In a robust clinical trial (i.e., randomized, double-blind, placebo-controlled, crossover study) research collaboration between Penn State and Ohio State led by professor and researcher Richard Bruno, Ph.D. R.D., participants followed a low-polyphenol diet while consuming 1 gram of green tea extract in supplement form each day for 28 days. This particular green tea extract featured 890 milligrams of catechins, the famous polyphenolic phytonutrients in green tea leaves (EGCG probably being the most well known).
By cutting down on polyphenol consumption (i.e., phytochemical compounds found in fruits, veggies, and many other plants) in their baseline diet, researchers were able to cut down on some of the surrounding nutritional “noise” to focus on the gut-liver axis impact of those fascinating green tea catechins.
At the end of the month, the authors of the study observed that the participants’ blood sugar levels decreased, while key markers of inflammatory status in the gut improved. What this means is that in participants who took 1 gram of green tea extract each day, there were significant and concurrent improvements in the gut barrier function as well as cardiometabolic health (aka, glycemic control as demonstrated by lower blood sugar levels).