Assessment of zinc nutritional status in rural China

Zinc nutriture was assessed in 6500 adults aged 35-64 years old in 65 mostly rural counties (two communes per county) in China on the basis of plasma zinc levels and dietary zinc intakes. In addition, the use of plasma albumin and red blood cell superoxide dismutase (SOD) for assessing zinc nutritional status was evaluated. Plasma levels of zinc and albumin were highly correlated between sexes (p<0.001) and between neighbouring communes in the same county (p<0.005), indicating a high degree of data reliability as assessed by this measure of "within county" homogeneity. Zinc deficiency, defined as plasma zinc values less than 70 μg/dL, was not observed for the populations in any of the 65 counties included in the survey. Dietary zinc intake was estimated on the basis of the newly revised Chinese food composition tables in conjunction with a 3-day household dietary survey of approximately 2000 households in the same study. Average dietary zinc intake was 11.9 mg/day, with a wide variability (7.4-34.9 mg/day) across the sample of 65 counties. The average levels of plasma zinc and dietary zinc intake observed in this adult rural Chinese population were comparable to those reported in healthy U.S. subjects, suggesting that zinc deficiency may not be a cause for concern in rural Chinese adults. However, marginal zinc deficiency may be prevalent in some rural areas.