Chia Seeds vs Fish Oil: Omega-3 Content

Both chia seeds and fish oil contain a lot of omega-3 fatty acids: a teaspoon of chia seeds contains about 720 milligrams of omega-3 fatty acids, compared with 800 milligrams of omega-3 in a teaspoon of cod liver oil and 470 milligrams in a teaspoon of herring oil [1, 2]. But, it's not only quantity that matters. Fish oil contains docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are classified as long-chain omega-3 fatty acids, whereas chia seeds contain alpha-linolenic acid (ALA), which is a short-chain omega-3 fatty acid. DHA and EPA have been extensively researched, and they have been linked to a whole host of health benefits. Some of the most famous potential health benefits of fish-derived DHA/EPA include improved cardiovascular function, healthy fetal development, and protection against Alzheimer's disease [3].

Although the alpha-linolenic acid from foods like chia seeds can be converted into DHA and EPA by the human body, it has not received as much attention from the scientific community and the media as the long-chain fatty acids because the human body is not very efficient at converting plant-based ALA from foods like chia seeds or flax seeds into DHA and EPA. The range of conversion of ALA to EPA typically lies somewhere between 0.2% and 9%, and the conversion of ALA to DHA has been found to be even lower. Women of childbearing age, however, might be able to convert up to 21% of their dietary ALA to EPA [4].

As a result of the generally low conversion rate, many researchers have concluded that foods rich in ALA, such as chia seeds, do not have the same health benefits as fish oil and other sources of DHA and EPA.

But, make no mistake: not having the same benefits does not mean having no benefits! Indeed, an increasing body of scientific evidence suggests that ALA has several health benefits, independent of its role as a precursor to DHA and EPA, suggesting that also foods like chia seeds have a role in a healthy, balanced diet.

For example, a four-week placebo-controlled study published in the journal International Archives of Allergy and Immunology found that the patients taking perilla seed oil, which is loaded with ALA, experienced a significant increase in lung capacity as well as enhanced air-flow capabilities. In another study, published in the journal Nutrients, ALA-rich chia seed oil increased the EPA content of red blood cell phospholipids as well as the DHA content of breast milk in pregnant and nursing women [6], an observation that lends credence to the claim that chia seeds are good for pregnant women.

In addition, there is some evidence suggesting that ALA is good for your heart, but it is worth noting that the evidence is not as strong as for the omega-3 fatty acids found in fish oil and other marine sources [7]

What's more, just like fish oil, plant-based sources of omega-3 fatty acids have been shown to lower various biomarkers of inflammation in humans [8, 9].

To sum up, the omega-3 fatty acids in chia seeds are different from the much talked-about DHA and EPA omega-3 fatty acids found in fish oil, but it doesn't mean they are useless. In fact, research shows that ALA, the omega-3 fatty acid found in chia seeds, has numerous health benefits in its own right. Therefore, to answer the question whether you should go for chia seeds or fish oil, the best answer may be: go for both!

It is also important to keep in mind that chia seeds and fish oil are by no means the only good sources of omega-3 fatty acids, and in order to keep your diet balanced, it is a good idea to include a wide variety of omega-3 rich foods in your diet. In addition to chia seeds, other good sources of plant-based omega-3 include flaxseeds, hemp hearts, camelina seeds, walnuts, and sacha inchi. Fish oil aside, good sources of DHA and EPA include omega-3 enriched eggs, algae oil, and, of course, fatty fish such as salmon and trout. But beware, some fish may contain high levels of mercury, a heavy metal may cause some serious health problems (see High Omega-3, Low-Mercury Fish).

Sources:
1. HealWithFood.org. Chia Seeds: Nutrition Facts.
2. USDA National Nutrient Database for Standard Reference (Release 28, released September 2015, slightly revised May 2016). USDA Database
3. D. Swanson et al (2012). Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Advances in Nutrition, 3: 1-7.
4. J. Greenberg et al (2008). Omega-3 Fatty Acid Supplementation During Pregnancy. Reviews in Obstetrics and Gynecology, 1(4): 162-169.
5. M. Okamato et al (2000). Effects of perilla seed oil supplementation on leukotriene generation by leucocytes in patients with asthma associated with lipometabolism. International Archives of Allergy & Immunology, 122(2):137-42.
6. R. Valenzuela et al (2015). Modification of Docosahexaenoic Acid Composition of Milk from Nursing Women Who Received Alpha Linolenic Acid from Chia Oil during Gestation and Nursing. Nutrients, 7(8): 6405-6424.
7. S. Rajaram (2104). Health benefits of plant-derived alpha-linolenic acid. The American Journal of Clinical Nutrition, 100, Supplement 1, 443S-448S.
8. B. de Roos et al (2008). Identification of potential serum biomarkers of inflammation and lipid modulation that are altered by fish oil supplementation in healthy volunteers. Proteomics, 8(10):1965-74.
9. A. Stark et al (2008). Update on alpha-linolenic acid. Nutrition Reviews, 66(6).

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