Wine - Health Effects

Health Effects

Although excessive alcohol consumption has adverse health effects, epidemiological studies have consistently demonstrated that moderate consumption of alcohol and wine is statistically associated with a decrease in death due to cardiovascular events such as heart failure according to additional news reports on the French paradox. This paradox concerns the comparatively low incidence of coronary heart disease in France despite relatively high levels of saturated fat in the traditional French diet. Some epidemiologists suspect that this difference is due to the higher consumption of wines by the French, but the scientific evidence for this theory is limited. Because the average moderate wine drinker is likely to exercise more often, to be more health conscious, and to be from a higher educational and socioeconomic class, the association between moderate wine drinking and better health may be related to confounding factors or represent a correlation rather than cause and effect.

Population studies have observed a J-curve association between wine consumption and the risk of heart disease: heavy drinkers have an elevated risk, while moderate drinkers (up to 20g per day, approximately 20ml) have a lower risk than non-drinkers. Studies have also found that moderate consumption of other alcoholic beverages may be cardioprotective, although the association is considerably stronger for wine. Additionally, some studies have found greater health benefits for red than white wine, though other studies have found no difference. Red wine contains more polyphenols than white wine, and these are thought to be particularly protective against cardiovascular disease.

A chemical in red wine called resveratrol has been shown to have both cardioprotective and chemoprotective effects in animal studies. Low doses of resveratrol in the diet of middle-aged mice has a widespread influence on the genetic factors related to aging and may confer special protection on the heart. Specifically, low doses of resveratrol mimic the effects of caloric restriction—diets with 20–30% fewer calories than a typical diet. Resveratrol is produced naturally by grape skins in response to fungal infection, including exposure to yeast during fermentation. As white wine has minimal contact with grape skins during this process, it generally contains lower levels of the chemical. Beneficial compounds in wine also include other polyphenols, antioxidants, and flavonoids.

To benefit fully from resveratrol in wine, it is recommended to sip slowly when drinking. Due to inactivation in the gut and liver, most of the resveratrol consumed while drinking red wine does not reach the blood circulation. However, when sipping slowly, absorption via the mucous membranes in the mouth can result in up to 100 times the blood levels of resveratrol.

Red wines from the south of France and from Sardinia in Italy have been found to have the highest levels of procyanidins, compounds in grape seeds thought to be responsible for red wine's heart benefits. Red wines from these areas contain between two and four times as much procyanidins as other red wines tested. Procyanidins suppress the synthesis of a peptide called endothelin-1 that constricts blood vessels.

A 2007 study found that both red and white wines are effective antibacterial agents against strains of Streptococcus. In addition, a report in the October 2008 issue of Cancer Epidemiology, Biomarkers and Prevention posits that moderate consumption of red wine may decrease the risk of lung cancer in men.

While evidence from laboratory and epidemiological (observational) studies suggest a cardioprotective effect, no controlled studies have been completed on the effect of alcoholic beverages on the risk of developing heart disease or stroke. Excessive consumption of alcohol can cause cirrhosis of the liver and alcoholism; the American Heart Association cautions people to "consult your doctor on the benefits and risks of consuming alcohol in moderation."

Wine's effect on the brain is also under study. One study concluded that wine made from the Cabernet Sauvignon grape reduces the risk of Alzheimer's Disease. Another study found that among alcoholics, wine damages the hippocampus to a greater degree than other alcoholic beverages.

Sulfites in wine can cause some people, particularly those with asthma, to have adverse reactions. Sulfites are present in all wines and are formed as a natural product of the fermentation process; many winemakers add sulfur dioxide in order to help preserve wine. Sulfur dioxide is also added to foods such as dried apricots and orange juice. The level of added sulfites varies; some wines have been marketed with low sulfite content.

A study of women in the United Kingdom, called The Million Women Study, concluded that moderate alcohol consumption can increase the risk of certain cancers, including breast, pharynx and liver cancer. Lead author of the study, Professor Valerie Beral, has asserted that there is scant evidence that any positive health effects of red wine outweigh the risk of cancer. She said, "It's an absolute myth that red wine is good for you." Professor Roger Corder, author of The Red Wine Diet, counters that two small glasses of a very tannic, procyanidin-rich wine would confer a benefit, although "most supermarket wines are low-procyanidin and high-alcohol."