Moderate drinking does not appear to prevent heart attacks. An analysis of 45 studies of relationships between heart attacks and alcohol consumption reports that the studies that associated moderate drinking with reduced heart attack rates are flawed (Journal of Studies on Alcohol and Drugs, May 2017;78(3):375-386). To show that moderate drinking is associated with heart attack prevention, researchers must show that non-drinkers have more heart attacks than moderate drinkers. The problem is that in most of the studies, the non-drinking group includes a high number of people who have been told that they need to stop drinking because they:
• have liver, heart, lung or kidney disease
• are diabetic
• are alcoholic
• have had heart attacks
• have any of the many other reasons that alcohol can harm them. Once the researchers remove people who have stopped drinking alcohol for critical health reasons from their non-drinking groups, the drinkers show no advantage over the non-drinkers. Long-term studies that have followed people into their later years have shown no advantage from moderate drinking.
A new study reported in the same journal followed more than 9000 British adults from the age of 23 to 55 and found that most people who were non-drinkers by age 55 were former drinkers who had given up alcohol (often on their doctors' advice), were more likely to be smokers and tended to be in poorer physical and mental health compared with those who drank moderately (Journal of Studies on Alcohol and Drugs, May 2017;78(3):394-403). The authors believe that nobody should drink because they have been told that alcohol has health benefits.
In the studies cited by the alcohol industry, more than half of the people in the "non-drinker" groups were recovering alcoholics or people who had been told to stop drinking because they had already suffered from diseases caused in part by drinking, such as liver, heart or kidney disease, high blood pressure, heart attacks, certain cancers, alcoholism, stomach ulcers or other major health problems (J Stud on Alc and Drugs, March 2016;77(2):185–198). When people with alcohol-related diseases were removed from the abstainer groups, the data showed that moderate drinkers did not have a lower incidence of heart attacks than the non-drinkers.
Researchers at the University of Victoria in British Columbia reviewed 54 studies and found that only seven of those studies corrected their non-drinking population for people who had been told to stop drinking for health reasons (Addiction Research and Theory, April 2006). The Canadian researchers re-analyzed 47 studies that associated wine or other alcohol with a longer life and decreased risk for heart attacks. When the studies were corrected to remove the people who had been ordered to stop drinking for health reasons, they found no advantage in death rate between moderate drinkers and those who do not drink at all. A study from England followed 53,000 men and women over 50 for 6-10 years and found that alcohol consumption had no demonstrable health benefit and did not reduce risk of death during the study period (British Medical Journal, February 10, 2015).
Definition of a Drink
In the studies and reports mentioned here, a "drink" is defined as the amount that takes an average person's liver one hour to clear half the alcohol from the bloodstream. However, this can vary with body weight, sex, age, metabolic rate, recent food intake, the type and strength of the alcohol, and any medication you take. Typically, one drink contains 0.6 ounces (14.0 grams or 1.2 tablespoons) of pure alcohol, the amount found in:
• 12 ounces of beer (5% alcohol content)
• 8 ounces of malt liquor (7% alcohol content)
• 5 ounces of wine (12% alcohol content)
• 1.5 ounces of 80-proof (40% alcohol content) liquor (e.g., gin, rum, vodka, whiskey)
Alcohol and Heart Damage
People who take in just one drink a day are at increased risk for heart disease (American College of Cardiology. December 5, 2016) and enlarged upper heart and irregular heartbeats called atrial fibrillation that causes clots and strokes (J Am Heart Assoc, Sep 14, 2016;5:e004060 & Am Coll Cardiol, 2016;68(23):2567-2576).
Alcohol and Increased Risk for Cancer
Thirty percent of all alcohol–related deaths are caused by cancer, with 60 percent of these deaths from breast cancer, and one third of these deaths were associated with an average of fewer than two drinks a day (Drug Alcohol Rev, June 16, 2016). A review of scientific articles shows that drinking even one glass of wine a day raises the risk of cancer of the throat, esophagus, liver, colon, rectum and breast (Addiction. Jul 21, 2016). The more you drink, the greater your risk for developing these cancers. Alcohol has also been associated with cancers of the skin (Am J Clin Nutr, Nov 2015;102(5):1158-66), prostate and pancreas. A review of 27 studies showed that taking up to two drinks a day is associated with a 23 percent increased risk for prostate cancer (BMC Cancer, Nov 5, 2016).
A review of 222 scientific papers that followed 92,000 light drinkers and 60,000 non-drinkers showed that taking just one alcoholic drink a day is associated with increased risk for cancer of the mouth and throat, esophagus and breast (Annals of Oncology, Feb 2013; 24(2):301-308). Thirty-seven percent of North American adults take up to two drinks a day. Several studies show that mouth, throat and liver cancer patients who stop drinking have a reduced chance of recurrence of their cancers compared to those who continue to drink.
How Alcohol Can Lead to Cancer
Alcohol can damage every cell in your body. Your liver is the only organ that can break down significant amounts of alcohol and it does this on a time-limited basis. The alcohol is first converted to acetaldehyde, which is even more damaging to your cells than alcohol. Acetaldehyde can cause cancer by damaging DNA and stopping your cells from healing from this damage. The highest risk for alcohol-induced cancer is in your mouth and throat because some bacteria there are able to convert ethanol directly into acetaldehyde. Alcohol damages cells to produce Reactive Oxygen Species (ROS) that can alter DNA to cause cancer. Alcohol reaches the colon, rectum and liver later so the link between these cancers and alcohol is not as strong.
Unhealthful Lifestyles Increase Cancer Risk from Alcohol
Smoking, being overweight, eating an unhealthful diet and not exercising markedly increase risk for alcohol-related cancers. The risk for cancers of the mouth, throat and esophagus is much higher if you both drink and smoke than if you use either alcohol or tobacco alone, and the more you drink and smoke, the greater your risk (Int J Cancer, 2011;128:533-540).
Alcohol and Breast Cancer
One alcoholic drink a day can increase a woman's breast cancer risk by five percent in premenopausal women and nine percent in postmenopausal women by damaging DNA and increasing blood levels of estrogen (American Institute for Cancer Research (AICR) and the World Cancer Research Fund). The report analyzed 119 studies, including data on 12 million women and 260,000 cases of breast cancer and also found that breast cancer rates are lower in women who exercised regularly, breast-fed their babies, were not overweight, and did not gain a lot of weight at menopause.
Alcohol and Diabetes
By restricting alcohol, diabetics can gain better control of their blood sugar levels (HBA1C, insulin and blood sugar(Diabetes Care. 2015;38(9):1804-1812 & 2015;35(4):723-732)).
Alcohol and Osteoporosis
Drinking alcohol is associated with increased risk for hip and vertebral fractures (NIH Osteoporosis and Related Bone Diseases National Resource Center, April 2016).
Alcohol and Liver Damage
Drinking alcohol regularly increases risk for permanent liver damage called cirrhosis (Journal of Hepatology, January 26, 2015). Wine is associated with a lower risk for liver damage than beer or liquor. The authors of this study warn that older drinkers are more likely to have health conditions affected by alcohol or to take medicines that impair their ability to metabolize alcohol.
Many people have the mistaken belief that it is safe for women to take up to one drink per day and for men to take up to two drinks per day. Almost 30 percent of North Americans drink more than that. The studies I have listed in this article and many more show that no amount of alcohol is "safe" or beneficial. Whatever you decide about your own consumption of alcohol, do not base your decision on bad information from the alcoholic beverage industry.