Green Tea Found To Improve Gut Health and Lower Blood Sugar

Ingesting green tea extract for four weeks can lower blood sugar levels and improve gut health by lowering inflammation and "leaky gut," says recent research on people with a cluster of heart disease risk factors.

Researchers claim that this is the first study to look at whether green tea's anti-inflammatory characteristics may help guard against the health risks linked to metabolic syndrome, a condition that affects more than three million Americans each year.

According to Richard Bruno, senior study author and professor of human nutrition at The Ohio State University, "there is a lot of evidence that higher consumption of green tea is associated with good levels of cholesterol, glucose, and triglycerides, but no studies have linked its benefits in the gut to those health factors."

The clinical experiment, which involved 40 participants, was a follow-up to a 2019 study that found mice who took green tea supplements had improved gut health, which was associated with less obesity and fewer health risks.

Unexpectedly, the new study discovered that green tea extract also decreased blood sugar, or glucose, and intestinal inflammation and permeability in healthy individuals.

It suggests that lowering blood glucose is related to reducing leaky gut and gut inflammation, independent of health status, Bruno said. "What this tells us is that within one month we're able to drop blood glucose in both those with metabolic syndrome and healthy people."

Recent publications in the journal Current Developments in Nutrition covered the effects of glucose and decreased intestinal permeability and inflammation.

Excess belly fat, high blood pressure, low HDL (good) cholesterol, high levels of fasting blood glucose, and triglycerides, a type of blood fat, are at least three of the five risk factors for heart disease, diabetes, and other health problems that are present in metabolic syndrome sufferers.

According to Bruno, the problematic thing about these risk variables that make up metabolic syndrome is that they frequently just have minor changes and do not yet require pharmacological management, although still posing a serious risk to health.

"The majority of doctors will initially advise dieting and exercise. Unfortunately, we are aware that the majority of people struggle to adopt new lifestyles for a variety of reasons," he stated. Our research aims to provide patients with a novel food-based tool to assist them manage their risk for developing metabolic syndrome or to reverse it.

For 28 days, 40 participants—21 with metabolic syndrome and 19 healthy adults—consumed gummy candies containing green tea extract, which is high in catechins, an anti-inflammatory agent. Five cups of green tea made up the recommended daily intake. All participants in the randomized double-blind crossover trial took a placebo for a further 28 days, followed by a month without taking any supplements.

During the placebo and green tea extract confection phases of the study, participants were advised to consume a diet low in polyphenols, which are naturally occurring antioxidants found in fruits, vegetables, teas, and spices. As a result, any results could be attributed to the effects of green tea alone.

As a result of eating green tea extract, all subjects' fasting blood glucose levels were much lower than they were after taking the placebo, according to the results. An investigation that revealed a decrease in pro-inflammatory proteins in fecal samples was used to establish that the green tea treatment reduced intestinal inflammation in all subjects. Researchers also discovered that drinking green tea significantly reduced individuals' small intestinal permeability using a method to analyze sugar ratios in urine samples.

Leaky gut, also known as gut permeability, allows intestinal bacteria and related harmful chemicals to enter the bloodstream, causing chronic low-grade inflammation.                                                                                                      

According to Bruno, the central components of all cardiometabolic disorders—obesity and insulin resistance—are assumed to be brought on by the absorption of gut-derived metabolites. The idea is that if we can strengthen gut lining and decrease leaky gut, we may be able to not only lower the low-grade inflammation that leads to cardiometabolic illnesses but also maybe reverse them.                        

With a one-month research, "we did not try to treat metabolic syndrome," he claimed. However, given what is known about the causes of metabolic syndrome, green tea may have some effect at the gut level to reduce the likelihood of either getting the condition or, if you already have it, to reverse it.

The levels of bacteria-related toxins in study participants' blood are being completed by Bruno's lab, as well as additional examinations of the microbial populations in their stomachs.

Joanna Hodges, Min Zeng, Sisi Cao, Avinash Pokala, Shahabbedin Rezaei, Geoffrey Sasaki, Yael Vodovotz, and Richard Bruno, "Catechin-Rich Green Tea Extract Reduced Intestinal Inflammation and Fasting Glucose in Metabolic Syndrome and Healthy Adults: A Randomized, Controlled, Crossover Trial," 14 June 2022, Current Developments in Nutrition.

The Ohio Agricultural Research and Development Center at Ohio State and the United States Department of Agriculture both provided funding for this effort.

By OHIO STATE UNIVERSITY