Green tea reduces the risk of obesity and a number of inflammatory biomarkers associated with poor health, according to a new study published in the journal Journal of Nutritional Biochemistry.
Mice fed a diet with 2% green tea extract proceeded much better than those who ate without it, which led to an upcoming study of the potential benefits of green tea to people at high risk of diabetes and heart disease.
The benefits of the research appear to be derived from improving bowel health, including the most beneficial microbes in the intestines and less permeability in the intestinal wall – a condition commonly called "gutted" in humans.
Richard Bruno, the lead author of the study, said: "This study proves that green tea encourages the development of good bowel bacteria and this leads to a number of benefits that greatly reduce the risk of obesity."
Negative changes in the microbial intestine have previously been linked to obesity, and green tea has been shown to promote healthy bacteria. The Ohio State team wanted to investigate if there was an argument about green tea that prevents obesity, inflammation and other factors associated with poor metabolic health.
"The results of studies dealing with obesity management so far have been a real mixed bag. Some seem to support green tea for weight loss, but many other studies have shown no effect, probably due to the complexity of diet versus many lifestyle factors. Our goal is to understand how it prevents weight gain. This will lead to better health recommendations ".
Bruno and his colleagues suspect that green tea can prevent obesity and protect against inflammation in the intestine on the basis of previous studies and thus devised an experiment that looked at the effects of green tea on male mice eating a normal diet and diet with a high fat content designed to cause obesity. (Female mice are resistant to diet-induced obesity and resistance to insulin, a precursor to diabetes, so they were not included).
For eight weeks, half of the animals ate a high-fat diet designed to lead to obesity and half had regular food. In each of these groups, half an empty green tea extract is mixed with their food.
The researchers then measured body weight and fat, insulin resistance and other factors including:
- Permeability of the intestine or how the intestine leaks
- Endotoxin shift or the movement of an intestinal bacterial component into the bloodstream, where it causes inflammation and insulin resistance
- Inflammation of the adipose tissue and intestines
- The composition of intestinal microbes, which are known to contribute to various health factors
Mice fed a high-fat diet supplemented with green tea gained about 20% less weight and had lower insulin resistance than mice eating an otherwise similar tea-free diet.
These mice also had less inflammation within the adipose tissue and intestine. In addition, green tea seemed to protect against the movement of endotoxin, the toxic bacterial component, its intestines and blood circulation.
In addition, researchers found evidence of stronger intestines in these mice. Lungs is a problem in people who contribute to widespread low quality inflammation and is involved in many health problems.
Researchers also found that green tea appears to contribute to a healthier microbial community in the intestines of high-fat fed mice. Mice fed a normal or low-fat diet supplemented with green tea also had benefits including reduced weight gain and lower endotoxin levels and bowel leakage points, but these were relatively moderate compared to the effects observed in mice received high-fat food.
Consuming green tea in the experiment will be equivalent to about 10 cups of green tea all day for one person, said Bruno.