Researchers at Ohio State University (OSU) administered mice a diet containing two percent green tea extract and found that they were more successful than those who ate without it. which prompted an upcoming study on the potential benefits of green tea in people at risk for heart disease. The results of the new study have been published recently in Diary of nutritional biochemistry, in an article titled "Green Tea Extract prevents obesity in male mice by relieving intestinal dysbiosis in combination with improved intestinal barrier function that limits endotoxin translocation and inflammation fat. " The benefits seen in the new study seem to come from better intestinal health, including more beneficial microbes in the intestines of the mice.
"This study shows that green tea encourages the growth of good intestinal bacteria, which leads to a series of benefits that significantly reduce the risk of obesity," said Richard Bruno, senior research scientist for the study. study, human nutrition professor at OSU.
Negative changes in the intestinal microbiome have already been associated with obesity and it has been shown that green tea promotes the promotion of healthy bacteria. The USO team investigated whether there was an argument for green tea preventing obesity, inflammation and other factors related to poor metabolic health, said Bruno, also a member Ohio Agricultural Research and Development Center.
"The results of studies on the management of obesity so far have been very mixed," said Bruno. "Some seem to support green tea for weight loss, but many other researches have shown no effect, probably because of the complexity of the diet compared to a number of lifestyle factors. Our goal is to understand how this prevents weight gain. This will lead to better health recommendations.
The research team suspected green tea to prevent obesity and protect against intestinal inflammation based on previous studies. She has therefore developed an experiment examining the effects of green tea on male mice fed a normal diet and a high-fat diet designed to cause obesity. (Female mice are resistant to diet-induced obesity and insulin resistance, a precursor to diabetes, so they were not included.)
"We hypothesized that catechin-rich green tea extract would protect against TLR4 / NFκB inflammation associated with obesity by attenuating intestinal dysbiosis and by limiting the translocation of endotoxins, "the authors wrote. "C57BL / 6J male mice were fed a low fat (LF) or high fat (HF) diet containing 0% or 2% TET for 8 weeks. At week 7, fluorescein isothiocyanate (FITC) -extran was administered by oral gavage before assessing its serum concentrations as a marker of intestinal permeability. "
The researchers found that mice fed a high-fat diet and supplemented with green tea took about 20% less weight and had lower insulin resistance than mice fed otherwise identical diets. , without tea. In addition, these mice also exhibited less inflammation in adipose tissue and in the intestine. In addition, green tea appeared to protect against the movement of endotoxins, the toxic bacterial component, out of their intestines and into the bloodstream.
In addition, the OSU team found that green tea appeared to contribute to the health of the microbial community in the gut of mice fed a high-fat diet. Mice fed a normal or low-fat diet, supplemented with green tea, also have advantages, including reduced weight gain, lower endotoxin levels and intestinal permeability of markers, but they were relatively modest compared to the effects observed in mice fed high fat diet. .
The consumption of green tea during the experience would equate to about 10 cups of green tea a day for one person. "It may sound like a lot of tea, but it's not very unusual in some parts of the world," Bruno said.
The researchers are currently working on a human study that will explore the effects of green tea on intestinal permeability in people with metabolic syndrome, a condition that predisposes people to type 2 diabetes and heart disease.
For the moment, it is too early to extrapolate the results in animals. He also warned that, if the benefits were to be verified in humans, green tea supplements would not be an obvious substitute for the drink during the day, because of the way the body metabolizes catechins in the tea.
"Consuming a bit during a day with food – as the mice did in this study – might be better," noted Bruno.
The researchers hope future research will determine whether consuming green tea could be a good strategy for those seeking to reduce their risk of becoming obese.
"Two-thirds of American adults are overweight or obese, and we know that telling people to eat less and do more is not effective. It is important to develop complementary approaches to health promotion that can prevent obesity and related problems, "concluded Bruno.