This story is a part of The Elemental Guide to Vitamins. Here are the vitamins and supplements that are covered: multivitamins, vitamin D, vitamin C, calcium, B vitamins, omega-3, vitamin E, fiber, protein, and probiotics.
During the past two decades, omega-3 supplements have gone from marginal to mainstream. By some estimates, roughly 10% of American adults now take omega-3 add-ons, which include “fish oil” products.
Omega-3s are termed “polyunsaturated” fatty acids, a word that refers to their molecular structure. They’re found mainly in foods like fish, nuts, seeds, and some plant oils. There are a handful of omega-3s, but the ones that have garnered the most attention are docosahexaenoic acid (DHA), alpha-linolenic acid (ALA), and eicosapentaenoic acid (EPA). In the human body, these and other omega-3s help form the walls of cell structures. They also serve as an energy source, and they play important roles in the function of the heart, brain, lungs, and immune system. People often take them for brain health, heart health, or psychological health because studies have linked omega-3s to lower rates of heart disease, brain disease or disorders, and many other common illnesses.
The popularity of Mediterranean-style diets, which emphasize omega-3-packed fatty fish and olive oil, has also had a lot to do with the supplement’s star turn. And there’s a small mountain of evidence linking the consumption of foods that contain omega-3s with improved health outcomes.
A 2018 study in the New England Journal of Medicine found people at high risk for heart disease who ate an olive-oil-heavy Mediterranean diet experienced fewer heart attacks and other problems than people who ate a low-fat diet. And a 2011 review in the European Heart Journal found that omega-3s from food could “reduce blood pressure, improve arterial and endothelial function, reduce platelet aggregation,” and promote other heart-healthy changes.
There’s zero doubt that the human body needs omega-3s and nearly as little doubt that people benefit from eating foods that contain these fatty acids.
While those heart benefits are impressive, there may be even more research linking omega-3s to brain health and functioning. Studies have found diets rich in omega-3s protect the brain during aging, and DHA, in particular, may limit the production and accumulation of proteins that are implicated in Alzheimer’s disease. Research has also linked omega-3s to anti-inflammation benefits and improved mental health.
There’s zero doubt that the human body needs omega-3s and nearly as little doubt that people benefit from eating foods that contain these fatty acids. But the research in support of omega-3 supplements tells a different story.
A long-term, government-funded study on omega-3 supplements found no evidence that taking them improved the cognitive functioning of older adults, and this finding was more or less reiterated in a 2018 PLOS One study. Meanwhile, a 2018 review in the journal JAMA Cardiology found that people at high risk for heart trouble were no better off after long-term omega-3 supplementation that people who did not take the supplement.
Prescription omega-3 drugs, which feature omega-3 formulations that are backed by clinical evidence and FDA approval, have been shown to help treat some specific conditions. These include elevated triglyceride levels, which are a risk factor for heart trouble, as well as some specific types of stroke. And early evidence has found that omega-3 supplements may provide a wide range of health benefits, from treating inflammatory diseases and depression to reducing a person’s risk for some cancers.
But on the whole, the evidence backing omega-3 supplements has been disappointing compared with the research on the benefits of omega-3-rich foods.
What explains the discrepancy? Aron Barbey, a professor of psychology at the University of Illinois, says that when people eat foods like fish, the health benefits they derive may come from the combination of omega-3s and other nutrients found in fish. It’s also possible that people who eat a lot of fish are generally more health-conscious, he says. In other words, there are multiple explanations for why people who eat foods containing omega-3s may be healthier than people who don’t, and some of these may explain why supplements have not performed well in clinical trials. “The general recommendation now is to obtain omega-3s in your diet by eating fish,” Barbey says.
Quality control is also an issue when it comes to fish oil and other omega-3 supplements. “Oxidation” refers to the breakdown of an oil’s molecular structure into something that is toxic. And this can happen inadvertently during the manufacture of fish oil supplements, says Chandan Sen, associate vice president of research at the Indiana University School of Medicine. “Oxidized fish oil is exactly the opposite of good fish oil,” he says. “Sometimes you’re not buying benefit, you’re buying trouble.” Heavy metal contamination is another concern when it comes to fish oil products.
While those concerns exist, a recent analysis from ConsumerLab.com, a private company that tests consumer supplements, found that most omega-3 products were not contaminated and had not oxidized. Also, omega-3 supplements seem to be very safe. Side-effects tend to be mild and rare, according to the NIH, although there’s not much research on the effects of very long-term omega-3 supplement use.
The bottom line: It’s likely that some people could benefit from an omega-3 supplement. But to date, researchers are still sorting out exactly who should be taking these products. Your physician can help you decide if you need them.
This story is a part of The Elemental Guide to Vitamins.