Basics: The anti-oxidant EGCG can cause DNA strand breaks and mutations.
EGCG stands for Epigallocatechin gallate. Epigallocatechin gallate (ECGC) is a polyphenol found in green tea. Some people take it as a supplement. Or it may be part of “green tea extracts.” Anti-oxidants are thought to protect cells and DNA from oxidative damage. Oxidative damage can occur when one atom or molecule “steals” electrons from important molecules in your body. Cell membranes, for example. Or DNA. When DNA undergoes oxidative damage it may become mutated. Mutations in body cells can lead to cancer. So, protecting your body by taking anti-oxidants seemed to make a lot of sense. No oxidants, no oxidation, no mutations, no cancer. Many people believe(d) that taking anti-oxidants would protect against illness and aging and extend life. The benefits of anti-oxidant supplements now appears to be more complicated that we thought.
Anti-oxidants have had a mixed history when used medicinally.
There are many anti-oxidants. Vitamins C, A, E and selenium are commonly used as nutritional supplements for their anti-oxidant properties. And many have assumed that more is better. As with many other things in life, more is not always better. Sometimes “more” makes more trouble than less. Selenium, for example, seems to have protective effects against cancer. Unfortunately when too much selenium is taken, it can increase the risk of cancer. One of the problems with taking supplements is that we rarely know how much is too much. And we almost never know how much is optimal. Studies of Vitamin A, C and E have also shown signs of creating problems when taken above levels one would normally get eating from food.
EGCG as an inducer of mutations and cancer.
A paper newly released by Nature (Lu et al. 2013) shows how anti-oxidants are able to cause DNA damage and increase risk of mutations. The researchers used epigallocatechin gallate as the test anti-oxidant. The researchers present their data very clearly and efficiently with minimal interpretation. They simply report that Epigallocatechin gallate caused DNA damage and increased number of mutations (among other non-good things.) These results may or may not apply to other anti-oxidants, but they are a good indication that we should exercise caution with anti-oxidant supplements. There is sure to be a lot of discussion and debate over the results of the Lu study. And many additional studies are sure to follow.
This is a very interesting paper and sure to upset a lot of boats. ECGC is a powerful anti-oxidant. Other anti-oxidants may not be strong enough to cause damage. It was just a year ago that ECGC was reported to be the most effective anti-cancer chemo protective compound in green tea. ECGC may turn out to be health protective. It may turn out to be one of those “nutrients” that is good for you at low levels but dangerous when high. Its too early to tell. More research is needed.
Until we know more, eat real food. Eat a varied diet so you don’t get too much of something that may be harmful.
Lu LY, Ou N, & Lu QB (2013). Antioxidant induces DNA damage, cell death and mutagenicity in human lung and skin normal cells. Scientific reports, 3 PMID: 24201298
Du GJ, Zhang Z, Wen XD, Yu C, Calway T, Yuan CS, & Wang CZ (2012). Epigallocatechin Gallate (EGCG) is the most effective cancer chemopreventive polyphenol in green tea. Nutrients, 4 (11), 1679-91 PMID: 23201840
Thangapazham RL, Passi N, & Maheshwari RK (2007). Green tea polyphenol and epigallocatechin gallate induce apoptosis and inhibit invasion in human breast cancer cells. Cancer biology & therapy, 6 (12), 1938-43 PMID: 18059161