Whether that second glass of wine will really harm your health remains a matter of contention even as the USDA reexamines its guidelines on alcohol. The committee responsible for those guidelines has just recommended that men consume no more than one drink on any given day; women were already limited to one.
It’s hard to be objective and stick to the data on a topic as loaded with moral and cultural weight as alcohol. Some studies show moderate drinkers are a little more prone to certain cancers, but the data might be skewed by other bad habits that go along with drinking, such as smoking or just hanging around smoky bars. Other studies show moderate drinkers have better cardiovascular health, but those might be confounded by other good habits that go along with drinking, such as eating healthy meals in the company of friends and family.
Separating trivial risks from serious ones is hard — but we’d better start getting used to it. It’s the same sort of calculation the pandemic has forced on us. People are looking to scientists to decide if it’s “safe” to go to the park, the beach, to travel, or return to a modified office or classroom. And there, too, there are different ways to interpret the same data.
And so it’s useful to understand why the experts disagree. All told, alcohol is terrible, responsible for killing around 100,000 people every year. But those are almost entirely associated with alcohol-fueled violence, drunk driving and heavy drinking. Is light drinking really a problem, or is it wrongly deemed guilty by association?
Timothy Naimi, an alcohol researcher at Boston University and head of the committee charged with updating the guidelines, says even moderate alcohol has been shown to raise the risk of some cancers — especially breast cancer, which goes up 10% for every daily drink. That’s not a huge increase, but it’s worth noting. According to the American Cancer Society, the lifetime risk of getting breast cancer is 12.8%, so a 10% increase would raise the risk to about 14.1%. Alcohol also raises the risks of esophageal, stomach, liver, and head and neck cancers, though these are relatively rare in both abstainers and moderate drinkers. (Note that we’re talking here about getting cancer, not dying from it.)
Naimi says alcohol guidelines are just guidelines — not orders. He’s a doctor, not a police officer. He believes the evidence shows that for people who drink, it’s better for our health to drink less.
The evidence, he says, suggests that for men, the ideal is closer to one drink than two. Why not suggest that men limit themselves to less than 10 drinks a week, then? That, he says, would be too complicated. Then you’d need both a weekly limit, and a daily one to warn against binge drinking.
And yet the guidelines already suffer from ambiguity. Without very close scrutiny, it’s hard to tell whether the recommendation is that you shouldn’t average more than one drink a day or that you should never have more than one drink a day. (Naimi says the correct reading is that you should never have more than one.)
Epidemiologist Eric Rimm of the Harvard School of Public Health says that unlike sugar and other undisputed health villains, alcohol is associated with some health benefits. A number of studies going back years show that moderate drinkers enjoy better cardiovascular health than non-drinkers. And while those might be explained away by other lifestyle factors or the fact that moderate drinkers are wealthier, there’s also some biological evidence for a benefit. In controlled studies, people who drank moderately had higher HDL (good cholesterol) and maintained healthier blood sugar levels. Other studies show moderate drinking had a small protective effect against age-related cognitive decline.
So are the downsides enough to outweigh the upsides?
One way scientists tried to sort it out was to follow lots of people over time to measure health problems and deaths from various causes. They published their results in 2018 in “The Lancet,” but again, the results were subject to interpretation.
Some interpreted the results to mean there’s no safe level of drinking. Others, who looked at the data more closely and with a skeptical eye, pointed out that for every 100,000 people in the study, there were 914 health problems for non-drinkers and 918 for moderate drinkers — not a difference that seems worthy of alarm.
It’s a little hard to tell, also, what it means for people’s health if they drink heavily in their 20s and 30s and then cut back later — a fairly common pattern. Maybe the light drinkers who get cancer are suffering the ill-effects of long-ago binges. “It’s really hard to capture that in the data,” says Rimm. It’s also hard to capture the difference between someone who drinks a small glass of wine with dinner each night and someone who drinks a whole bottle once a week.
If we’re going to look to experts to tell us whether something is safe, it’s worth remembering that safe is not a well-defined scientific term but a subjective judgment, whether they’re talking about a second drink or your ability to venture out in public. Staying safe isn’t going to keep you from dying — it will only delay the inevitable. – Bloomberg