Study: Green Tea Extract Reduces Blood Sugar Levels, Improves Gut Health

Individuals with heart disease risk factors who consumed green tea extract for 4 weeks were found to have reduced blood sugar levels and improved gut health from lower inflammation and decreased leaky gut, according to a study published in Current Developments in Nutrition.

Investigators said this study is the first to assess whether the health risks linked to the condition known as metabolic syndrome could 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,” Richard Bruno, PhD, senior study author and professor of human nutrition at The Ohio State University, said in a statement.

The study followed 40 individuals who participated in a 2019 study that associated lower obesity and fewer health risks in mice that consumed green tea supplements with improvements to their gut health.

In the new study, investigators found that green tea extract also lowered glucose and decreased gut inflammation and permeability in healthy individuals.

“What this tells us is that within 1 month, we’re able to lower blood glucose in both [individuals] with metabolic syndrome and healthy [individuals], and the lowering of blood glucose appears to be related to decreasing leaky gut and decreasing gut inflammation, regardless of health status,” Bruno said in the statement.

Individuals who have metabolic syndrome are diagnosed with at least 3 of 5 factors, including excess belly fat, high blood pressure, low high-density lipoprotein cholesterol, high levels of fasting blood glucose, and high levels of triglycerides.

These factors increase the risk for heart disease, diabetes, and other health problems. Investigators said that the issue with these factors is they do not require assistance from medication to keep the issues under control.

Most physicians recommend weight loss; however, investigators aim to help individuals with a new food-based tool to help manage their risk for metabolic syndrome or help reverse it.

In the study, 40 individuals consumed gummy confections containing green tea extract that was rich in anti-inflammatory compounds, known as catechins, for 28 days. Out of the 40 individuals, 21 had metabolic syndrome while 19 were healthy individuals.

In the randomized double blind crossover trial, all individuals took the placebo for 28 days, with a month off any supplements between the treatments. The individuals followed a diet low in polyphenols, which occur in antioxidants in fruits, vegetables, teas, and spices, during the placebo and green tea phases of the study, so investigators could make informed conclusions about the effects of green tea alone.

Investigators found that fasting blood glucose levels for all individuals were significantly lower after taking green tea extract compared to levels after taking the placebo. Additionally, decreased gut inflammation was also established in all individuals through an analysis that showed a reduction in pro-inflammatory proteins in fecal samples.

Investigators also used a technique to assess sugar ratios in urine samples and found that with green tea, individuals’ small intestine permeability decreased.

“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,” Bruno said in the statement. “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.”

Investigators are completing further analyses of microbial communities in the guts of the individuals in the study as well as the levels of bacteria-related toxins in their blood.

Reference

Green tea extract promotes gut health, lowers blood sugar. News release. EurekAlert. July 26, 2022. Accessed July 26, 2022. https://www.eurekalert.org/news-releases/959851