By testing the effects of green tea extract in people with a cluster of heart disease risk factors, scientists discovered that consuming green tea extract for four weeks can reduce blood sugar levels and improve gut health by lowering inflammation and decreasing ‘leaky gut.’
This is the first time that a study has looked at the health risks linked to the condition known as metabolic syndrome, which affects about one third of Americans. It turns out metabolic syndrome may be diminished by green tea’s anti-inflammatory benefits in the gut.
“There is much evidence that greater consumption of green tea is associated with good levels of cholesterol, glucose and triglycerides, but no studies have linked its benefits at the gut to those health factors,” commented Richard Bruno, senior study author and professor of human nutrition at The Ohio State University.
Managing metabolic syndrome through supplements
The clinical trial was conducted as a follow-up to a 2019 study that associated lower obesity and fewer health risks in mice that consumed green tea supplements. They also noted improvements to gut health.
The new study, published in Current Developments in Nutrition, delivered some unexpected findings.
Green tea supplements can also lower blood sugar and decrease gut inflammation and permeability in healthy people.
Bruno explains: “What this tells us is that within one month we’re able to lower blood glucose in both people with metabolic syndrome and healthy people, and the lowering of blood glucose appears to be related to decreasing leaky gut and decreasing gut inflammation – regardless of health status.”
Green tea extract reduces risks of obesity and high blood pressure
Individuals with metabolic syndrome are diagnosed with at least three of five factors that increase the risk for heart disease, diabetes and other health problems. These include:
- Excess belly fat
- High blood pressure
- Low HDL (good) cholesterol
- High levels of fasting blood glucose
Though metabolic syndrome carries great health risks, the symptoms are often only slightly altered and do not yet require drug management, Bruno claims.
“Most physicians will initially recommend weight loss and exercise. Unfortunately, we know most persons can’t comply with lifestyle modifications for various reasons,” he said. “Our work is aiming to give people a new food-based tool to help manage their risk for metabolic syndrome or to reverse metabolic syndrome.”
Supplements equivalent of five cups of green tea
Forty participants – 21 with metabolic syndrome and 19 healthy adults – consumed green tea gummies for 28 days. The dosage was the equivalent of five cups of green tea.
In the randomised double-blind crossover trial, all participants spent another 28 days taking a placebo, with a month off of any supplement between the treatments.
Participants were advised to follow a diet low in polyphenols –naturally occurring antioxidants in fruits, vegetables, teas and spices – during the placebo and green tea extract confection phases of the study so any results could be attributed to the effects of green tea alone.
Fasting blood glucose levels were significantly lower after taking green tea extract compared to levels after taking the placebo
The results demonstrated that fasting blood glucose levels for all participants were significantly lower after taking green tea extract compared to levels after taking the placebo.
There was decreased gut inflammation and gut permeability, or ‘leaky gut’.
“That absorption of gut-derived products is thought to be an initiating factor for obesity and insulin resistance, which are central to all cardiometabolic disorders.
“If we can improve gut integrity and reduce leaky gut, the thought is we’ll be able to not only alleviate low-grade inflammation that initiates cardiometabolic disorders, but potentially reverse them.
“We did not attempt to cure metabolic syndrome with a one-month study. But based on what we know about the causal factors behind metabolic syndrome, there is potential for green tea to be acting at least in part at the gut level to alleviate the risk for either developing it or reversing it if you already have metabolic syndrome,” concludes Bruno.