There seems to many conflicting studies on the affects of alcohol on cancer risk. For the most part, they all agree that heavy drinking (3 or more drinks per day) increases cancer risk and cancer recurrence. Talk to your doctor about your individual risks.
Understanding Alcohol and Cancer Risk
In a study published in October 2011, researchers found "that light to moderate alcohol intake does not appear to increase the risk of all-site cancer (and light drinking was shown in this study to be associated with a significant decrease in risk).":
Details of this study follow:
A paper from the National Institutes of Health in the United States has evaluated the separate and combined effects of the frequency of alcohol consumption and the average quantity of alcohol drunk per occasion and how that relates to mortality risk from individual cancers as well as all cancers. The analysis is based on repeated administrations of the National Health Interview Survey in the US, assessing more than 300,000 subjects who suffered over 8,000 deaths from cancer. The research reports on total cancer deaths and deaths from lung, colorectal, prostate, and breast cancers.
The overall message of this analysis is that light to moderate alcohol intake does not appear to increase the risk of all-site cancer (and light drinking was shown in this study to be associated with a significant decrease in risk). Similarly, light to moderate consumption was not associated with site-specific cancers of the lung, colorectum, breast, or prostate.
As quantity consumed increased from 1 drink on drinking days to 3 or more drinks on drinking days (US drinks are 14g), risk of all-site cancer mortality increased by 22% among all participants. For total alcohol consumption (frequency x quantity), the data indicate a significant reduction in the risk of all-site cancers (RR=0.87, CI 0.80-0.94). Moderate drinking consistently shows no effect in the analysis, and only heavier drinking was associated with an increase in all-site cancer risk. For site-specific cancers, an increase in risk of lung cancer was seen for heavier drinkers, with a tendency for less cancer among light drinkers. There was no evidence of an effect of total alcohol consumption on colorectal, prostate, or breast cancer.
This study follows several other studies that link an increase risk of cancer with even moderate consumption of alcohol. Depending on the study, different amounts were associated with different levels of risk.
Alcohol and Reduced Risk of Some Cancers
Moderate alcohol consumption has been associated with a reduced risk of some cancers, such as Hodgkin's Lymphoma, Non-Hodgkin's Lymphoma, and Kidney Cancer (Renal Cell Carcinoma).
Alcohol and Cancer Risk in Women
Another challenge is the association between moderate alcohol consumption and increased risk for breast cancer. Drinking as few as three to six glasses of wine per week may increase a woman's lifetime risk of breast cancer by 15%, according to an analysis by Harvard researchers. (see more info here: Light drinking linked to increased breast cancer risk)
On average, a U.S. woman's baseline risk of breast cancer is 1 in 8 over her lifetime, according to the American Cancer Society. The 15% increased risk that was linked to consumption of 5 to 9.9 grams of alcohol per day is modest, similar to the heightened risk associated with using estrogen-progesterone hormone therapy to treat symptoms of menopause. But it's far smaller than the fivefold increased risk that comes from inheriting certain mutations in the BRCA1 and BRCA2 genes.
Yet, having a few drinks a week has been found to lower the incidence of heart disease by 25% to 40%. The average woman's lifetime risk for heart disease is 1 in 2. So, the decision on whether to drink, and how much must be individualized.
Dr. Wendy Y. Chen, the lead author of the paper and an assistant professor of medicine at Brigham and Women's Hospital and Harvard Medical School in Boston, and her colleagues also demonstrated that binge drinking, defined as six or more drinks in one sitting, was associated with a 33% increase in cancer risk independent of total alcohol intake over time and that alcohol consumption between the ages of 18 and 40 was linked with higher breast cancer risk later in life no matter what a woman's drinking habits were after age 40.
Hormones probably play a key role in the alcohol-breast cancer relationship, Chen said, because alcohol intake increases levels of the hormone estrogen, which is known to fuel breast cancer growth.
But modest alcohol consumption also raises HDL, the good cholesterol, and other substances that promote heart health. The cardiovascular benefits probably negate a small increased risk of breast cancer, said Dr. Tim Byers, associate director for cancer prevention and control at the University of Colorado Cancer Center.
"The trade-off makes it very difficult for women to know what to do," he said. "There are not many examples of where there is trade-off for heart disease and breast cancer. Most of the risks for heart disease and breast cancer are the same."
Considering that more women develop heart disease than breast cancer, Byers said, "it's reasonable" for women at average risk for both conditions to drink at low to moderate levels. "But for women at higher risk of breast cancer it becomes a more difficult decision," he said. "The prudent thing for them may be to avoid alcohol."
Chen said she doesn't tell her patients to stop drinking but to limit intake to a few drinks a week.
Red Wine and Cancer: Health Benefits or Health Risk?
Red wine has been associated with health benefits, and cultures that consume red wine have shown a decrease in death due to cardiovascular events like heart failure. But the average moderate wine drinker is more likely to exercise more, to be more health conscious, and to be of a higher educational and socioeconomic class, evidence that the association between moderate wine drinking and health may be related to confounding factors.
Additionally, those studying the affects of alcohol and cancer are hesitant to promote any benefits of Red Wine because of the strong associations between cancer and increases in alcohol consumption.
In general, here are the benefits and risks (source: meteck.org/wine.html):
Risks of Red Wine
- Alcohol: the presence of alcohol is the greatest cancer risk of drinking red wine. As cancer risk increases with regular and heavy consumption of alcohol, it is important to keep quantities in check. You don't have to be 'drunk' to consume too much.
- Tannin: plant polyphenols and may cause headaches
- Sulfites: some people are sensitive to sulfites
Benefits of Red Wine
- Reduced Coronary Heart Diseases: wine is altering the blood lipid levels. It lowers the total cholesterol count, and raises the high density lipoprotein (HDL) levels.
- Maintains the Immune System: According to a study published by the University of Florida, red wine does not suppress the immune system like other alcoholic beverages.
- Polyphenols in wine: like the tannin mentioned above, do have a positive effect on your body as well: they are excellent antioxidants. In short: they lower total cholesterol and blood pressure, lessen risks of cancer, stimulate the immune system, and have anti-bacterial properties.
- Resveratrol (trans-3,5,4'-trihydroxystilbene): is a naturally occurring antioxidant too that decreases the stickiness of blood platelets and helps blood vessels remain open and flexible. It is said that it inhibits the enzymes that can stimulate cancer-cell growth and suppress immune response.
- Flavonoids: Red grapes contain flavonoids, also powerful antioxidants that work as cancer preventives.
- Anti-bacterial activity: In a study of 1800 people, scientists tested for the presence of Helicobacter pylori, which causes ulcer infections. Compared to non-drinkers, those who had one glass of wine a day had 7% fewer of these bacteria.
- Anti-stress: wine does have a calming influence (surprise, surprise). The fact that a dinner is accompanied by a drink which helps the body relax and unwind can help the mental transition between work and relaxation. Also, people fighting other illnesses can combat them better when calm and focused.