Catechins have shown to have antioxidative, anticarcinogenic and hypocholesterolemic activities. In this clinical trial, we investigated the influences of catechins, which are contained in green tea, on vitamins and minerals of serum and intestinal microflora in healthy 9 adult women. On 14 days after daily ingestion of green tea containing a large amount of catechins (1,080 mg/day), the concentrations of serum vitamin B2 and biotin were significantly increased. However, such a change in serum vitamin B1 concentration was not observed during the experimental period. On the other hand, the serum concentrations of minerals such as zinc, sodium, potassium, chloride and calcium, were significantly increased. The proportion of Bifidobacterium on 14 days was significantly higher than that on 0 day, whereas the number of Enterobacteriaceae was decreased by the ingestion of green tea. Also the ammonium concentration in feces decreased to 47.5%. These findings suggest that the green tea widely consumed in Japan may have a beneficial action for maintaining the good health.
