Black tea shrinks guts by working inside them

You’re likely familiar with the fact that green tea has been linked with weight loss, but a research out of the University of California Los Angeles (UCLA) shows that black tea can also blast away the fat by working through a different mechanism.

It is known that compounds in green tea called polyphenols are smaller than those found black tea, so they can be absorbed through the body’s tissues and can impact energy metabolism in the liver. But black tea polyphenols are too big to pass through the small intestine into the rest of the body, so it was unclear whether or not they could have a beneficial weight-loss effect. 

UCLA research, published in the European Journal of Nutrition, suggests that black tea, through a specific mechanism through the gut microbiome, may also contribute to good health and weight loss in humans.”

Specifically, research shows that black tea changes the ratio of bacteria in the intestine by increasing the microbes associated with lean body mass and decreasing those associated with obesity. While both green and black teas act as prebiotics in this way, it seems that black tea might have a leg up over its green partner.

The UCLA group fed four groups of mice different diets. One group ate low-fat, high-sugar foods, while another had high-fat, high-sugar meals. The other two were both on a high-fat, high-sugar diet but one got green tea extract, while the other received black tea extract.

At the end of four weeks, both groups that got the tea extracts had weights that were in line with those on the low-fat diets. And in both of those groups, intestinal samples showed lower obesity-related bacteria and high lean-related bacteria. But only the mice that were given the black tea extract showed increased levels of a bacteria called Pseudobutyrivibrio, which, the researchers suspect, is the secret to the extract’s success. 

These mice also demonstrated an increased level of short-chain fatty acids in their guts, compounds that have previously been linked to a benefic Because black tea seems to work in the gut, while green tea works in the liver as well as the gut, a combination of both drinks might be most helpful, especially since both beverages have been linked to multiple health benefits beyond weight loss. 

Thanks for reading.

Journal Reference:  Henning, S.M., Yang, J., Hsu, M. et al. Decaffeinated green and black tea polyphenols decrease weight gain and alter microbiome populations and function in diet-induced obese mice. Eur J Nutr 57, 2759–2769 (2018).  DOI