Research conducted in animals found the ratio of intestinal bacteria changed due to black and green tea. Meanwhile, the percentage of obesity-related bacteria decreased. Bacteria that supports lean body mass increased.
The findings suggest that black tea polyphenols stimulate the growth of gut bacterium. This forms short-chain fatty acids, a type of bacterial metabolites which can improve 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 professor at the UCLA Centre 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 green and black teas are prebiotics, substances that induce the growth of good microorganisms that contribute to a person’s well-being,” continues Henning.
In the investigation, scientists gave four groups of mice different diets: low-fat, high-sugar, high-fat, high-sugar, high-fat, high-sugar and green tea extract and high-fat, high-sugar and black tea extract.
Four weeks later, researchers noticed that mice given green or black tea extracts lost weight, the same amount as mice that were put on a low-fat diet throughout the study.
After collecting samples from the large intestines and liver tissues of the mice, study authors found an increase of healthy bacteria from consuming the tea extract and a decrease of bacteria linked to obesity.
Further, only black tea drinkers showed increased signs of Pseudobutyrivibrio, a type of bacteria associated with metabolism levels.
“For black tea lovers, there may be a new reason to keep drinking it,” says senior study author and director of the UCLA centre for Human Nutrition, Dr. Zhaoping Li.