Fish Oil vs. Omega-3: Which Is The Better Supplement Option? Experts Weigh In

Not exactly, but there is some overlap. We asked mbg Collective member and registered dietitian Jess Cording, M.S., R.D., CDN, to help clear up the confusion. "All fish oil supplements are providing omega-3s, but not all omega-3 supplements are from fish oil," she explains.

"There's three types of omega-3 fatty acids," Cording goes on to say. "There's ALA, DHA, and EPA. ALA is a plant source, and then EPA and DHA are both found in animal products—primarily fish." Oily fish—such as tuna, anchovies, salmon, mackerel, and sardines—are especially rich in EPA and DHA, which is why they're often featured in fish oil supplements. 

At this point, research reveals that most of the omega-3 health benefits come from EPA and DHA rather than plant-sourced ALA (in other words, they're not interchangeable). Although our bodies technically have the ability to convert small amounts of ALA from food sources into EPA and DHA, the process is very inefficient and variable (because of gender, age, etc.), so it's best to also consume some EPA and DHA to ensure you're reaching optimal omega-3 levels. 

Omega-3 supplements with algal (algae) oil is Cording's first choice for her plant-based patients. "I often recommend an algae-based supplement for them if fish is not an option," she says. Like us, fish aren't able to produce their own EPA and DHA. Instead, they get their omega-3s by consuming microalgae, so algae is a primary source of both DHA (mostly) and EPA (a little bit)1 for those who cannot or choose not to eat seafood. 

Flaxseed oil is another plant-based option for omega-3 supplementation. Flaxseed is high in ALA (the plant-sourced essential omega-3 fatty acid) and can help provide omega-3s for those who avoid meat and seafood. While there isn't an official recommendation for daily EPA or DHA intake (yet), the National Academies recommend that men and women get 1.6 grams and 1.1 grams of ALA per day2, respectively. 

Fish oil is the concentrated and purified oil from—you guessed it—the tissue of oily fish. There are a variety of forms this fat can be delivered in based on how the fish oil is processed. (By "form," we mean the type or chemical structure of the omega-3 fats.)

The main forms are triglyceride, ethyl ester, and phospholipid. The native form of fat is triglyceride for fish and humans. It's also the most bioavailable form3 (i.e., more easily absorbed and accessible to your cells).* 

"For fish oil, the triglyceride form is where it's at," Ferira shares. "The triglyceride form is how marine omega-3 fatty acids EPA and DHA are found in the fat of the fish—and how we consume and absorb fat in our diet. In other words, it's the form found in nature and native to the fish."

Krill are small, shrimplike crustaceans that, like fish, mostly eat microalgae. If you're a marine biology aficionado, you may know that many fish and mammals—like whales—depend on krill as a diet staple.

Omega-3 supplements are not one-size-fits-all. For those who don't eat fish by choice or because they cannot (e.g., because of an allergy), there are some viable options derived from plants. "Algae is great, flax is great—but again, it's not quite as efficient," Cording reminds us. For plant-based folks, eating lots of ALA-rich foods and finding a high-quality omega-3 supplement to meet the recommended intake for ALA is important for whole-body health.

If you're in the 10% of Americans5 who actually eat two or more servings of oily fish per week, you might not need to take a supplement every day to meet baseline levels of omega-3s. Or you may still leverage an omega-3 supplement to meet the higher levels recommended by the American Heart Association6 for cardioprotection (i.e., 1 gram or more of EPA and DHA daily).*

If you're in the other 90%, you're definitely not alone, and there's no need to stress. There are high-quality omega-3 supplements out there to help you thrive on daily omega-3 intake so you can reap the benefits, just like avid fish-eaters.