On the first Monday of each month, my local newspaper publishes a list of local DUI convictions for the previous month (which of course, I scan carefully for people I may know). Along with the list is a guideline for avoiding a DUI: “if you weigh 150-169 pounds, three drinks in an hour will get you past the legal limit.” Seriously? Three drinks in an hour? That’s a lot of alcohol to drink in one hour, or maybe even for a whole day. For over 100 years, many people followed “Anstie’s Rule” (named for a 19th century neurologist) which suggested an upper limit of three drinks a day.
We often hear about the health benefits of alcohol, but what do we know about the benefits and risks of alcohol consumption? How much alcohol should we drink or advise our patients to drink?
What is a drink?
The standard measure for a drink of alcohol in the United States is 12 ounces of 5% beer, 5 ounces of 12% wine, or 1.5 ounces of 80 proof spirits. Each provides the same volume (0.6 ounces) of ethanol. Light beers will have fewer calories and usually have a little less alcohol. Your popular IPA may have a 7-8% alcohol content and contain over 200 calories.
|Serving Size (ounces)||12||5||1.5|
|Grams of alcohol||14||14||14|
Light, moderate, or heavy
People often describe themselves as “moderate” drinkers, but there is a lot of variation in what people consider moderate drinking. The Dietary Guidelines for Americans, 2010, define moderate drinking as 1-2 drinks a day for a man or 1 drink a day for a woman or anyone over 65. Heavy drinking is defined as 3 or more drinks per day, but there are really two separate issues in heavy drinking: the risk of hazardous drinking (alcohol abuse and dependence), and the risk of medically significant drinking (causing harm instead of benefit).
Two common tools for assessing the risk of hazardous drinking habits are the CAGE and AUDIT questionnaires. CAGE is a simple 4 question screen for alcohol abuse or dependence, but it may be insensitive for heavy drinking behaviors.
- Have you felt you should CUT down on your drinking?
- Have you been ANNOYED by people criticizing your drinking?
- Have your felt GUILTY about your drinking?
- Have you ever had a drink first thing in the morning to steady your nerves or cure a hangover (EYE-OPENER)?
The AUDIT-C is a three question alcohol screening tool:
- How often do you have a drink containing alcohol?
- How many standard drinks containing alcohol do you have on a typical day?
- How often do you have six of more drinks on one occasion?
CAGE is positive with a score of 2 or more, although many would consider a positive answer to the last question enough to identify risky drinking behavior. The AUDIT-C is scored from 0 – 12 points (you can see this test on-line at http://www.integration.samhsa.gov/images/res/tool_auditc.pdf). This test is very sensitive for problem drinking (about 80%) and will be positive for risky drinking with only one drink a day on four days a week. The higher the score, the more risk for problem drinking.
Medically significant drinking
We can begin to define medically significant drinking as we look at studies on the benefits and risks of alcohol. We have to consider that alcohol may be beneficial at one dose and toxic at a higher dose. We need to also recognize that moderate drinking today may progress to worrisome drinking later and temper our advice to patients with appropriate caution. We also have patients who should not drink at all. Patients with a contraindication to drinking any alcohol:
- Women who are pregnant or considering pregnancy
- A medical condition that can be worsened by alcohol
- Family or personal history of alcoholism
- Medications that may react with alcohol
- Planning to drive a car, operate machinery, or need to stay alert
- Under age 21
Benefits and risks of alcohol
There have been numerous studies on the beneficial effects of moderate alcohol consumption to lower the risk for coronary artery disease and heart failure. The benefits appear to be due to higher HDL cholesterol levels, decreased fibrinogen and antithrombin actions, and reduced insulin resistance. The benefit in lowering risk of CAD plateaus at about 1 drink per day. Meta-analyses have shown a 20-30% lower mortality for drinkers compared to non-drinkers after an MI. The optimal dose of alcohol in decreasing the risk for men (35% lower risk) occurred with consuming alcohol 5-7 days a week.
Moderate drinking has also shown to significantly lower the risk of stroke and peripheral vascular disease and to lower the incidence of type 2 diabetes. The risk of heart failure was 50% less for people drinking at least 1.5 drinks a day. The protective effects for ischemic stroke were seen from 1-4 drinks a day with the lowest level at 2 drinks per day. The US Nurse’s Health Study showed a protective effect for stroke incidence in women with up to 1.2 drinks per day. Studies have also shown a lower risk for developing dementia with alcohol consumption of 1-6 drinks per week.
Alcohol, however, may also add some risks, even with moderate intake. Moderate drinking has been associated with an increased risk for breast cancer in women with a linear dose-response curve, with 1% increased risk for every gram per day of alcohol. This amounts to a 0.1% increase in 5 year risk for a 50 year old woman drinking just about one drink per day. Other cancers associated with moderate alcohol consumption (two drinks per day) include oral, laryngeal, and esophageal cancer.
Although moderate alcohol consumption may increase bone density, it is also associated with falls and fractures, particularly in our older patients.
Heavy drinking has many risks. Blood pressure rises in men at 3-4 drinks per day. Hemorrhagic stroke increases significantly at >3 drinks per day. Heavy drinking reverses the heart benefits of moderate drinking and increases the risk of hypertension, arrhythmias, hemorrhagic stroke, and cardiomyopathy. Heavy drinking varies by study but is generally four or more drinks per day. Heavy drinking may also lead to cirrhosis, pancreatitis, vitamin deficiencies, obesity, nervous system damage, memory loss, as well as psychological disorders, and of course trauma and motor vehicle accidents.
The studies for heart disease and heart failure show the lowest risk with ethanol consumption of 10 gm/day for women and 25 gm/day for men. All-cause mortality is lowest at one drink per day. Ischemic stroke risk is lowest at 1.2 drinks/day for women and 2 drinks/day for men.
Although there are some increases in cancer rates with moderate alcohol consumption, most medical risks with alcohol increase markedly at about three drinks a day.
It is safe to say that low to moderate alcohol consumption may reduce the risk of coronary heart disease, heart failure, ischemic stroke, dementia, and overall mortality for people who can safely drink alcohol. It does not matter (medically) whether it is beer, wine, or spirits.
Back to our definitions. Based on medical risks and benefits alone, we can define beneficial moderate drinking as 1-2 drinks per day for men and 1 drink per day for women or adults over 65. A medically worrisome level of drinking is 3 or more alcoholic drinks per day.
Our medically-based recommendations for moderate alcohol use for people who can safely drink turn out to be the same as the Dietary Guidelines for Americans, 2010:
- Men: 1-2 drinks per day
- Women: 1 drink per day
- Adults over 65: 1 drink per day
Jim Cotter, MD, MPH