Myth: Omega-3 fatty acid supplements will help your heart.

The argument: Eating fish may lower your risk of dying of heart disease thanks to the unsaturated fatty acids in seafood, which may reduce inflammation and lower levels of blood fats called triglycerides. But if you don't eat fish regularly (or at all), reaching for an omega-3 or fish oil supplement seems like a good shortcut.

The reality: A major review of studies including nearly 80,000 patients found no link between omega-3 supplements and heart disease. The takeaway: While supplements probably aren't harmful, you may be better off getting your omega-3s from your diet, rather than from a bottle.