In recent years, people began to extract the natural components of green tea, mainly including tea polyphenols, that is, catechins. Some people think that catechins can affect liver function. More than 500 studies on green tea and green tea extracts were conducted an open comprehensive review, and only 34 were found to meet the ingredient standards. Most of these studies only analyzed the effect of green tea extract, and only six of them analyzed its safety. Another 10 studies were for healthy people, seven for obese people and five for cancer patients. A total of 1405 volunteers were involved in these studies, but 0.5% of them showed mild liver effects.

The researchers concluded that most randomized controlled clinical trials did not find that green tea extract could cause liver damage, and a few trials only analyzed the effects of green tea extract on liver enzymes such as ALT and ALP. Most studies on green tea extract have found that it has a slight effect on the liver, so it is impossible to prove that green tea extract can cause liver damage. In addition, as for the serious liver injury caused by green tea supplements, it is also the result of many factors, such as the intake of supplements, the physical condition of the receptor and so on.

Reliable evidence of green tea safety

Rick Kingston, Professor of clinical pharmaceutics at the University of Minnesota, said only four studies had shown that green tea extract had an effect on the liver, but the researchers did not specify which liver enzymes were affected. He analyzed these studies and found that green tea extract had little effect on the liver. Mark Blumental, executive director of the American botany Council, said the Japanese study strongly demonstrates that green tea extracts are generally safe, despite the occasional negative reports. Kingston said that the slight effect of green tea extract can be eliminated by some drugs, such as statins. If people have adverse reactions when using green tea extract, adjust the dosage and take statins. In other words, take care of the patient, give him statins, and wait for liver enzyme levels to return to normal. People should distinguish between green tea and green tea extract, and general green tea extract products usually contain other herbs. Green tea beverage is a kind of steeping substance, which is different from green tea extract in catechuic acid concentration. In fact, there is evidence that green tea can protect liver. There are many reasons why supplements containing green tea extract damage liver function. First of all, these products are usually used to lose weight, so the catechuic acid in them will directly affect the liver when they are taken on an empty stomach, and the liver is more vulnerable to damage at this time. There is also the problem of solvent. Many green tea extracts are extracted by ethanol, usually grain alcohol. Sometimes manufacturers also use hexane or other solvents, which may have adverse effects on the liver.