How Does Green Tea Prevent Obesity?

For thousands of years, Chinese has turned to green tea for its mix of health benefits.  Modern studies have reported a myriad of healthy benefit from green tea, including everything from protecting sensitive teeth, dampening Alzheimer’s symptoms, repelling bacteria and even preventing heart attacks.  Previous studies have also suggested that green tea can be a factor in obesity through its anti-inflammatory effects on gut health, so the researchers at Ohio State University (OHU) drew up some experiments to explore this very idea.

The study took place over 8 weeks and involved a group of male mice, with half of those fed a high-fat diet to induce obesity and the other half fed a normal healthy diet. Within those two groups, half of each had a green tea extract mixed through their food, constituting around two percent of their total diet, or the equivalent to a human drinking 10 cups a day. The scientists say female mice were not included as they are resistant to diet-induced obesity and insulin resistance.

Meanwhile, the researchers measured body weight, fat tissue, insulin resistance, inflammation in the intestines and fat tissue, the makeup of gut microbes, and how the gut bacteria and its derivatives shift into the bloodstream to promote inflammation. This allowed them to tease out a number of useful observations, primarily, that the high-fat mice whose diets were supplemented with green tea gained around 20 percent less weight than those whose were not. These mice also exhibited lower insulin resistance, a factor in the onset of diabetes. 

These green tea-fed mice also featured healthier communities of microbes in the gut and less inflammation in the fat tissue and intestines. They were less prone to leaky gut, where the wall of the small intestines are damaged and allow toxic products to flood into the blood stream.

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.

It is unclear whether these results will translate to humans, and even if they do, whether we’d be better taking supplements or drinking tea as normal, due to the way the body metabolizes its antioxidants.  However, the lead researcher suggested that consuming a little throughout the course of a day with food, like the mice did in this study, might be better.

Thanks for reading.

Journal Reference:

Dey P. et al., Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation, The Journal of Nutritional Biochemistry, Volume 67, May 2019, Pages 78-89 https://www.sciencedirect.com/science/article/pii/S095528631830723X