Ameliorating prediabetic subject status via fermented tea supplementation: A randomized, double-blind, parallel-group comparison study

Abstract

Fermented tea consumption has been reported to alleviate diabetes and dyslipidemia, inducing an antiobesity effect. Here, we investigated the effects of microbial fermented tea and microbial fermented twig tea, which are made from Camellia sinensis by fermentation with Aspergillus sp., on glucose tolerance and metabolic syndrome in prediabetic subjects in a randomized, double-blind study. They were asked to consume the tea three times a day for 12 weeks. Fasting blood glucose, HbA1c, and 2-h oral glucose tolerance test (OGTT) were measured as primary endpoints. After 12 weeks, fasting blood glucose level was significantly reduced in the microbial fermented twig tea group (n = 19) as compared with that in the microbial fermented tea group (n = 16, p = 0.017). There was no significant difference in the 2-hour OGTT and HbA1c values between the two groups. Triglyceride levels were significantly lower in the microbial fermented tea group than in the microbial fermented twig tea group at 12 weeks (p = 0.049).