Green tea is known for its long list of potential health benefits, like improved brain function and protection against cancer.
Now new research on people with a handful of heart disease risk factors is showing that ingesting green tea extract for four weeks can also reduce blood sugar levels and lower gut inflammation. Researchers say this is one of the first studies to assess whether health risks linked to metabolic syndrome may be lessened by green tea.
“Green tea is known to be a rich source of antioxidants, substances that help fight inflammation in the body. Now we are learning more about how green tea can have a positive impact on the gut,” said Dr. Anjali Mone, a gastroenterologist at Lenox Hill Hospital. “In a new study researchers sought to investigate the effects of green tea on gut health. Intestinal permeability or “leaky gut” allows bacteria and other toxins to enter the bloodstream leading to inflammation.”
What the study found
This study published in Current Developments in Nutrition included 40 participants, 21 with metabolic syndrome and 19 healthy adults. They were given green tea extract for 28 days followed by a placebo for 28 days, with one month off of supplements in between treatments.
Researchers found that fasting blood glucose levels for participants were lower for those taking the green tea extract compared to the placebo. Green tea treatment in the study was also shown to decrease gut inflammations signaled by a decrease in stool inflammatory proteins.
Senior study co-author Richard Bruno, PhD, a professor of human nutrition at The Ohio State University, said the findings showed benefits after one month.
“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,” he said in a statement.
“This could be a simple yet powerful intervention for people with metabolic syndrome or those at risk for it. It could be a therapy to start while we continue to promote healthy lifestyle changes,” said Olivia Vaughn, a registered dietitian nutritionist at The Ohio State University Wexner Medical Center.
What is metabolic syndrome?
Metabolic syndromeTrusted Source stems from several conditions that occur together, which increase your risk of heart disease, stroke, and type 2 diabetes. The conditions include increased blood pressure, high blood pressure, excess fat around the waist, and abnormal cholesterol or triglyceride levels. Up to one in three U.S. adults have metabolic syndrome.
One of the main risk factors for metabolic syndrome is that it is triggered by “leaky gut.Trusted Source”
High blood sugar can do damage to the gut barrier, thus triggering leaky gut, which, in turn, can contribute to metabolic syndrome. Traditionally if a patient is at risk for metabolic syndrome, they are recommended lifestyle modifications including diet changes and weight loss, which can be challenging for various reasons.
“These study results are promising and may offer a new tool to help manage patients at risk with metabolic syndrome,” said Mone. “The antioxidants in green tea may help fight cellular damage and inflammation for better gut and overall health.”
According to the National Center for Complementary and Integrative HealthTrusted Source, green tea has been used for medicinal purposes in China and Japan for millennia. It is safe to consume up to eight cups of green tea per day when consumed as a beverage, and up to six cups per day for pregnant women.
Green tea health risks
Drinking too much green tea or ingesting too much green tea extract can have some adverse side effects.
An eight-ounce cup of green tea has 28 milligrams of caffeine. This number is far less when compared to coffee, which has 96 milligrams of caffeine in an eight-ounce serving. But if you are ingesting green tea extract you may be able to ingest a high level of caffeine.
“We do know that green tea or its compounds as a drink versus those in solid-dose form like the [gummies] or pills act differently in the body, and therefore have a different toxicity threshold,” said Vaughn. “There have been cases of liver injury with large doses, but at a low rate. I would recommend a person with liver disease discuss their use of green tea/green tea extract with their physician.”
Intestinal permeability, or leaky gut, is not technically a recognized medical diagnosis and as such, there is limited clinical data about the condition. Treatments for other medical conditions like celiac disease, inflammatory bowel disease, irritable bowel syndrome, ulcerative colitis, etc., have helped to shed light on how to treat leaky gut and metabolic syndrome.
For example, a gluten-free diet may relieve symptoms, as well as anti-inflammatory drugs, immune system suppressors, antibiotics, and supplements like iron, calcium, and vitamin D. Staying away from certain foods like processed foods, high-fat foods, high-sugar foods, gluten, dairy, and alcohol is also helpful.
Consuming foods that contain both probiotics and probiotics can be very helpful in promoting healthy bacteria in the gut, as well.
“I stress the importance of a diet low in added sugars since this can contribute to an imbalance in the gut microbiome and increase chronic inflammation,” said Vaughn. “I recommend a diet that is rich in dietary fiber from vegetables, fruits, beans, nuts and seeds, and whole grains since certain fibers can promote the growth and diversity of good microorganisms in our gut. Minimizing added sugars and consuming adequate dietary fiber are also very beneficial for blood sugar control.”