Red-Wine Compound May Protect Liver
Resveratrol appears to control enzymes that regulate fat metabolism in mice
The accumulation of fat in the liver is a chronic condition commonly associated with alcoholism. But scientists involved in new research say that a compound found abundantly in red wine might one day help in treating this disorder.
According to research published in the October issue of American Journal of Physiology-Gastrointestinal and Liver Physiology, the red-wine compound resveratrol, also found in grapes, nuts and berries, reduces the amount of fat produced in the livers of mice fed dangerous levels of alcohol. Furthermore, resveratrol also appears to increase the rate at which existing liver fat is broken down. The scientists also found that a combination of alcohol and resveratrol seemed to have a greater impact than resveratrol alone.
"It seems fairly clear at this time, based on our research as well as others, that the combination of the two, ethanol and resveratrol, will reverse the accumulation of fat in mammals' livers," study co-author Dr. Min You, associate professor at the department of molecular pharmacology and physiology at the University of South Florida, said in a statement.
Min added a caution, however. "We are still in the early stages of this research and do not know, even in mice, what doses of alcohol and resveratrol in combination would be the most beneficial."
Earlier research has found that resveratrol may have the ability to stimulate genes that control the production and activity of sirtuin, enzymes associated with the metabolism of fat. One previous study showed that resveratrol helped maintain the health of livers of mice on an unhealthy diet, most likely due to an uptick in sirtuin activity. Alcohol is believed to deactivate sirtuin, however, thus leading to fat build up in the liver.
For the current research, Min and her team separated six- to eight-week-old mice into six separate groups fed a liquids-only diet. Half the groups received no alcohol, while the other three received heavy doses of alcohol, which were gradually increased to simulate the accelerated affects of alcoholism—eventually, 29 percent of the mice's daily calories came from ethanol. Four of the six groups (two alcoholic groups and two dry groups) received resveratrol supplements at either 200 milligrams per kilogram of weight or 400 mg/kg.
Blood alcohol levels were measured throughout the experiment and after four weeks the mice's livers were examined. The researchers found that the mice that received alcohol but no resveratrol had a level of liver fat three times higher than all of the other groups.
After further tests, the scientists also found that resveratrol, at either dosage, seemed to perform four different activities that trigger the metabolism of lipids, the building blocks of fat, thus reducing the amount that builds up in the liver.
One of these activities was activation of sirtuin: The group of mice on alcohol and the higher dosage of resveratrol had five times more sirtuin in the liver than the alcohol-only mice. Mice given resveratrol but no alcohol had between three to four times more sirtuin than the alcohol-only mice. The control mice (no resveratrol or alcohol) had two times more sirtuin than the alcohol-only mice.
The activation of sirtuins has been linked to benefits in humans as well. Another study, conducted at the department of internal medicine at the University of Naples, Italy, and published in the October journal of Metabolic Syndrome and Related Disorders finds that sirtuins may aid in the repair of damaged DNA and other types of cell damage in diabetics who have suffered a heart attack. As part of their recovery, the diabetics experienced improved ventricular function, "when a moderate red wine amount, containing resveratrol, was taken daily by patients receiving therapy," study author Dr. Federico Cacciapuoti said in a statement.
But Min added that the results of her study are limited in that the research was conducted on mice and are more likely applicable to a type of synthetic resveratrol therapy—the amounts of resveratrol administered to the rodents is equal to several hundred bottles of red wine per day.
"Concerning the problem drinker, as the effects of alcohol abuse go far beyond liver damage, I would unreservedly advise abstinence," she said. "However, the more casual drinker who is concerned about his liver would be well advised to opt for a moderate amount of red wine over liquor. Alternatively, liquor or beer in combination with a concentrated form of resveratrol, such as that found in capsules, may also do the trick."
