19 May 2008 - Researchers at UC San Diego School of Medicine are challenging conventional thinking with a study showing that modest wine consumption, defined as one glass a day, may not only be safe for the liver, but may actually decrease the prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD).
The study, which appears in the June 2008 issue of the journal Hepatology, showed that for individuals who reported drinking up to one glass of wine per day, as compared to no alcohol consumption, the risk of liver disease due to NAFLD was cut in half. In contrast, compared with wine drinkers, individuals who reported modest consumption of beer or liquor had over four (4) times the odds of having suspected NAFLD.
NAFLD is the most common liver disease in the United States, affecting over 40 million adults. Previous research has shown that as many as five percent of adults with NAFLD will develop cirrhosis. The major risk factors for NAFLD are similar to many of the risk factors for cardiovascular disease-obesity, diabetes, high triglycerides, and high blood pressure. Multiple studies have shown that modest alcohol consumption may reduce the risk for heart disease. However, recommendations for modest alcohol consumption in individuals at risk for cardiovascular disease have overlooked that these same people are also at an increased risk for NAFLD. Thus, there exists a dilemma as to whether modest alcohol consumption for the heart is safe in regards to the liver. The UC San Diego investigators sought to clarify this important question.
"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. The odds of having suspected NAFLD based upon abnormal liver blood tests was reduced by 50 percent in individuals who drank one glass of wine a day," said Jeffrey Schwimmer, M.D., associate professor of gastroenterology, hepatology and nutrition, Department of Pediatrics, UC San Diego School of Medicine and Director, Fatty Liver Clinic at Rady Children's Hospital San Diego. The result remained constant, even after adjusting for age, sex, race, education, income, diet, physical activity, body mass index and other markers of health status.
Research did not provide any support for drinking larger amounts. "We want to emphasize that people at risk for alcohol abuse should not consider consuming wine or any other alcoholic beverage," said Schwimmer, who also pointed out that, although this is the first study to address this important dilemma, the findings do not address those who already have liver disease and should not be drinking alcohol at all.
"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," added Schwimmer.
The cross-sectional, population-based study of nearly 12,000 participants in the National Health and Nutrition Examination Survey (NHANES) included 7,211 nondrinkers and 4,543 modest alcohol drinkers. Modest alcohol consumption was defined as up to an average of one drink per day of either four ounces of wine, 12 ounces of beer, or one ounce of liquor. NHANES is a large epidemiological survey conducted by the Centers for Disease Control and Prevention (CDC). The alcohol history was obtained by a trained interviewer, in a private room, to ensure confidentiality.
The study was funded in part with grants from the National Institutes of Health National Research Service Award (NIH NRSA) and from the National Center for Research Resources of the National Institutes of Health for the General Clinical Research Center at UC San Diego.
The research team included Schwimmer, Winston Dunn, M.D., division of gastroenterology, Department of Medicine, UC San Diego and Ronghui Xu, Ph.D., Department of Family and Preventive Medicine and Department of Mathematics, UC San Diego.