We have all been reading all the health promotions used in the sale of various tea varieties and products. We were wondering: “where is the dividing line between what is real and what is fantasy?” Therefore, we decided to do some investigation into one of the most touted antioxidants discussed in the advertising of tea or tea products, EGCG. Based on our research, we found we did not know nearly as much about antioxidants and the current research in this arena as we thought. The bottom line is that the potential EGCG health benefits are providing a fascinating area of investigation in the scientific research community. Read on!
- Green, black, white, yellow, oolong and pu-erh teas all come from the same plant, Camellia sinensis. But, the final products are primarily differentiated by variations in the processing or manufacturing methods used. Yes, there are also terroir and plant varietal factors at play here but fundamentally, any of the different primary categories of tea could be made from the same plants from the same tea garden (perhaps with greater or lesser success).
- Tea has been used for medicinal purposes in China and Japan for thousands of years.
- Currently promoted benefits of green tea as a beverage or dietary supplement include improving mental alertness, relieving digestive symptoms and headaches, and promoting weight loss. Green tea and its extracts, such as one of its components, EGCG, have been studied for their possible protective effects against heart disease and cancer.
- Green tea is consumed as a beverage. It is also sold in liquid extracts, capsules, and tablets and is sometimes used in topical products (intended to be applied to the skin).
- EGCG is found in high content in the dried leaves of green tea (7380 mg per 100 g), white tea (4245 mg per 100 g) and, in smaller quantities, black tea. During black tea production, the catechins are mostly converted to theaflavins and thearubigins via polyphenol oxidases (fancy phrase for browning due to oxidation).
- EGCG has been the subject of a number of basic and clinical research studies investigating its potential use as a therapeutic for a broad range of disorders. As of 2015, however, these effects remain unsubstantiated in humans and there are no approved health claims for EGCG in the United States or Europe. The US Food and Drug Administration has issued warning letters against marketers of products claiming that EGCG provides anti-disease effects or overall health benefits.
So What is EGCG?
- Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin (an antioxidant).
- EGCG, the most abundant catechin in tea, is a polyphenol under basic research for its potential to affect human health and disease. EGCG is used in many dietary supplements.
- EGCG is the most prominent member of the family of green tea catechins (polyphenols) and accounts for 50–80% of all catechins in a cup of green tea.
- In selected studies and under laboratory conditions, EGCG was found to exert profound anti-inflammatory, antioxidant, anti-infective, anticancer, anti-angiogenetic, and chemopreventive effects.
- When taken orally, EGCG has a poor ability to be used by the human body even when taken in very high doses equivalent to 8–16 cups of tea (800 mg). Please note that a dose this large could cause mild adverse effects, such as nausea or heartburn. After consumption, EGCG blood levels peak within 1.7 hours, then are passed out of the body over the next 3–15 hours.
What are the Facts?
- There’s evidence that green tea enhances mental alertness, as would be expected because of its caffeine content.
- The U.S. Food and Drug Administration has approved a specific green tea extract ointment as a prescription drug for treating genital warts.
- Studies of green tea and cancer in people have had inconsistent results. The National Cancer Institute does not recommend for or against using green tea to reduce the risk of any type of cancer.
- Very few long-term studies have investigated the effects of tea on heart disease risk. However, the limited evidence currently available suggests that both green and black tea might have beneficial effects on some heart disease risk factors, including blood pressure and cholesterol.
- Green tea extracts have NOT been shown to produce a meaningful weight loss in overweight or obese adults. They also have not been shown to help people maintain a weight loss.
- The National Center for Complementary and Integrative Health (NCCIH) is funding research on green tea and its extracts, including: 1) studies of the effects of high doses of tea components on the liver; 2) whether substances in green tea can be helpful for iron overload disease; and 3) the safety of a component of green tea in people who are HIV-positive.
- In 2006, a green tea extract was approved as an element of a prescription drug for the topical treatment of genital and anal warts (condylomata acuminata).
What’s Going On in the Future with EGCG?
- Seventeen open EGCG studies are listed on http://www.clinicaltrials.gov/
- Studies will examine whether:
- EGCG affects insulin resistance,
- Gargling with EGCG prevents influenza infections in teenagers
- Topical EGCG exerts an anti-carcinogenic potential in patients with superficial basal cell carcinoma.
- Trials will analyze the potential effects of EGCG on:
- Reactivation of the Epstein-Barr virus in remission patients
- Preventing colon polyps in patients at high risk for recurrent colon adenoma
- EGCG will be tested for its effects on:
- Albuminuria in diabetic nephropathy (OK, I had to look this up so here is a quick definition: Nephropathy is a broad medical term used to denote disease or damage of the kidney, which can eventually result in kidney failure.)
- Patients with:
- Cardiac amyloid light-chain amyloidosis
- Muscular dystrophy of the Duchenne type
- Alzheimer’s disease (early stage)
- Down syndrome
- Fragile X syndrome
- Huntington’s disease
- Multiple-system atrophy
Congratulations! You made it to the end of a longer than normal article. We hope that you learned as much as we did in the creation of this feature. And, we hope that this information was useful in clearing up some of the fiction that advertisers may be peddling out there in the tea world. Now go and enjoy some tea for the inherent beauty and wonderful flavor profiles you will find 😎.