. Women from a poor rural population who were dependent on a moderately high-phytate diet had low TDZ and low plasma zinc concentrations in the third trimester of pregnancy. TAZ was modestly higher than that predicted but did not meet physiologic requirements.