Stem sell: Twig tea lowers fasting blood glucose more than regular tea – 12-week study

Twig tea is made from microbial fermented stem of the tea plant instead of using tea leaves. Regular tea is usually made of microbial fermented tea leaves. 

Twig tea also contains minute amounts of the polyphenols teadenol and catechins typically present in tea leaves. 

Writing in Journal of Functional Foods, ​the researchers reported that twig tea had significantly reduced fasting blood glucose in prediabetic individuals. Those who drank regular tea reported an increase in their fasting blood glucose instead.

The randomised, double-blind, parallel-group comparison study involved 40 subjects between 20 and 80 years old.

Being prediabetic, their fasting glucose level was between 100 and 126 mg/dL, while their two-hour blood glucose was 140 to 199 mg/dL. 

They were randomised to drink either microbial fermented twig tea or microbial fermented tea three times per day. Both teas were supplied by Japanese firm Osada Seicha.

Results showed that fasting blood glucose had dropped significantly from the baseline level of 108 ± 7 to 104 ± 9 mg/dL by the end of the study for the group taking twig tea.

However, those from the other group saw their fasting glucose went up from 107 ± 6 to 111 ± 8 mg/dL.

“Microbial fermented twig tea contains some dietary fibers but not catechins and teadenols, which are present in fermented tea; this different composition may change the beneficial effects of fermented teas. ​

“The tea plant contains abundant dietary fibers. Notably, dietary fibers in foods exhibit health benefits for metabolic syndrome. They reduce not only glucose absorption but also fasting blood glucose in the long term,”​ the researchers explained.

Regular fermented tea still useful ​

Nonetheless, drinking regular tea has its own set of benefits, such as a reduction in triglyceride levels – a result also seen in the group drinking twig tea.

Specifically, triglyceride level had dropped from 103 ± 44 to 86 ± 36 mg/dL for the group taking regular fermented tea, while that of the group drinking twig tea was down from 131 ± 78 to 115 ± 48 mg/dL.

In addition, the two-hour oral glucose tolerance test for both groups had also dropped significantly.

The reduction was from 163 ± 20 to 127 ± 29mg/dL for the group taking fermented twig tea and from 166 ± 19 to 134 ± 30 mg/dL for the group taking regular tea.

“Microbial fermented tea contains a larger amount of teadenol and catechins than microbial fermented twig tea.​

“Teadenol has been reported to promote secretion of adiponectin, a well-known adipokine that lowers triglycerides and LDL cholesterol levels,” ​the researchers explained.

Source: Journal of Functional Foods ​

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

https://doi.org/10.1016/j.jff.2022.105257​

Authors: Yasufumi Katanasaka et al​