Researchers from UCLA have found that black tea may promote weight loss, the university reports.
In the new study, the scientists found that black tea alters energy metabolism in the liver of mice by changing gut metabolites. The results were published in the European Journal of Nutrition.
Both black and green tea changed the ratio of intestinal bacteria in the animals, according to the researchers. The percentage of bacteria associated with obesity decreased, while bacteria associated with lean body mass increased.
Previous studies indicated that polyphenols in green tea are absorbed and alter the energy metabolism in the liver. The new findings show that black tea polyphenols, which are too large to be absorbed in the small intestine, stimulate the growth of gut bacterium and the formation of short-chain fatty acids, according to the UCLA research. That’s a type of bacterial metabolites that has been shown to alter the energy metabolism in the liver.
“It was known that green tea polyphenols are more effective and offer more health benefits than black tea polyphenols since green tea chemicals are absorbed into the blood and tissue,” said Susanne Henning, the study’s lead author and an adjunct professor at the UCLA Center for Human Nutrition. “Our new findings suggest that black tea, through a specific mechanism through the gut microbiome, may also contribute to good health and weight loss in humans.”
The results suggest that both types of teas are prebiotics, she said in the UCLA news release, which are “substances that induce the growth of good microorganisms that contribute to a person’s well-being.”
Dr. Zhaoping Li, director of the UCLA Center for Human Nutrition and chief of the university’s division of Clinical Nutrition, said the findings suggest that the health benefits of both green tea and black tea go beyond their antioxidant benefits, and that both teas have a strong impact on the gut microbiome.
“For black tea lovers, there may be a new reason to keep drinking it,” she said.