So, should you take fish oil pills or not? Most researchers agree that oily fish such as salmon and mackerel are far better way to get your fill of good fats. Many of the early, promising studies on omega-3s involved fish rather than fish oil pills (in one, men who were advised to eat fish were 29 percent less likely to die in the two years following a heart attack than men who were not), and a 2010 study by Columbia University scientists reported that following a Mediterranean diet—which, among other things, is rich in fatty fish—reduces the risk of Alzheimer's disease by 34 percent. "Not only may people be benefiting from the omega-3 fatty acids in fish, but the fish may be displacing such foods as hamburgers and quiche from the diet, both high in saturated fat," explains Alice Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tufts University.
If you don't eat fish, then the question of what to do becomes more difficult. Researchers argue that, ultimately, we need more randomized, controlled clinical trials on omega-3 supplements—particularly in healthy people who don't take medications—but these are becoming rare, in part because the supplements will never be big moneymakers. "Generic fish oil is available, so drug companies don't have any strong motivation to fund trials," Mozaffarian says.
But despite the murky science, if you don't get omega-3s from other sources—or if you have heart disease risk factors but aren't taking medications—omega-3 pills may still be a good idea. "There's no harm in taking a fish oil supplement, and there could be benefits," Mozaffarian says. "The bottom line is that getting some [omega-3] is better than getting none."