Do I need to take omega-3 or fish oil?

The research draws a clear line between two things: eating fish and taking a supplement. A large Cochrane review of 86 randomised trials with more than 160,000 participants found that supplementing with long-chain omega-3 (EPA and DHA) has little or no effect on overall mortality. That finding rests on high-certainty evidence. The effect on cardiovascular death and coronary heart disease was weak at best, and built on lower certainty. The large VITAL trial, where nearly 26,000 people took one gram of marine omega-3 a day for just over five years, points the same way: no reduction in major cardiovascular events compared with placebo. A lower risk of heart attack showed up in a secondary analysis, but that is a weaker finding that needs confirming.

The picture looks different for fish as food. A review behind the Nordic Nutrition Recommendations 2023 found that regular fish consumption is linked to lower risk of coronary heart disease, stroke and cardiovascular death. NNR2023's recommendation, built on that combined evidence, lands at roughly two to three fish meals a week. The benefit is attributed to EPA and DHA in oily fish.

So the likeliest reading is that much of the effect comes from the eating pattern around fish, not from an isolated capsule. EPA and DHA are still important nutrients. If you rarely or never eat fish, for example if you live vegan, a modest source from algae or fish oil is a reasonable way to cover your intake. But as a shield for the heart and brain, the supplement struggles to live up to its reputation.

Omega-3 is one of the supplement world's best-selling products, and the story of heart and brain protection is easy to accept. It builds on a real observation, that people who eat a lot of fish tend to be healthier, but skips the step where a capsule doesn't automatically carry the same effect as the diet it came from. The incentives widen that gap. A manufacturer earns money when you buy the bottle every month, not when you put fish on your plate. The marketing also borrows authority from early studies of high-fish-eating populations and stretches them further than the evidence holds. Swallowing a capsule also feels like a concrete health act, cheaper and simpler than changing how you eat.

If you eat oily fish a couple of times a week, you almost certainly don't need a supplement. Put the money into the fish instead. If you rarely or never eat fish, a modest omega-3 source, from algae if you're vegan, can be reasonable to cover your EPA and DHA intake, but treat it as nutrition and not as heart insurance. If you have cardiovascular disease or high blood lipids, omega-3 is a question for your healthcare provider, not for self-dosing.