Did you know that green tea and black tea are both the same leaves from the same plant? Black tea is simply prepared differently through fermentation. Sometimes it takes awhile for science to widen their scope of study. Poor black tea! It has lived in the shadow of green tea’s health benefits this whole time when it turns out it has many of the same benefits.
Black tea also has benefits that are unique from green tea – black tea helps weight loss in different ways than green tea. Previously, we reported that black tea can drain endocrine disruptors from the body – but it can do so much more.
Benefits of green tea were already known; new UCLA study shows that polyphenols in both varieties alter gut bacteria
UCLA researchers have demonstrated for the first time that black tea may promote weight loss and other health benefits by changing bacteria in the gut.
In a study of mice, the scientists showed that black tea alters energy metabolism in the liver by changing gut metabolites.
The research is published in the European Journal of Nutrition.
The study found that both black and green tea changed the ratio of intestinal bacteria in the animals: The percentage of bacteria associated with obesity decreased, while bacteria associated with lean body mass increased.
Previous studies indicated that chemicals in green tea called polyphenols 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, a type of bacterial metabolites that has been shown to alter the energy metabolism in the liver.
Susanne Henning, the study’s lead author and an adjunct professor at the UCLA Center for Human Nutrition, which is part of the David Geffen School of Medicine at UCLA, said:
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. 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 green and black teas are prebiotics, substances that induce the growth of good microorganisms that contribute to a person’s well-being.
In the study, four groups of mice received different diets — two of which were supplemented with green tea or black tea extracts:
High-fat, high-sugar and green tea extract
High-fat, high-sugar and black tea extract
After four weeks, the weights of the mice that were given green or black tea extracts dropped to the same levels as those of the mice that received the low-fat diet throughout the study.
The researchers also collected large intestinal bacteria samples from the mice and fat deposits from liver tissues. In the mice that consumed either type of tea extract, there was less of the type of bacteria associated with obesity and more of the bacteria associated with lean body mass.
However, only the mice that consumed black tea extract had an increase in a type of bacteria called Pseudobutyrivibrio, which could help explain the difference between how black tea and green tea change energy metabolism.
Dr. Zhaoping Li, director of the UCLA Center for Human Nutrition, chief of the UCLA Division of Clinical Nutrition and the study’s senior author, 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.
The findings build on a 2015 UCLA study that demonstrated that both green tea and black tea helped prevent obesity in mice that consumed a high-fat, high-sugar diet.
Did you know that you can receive the same benefits from drinking decaffeinated tea? Learn to pick the right kind of decaf.