(ORDO NEWS) — It is known that long-term and repeated consumption of green tea may contribute to some prevention of cancer, cardiovascular disease, obesity and type 2 diabetes. But it turned out that this drink is harmful to some people.
Research on the benefits of green tea is conflicting. Some work confirms its anti-cancer effects, benefits for the eyes, lowering blood pressure, body weight and the risk of developing cardiovascular diseases.
Others, on the contrary, refute such conclusions. However, in general, it is believed that this drink is good for health.
Scientists from Rutgers University (USA) conducted their own study and came to the conclusion that there are people for whom drinking green tea in large doses is definitely harmful.
Using data from a study of the drink’s effect on breast cancer prevention, the researchers found whether participants with certain genetic variations were more likely to show signs of liver stress after a year of daily intake of 843 milligrams of epigallocatechin gallate, the main antioxidant found in green tea, compared with those participants who did not have these genetic features.
Each of these genetic variations controls the synthesis of an enzyme that breaks down epigallocatechin gallate.
The scientists’ analysis showed that early signs of liver damage were slightly more common in women who had a variation in the catechol-O-methyltransferase (COMT, an enzyme that plays an important role in the breakdown of catecholamines, including dopamine, adrenaline, and norepinephrine) genotype, and was strongly predicted by variation genotype of glucuronosyltransferase (UGT1A4).
Overall, in participants with the UGT1A4 genotype, levels of an enzyme that indicates liver stress increased by almost 80 percent after nine months of epigallocatechin gallate.
In subjects who did not have this variation, the same enzyme increased by only 30 percent.
The researchers believe that variations in genotype do not fully explain changes in liver enzyme levels in study participants.
It is likely that a number of non-genetic factors also play a role. However, according to scientists, they still managed to identify an important problem in predicting the health risks of green tea.
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