Folacin content of tea.

Total folacin and free folacin activities of 22 commercial tea samples, involving 5 types and 14 brands, were determined by a microbiological assay, using Lactobacillus casei (ATCC 7469). Substantially higher amounts of folacin were found in tea leaves than had been reported previously, due to an improved assay method with added ascorbic acid to protect the labile folate forms. Tea brews made from green and black teas contained approximately three to four times more folacin than the brews made from oolong tea, herb tea, and instant tea powders. Tea brews made from loose leaf teas and tea bags did not differ appreciably in folacin content. However, the tea bag itself inhibited folacin extraction. A range of 3% to 25% of the RDA for folacin can be met by consuming five servings (5 to 6 oz. per serving) of tea daily.