Researchers have done a study investigating how a molecule in green tea might help improve health, and confirmed what many anecdotal stories have indicated - green tea can help alleviate cognitive impairment and insulin resistance that is due to a diet high in fats and high-fructose corn syrup. Previous research by many other groups has suggested that EGCG (epigallocatechin-3-gallate), a biologically active component of green tea, can have therapeutic effects on disease, but how it affects insulin resistance and cognitive function has not been thoroughly explored until now.
This new work is outlined in the video above and has been reported in The FASEB Journal.
"Green tea is the second most consumed beverage in the world after water, and is grown in at least 30 countries," noted the senior author of the new study, Xuebo Liu, Ph.D., a researcher at the College of Food Science and Engineering of Northwest A&F University in Yangling, China. "The ancient habit of drinking green tea may be a more acceptable alternative to medicine when it comes to combating obesity, insulin resistance, and memory impairment."
This study utilized a mouse model in which three different groups of mice received three different diets. The control group got a typical diet, another group was fed with a diet meant to result in high-fructose (HFFD)-induced insulin resistance, and the last group received the HFFD diet along with drinking water spiked with EGCG. For the dosed mice, there were two grams of the molecule in every liter of their drinking water. There can be up to 180 milligrams of EGCG in only one cup of green tea, so that was a relevant concentration.
Over a period of 16 weeks, the HFFD mice became the heaviest, having a higher body weight than control mice, and a significantly higher final weight compared with the mice fed HFFD and EGCG.
Additionally, a water maze test indicated that the HFFD group needed more time to find a platform compared to control mice. The researchers used this test to gauge memory impairment. Indeed, the EGCG was able to stop HFFD-induced memory deficits and damage to neurons.
The researchers dug deeper into the mechanisms of these actions as well. EGCG acted to relieve insulin resistance and cognitive dysfunction through cellular signaling cascades including AKT, ERK, and CREB. EGCG exposure also ameliorated long-term HFFD-triggered neuroinflammation through an inhibition of the MAPK and NF-κB pathways, and the expression of inflammatory mediators like TNF-α.
This research is an impressive study that lends real support to the idea that green tea benefits health. "Many reports, anecdotal and to some extent research-based, are now greatly strengthened by this more penetrating study," The FASEB Journal editor-in-chief Thoru Pederson concluded.