A cup of green tea a day to lose weight? This is the study of the controversy

The consumption of green tea contributes to reduce obesity and reduce the incidence of biomarkers linked to l & # 39; inflammation, a factor badociated with a worse general state of health according to a study published in Diary of nutritional biochemistry. This would be due to an improvement of the intestinal flora, with a greater proportion of beneficial microbes and lower permeability of the intestinal wall at the time of absorption of substances harmful to the body.

The conclusions are derived from a study on mice, in which rodents who consumed 2% of green tea extract showed a much better health than those in the control group and who opens the door to the treatment of cardiovascular risk and Diabetic in humans. "This shows that green tea promotes the growth of good intestinal bacteria and, with them, a series of benefits that significantly reduce the risk of obesity," said Richard Bruno, Professor of Human Nutrition of the State University of Ohio and principal investigator.

"Studies that deal with the management of obesity have given very different results", Admits Bruno." Some have argued the theory that green tea helps to lose weight, while others have found no effect, presumably because of the complexity of diet related to several factors related to to the way of life. Our goal is to discover how to avoid weight gain and develop better recommendations. "

The medicinal virtues of green tea, consumed historically in Asian countries and increasingly popular in the West, would be at the rendezvous. catechinspolyphenols with anti-inflammatory and antioxidant potential having already been badociated with protective effects against cancer as well as diseases of the liver and heart. However, they are very far from being an "elixir": the OCU recently issued an alert about extracts with triggered levels of this compound that can damage the liver instead of protecting it.

The experiment consisted in providing male mice (oddly enough, females are resistant to obesity and insulin resistance, precursors of diabetes, diet-induced). high caloric food. Half of the rodents received tea extract mixed with food and after eight weeks their weight, the degree of inflammation of the intestine and adipose tissue, their degree of resistance to the Insulin, their intestinal permeability and their quantity and quality of their intestinal microbes, as well as the filtration of their compounds to the bloodstream.

So, the mice that had consumed green tea won 20% less weight than his colleagues and presented a better insulin performance. In addition, they presented minor inflammation and the nutritional supplement seemed to have protected them from endotoxin filtration, component of the bacteria harmful to the body, beyond the intestine and to the blood. In humans, high intestinal permeability is badociated with a greater distribution of low level inflammations and a deterioration in general health.

Finally, the mice that took the extract presented a healthier intestinal flora than the control groups. But these bio-healthy markers even surpbaded those of a third group, mice that had been fed "normally" – with a low-calorie diet – but had not received nutritional inputs. in green tea.

Controversy over human application

Now comes the million dollar question: can this result be extrapolated to humans? Bruno states that the amount taken by rodents would be equivalent to "ten cups a day for one person", which, as outrageous as it may sound to us," is not at all unusual in some parts of the world. "However, there is no evidence that such consumption has health effects to the same extent as those of the experiment, and under no circumstances should you try to match it to supplements by "the way the human organism metabolizes catechins".

In this sense, Cochrane Library In 2012, he included an badysis based on a meta-badysis based on Bruno's "many contradictory conclusions". The conclusion was that "green tea preparations seem to induce a small weight loss and not statistically significant in obese or overweight adults, "so small that they called it" clinically irrelevant. "In 2010, recalls the dietician-nutritionist and biologist Juan Revenga, the European Food Safety Agency ruled that "you can not establish a cause and effect relationship between consumption of green tea catechins […] and its contribution to maintaining or achieving a normal body weight. "

In the end, Bruno insists that nothing is lost by trying. "Take a little each day with mealsas the mice did, it would be a better solution, "suggests the researcher, in hopes of confirming the extent of the preventative effects of green tea on weight gain and diabetes." We already know that just telling people that eating less and playing sports does not work. There is a need for complementary approaches to health promotion that avoid obesity and related problems. "