Suboptimal zinc status in pregnant Malawian women: its association with low intakes of poorly available zinc, frequent reproductive cycling, and malaria

Abstract

A study of 152 rural Malawian women aged 23.2+/-5.5 y (x+/-SD) at 24 wk gestation included measurements of biochemical indexes of zinc (plasma and hair), protein (serum albumin), and infection (serum C-reactive protein, white blood cell count, and malaria), and dietary intakes (via three interactive 24-h dietary recalls). Data on health, demographic and socioeconomic status, family characteristics, reproductive history, and anthropometry were also collected. The study revealed a high prevalence of suboptimal zinc status: 36% of the women had low plasma and 46% had low hair zinc values. Median daily intake of zinc (9.0 mg) was low and poorly available: 61% was provided by cereals and 20% by flesh foods. Median intake of animal protein was only 5.6 g/d, and phytate intakes were high (1.4 g/d). Women consuming diets with phytate-zinc ratios > 17 (the median) had lower hair zinc concentrations (1.6 compared with 1.8 micromol/g, P < 0.03), were older (24 compared with 20 y, P < 0.02), and had a higher number of pregnancies (3 compared with 2, P < 0.02) than those consuming diets with a phytate-zinc ratio < 17. Frequent reproductive cycling was related to zinc status; hair zinc was higher for a prima- than for a multigravida (2.0 compared with 1.6 micromol/g, P < 0.01). Malaria prevalence was also associated with hair zinc (P < 0.05) but not with plasma zinc, after the number of pregnancies was controlled for. We conclude that low intakes of poorly available dietary zinc, frequent reproductive cycling, and malaria prevalence are three major factors in the etiology of suboptimal zinc status in these rural, pregnant Malawian women.