Vitamin A and carotenoid status in rural China.

Vitamin A status of 260 groups of twenty-five males or twenty-five females, aged 35-64 years, surveyed in twenty-four provinces of the People's Republic of China, was assessed by measuring plasma retinol. retinol-binding protein and beta-carotene concentrations. Direct measurements of food intake over a 3 d period and questionnaire data on the frequency of consumption of vegetables, fruits, animal products and other dietary items were also used. Vitamin A status appeared to be low only in specific counties but in general was satisfactory or only marginally deficient. Plasma beta-carotene levels were strikingly low in comparison with Western levels despite generous vegetable consumption suggesting that intake of vitamin A precursors may have been adequate but not abundant enough to maintain high circulating plasma levels of beta-carotene. Plasma beta-carotene, for both males and females, was significantly correlated with the frequency of consumption of green vegetables. Plasma retinol, for males, was highly correlated with meat, fish, oil and alcohol consumption expressed both in quantity or frequency of consumption. Higher levels of plasma retinol, together with lower levels of plasma beta-carotene in males compared with females, suggest that men consume more animal products or may have higher retinol requirements and therefore a higher rate of conversion of beta-carotene to retinol.