Debunking the Top 3 Myths about Omega-3 Fats

Mia Syn, MS, RD



Published on

23 October 2017


Omega-3 fats are often touted important nutrients by the media. In fact, fish oil was the most popular natural product used by adults in the U.S. in 2012. (1) It is true that omega-3 fats have been linked to heart, brain and eye health by research. (2) However, there are many myths that have been propagated and should be debunked. Here are three that you need to know:

Myth No. 1: All omega fats are the same.

Omega-3 and omega-6 fats are similar in the fact that they are both essential. We need to obtain them from food since our bodies cannot produce them on our own in sufficient amounts. Omega-6 fats are needed for skin and hair growth, regulating metabolism and maintaining the reproductive system. (11) Omega-3 fats are an integral part of cell membranes and hormones involved in combatting inflammation and relaxing artery walls.(12) Because of these roles, omega-3 fats may help prevent heart disease and ameliorate inflammation associated with eczema and rheumatoid arthritis. (3)

They differ in that omega-6 fats are much easier to obtain and most of us get enough from our diet already, without putting much thought or effort into it. Omega-6 fats are mostly found in plant oils like soybean, corn and sunflower. Most processed and fast foods use these oils because of their convenience and price. (6) Because these foods are a mainstay in the modern diet, it is no surprise that omega-6 fats are consumed in abundance and thus omega-6 supplements are not typically needed. (4) Omega-3 fats, which come from limited food sources like cold-water fish are not as predominant in the modern diet, which may explain why supplementation is so prevalent.

Some omega-6 fats tend to promote inflammation while omega-3 fats reduce it. (5) Some studies advise that we keep the ratio of omega-6 to omega-3 at one to one for optimal health. (5)

Myth No. 2: Bigger isn’t always better.

When it comes to your fish oil capsules, it is the concentration that matters. Large capsule size is not indicative of having greater efficacy. Look for fish oil in smaller, easy-to-swallow capsules at the same concentration that you would find in standard fish oil capsules. It is important to always read the label and seek out the concentration that best meets your nutrient needs.

Myth No. 3: Omega-3 fats from plants and fish are equally beneficial.

We’ve all heard that salmon and walnuts are good sources of omega-3 fats, but the truth is that their fats vary greatly in structure and function. Omega-3 fats exist in three principle forms: docosahexaenoic acid (DHA) eicosapentaenoic acid (EPA) and alpha-linolenic acid (ALA). EPA and DHA are largely found in cold-water fish like salmon, sardines and mackerel while ALA is found in plant sources like walnuts and flaxseeds.

In order for ALA to be active in the body, it must be converted into EPA and DHA. Studies have shown that the conversion is small and dependent on many factors including current nutritional status. (6)

EPA and DHA have been linked to several important functions including aiding proper fetal development and helping to support the cardiovascular system. (7) Fish oil dietary supplements provide omega-3 fats in the forms EPA and DHA while flaxseed oil provides ALA. Algae oil is one of the only vegetarian sources of DHA.

Myth No. 4: Fish is the only way to meet your omega-3 needs.

As a dietitian in America, I follow the dietary guidelines, which recommends that adults eat eight or more ounces of seafood per week. This is thought to provide EPA and DHA in sufficient amounts to support overall heart health without preexisting cardiovascular disease. (8)

While fish is a potent source of DHA and EPA omega-3 fats, it is important to remember that fish will vary in the amount that they contain. This is often dependent on how and where it was raised, its feed and the time of year. (9) Many farm-raised fish are fed grain devoid of omega-3 fats and thus lowers the amount that the fish will contain and how much will make it onto our plate. (9)

In addition, many of the fish that contain omega-3 fats may also contain high levels of environmental contaminants. Children and pregnant women are advised to avoid eating fish with potential for high mercury contamination including shark, swordfish and mackerel.

Become cognizant of the fish that you eat. Seek out smaller fish like sardines and anchovies as opposed to large ones like cod, mackerel and swordfish, which tend to be higher in mercury. Fish oil capsules are generally low in mercury and other pollutants (10). To be safe, consumers can seek out supplements with the USP Verified Mark, which indicates that it has been tested and does not contain harmful levels of contaminants.


1. [Internet]. Bethesda: National Center for Complementary and Integrative Health; c2012 [cited 2017 April 10]. Available from:

2. Zheng JS, Hu XJ, Zhao YM, et al. Intake of fish and marine n-3 polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies. BMJ. 2013;346:f3706.

3. Leaf A. Prevention of sudden cardiac death by n-3 polyunsaturated fatty acids. J Cardiovasc Med. 2007; 8 Suppl 1:S27-29.

4. Patterson E, Wall R, Fitzgerale GF, et al. Health Implications of High Dietary Omega-6 Polyunsaturated Fatty Acids. J Nutr Metab. 2012;539426.

5. Simopoulos AP: The Importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother 2002; October.

6. Harris W, Mozaffarian D, et al: Omega-6 Fatty Acids and Risk for Cardiovascular Disease. Circulation 2009; February 16.

7. Swanson D, Block R, Mousa SA: Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Adv Nutr. 2012; 3(1): 1–

8. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at

9. Sargent J. R., Tocher D. R. & Bell J. G. The Lipids in Fish Nutrition 3rd edn, (eds Halver J. E. & Hardy R. W.) Ch. 4, 181–257 (Elsevier Science, 2002).

10. Foran SE, Flood JG, Lewandrowski KB. Measurement of Mercury Levels in Concentrated over-the-Counter Fish Oil Preparations: Is Fish Oil Healthier than Fish? Arch. Pathol. Lab. Med. 2003;127:1603-5.

11. [Internet]. Baltimore: University of Maryland Medical Center; c2017 [cited 2017 April 10] Available from:

12. [Internet]. Boston: Harvard University: c2017 [cited 2017 April 10] Available from:

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