What Is EGCG in Green Tea?
Green tea owes its subtle flavors and gentle, mouth-cleansing astringency to a number of organic compounds. One of them is epigallocatechin gallate, usually abbreviated as EGCG, which has attracted attention within the medical and wellness communities for its potential health benefits. More research is required, but in the meantime green tea remains an appealing beverage, and any long-term health benefits will be a pleasant bonus.
Putting EGCG Into Context
Epigallocatechin gallate is one of a group of plant phenols commonly described as tannins, since some of these compounds have long been used to tan hides for leather. They give tea its mild astringency, the characteristic that makes your mouth feel clean and fresh after you've had a cup. Some plant phenols, including EGCG, are especially "bioactive," meaning they're very likely to interact with other organic molecules and cellular processes. That activity is exactly what makes EGCG so interesting to researchers.
It's a Potent Antioxidant
One of the first things to know about EGCG is that it interferes with oxidation, and therefore can help minimize oxidative damage in cells. Oxidative damage is known to be a contributing factor in a number of illnesses, notably cancer. So some sources, most notably the supplements industry, argue that consuming lots of antioxidants should provide protection against numerous cancers. The reality is probably more nuanced.
The American Cancer Society points out that while antioxidant-rich foods have shown some protective effect, it's not yet clear that it comes from the antioxidants themselves. Further, antioxidant supplements may actually increase your risk of some cancers.
It May Protect Against Cancer
That being said, there is reason to believe that the EGCG in green tea does provide some protective effect against cancer. Test-tube and animal studies have shown that EGCG interferes with the formation of several types of cancer, though the mechanisms aren't yet fully understood. The National Cancer Institute counts over 50 studies investigating tea consumption and its effect on cancer since 2006, many of which showed some degree of promise. Unfortunately results in test tubes and animals aren't as meaningful as results in living, breathing humans, and the results of studies in humans have been inconclusive.
It Helps Alertness and Cognition
Green tea is well known for aiding in mental alertness, which is not surprising given its caffeine content and the presence of a second well-established stimulant called L-theanine. Interestingly, a 2017 paper in Phytomedicine reviewed numerous studies and concluded that green tea's beneficial effects on brain activity couldn't be fully explained by those two stimulants.
Other studies that have looked directly at EGCG for potential benefits in cognition and alertness. For example a 2016 study in Neuroscience showed that EGCG protects newly developed neurons, while a 2017 paper reviewing EGCG's effect on Down Syndrome concluded that EGCG had at least some beneficial effects on the brain. Perhaps most excitingly, a 2015 paper in the Journal of Azheimer's Disease demonstrated that EGCG, especially in conjunction with exercise, might help minimize the impact of Alzheimer's.
EGCG, Cardiovascular Function and Weight Loss
One of EGCG's most attention-getting potential benefits is its suggested role in weight loss and cardiovascular function. A 2015 review published in the journal Nutrients found reason to believe that EGCG might play a role in reducing the risk of metabolic syndrome, a grouping of disorders that contribute to obesity and cardiovascular issues. EGCG also seems to help the liver break down and process fats, according to a study published on PLOS One in 2014. Drinking green tea will not magically make you lose weight, but incorporating green tea regularly into a balanced program of healthy diet and exercise may well prove beneficial for overall health.
- Groupe Polyphenols: Why Bother With Polyphenols?
- American Cancer Society: Common Questions About Diet and Cancer
- National Cancer Institute: Tea and Cancer Prevention
- Phytomedicine: Green Tea Effects on Cognition, Mood and Human Brain Function -- a Systematic Review; Edele Mancini, et al.
- Neuroscience: Green Tea Compound Epigallo-catechin-3-gallate (Egcg) Increases Neuronal Survival in Adult Hippocampal Neurogenesis in Vivo and in Vitro; L. Ortiz-Lopez, et al.
- Journal of Azheimer's Disease: Beneficial Effects of Dietary EGCG and Voluntary Exercise on Behavior in an Alzheimer's Disease Mouse Model; Jennifer M. Walker, et al.
- Nutrients: Epigallocatechin Gallate -- A Review of Its Beneficial Properties to Prevent Metabolic Syndrome; Samuel Legeay, et al.
- PLOS One: Epigallocatechin-3-Gallate (EGCG), a Green Tea Polyphenol, Stimulates Hepatic Autophagy and Lipid Clearance; Jin Zhou, et al.
- Neurogenesis: Epigallocatechin Gallate -- A Useful Therapy for Cognitive Disability in Down Syndrome?; Fiorenza Stagni, et al.
Fred Decker is a trained chef, former restaurateur and prolific freelance writer. A self-described "food-science geek," he reads academic papers for entertainment. He was educated at Memorial University of Newfoundland and the Northern Alberta Institute of Technology. His food and nutrition articles have appeared on high-profile sites including Livestrong, Healthfully, Walgreens.com, LeafTV, GoBankingRates, Vitamix.com and many others.