Growing up, my mom encouraged my siblings and me to take fish oil, but I never knew why. These days, fish oil, found in fatty fish with omega-3s, is a total wellness buzz phrase. And all its supposed health benefits, from improving heart health to improved mood, have me wondering if mom was right all along.
Here’s the thing: Not everyone needs to take fish oil in the supplement form, especially if you consume a good amount of fish in your diet already. Ahead, find out exactly what fish oil is, how supplements work, who should be taking them, and the proven benefits.
Meet the experts: JoAnn E. Manson, MD, is a professor of medicine at Harvard Medical School and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital. Valerie Agyeman, RD, is a dietitian and host of the Flourish Heights podcast.
What is fish oil?
“Fish oil is the polyunsaturated fatty acids, primarily EPA and DHA, that are found in marine animals,” says JoAnn E. Manson, MD, professor of medicine at Harvard Medical School and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital.
The specific type of polyunsaturated fatty acids in fish oil are also known as omega-3 fatty acids, which include EPA, DHA, and ALA, adds Valerie Agyeman, RD, dietitian and host of the Flourish Heights podcast.
“Omega-3s are considered essential just because our bodies can’t produce them, so we have to get them from dietary sources,” Agyeman explains. EPA and DHA can be found in darker fatty fish, like salmon, sardines, tuna, herring, and mackerel. You can also get them in supplement form. (More on this soon!)
4 Potential Fish Oil Benefits
The studies are ongoing and evidence is inconclusive surrounding the benefits of fish oil, Agyeman and Dr. Manson agree. But here are a few of the possible perks of these omega-3 fatty acids:
1. They may improve heart health.
Due to the anti-inflammatory properties of EPA and DHA, foods with these omega-3s in your diet can help support your heart through their ability to support your blood pressure and triglycerides, Agyeman says.
In fact, people with a low fish consumption who took one gram a day of marine omega-3 or fish oil supplements reduced their risk of major cardiovascular events, such as heart attack, strokes, and cardiovascular deaths, in a trial on vitamin D and omega-3s led by Dr. Manson.
2. They help reduce your risk for autoimmune diseases.
Omega-3s have been associated with lowering the risk of developing autoimmune disease or being diagnosed with an autoimmune condition, like rheumatoid arthritis, psoriasis, and lupus. Taking vitamin D in conjunction with omega-3 fatty acids for five years reduced the risk of autoimmune disease by 22 percent, per a 2022 study worked on by Dr. Manson.
3. They might help fetal development.
For pregnant women, EPA and DHA can support their health and are important for the development of their baby’s brain and heart, Agyeman says.
In fact, maternal fish intake during pregnancy was also associated with a reduced risk of a child’s delay in problem-solving and in fine motor skills at six months old, a 2020 study found. And a higher dose of DHA during pregnancy was associated with fewer adverse effects, like early preterm birth, according to a 2021 study.
Of course, it’s not generally considered safe for pregnant women to eat all types of fish, due to high mercury levels in certain types, so you’ll want to check this chart from the FDA for best options and serving recommendations and ask your doctor for more information on what seafood makes the most sense for you.
4. They may assist with fertility.
Omega-3 supplementation can possibly increase the probability of a woman conceiving, per a 2022 study. The women in the study taking omega-3 had 1.51 times the chance of conceiving as the ones who weren’t taking it. However, it was not a randomized controlled trial, so the women who used omega-3 supplements may represent a more health-conscious population.
Where Fish Oil May Fall Short
While some believe that mood, memory, and cognitive function can be improved by fish oil, research hasn’t shown a clear benefit there, Dr. Manson says. “More research is needed on the effects of the omega-3 on mood, depression and memory, [and] cognitive decline,” she notes.
Regarding claims that omega-3s can help with eye health, skin health, liver health, and bone health, “some findings are promising but they’re not conclusive—additional research is needed,” Dr. Manson adds.
How To Get More Omega-3s In Your Diet
The current recommendations are to have two servings of fatty fish per week, Dr. Manson and Agyeman say. It’s generally easy to get omega-3s through your diet with seafood, Agyeman says. (BTW, not only do fish have omega-3s, but they also have other vital nutrients like vitamin D, iron, and vitamin B12.)
There’s a ton of varieties, from canned to frozen to fresh seafood, and a lot of fish can be prepared in 15 to 20 minutes through grilling, air frying, and steaming. Plus, you can always add it to your favorite foods, like pizza or pasta.
Say you’re not into the taste of seafood but you’re trying to get omega-3s through your diet—the first step might be to try white meat seafood, like flounder or halibut, since they’re not as potent with that fishy taste, Agyeman says.
If you’re unable to eat at least one or 1.5 servings of fish a week, then you should consider a fish oil supplement, Dr. Manson adds, since EPA and DHA aren’t available in other food sources outside of these fatty fish.
Now, there’s a third type of omega-3 called ALA, which you can get through plant products such as walnuts, seeds like hemp, chia, and flax, and certain oils, like canola oil, Agyeman says. ALA can convert into EPA and DHA, but it’s very limited, which is why it’s best to get them through fatty fish, she notes.
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What To Know About Fish Oil Supplements
Who should take fish oil supplements?
If you’re a vegan or just can’t stomach the taste of fish, talk to your healthcare provider about adding a supplement. (Vegans can opt for algae-based omega-3 supplements.) Those with a history of cardiovascular disease may be good candidates, too, but should talk to their doctor about a prescription medication with a high dose of EPA, Dr. Manson explains.
Dr. Manson and Agyeman typically recommend a minimum of 1000 milligrams (or one gram) per day and no more than 5,000 milligrams, but it’s different for everyone. “Some people may need more, some people may need less,” Agyeman says. That’s why it’s important to talk to your doc before starting any new supplement.
What are the potential risks of fish oil supplements?
Generally, omega-3s are quite safe at the dose of one gram per day, but there are some potential risks, Dr. Manson says. “Higher doses have been linked to an increased risk of bleeding and an increased risk of atrial fibrillation,” she adds.
So, if you’re about to get surgery, you may need to stop taking your supplement before the procedure. And if you’re at increased risk of atrial fibrillation, or are on any medications that can decrease clotting, like aspirin or another anticoagulant medication, let your doctor know. “Fish oil may interact with some of these medications to increase risk of bleeding,” Dr. Manson says.
On a smaller scale, fish oil can sometimes cause stomach discomfort or digestive issues like nausea or diarrhea, or even allergies, so definitely listen to your body, says Agyeman. (For example, if you’re allergic to fish, taking a fish oil supplement might still give you a reaction.)
What else should you know when shopping for fish oil?
There are a ton of different OTC fish oil types out there, from liquid to capsules, Agyeman says. When looking for a supplement, prioritize brands with a third-party certification, like the U.S. Pharmacopeia (USP) or National Science Foundation (NSF) seal. Products with this seal will have undergone quality control assessments that confirm the dose on the label is actually in each capsule, and that the supplements are free of contaminants like heavy metals or other toxins, Dr. Manson says. You’ll also want to make sure that the supplement has both EPA and DHA in it, Agyeman adds.
Always smart: Abide by the expiration date and check to see if the supplements need to be stored in a certain way.
Addison Aloian (she/her) is an editorial assistant at Women’s Health. When she’s not writing about all things pop culture, health, beauty, and fashion, she loves hitting leg day at the gym, shopping at Trader Joe’s, and watching whichever hockey game is on TV. Her work has also appeared in Allure, StyleCaster, L’Officiel USA, V Magazine, and Modern Luxury Media.