Study: Green tea may strengthen gut health, protect against obesity

COLUMBUS, Ohio — Green tea may pack a powerful punch in the gut, at least when it comes to fighting obesity and maintaining strong intestinal health, a new study finds.

Researchers from The Ohio State University tested the effects of green tea extract on mice consuming a high-fat diet and discovered that the rodents gained less weight and showed improved gut health compared to those not taking the supplement.

The authors say that chemicals found in green tea may help prevent what’s known as a “leaky gut,” a condition in which toxins and harmful bacteria are able to slip through a weakened intestinal wall. Scientists believe gut health may dictate numerous health conditions, and the makeup of one’s gut microbiota — the collection of both healthy and unhealthy bacteria in our intestines — can improve or worsen the chances of developing various ailments.

“This study provides evidence that green tea encourages the growth of good gut bacteria, and that leads to a series of benefits that significantly lower the risk of obesity,” says lead author Richard Bruno, a professor of human nutrition at the university, in a media release.

For their research, Bruno and his co-authors fed groups of male mice either a high-fat diet or a normal diet, and included 2 percent green tea extract in both over a period of eight weeks. As a control, they did the same with two other groups of mice, but did not add the green tea.

They found that the mice fed a high-fat diet with the green tea supplement gained 20 percent less weight, had lower insulin resistance, and less intestinal inflammation — a sign of stronger gut health —  than those consuming fatty meals without the supplement. Researchers also say that green tea prevented toxic bacteria from being absorbed into the rodents’ bloodstream, an indication of a less leaky gut.

Mice that consumed the regular diet with green tea also showed the weight gain benefits and signs of healthier gut bacteria, but not to the same extent as the mice in the high-fat group.

Bruno and his colleagues are now researching how green tea could benefit a leaky gut in humans, particularly those prone to developing diabetes and heart disease. Though the results from the mouse study are promising, he notes that the amount of green tea consumed by the mice would be comparable to a person drinking 10 cups of green tea in a single day. Taking a green tea supplement likely won’t offer the same benefits as the beverage.

“Consuming a little throughout the course of a day with food – like the mice did in this study – might be better,” he says.

In the meantime, Bruno is hopeful his work will lead to more options for adults who consume poorer diets or are concerned about their weight.

“Two-thirds of American adults are overweight or obese, and we know that just telling people to eat less and exercise more isn’t working. It’s important to establish complementary health-promoting approaches that can prevent obesity and related problems,” he says.

Check out our list of the best green teas, according to experts.

The study is published in The Journal of Nutritional Biochemistry.