Making Sense of Alcohol Studies

6 min read  |  April 20, 2018  | 

Who to believe? One month a study touts the benefits of alcohol and all your friends are downing the requisite two glasses of red wine with dinner. Then another research study reveals that oops, alcohol can do more harm than good.

News reports about the benefits and dangers of alcohol can be confusing, even misleading. Dueling studies appear to contradict each other, making it difficult for the consumer to know exactly who and what to trust. But don’t worry: it’s not you.

“First of all, every study is not conclusive,” says Ihsan M. Salloum, M.D., a University of Miami Health System addiction specialist. “A lot depends on the way the study is conducted, how many people were involved, if it was appropriately controlled.”

For the layperson who doesn’t hear the disclaimers, all findings may sound equally significant, fueling what has been a centuries-old debate on the effects of alcohol.

But Dr. Salloum a psychiatrist and chief of the division of Alcohol and Drug Abuse: Treatment and Research, has a word of advice:

It comes down to quantity and frequency. If you use a lot and consistently, you’re going to get the bad effects of alcohol.

Dr. Ihsan M. Salloum

As in all things in life, moderation is called for. As a moderate drinker, alcohol may help your heart and it might protect you against type 2 diabetes.  If you’re hitting the sauce too much, however, the consequences can be devastating. The World Health Organization has connected alcohol to 67 different diseases, from impotence to gastritis to impaired cognitive function, Dr. Salloum adds.

What’s more, overuse of alcohol can lead to depression and ruined relationships. It is estimated to be a factor in half of fatal traffic accidents and one in third violent crimes.

So what’s moderate drinking?

While some studies differ in their definition of the term, the U.S. Dietary Guidelines for Americans 2015-2020 recommends up to one drink per day for women and no more than one to two drinks for men. The National Institute on Alcohol Abuse & Alcoholism (NIAAA) defines moderate drinking as up to four alcoholic drinks for men and three for women in any single day and a maximum of 14 drinks for men and seven drinks for women per week. Dr. Salloum abides by the U.S. dietary guidelines.

Of course, not all drinks are created equal.

The accepted definition of a standard drink is 1½ ounces of hard liquor, 12 ounces of beer and 5 ounces of wine. All contain about 15 grams of alcohol. However, this doesn’t mean you can overdo it on a Saturday night, drinking all seven in one day.  You can’t “average out” consumption.

What’s more, gender and genes also affect how you metabolize alcohol. Because women have less water in their bodies and tend to weigh less, alcohol affects them differently.  Women also have lower levels of an enzyme known as alcohol dehydrogenase (AHD), which breaks down alcohol in the liver. As a result, those three or four drinks can build up faster and stay longer in the female bloodstream.

“It’s not like you can say you have one drink or two and you’ll be fine,” Dr. Salloum adds. “It can be variable. People have different vulnerabilities and risk factors.”

Here’s what we know about the effects of alcohol

Dozens of studies have shown moderate drinking likely reduces the risk for stroke, heart attack, sudden cardiac death and other cardiovascular issues — up to a 40 percent reduction, in fact. The benefits apparently extend to both men and women, to those with or without heart disease or at a high risk of cardiovascular disease. This is due to the fact that lower to moderate amount of alcohol tends to slightly raise HDL, or the good cholesterol that helps protect against heart disease.  Also, moderate consumption is associated with factors that help prevent small blood clots in the heart, brain and neck.

On the other hand, too much of a good thing is linked to congestive heart failure and heart attacks. Overdoing it can raise the levels of triglycerides and increase caloric intake as well as damage the heart muscle and raise blood pressure. In fact, the American Heart Association cautions people NOT to start drinking if they don’t already do.

In several studies, including the better-known Nurses’ Health Study and the Health Professionals Follow-up Study, researchers found that moderate drinkers were less likely than non-drinkers to develop gallstones and type 2 diabetes. This benefit didn’t extend to heavy drinker, though, and downing a few too many actually works to damage certain organs. It’s well-known that too much alcohol can cause alcoholic hepatitis (inflammation of the liver) and cirrhosis (scarring of the liver).

Alcohol has been associated with several cancers, and if you also smoke, the risk is multiplied several times over. The ethanol found in alcoholic drink is metabolized into acetaldehyde, “a probable human carcinogen” which can damage your DNA, according to the National Cancer Institute. It also impairs the absorption of nutrients and increases the blood levels of estrogen, both cancer risk-factors.

On the positive side, alcohol serves as “a social lubricant” that helps us relax after a long day at work or when out with friends, Dr. Salloum points out. A drink can also improve digestion. However, it has a dark side. “It’s not a benefit people can rely on,” Dr. Salloum adds. “You can build up a tolerance and before you know it, you need two drinks, then three drinks to get the same effect.”

Alcohol, a depressant, will help you fall asleep, and as many as 20 percent of Americans use it to help them nod off, according to the National Sleep Foundation. Unfortunately, it is also common to wake up more in the middle of the night as a result.
“It impairs deep sleep,” Dr. Salloum says, “and that’s the kind of sleep that helps in learning and memory.”

Alcohol has been part of human history for eons, both in social and sacramental contexts, and of the 80 to 90 percent of Americans who drink, only about 15 percent have a problem.

Nevertheless, Dr. Salloum adds, “you have to keep in mind that the benefits are moderate.”

Ana Veciana-Suarez, Guest Contributor

Ana Veciana author

Ana is a regular contributor to the University of Miami Health System. She is a renowned journalist and author, who has worked at The Miami HeraldThe Miami News and The Palm Beach Post. Visit her website at or follow @AnaVeciana on Twitter.

Tags: alcohol and cancer, alcohol consumption, Dr. Ihsan Salloum, wine and heart health

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