Questioning riboflavin recommendations on the basis of a survey in China

Riboflavin status was surveyed in adults aged 35-64 y in 65 counties (two communes per county) in the Peo- ple's Republic of China by erythrocyte glutathione reductase activity coefficients (EGRACs), by urinary excretion of nbo- flavin 4 h after the oral administration of 5 mg riboflavin (one commune per county), and by direct measurement of food in- take over a 3-d period (one commune per county). EGRAC data were highly correlated between sexes (p < 0.001) and be- tween neighboring communes within the same county (p < 0.001) and with riboflavin intake (p < 0.001). The urinary- riboflavin-load test data were not correlated either with EGRAC or with riboflavin intake. Approximately 90% of the survey subjects were found to be deficient by Western and Chi- nese reference standards and allowances. Upon reconsidera- tion ofthe Western experimental data originally used to estab- lish these recommendations, it is suggested that riboflavin al- lowances are set too high both in China and in Western countries. Am J C/in Nutr 1990;5 1:436-45.