Los Angeles, Oct 5: Want to get rid of those extra kilos? Grab a cup of black tea, say scientists who have found that the beverage may promote weight loss by encouraging growth of metabolism-boosting bacteria.
Researchers at University of California, Los Angeles (UCLA) in the US found that both black and green tea changed the ratio of intestinal bacteria in mice.
They noted that the percentage of bacteria associated with obesity decreased, while bacteria associated with lean body mass increased.
Previous studies show that chemicals in green tea called polyphenols are absorbed and alter the energy metabolism in the liver.
The new study, published in the European Journal of Nutrition, shows 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.
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, researchers 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," said Susanne Henning, professor at UCLA.
"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," Henning said.
Researchers gave four groups of mice different diets - two of which were supplemented with green tea or black tea extracts.
The first group received low-fat, high-sugar diet, the second a high-fat, high-sugar diet, the third a high-fat, high-sugar and green tea extract, and the last group got a high-fat, high-sugar and black tea extract diet.