A Compound Found in Red Wine Could Improve Liver Health
Is it possible wine could help your liver? According to new research, moderate consumption of wine, grapes and grape juice can prevent the accumulation of fat in the liver. The findings point to ellagic acid—a compound found in red grapes and wine—as the key ingredient that may improve the health of those who suffer from fatty liver disease, even at very low doses.
Fatty liver disease, while potentially benign for many years, can eventually lead to nonalcoholic steatohepatitis (an inflammation of the liver), cirrhosis and liver failure. "The incidence of fatty liver has tied itself 100 percent to the obesity epidemic that we've seen in the last 20 years," Dr. Neil Shay, professor of food science and technology at Oregon State University, told Wine Spectator. "If you are obese, you're very likely to have fatty liver as well."
Could grapes and wine restore liver function and improve overall metabolic performance among those who are already overweight? Shay and his colleagues, Liwei Gu of the University of Florida and Soonkyu Chung of the University of Nebraska, tackled that question in three studies over the past three years.
In the first two studies, the researchers fed mice either high-fat or low-fat diets, then supplemented some of the high-fat diets with grape phytochemicals (chemical compounds from plants), including resveratrol, quercetin and ellagic acid. In general, the mice on the high-fat diets who also consumed phytochemicals showed significant reductions in metabolic problems, with some phytochemicals more effective than others (resveratrol, according to the findings, did not reduce weight gain in high-fat dieters).
Ellagic acid, a phenol and antioxidant found in grapes and other fruits, proved particularly effective. In fact, in one study, the blood glucose levels of mice on the high-fat diet who also consumed ellagic acid were equivalent after six weeks to the levels of the mice on the low-fat diet. Lower blood glucose levels mean less fat accumulation.
Next, the researchers wanted to take a closer look at exactly how ellagic acid affects fat accumulation in the liver. Their most recent study involved an in-vitro exposure of human liver and fat cells to ellagic acid. Sure enough, the phytochemical slowed the formation of fat in the liver and improved fatty acid metabolism. In other words, ellagic acid could help burn some of the fat in a fatty liver.
Visually, the lab results are striking. "When you examine these [fatty liver] tissues on a microscope slide, you can see the cells are just filled up with these lipid droplets," Shay explained, whereas a normal liver cell would appear free of lipid droplets. "But if we compare that high-fat appearance to the high-fat animals that received the wine and grape extracts, you see a lot less of these droplets, and the droplets that you do see are reduced in diameter. Everyone who has looked at the photographs says they look more like the normal liver."
The improvements in fat accumulation appear to begin at very small doses of ellagic acid. "It's a dietary level," said Shay, estimating its equivalency to about two or two and a half servings of grapes, or "a few servings of wine." Grape juice has higher concentrations of ellagic acid than wine does. "A lot of the ellagic acid, or at least some of it, precipitates out into the lees in the winemaking process," Shay explained. However, there's one other plant involved in vinification that contains high levels of ellagic acid: oak. It's possible that wine aged in oak barrels could have higher levels of ellagic acid.
Ellagic acid does not seem to be a weight-loss solution, however. "We saw very minor differences in total body weight or body composition," Shay said of the mice studies. But if the phytochemical is removing lipid from places where it’s harmful—such as the liver—and redirecting it into body fat, that could signal significant improvements in people’s overall health.