New research suggests that green tea extract can cause liver damage in a small subset of the population.
Recent studies show that long-term high doses of green tea extract may provide some protection against cancer, cardiovascular disease, obesity, and type 2 diabetes, although a minority of people have liver damage. It can also cause disability.
WHO IS AT RISK? Rutgers’ research, Journal of Dietary Supplementsprovides the first solid clue: two genetic variants that predict some of the risk.
“As there is increasing evidence that high doses of green tea extract can provide significant health benefits in those who can safely consume it, learning to predict who will suffer liver damage has potential. PhD in Nutritional Sciences from Rutgers School of Health.
Using data from the Minnesota Green Tea Trial, a large-scale study of the effects of green tea on breast cancer, the researchers found that people with specific genetic mutations, after consuming 843 milligrams per day for one year, were less likely to experience other We investigated whether people were more likely to show signs of liver stress than a catechin called epigallocatechin gallate (EGCG), a major antioxidant found in green tea.
The researchers, led by then PhD student and now graduate Laura Acosta, selected two gene mutations of interest. This is because each controls the synthesis of enzymes that break down her EGCG. They chose the Minnesota Green Tea Trial because it was a large, well-designed study in a unique population. Data were collected for 3, 6, 9 and 12 months.
Analysis by the investigators revealed one mutation in the catechol-O-methyltransferase (COMT) genotype and the uridine 5′-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotype.
On average, participants with the high-risk UGT1A4 genotype saw a nearly 80% rise in liver stress-indicating enzymes after taking green tea supplements for 9 months, compared to those with the low-risk genotype. participants saw a 30% increase in the same enzyme.
“We still have a long way to go before we can predict who can safely consume high doses of green tea extract,” he said. The differences do not fully explain the differences in liver enzyme alterations among study participants, and a complete explanation probably involves many different genetic variants and possibly many non-genetic factors. ”
“Nevertheless, we believe we have taken a step towards identifying an important piece of the puzzle and predicting who can safely enjoy the health benefits high doses of green tea extract provide.”
Reference: “Hepatotoxicity from high-dose green tea extract: catechol-O-methyltransferase and uridine 5′-diphospho-glucuronosyltransferase 1A4 Genotypes,” Laura Acosta, Laura Byham-Gray, Mindy Kurzer, Hamed Samavat, 30 Sept. 2022, Available here. Journal of Dietary Supplements.
DOI: 10.1080/19390211.2022.2128501
