Drinking in moderation is supposed to be good for you, right? At least, that's what you'd think reading some news reports and medical studies (and maybe even talking to your doctor). But a new study suggests that those claims about drinking—even in moderation—are questionable at best.
Though Americans are often accused of teetotaling, there have been a number of studies that indicated moderate drinking—definitions vary, but somewhere around six or seven drinks a week—might be good for your heart. But many of those studies were based on surveys, which are susceptible to problems of interpretation. For one, surveys can't say whether a relationship is causal; that is, whether light drinking is the cause of better cardiac health or merely correlated with it. A second, compounding issue is that if an analysis doesn't properly take into account other relevant factors, it might appear there's an effect of alcohol when there isn't.
Surveys can't say whether a relationship is causal; that is, whether light drinking is the cause of better cardiac health or merely correlated with it.
In particular, notes University College London doctoral candidate Craig Knott, most surveys didn't account for how alcohol's effects vary with age or separate out those who'd never had a drink from those who no longer drink—thus equating recovering alcoholics and those who'd always abstained, as long as they didn't have a drink in the last week, month, or year.
That, Knott and his fellow researchers argue in the British Medical Journal, doesn't make a lot of sense. Sure, the results could mean a glass of wine every night is good for your heart, but they could also mean the studies had grouped people in a way that masked alcohol's true effects.
To sort through the confusion, the group looked at two measures of alcohol use from the Health Survey for England: the average number of alcohol units consumed in a week, as well as how many units they'd had on their heaviest drinking day in the last week. (A unit, by the way, is about half an American standard drink.) The team focused on 18,368 adults aged 50 and over, who were broken into groups based on whether they were older than 65 and whether they had quit drinking. The researchers took a variety of other factors, like education, into account to minimize the possibility they'd attribute to light drinking health outcomes that were actually due to something else.
The team found there's at best a small decline in mortality rates for men aged 50 to 64 and women aged 65 and older. Former drinkers, meanwhile, had somewhat higher mortality rates than others, suggesting that past claims light drinking was good for your heart were based on faulty comparisons. After all, some of those who'd quit were probably heavy drinkers in the past, and, compared to them, light drinkers had likely done less damage to their hearts.
In an editorial accompanying the paper, Curtin University professor of health policy Mike Daube writes there's growing evidence alcohol just isn't that good for you: "If something looks too good to be true, it should be treated with great caution."