Dr. Richard Kreider’s Conclusions Help Clear Supplement Company Over Claims Green Tea Extract Caused Liver Failure

Dr. Richard Kreider, a professor at Texas A&M and an expert on exercise and sports nutrition, testifies in a 2019 Florida trial over claims that a plaintiff’s consumption of the defendant’s green tea extract supplements caused his liver failure. 

Kreider explains how he came to the conclusion that the ingredients in a dietary supplement manufactured by Vitacost, in and of themselves, could not have caused the plaintiff’s liver failure. He evaluated the scientific literature looking at clinical trials to learn if the amount of the green tea extract found in supplements such as this and others had an effect on liver function. This review included adverse events reported to the Food and Drug Administration as well as data from animal studies, and he found that the amount of the extract found in this supplement were well within the recommended and safe dosages. 

EGCG is the most potent of four major antioxidants found in green tea. Recent studies have indicated that EGCG could be a powerful natural fat burner by helping the liver break down and process fats. The expert concludes that“there is no evidence that those small doses [in the Vitacost supplement] would cause the type of liver failure that [plaintiff] has experienced.”

Kreider further evaluated all supplements and medications that the plaintiff was taking and found there were a number of products that the plaintiff had been using as far back as 2011 that contained green tea. This activity increased in the months leading up to the actual liver failure as the plaintiff attempted to treat or prevent cardiovascular disease, hypertension, insomnia, and diabetes by ingesting multiple supplements containing green tea, green tea extracts, or amino acids that are derived from green tea. Some of the multivitamins contained higher doses of green tea or green tea extracts than the Vitacost product that plaintiff took. The plaintiff had also taken a nasal decongestant that contains green tea. 

One of the supplements taken contained L-arginine and citrulline, molecules that cause vasodilation. Taken together they can be effective at managing high blood pressure. However, the packaging cautions that at high doses these together can cause liver toxicity, though not at doses normally recommended. 

The liver toxicity related to green tea is not a predictable event, but is instead considered idiosyncratic, that is, it is peculiar to each individual that imbibes it. 

“It just happens, and we are not really sure why it happens,” the doctor says. “In studies that follow up such events, they have not been able to show liver toxicity from green tea or its extracts at the dosages that humans would take.” 

An idiosyncratic result is not a predictable result, and it would be inappropriate to alarm the public unnecessarily about liver toxicity from green tea. “Think how many people drink green tea or consume green tea supplements throughout the world, yet we don’t have a rash of liver failures from this. There have only been about 35,000 liver transplants in the world in the past thirty years.” Given how commonly people absorb green tea, it is so rare and so unpredictable to have liver failure that it becomes very difficult to label green tea or its extracts as a causative agent.

In the extensive literature research performed by Kreider regarding the impact of green tea supplements at various doses in humans and animals on liver function leading to liver failure, including case studies, systemic reviews, and adverse outcome reports, he finds within a reasonable degree of scientific certainty that it would not be possible to isolate the intake of green tea supplements as the cause of the plaintiff’s liver failure. The jury concurred with the expert’s opinion, ruling for the defendant.

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Gary Gansar, MD, is residency trained and Board Certified in General Surgery. He previously served as Chief of Surgery and Staff at Elmwood Medical Center and on the Medical Executive Committee at Mercy Hospital and Touro Infirmary in New Orleans, LA. Dr. Gansar also served as Clinical Instructor and Professor of Surgery at Tulane University. He received his MD and served as Chief Resident at Tulane University Medical School. Dr. Gansar joined AMFS as a consulting medical expert in 2011 and has served as Medical Director since Nov. 2015. In this capacity, Dr. Gansar provides consultation, review and guidance to attorney clients.