It is well known that long-term and repeated drinking of green tea may help prevent cancer, cardiovascular disease, obesity and htmltype 12 diabetes . But it turns out that this drink is harmful to some people.
Research on the benefits of green tea is contradictory. Some work has proved its anti-cancer effect, its benefits for the eyes, its lower blood pressure, its weight and its risk of cardiovascular disease. Instead, others refuted such a conclusion. However, in general, this beverage is considered health-benefit.
Scientists at Rutgers University in the United States conducted their own research and concluded that drinking green tea in large quantities is definitely harmful for some people. They published in the journal Dietary Supplements .
researchers used data on the effect of the beverage on preventing breast cancer and found whether participants with certain genetic variants were more likely to experience signs of liver stress after a year of intake of 843 mg of epigallocate gallate per day, which is a major antioxidant green tea, compared with those without these genetic characteristics.
Each of these genetic variants controls the synthesis of enzymes that break down the epigallocate gallate. The researchers' analysis showed that early signs of liver damage were genotypes with catechol-O-methyltransferase (COMT, an enzyme that plays an important role in catecholamine breakdown, including dopamine , adrenaline and norepinephrine) and were strongly predicted by variant genotypes of glucuronyltransferase (UGT1A4).
Overall, among participants with the UGT1A4 genotype, an enzyme level indicating liver stress increased by nearly 80% after taking epigallocatecin gallate for nine months. In subjects without this variant, the same enzyme increased by only 30%.
researchers believe that changes in genotypes do not fully explain the changes in liver enzyme levels in the study participants. Many non-genetic factors may also play a role. However, according to scientists, they still managed to identify an important issue in predicting green tea health risks.
