Article 3 of 20 in the W.H.A.T? series.

 EGCG – epigallocatechin-3-gallate – Key to Health Benefits of Tea 

I was not a good chemistry student in either high school or college, so wrapping my head around the chemistry of the health benefits of tea – especially ECGC – was daunting. When Adams Media asked me to write “The Everything Healthy Tea Book”, they wanted 300 pages to explain the what’s healthy about drinking tea to people who knew very little about tea. It was important to begin by translating terms like EGCG into plain language. In this series, I hope to improve on the original version. So, let’s begin with EGCG.

What's Healthy About Tea graphic
preparing matcha with wisk

Most people are confident that tea is one of the healthiest beverage choices. But why? We now live in an age where we’ve come to distrust the claims crafted by marketing … to sell products. Many contact me to ask about how they can consume more tea even though they don’t like the taste and have little interest in learning more about brewing it. They want to slurp down a “dose” of the famous EGCG as conveniently as possible. So I sometimes question that we’ve invested so much in the health benefits of tea, sacrificing some opportunities to share more about the flavor. In fact, elements in tea like EGCG actually contribute to the flavor. 

“A number of studies have shown epigallocatechin gallate to have so many different beneficial effects that some enthusiasts today claim this substance to be as essential to proper cell metabolism as a vitamin.” 

The Tale of Tea, pg. 770. by George van Driem was published by Brill in 2019.

Chemical image of ECGC

In fact, in the 1930s until the `1950’s, it was common to hear of the bioflavonoids in tea referred to as Vitamin P. The most well-known and well-researched bioflavonoids are the catechins like ECGC. So, as practiced as I am in avoiding confrontation with this level of scientific language, the fact that tea is one of the few natural resources with this healthful substance is motivation to dig a little deeper into the cell of the Camellia sinensis leaf that so richly nourishes our human cells.

Epigallocatechin gallate

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid and is a type of catechin. EGCG, the most abundant catechin in tea, is a polyphenol under basic research for its potential to affect human health and disease. (Wikipedia) 

What is EGCG? 

One of the confusing things when discussing the cellular makeup of the tea leaf is that so many of the elements fall into more than one category. EGCG is an excellent example. In fact, not only does ECGC provide nutritional benefits but it is also a critical element in producing unique flavor profiles. At face value, this seems odd until we break it down by characteristics. 

  • It is an organic compound of epigallocatechin and gallic acid. 
  • It is a secondary metabolite. Secondary metabolites are organic compounds that are not involved with the growth or reproduction of the organism and are not necessary for survival though, as, in the case of Camellia sinensis, they play a part in the plant’s defense.  
  • It is a catechin. Catechins are polyphenolic compounds with high antioxidant benefits. EGCG is the most abundant catechin in Camellia sinensis.
  • It is a phenol. A phenol is a naturally occurring compound in the tea plant of which ECGC is only one. They are responsible for aspects of taste and mouth-feel and are being actively researched to better understand their potential benefits for health and how they act in relationship with other compounds in the tea leaf.
  • It is an antioxidant. Antioxidants help reduce oxidative stress in the body by binding with unstable and destructive free radicals and then helping to neutralize their harmful potential and then eliminate them from the body.
  • It is an astringent. An astringent is a naturally occurring compound in many foods that shrink body tissue. In tea, this effect produces a slightly dry mouthfeel but it can also soothe sore and swollen throat tissue. When tea extracts are used in skincare products, it produces a tightening of pores and a refreshing feeling to the skin. 
  • It is a tannin. A tannin is one of the organically occurring plant compounds that has traditionally been used for tanning and preserving leather. We can understand it in many different ways but it is also one of the things that we can actually taste in tea. The astringency. The mouthfeel. Leads some to assume that, while fresh Camellia sinesis leaves may all contain approximately the same amount of the compound, that processing may change this.
Japanese Green tea - Kagoshima, 88th Night

Is EGCG only available in green tea?

