AT ONE POINT it appeared that fish oil supplements were going to save us all. Rescue from heart disease, defense against cognitive decline and eyesight problems, relief against rheumatoid arthritis—and all this while giving you thicker, lusher hair and more beautiful looking nails.
If all those too-good-to-be-true promises sound a little late-night-infomercial to you, well, yup. Many supplement companies built potent claims from emerging research, which later turned out to be not so true. And they conflated the study results that showed the benefits of the oil from fish—as in the food—with their fish oil supplements.
But as all things come around again, fish oil supplements are back with their promises, only this time dipping their line in the social media feeding frenzy around supplements. So let’s revisit fish oil supplements—and what the science has to say about their supposed benefits.
What Is Fish Oil?
NOT TO BE obvious, but it’s the oil from fish. More specifically, it’s omega-3s eicosapentaenoic acid (EPA) though largely docosahexaenoic acid (DHA). These fatty acids make up the oily nature of fish, some in greater presence in certain varieties. Salmon and mackerel are high in omega-3 fatty acids and are considered “oily” fish. Cod and tilapia are lower in omega-3s. Shellfish have omega-3s too.
In supplement form, fish oil is extracted from fish and shellfish that contain omega-3 fatty acids, sometimes krill, usually anchovies. (Yes, anchovies.)
What Is Fish Oil Good For?
FIRST, JUST KNOW that we’re talking about the omega-3 fatty acids found in seafood here—not supplements, yet.
Fish oil—from seafood—has a wide variety of well-studied benefits.
“There’s some pretty significant evidence that it’s important to have enough omega-3s for heart health, brain health, eye health, joint health—all of those areas rely on having plenty of omega-3s in your diet,” says Brian St. Pierre, M.S., R.D., C.S.C.S., C.I.S.S.N., Pn1, Director of Performance Nutrition at Precision Nutrition, and a Men’s Health Advisor.
What Are Fish Oil Supplements Good For?
THERE’S A VERTIABLE sea of studies of fish oil and fish oil supplements out there. And that’s a great thing—because unlike many other supplements, research can help build a scientific consensus. With fish oil supplements, we’re not quite at consensus status, but we’re getting closer in some areas.
Here’s where the research stands now.
Fish Oil Supplements and Heart Health
One of the most well-studied areas for fish oil supplementation is heart health, with many studies suggesting that fish oil supplements have cardioprotective benefits. (Cardiovascular health claims were the most common in a recent study of 255 fish oil supplements published in JAMA Cardiology.) High-dose fish oil supplements are even available by prescription to reduce high triglycerides—fats that circulate in the bloodstream and increase heart disease and stroke risk.
Still, research continues to turn up new questions.
In a new study published in BMJ Medicine, researchers found that fish oil supplements were associated with an increase in risk of stroke and atrial fibrillation in healthy people. However, in people with existing heart disease, fish oil was linked to a reduced risk of progression to bigger problems.
A new study published in the journal Nutrition showed that people who supplemented their diets with fish or fish oil supplements for a year experienced reductions in pro-inflammatory blood markers, with the biggest benefits in people who had previously eaten fish less than once a month.
Will those changes reduce your risk of diseases or help you avoid new ones?
That’s still being sorted out.
Just know that fish oil supplements should never replace your statin for high cholesterol. Statins work better than fish oil or other common supplements for reducing cholesterol, according to a study published in the Journal of the American College of Cardiology.
Fish Oil Supplements and Arthritis
In a study review published in the Journal of Orthopaedic Surgery and Research, researchers found that supplementing with omega-3s relieved arthritis pain and improved joint function compared to placebo. That might be because the fatty acids reduce inflammation that can break down cartilage, the researchers speculate.
Though here there exists conflicting research too.
Another study (from the same year) found that data on dietary intervention of omega-3 supplementation in patients with arthritis is “limited”—meaning that it’s tough to draw conclusions from the existing science.
Are you seeing a pattern here?
Fish Oil Supplements and Eye Health
In a study review published in Acta Opthalmologica, people with dry eyes who took fish oil reported an improvement in symptoms, although clinical tests showed no difference.
Fish Oil Supplements and Brain Health
A study review published in the journal Cureus suggests that fish oil supplements can boost learning, memory, cognitive performance, and brain blood flow. Another study published in GeroScience showed that people who took fish oil had a slight (7 percent) reduced risk of developing dementia. (Still more research is needed.)
And then there’s the whole idea that fish oil supplements can help treat mental health challenges.
In a study published in JAMA, people who took omega-3 supplements for an average of 5.3 years were slightly more likely to develop depression or depressive symptoms than those who took placebos.
And fish oil isn’t a substitute for medication for mental health, either. “The science isn’t quite there if you’re looking at things like mood improvement, like if somebody is truly diagnosed with a mental health disorder, such as major depression,” says LesLee Funderburk, Ph.D., R.D., C.S.S.D., C.S.C.S., Associate Professor in Nutrition Sciences at Baylor University’s Robbins College of Health and Human Sciences.
Should You Take a Fish Oil Supplement?
DO YOU EAT fatty fish twice a week or more? If not, a fish oil supplement might benefit you, says St. Pierre. Any time you eat a serving of fatty fish, you can skip the supplement that day and the next few days.
A dose of one to two grams of EPA and DHA per day is likely safe and beneficial, without requiring you to swallow more than one to three pills a day, says St. Pierre.
Choose a product independently verified by NSF, USP, ConsumerLab, or Informed Choice for purity and quality. Then, read the label closely—some products combine fish oil and other nutrients like vitamin D or vitamin K. You could accidentally overdo it when combining one of these varieties with other supps containing the same nutrients.
And of course, before starting a new supplement, chat with your doctor or pharmacist. This is especially important if you take a blood thinner because fish oil can also have anticoagulating properties, especially at high doses. And if you have a fish allergy, ask about alternatives like krill oil or algae oil.
One more thing: Don’t bother with eggs or milk with added DHA or EPA. The extra cost isn’t worth the minimal benefit. “The amounts that are present in products like that are too low,” says Funderburk. “There’s no therapeutic effect that’s going to occur from using those products during the week.”
