Doctors claim a component of green tea may protect people from developing hepatic steatosis—the medical term for fatty liver—a condition that experts point to as one of the most significant reasons for liver transplantation. The substance in question, epigallocatechin-3-gallate (EGCG), was tested in a study at the Medical University of South Carolina in Charleston.¹

Hepatic steatosis is a condition in which fat accumulates in the cells that make up the  liver. Simple fatty liver is usually not serious; however, other related conditions can be damaging to the liver, such as nonalcoholic steatohepatitis (NASH). The latter is characterized by inflammation in the liver caused by the accumulation of fat.²

Fatty Livers Discarded in Transplants
In this study, doctors only looked at hepatic steatosis, the more benign condition. While benign, fatty livers often aren't used in liver transplant procedures because they are more sensitive to injury caused by ischemia and reperfusion—the processes whereby bloodflow is temporarily halted in the liver during transplantation (ischemia), then later re-introduced to the organ (reperfusion). Hepatic steatosis is also associated with an increased risk of disease and death, resulting in fewer usable donors for transplantation.

"Liver steatosis is now a primary factor in determining the usability of potential organs," wrote lead study author Kenneth Chavin, MD, PhD, in the division of Transplant Surgery and department of Microbiology and Immunology at the Medical University of South Carolina. "As a result, nearly one third of all donated livers are discarded because of steatosis alone."

An Increasingly Common Condition
About 20 percent of the U.S. population is afflicted with hepatic steatosis due to a rising incidence of obesity, experts say. Despite the fact that fatty livers are making up a larger proportion of all donated livers for transplant, longer waiting lists are forcing physicians to consider using borderline organs. But there are complications that can be created from using fatty livers in these procedures. "The increasing use of steatotic livers for transplantation induces higher graft non-function rates, increased retransplantation rates, and increased recipient mortality," said Chavin, in an e-mail interview with Priority Healthcare. "Currently, livers with a high degree of steatosis are not offered for transplantation."

Fatty livers are more sensitive to ischemia followed by reperfusion, which Chavin's team theorizes involves a series of processes that results in increased oxidative stress and inflammation in these livers. In turn, an imbalance of pro-oxidants and anti-oxidants "may progress to fibrosis, necrosis and eventually cirrhosis," Chavin explained.

A recent study³ that suggested rinsing fatty livers with a solution containing EGCG protected the organs from failing prompted Chavin and his colleagues to initiate their own trial. They wanted to know if EGCG, the major flavonoid component of green tea, protected fatty livers from ischemia/reperfusion damage.

Does EGCG Work?
The idea for this study came from other research by Chavin and his colleagues on herbal screening in patients with liver disease. Since green tea flavonoids have shown in other studies to lower body weight, the scientists speculated that EGCG might be one flavonoid that inhibits the development of fatty liver, Chavin explained.

The study was performed using a group of mice. Chavin and his team administered EGCG either orally or by injection, and then performed surgery to induce ischemia/reperfusion injury in the rodent's livers. A separate group of mice was not given EGCG to compare the differences.

Approximately 1 week later, the researchers evaluated which mice survived and which didn’t. They found that 100% of the mice given EGCG either orally or by injection survived, compared to only about two-thirds of rodents not given the green tea flavonoid.

When liver tissue was subsequently analyzed, Chavin and his colleagues found that mice given EGCG had a lower rate of necrosis—liver cell death—caused by ischemia/reperfusion, and a higher percentage of viable tissue compared to those animals that had not consumed EGCG. This suggested that the flavonoid had a prophylactic effect against ischemia/reperfusion injury.

Other Tests Performed
To further confirm their findings, the investigators took measurements of alanine aminotransferase (ALT), a liver enzyme that at higher levels in the blood indicates liver disease. "After ischemia/reperfusion, mice protected by EGCG had significantly lower ALT levels when compared with [animals not given the flavonoid]," they wrote.

The next step was to determine the means by which EGCG protected fatty livers from this type of injury. They tested for the presence of two specific fatty acids that are present in fatty livers, and found that levels of both fatty acids were significantly lowered in the treated livers.

Antioxidant Properties Found
Further tests showed that EGCG acted as an antioxidant. In fact, it actually reduced liver fat content by more than half, the study found. "Significant differences to the fat content, energy stores [a marker of healthy liver function] and markers of cellular injury were observed regardless of how the compound was administered," Chavin and his team noted.

But there's more work to be done to understand the efficacy of the green tea compound in hepatic steatosis. "At this time, it is uncertain whether the antioxidant activity of EGCG is the more important variable or whether its ability to remodel and reduce the fat is the more significant of its activities," wrote Chavin and his team.

"We plan to further investigate EGCG, and hope to get a better mechanistic understanding of its protective properties," Chavin told Priority Healthcare. "We are excited about the EGCG results because EGCG doesn't seem to have the toxic effects that are seen with other investigated compounds."

John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.