Most of the research on EGCG is done on green tea because it contains so much more than other types of tea and also much more than in any other food. The oxidation of black tea results in a greatly reduced amount of EGCG. It is generally assumed that the amount present in green tea is approximately four times greater in green tea. But other teas that are not fully oxidized also contain the compound. This includes white, yellow and oolong, but all with varying amounts.

Very small, merely trace amounts can be found in other foods such as apples, strawberries, raspberries, blackberries, peaches, kiwi, avocado plums, onions, hazelnuts, pecans, and in carob. For this reason, tea has been used as a focus of medical research. And green tea has enjoyed the lion’s share of popularity with published articles. Green tea does have measurably the most catechins (EGCG) than black tea, but there are differences in the way that other tea leaf chemistry is absorbed to benefit the body that makes this a more complex discussion.

These results implicate that highly fermented black tea is equally potent as green tea in promoting beneficial endothelial effects. Theaflavins and thearubigins predominantly counterbalance the lack of catechins in black tea. The findings may underline the contribution of black tea consumption in prevention of cardiovascular diseases.  

International Journal of  Moleciular Science. 2011; 12(9): 5592–5603. Published online 2011 Aug 31. doi: 10.3390/ijms12095592 PMCID: PMC3189735 PMID: 22016611.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189735/

Does the way we store, brew, and drink tea change the benefits of EGCG?

YES!

When I said in a previous post that the healthiest tea is the freshest tea, the same variables apply to the health benefits of the leaf chemistry and EGCG. Tea that is not stored in a cool, dry place will be compromised in health benefits as well as flavor. Other factors that affect the viability of tea’s catechins are gastrointestinal and blood conditions. 

Can we increase the amount of EGCG by the way we make tea?

The answer is “probably yes”. But you may not want to drink the result. Because the actual flavor of EGCG is bitter, increasing the amount in your cup will probably be unpleasant. The technique would be to use boiling water and then steep green tea leaves for ten minutes or more. This goes against the recommendations for brewing green tea which is to use water that is between 185-195 degrees F, steeping for less than two minutes.

The U.S. Tea Association Promotes Tea Health Benefit 

I first met Joe Simrany in 2002, then the president of the United States Tea Association, at a presentation he gave at the World Tea Expo. He shared that, one of his duties was to market the health benefits of tea. U.S. Tea was willing to support the campaign financially. 

When it is finally proven that tea is a health benefit, you won’t need me to launch a marketing plan. You won’t need to spend a dime. The media will do that for you. 

One of the programs he created was a video competition called Calm-A-Sutra. Entries were required to give an accurate and entertaining spin on tea and health. It was a huge investment and took the marketing of tea in an aggressive approach toward the health benefits. 

Many of us have been anxiously waiting for the FDA to remove the restrictions on promoting the health benefits of tea with current medical research. We probably have decades before that happens. But there’s no limitation on marketing all the other legitimate aspects of Camellia sinensis. The reality is that we can and should do both – promote the health benefits and the delicious flavors of fine artisan, well-made tea.

Read More About Science Research into EGCG

 

Green tea compound epigallo-catechin-3-gallate (EGCG) increases neuronal survival in adult hippocampal neurogenesis in vivo and in vitro.   Journal of NeuroScience 2016.02.040

 

Beneficial Effects of Dietary EGCG and Voluntary Exercise on Behavior in an Alzheimer’s Disease Mouse Model

Authors : Jennifer Walker, Diana Klakotskaia, Deepa Ajit, Gary Weisman, W. Gibson Wood, Grace Sun, Peter Serfozo, Agnes Simonyi, Todd Schachtman.   Journal of Alzheimer’s Disease, vol. 44, no. 2, pp. 561-572, 2015

 

Epigallocatechin-3-Gallate (EGCG), a Green Tea Polyphenol, Stimulates Hepatic Autophagy and Lipid Clearance

Authors: Jin Zhou, Benjamin L. Farah, Rohit A. Sinha, Yajun Wu, Brijesh K. Singh, Boon-Huat Bay, Chung S. Yang, Paul M. Yen Published: journal.pone.0096884