In one of the first studies to examine alcohol's effect on middle-aged guys (rather than on college-age or elderly men), British researchers found that those who had three or more drinks daily suffered far greater memory loss and had hindered decision making.
In reality, if you truly have just a couple drinks a day, not four, five, or 12, you likely don't have to worry much, says Sara Jo Nixon, a psychiatry professor and substance abuse researcher at the University of Florida. "From this study, you shouldn't conclude that men who drink [three drinks] a week are going to have that extreme level of cognitive loss," Nixon says. "However, these findings do suggest that men ought to pay attention to their drinking in those middle years."
But you should be concerned if you have much more. Most of the men who show major cognitive impairment in this study likely fell into the upper range of heavy drinkers – as much as eight drinks a day. But when the researchers tally all the data and create averages, it reads like a few drinks a day does serious brain damage, which isn't always the case.
Daily, habitual drinking does damage the brain. "Alcohol used persistently has neurotoxic effects," says Nixon. "Most of the time those effects happen across various brain areas and are relatively mild. People don't feel clinically impaired. But this study suggests that alcohol exposure may have a cumulative effect, and it may impact some people more than others." In other words, practice moderation.