NEW YORK (Reuters Health) - Resveratrol, an antioxidant abundant in grapes, red wine, peanuts — and, according to a new study, dark chocolate and cocoa — may prevent and treat the build-up of fat in the liver caused by chronic alcohol drinking.
In experiments with mice, resveratrol reduced the amount of fat produced in the liver of mice fed alcohol and increased the rate at which liver fat was broken down.
Chronic heavy alcohol drinking causes fat to accumulate in the liver and can lead to cirrhosis, fibrosis, and other liver diseases. “Our study suggests that resveratrol may serve as a promising agent for preventing or treating human alcoholic fatty liver disease,” the researchers conclude in a report in the American Journal of Physiology—Gastrointestinal and Live Physiology.
Previous work has shown that chronic alcohol ingestion inhibits two proteins — AMPK and SIRT1 — that play a key role in the breakdown of fats in the liver. When alcohol inhibits these two proteins, it allows fat to accumulate.
By activating AMPK and SIRT1, resveratrol helps to clear fat from the liver, the new study indicates.
In the study, mice were maintained on a low-fat diet and some were fed resveratrol alone, alcohol alone, or the combination of resveratrol plus alcohol.
Tests on the animals showed that resveratrol treatment boosted levels of SIRT1 and stimulated the activity of AMPK in the livers of mice fed alcohol. Increased expression and activity of SIRT1 and AMPK also fueled a reduction in the levels and activity of other liver proteins involved in fat buildup and boosted levels of the fat metabolizing hormone adiponectin.
Taken together, these results indicate that resveratrol prevents alcoholic fatty liver disease by coordinating molecules that control fat metabolism.
In a separate study published this month, researchers report that cocoa powder, baking chocolate and dark chocolate all contain significant levels of resveratrol.
“This study shows that the levels of resveratrol found in cocoa and chocolate products is second to red wine among known sources of resveratrol and forms yet another important link between the antioxidants found in cocoa and dark chocolate to other foods,” said Dr. David Stuart, director of natural product science at The Hershey Company who partnered with Planta Analytica to conduct the study.
SOURCE: American Journal of Physiology-Gastrointestinal and Liver Physiology 2008.