Daily Wine Drinking Improves Liver Health

San Diego researchers find that a glass a day protects against liver disease

Jacob Gaffney

Posted: Wednesday, June 11, 2008

In what it calls "a major shift in thinking" when it comes to wine consumption and liver disease, a University of California-San Diego research team has found that a glass of wine a day can help keep a dangerous liver disease away.

The study, conducted by members of the school's division of gastroenterology, hepatology and nutrition, and published in the June 2008 issue of the journal Hepatology, says that people who drink up to one glass of wine a day are not harming their liver and, in fact, are decreasing their risk of non-alcoholic fatty liver disease (NAFLD).

"The results of this study present a paradigm shift, suggesting that modest wine consumption may not only be safe for the liver but may actually decrease the prevalence of NAFLD," said study co-author Jeffrey Schwimmer, an associate professor in the school of medicine at the university. "The odds of having NAFLD, based upon abnormal liver blood tests, were reduced by 50 percent in individuals who drank one glass of wine a day."

NAFLD is characterized as the inflammatory build-up of fat in the liver, the body's metabolic detoxifier. Sufferers do not typically consume excess amounts of alcohol, but under a biopsy microscope, NAFLD liver cells are similar in appearance to cirrhosis-infected livers. The condition is a risk factor for larger health problems, such as obesity and type 2 diabetes, and a fatty liver is also a major risk factor in chronic kidney disease, according to a study to be published in the August issue of the Journal of the American Society of Nephrology.

According to the UC San Diego research team, NAFLD is the most common liver disease in the United States, with more than 40 million adults affected. Schwimmer calls liver disease "an emerging epidemic," not only for America, but for many other western nations. But Schwimmer and his colleagues found that previous research has proven that wine consumption ameliorates several risk factors associated with both cardiovascular heart disease and NAFLD, raising the possibility that "wine may actually be protective against NAFLD," the study states.

To look for proof, the team analyzed data from the National Health and Nutrition Examination Survey (NHANES). This ongoing study is conducted by the U.S government's Centers for Disease Control, and tracks the prevalence of major diseases across the United States. The survey records whether an individual is likely to be suffering from NAFLD based on a number of indicators, including their dietary habits, socioeconomic status and body-mass index. Extensive blood tests are also performed.

The UC San Diego team pulled and analyzed the data from nearly 12,000 NHANES participants—7,211 non-drinkers and 4,543 modest drinkers. They only looked at drinkers who reported consumption levels of up to 10 grams of alcohol per day—equal to around 12 ounces of beer, 4 ounces of wine or 1 ounce of liquor. They also chose subjects who tended to exclusively drink one preferred type of alcoholic beverage.

When Schwimmer and his team separated the subjects into beverage-specific groups they found that 14.3 percent of non-drinkers were likely NAFLD sufferers, as were 14.9 percent of liquor drinkers, 12.4 percent of beer drinkers and 8.6 percent of wine drinkers. That means that liquor drinkers have a similar risk of NAFLD as non-drinkers, while beer drinkers are 27 percent less likely to get the disease and wine drinkers are 49 percent less likely.

When the UC San Diego researchers then compared the different beverage drinkers to each other, they found that beer and spirits drinkers were four times more likely to develop the disease when compared to wine drinkers.

"Because this effect was only seen with wine, not in beer or liquor, further studies will be needed to determine whether the benefits seen were due to the alcohol or non-alcohol components of wine," says Schwimmer. "If a physician recommends modest alcohol to patients for cardiovascular protection, these data suggest that wine is the best choice from a liver standpoint. Balance matters; a small amount is healthier than none or a lot."