Marine oils are known for being good sources of omega-3 fatty acids—they are reliable sources of EPA and DHA, which have been shown to support everything from heart health to cognitive health (1, 2). A study published in Mayo Clinic Proceedings concluded that people should consider taking omega-3 supplements at doses “far higher than what is typical, even among people who regularly eat fish” (1). That said, there are some concerns: Marine oils can be inaccessible to vegans, and many worry about the impact of omega-3 extraction on fish populations. Fortunately, not all marine oils come from fish—and many of the companies that do get their omega-3s from fish work to ensure the sustainability of the process. Here’s an overview of what’s available.

Fish Oil Generally sourced from anchovies or sardines, fish oil is the baseline omega-3—it is thoroughly researched, and constitutes a substantial source of omega-3 EPA and DHA. Amount of EPA and DHA is likely a customer’s first concern, but Trisha Sugarek MacDonald, BS, MS, Sr. Director of R&D/National Educator at Bluebonnet Nutrition, has told WholeFoods that rather than just going for the highest possible potency, consumers need to consider the end goal—a high ratio of DHA to EPA has been scientifically shown to support cognitive health, a 4:6 ratio has been shown to help support the heart, and a low ratio of DHA to EPA has been shown to help support the joints (3).

There’s also DPA. According to Aqua Biome, DPA is the “missing omega”—their website,, says it can switch into either EPA or DHA, depending on what the body needs at the moment.

Once a customer chooses a ratio, they may want to consider bioavailability. There are different ways of tackling this, but Barlean’s uses emulsification. According to its website, oils and fats have to be broken down and mixed with water to be digested—with fish oil, this results in ‘fish burps’ and potential nutrient loss (4). Emulsification solves that problem. Another way to handle the issue: offering the oil in the triglyceride form, as does Nordic Naturals. The company’s website explains that that’s the form naturally found in fish, and the form the body most easily absorbs—which also avoids a fishy taste, the company says (5).

Cod Liver Oil  The difference between the cod liver oil and fish oil is that cod liver oil contains substantial amounts of vitamins A and D—sometimes exceeding the daily requirements for adults—whereas fish oil does not (6). If a customer isn’t taking either vitamin and has discussed it with a doctor, cod liver oil may be the better option, but for those who are already taking supplements containing vitamins A and D or are looking to get large doses of omega-3s, fish oil is the way to go.


Sustainability is a crucial aspect of every fish oil product. Fortunately, there are a variety of ways that companies are addressing the issue. Aker BioMarine, for instance, has a dialogue open with WWF-Norway to ensure that their operations have a low impact on the Antarctic ecosystem, according to the company’s website (12). Aker is one of the co-founders of the Antarctic Wildlife Research Fund, which has so far funded nine research projects that will improve the management of the fishery for Antarctic krill. It is part of an association of krill harvesting companies that has pledged to stop fishing in certain areas—like buffer zones around breeding colonies of penguins—to protect Antarctic wildlife.

Aqua Biome sources fish oil from Peruvian anchoveta, which its website calls “one of the most sustainable sources on the planet,” and also donates a portion of each sale to Mote Marine to help rebuild coral reefs.

There’s also Friend of the Sea, a World Sustainability Organization project, which certifies sustainable fisheries, helping retailers and consumers find sustainable products.
Krill Oil Krill oil contains omega-3s in phospholipid form, rather than triglyceride form, which may boost bioavailability—something that researchers are still studying (7). And krill oil, like cod liver oil, has a bit of an added value: It contains astaxanthin, which has anti-inflammatory and antioxidant effects (7). One study, performed on 90 people with chronic inflammation, found that 300mg of krill oil daily was enough to reduce C-reactive protein, a marker of inflammation, by 30% (8). And according to Daiwa Health Development, krill oil delivers vitamins A and E.

Besides the fact that krill oil hasn’t been studied as much as fish oil, the downside is that it often comes with a higher price tag. Those who don’t need the added value of astaxanthin and vitamins A and E may prefer to stick with fish oil, but for some, the added value will be worth the cost.

Algae Oil Vegans can get their omega-3s from the ocean in the form of algae oil. Like fish oil, algae oil doesn’t have extra components—just the EPA and DHA, making it easy to fit into an existing routine. And according to one 2008 study, algal oil supplements were found to have the same effect on DHA levels as cooked salmon (9). It has also been found to be nutritionally equivalent to fish oil DHA supplements (10).

The amount of omega-3 in algae oil can also be manipulated by altering their exposure to UV light, oxygen, sodium, glucose, and temperature (11). Those who farm it can increase the amount of omega-3 produced, shrinking the dosage necessary. And getting omega-3s from algae is a foolproof way to avoid a fishy taste. WF


  1. WholeFoods Magazine Staff, “Increased Omega-3 Intake Linked to Cardioprotection,” WholeFoods Magazine. Posted 09/21/2020. Accessed 10/1/2020.
  2. WholeFoods Magazine Staff, “Study: Higher Omega-3 Index Could Protect Brain from Air Pollution.” WholeFoods Magazine. Posted 07/23/2020. Accessed 10/1/2020.
  3. Julia Peterman, “Omega-3, -6, -9 Update.” WholeFoods Magazine. Posted 10/17/2019. Accessed 10/1/2020.
  4. “Emulsion, Absorption and Bioavailability: The Secret to Getting More,” Accessed 10/1/2020.
  5. “Why Omega-3s,” Accessed 10/1/2020.
  6. Consumer Labs Staff, “What is the difference between fish oil and cod liver oil? Is one better than the other?” Posted 02/8/2019. Accessed 10/1/2020.
  7. Taylor Jones, “6 Science-Based Health Benefits of Krill,” Posted 08/19/2020. Accessed 10/1/2020.
  8. Luisa Deutsch, “Evaluation of the effect of Neptune Krill Oil on chronic inflammation and arthritic symptoms,” Journal of the American College of Nutrition, 26(1), 39-48. 2007. Accessed 10/1/2020.
  9. Linda M. Arterburn et al, “Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid,” Journal of the American Dietetic Association, 108(7), 1204-1209. 2008. Accessed 10/1/2020.
  10. Lisa Ryan and Amy M. Symington, “Algal-oil supplements are a viable alternative to fish-oil supplements in terms of docosahexaenoic acid (22:6n-3; DHA),” Journal of Functional Foods, 19 part B, 852-858. 12/2015. Accessed 10/1/2020.
  11. T Catalina Adarme-Vega et al., “Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production,” Microbial Cell Factories, Volume 11. 2012. Accessed 10/1/2020.
  12. “Sustainability,” Accessed 10/1/2020.