Gastrointestinal Absorption of Aluminum from Teas in Rats

ABSTRACT: Gastrointestinal absorption of aluminum (Al) contained in black tea, green tea, and oolong tea compared with that of Al citrate was investigated using Wistar rats. The serum Al level in the rats administered orally with Al citrate increased by 7.9 times that of the basal level. In contrast, the administration of teas, at the equivalent dose of Al, increased only slightly the serum Al level (30 to 58%). Among 3 types of tea infusions, the serum Al level in the green tea group was relatively high compared to those in the black tea and oolong tea groups, although the difference was not significant. These results showed that the absorption rates of Al from ingestion of tea infusions were much lower than that of free form Al. It was also suggested that there were no marked differences in Al absorption rates from black tea, green tea, or oolong tea in the gastrointestinal tract.