An ingredient of green tea called epigallocatechin gallate (EGCG) helps increase the activity of detoxification enzymes, according to a new study.
In a clinical study, backed by the US body, the National Cancer Insitute, reearch was carried out to determine the effect of repeated green tea polyphenol administration on a major group of detoxification enzymes known as glutathione S-transferases (GST).
A total of 42 healthy volunteers underwent a 4-week “washout” by refraining from tea or tea-related products. At the end of the washout period, the study authors collected a fasting blood sample and measured levels of GST activity. Following this baseline evaluation, the study participants consumed green tea polyphenols on an empty stomach for four weeks. The amount consumed (800 mg EGCG once a day) was equivalent to consuming between eight and 16 cups of green tea. After four weeks of green tea supplementation, researchers again collected blood samples and assessed levels of GST.
After four weeks of consuming EGCG, activity of the detoxification enzyme GST in blood lymphocytes increased. Further analysis revealed that a statistically significant increase in GST activity (80 percent) occurred in individuals who had the lowest activity at the start of the study. On the other hand, a small but statistically significant decrease in GST activity was observed in individuals who had the highest levels of the detoxification enzyme at the studys start. The scientists attributed this decrease to random variation.
According to the researchers, This suggests that green tea polyphenol intervention may enhance the detoxification of carcinogens in individuals with low baseline detoxification capacity.
Chow HHS, Hakim IA, DR Vining, Crowe JA, Tome ME, Ranger-Moore J, Cordova CA, Mikhael DM, Briehl MM, Alberts DS. Modulation of Human Glutathione S-Transferases by Polyphenon E Intervention. Cancer Epidemiol Biomarkers Prev. 2007 August 1;16(8):16621666.