Who’s in danger? Analysis from Rutgers, revealed in The Journal of Dietary Dietary supplements, gives the primary stable clue: two genetic variants that predict among the threat.

“Studying to foretell who will undergo liver harm is probably necessary as a result of there’s rising proof that high-dose inexperienced tea extract might have important well being advantages for individuals who can safely take it,” stated Hamed Samavat, senior writer of the examine and an assistant professor of diet sciences on the Rutgers College of Well being Professions.

Utilizing knowledge from the Minnesota Inexperienced Tea Trial, a big examine of inexperienced tea’s impact on breast most cancers, the analysis workforce investigated whether or not folks with sure genetic variations have been extra seemingly than others to indicate indicators of liver stress after a yr of ingesting 843 milligrams per day of the predominant antioxidant in inexperienced tea, a catechin referred to as epigallocatechin gallate (EGCG).

Researchers led by Laura Acosta, then a doctoral scholar, now a graduate, chosen two genetic variations in query as a result of every controls the synthesis of an enzyme that breaks EGCG down. They chose the Minnesota Inexperienced Tea Trial as a result of it was a big, well-designed examine of a singular inhabitants. The year-long, placebo-controlled trial included greater than 1,000 postmenopausal girls and picked up knowledge at 3, 6, 9 and 12 months.

An evaluation by researchers confirmed that early indicators of liver harm have been considerably extra frequent than regular in girls with one variation within the catechol-O-methyltransferase (COMT) genotype and strongly predicted by a variation within the uridine 5′-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotype.

On common, individuals with the high-risk UGT1A4 genotype noticed the enzyme that signifies liver stress go up almost 80 p.c after 9 months of consuming the inexperienced tea complement, whereas these with low-risk genotypes noticed the identical enzyme go up 30 p.c.

“We’re nonetheless a good distance from having the ability to predict who can safely take high-dose inexperienced tea extract,” stated Samavat, who famous the chance of liver toxicity is barely related to excessive ranges of inexperienced tea dietary supplements and never with ingesting inexperienced tea and even taking decrease doses of inexperienced tea extract. “Variations on this one genotype do not utterly clarify the variations in liver enzyme modifications amongst examine individuals. The total rationalization most likely consists of plenty of totally different genetic variations and doubtless plenty of non-genetic elements.”

“Nonetheless,” Samavat continued, “we do suppose we’ve recognized an necessary piece of the puzzle and brought a step towards predicting who can safely get pleasure from any well being advantages that high-dose inexperienced tea extract gives.”