Chia Seeds & Their Omega-3 Fatty Acid Content

Chia seeds are an excellent source of omega-3 fatty acids, with 100 grams of chia seeds providing about 18 grams of omega-3 fatty acids [1]. In plant-based foods such as chia seeds, omega-3 fatty acids occur in the form of alpha-linolenic acid, or ALA, which is classified as a short-chain fatty acid. In fish, by contrast, these polyunsaturated fatty acids occur in two forms: eicosapentaenoic acid (EPA) and docohexaenoic acid (DHA), which are classified as long-chain fatty acids. Also the omega-3 in oysters, microalgae and other marine sources occurs in the form of DHA and EPA.

The long-chain forms of omega-3 have been extensively researched, and both the scientific community and the media keep touting their health benefits. Although chia seeds do not contain these long-chain fatty acids, the human body can convert the short-chain omega-3 fatty acids in chia seeds to DHA and EPA. Unfortunately, however, the human body is not very good at converting omega-3 fatty acids in chia seeds and other plant-based sources to the long-chain forms. The range of conversion of ALA to EPA has been reported to be in the range of 0.2% to 9%, and the conversion to DHA appears to be even lower. That said, women of childbearing age might be able to convert up to 21% of their dietary ALA to EPA. [2].

Given the fact that the omega-3 fatty acids in chia seeds are not easily converted to DHA and EPA, you might think that the omega-3 in chia seeds is not particularly beneficial for your health. That, however, couldn't be further from the truth! A growing body of evidence shows that plant-derived alpha-linolenic acid has many health benefits that are not related to its role as a precursor to DHA and EPA.

One of the most researched potential health benefits of ALA is its ability to provide protection against cardiovascular disease. A study published in The American Journal of Clinical Nutrition concluded that plant-based ALA appears to provide at least some protection against cardiovascular disease (CVD), although the strength of the evidence is not nearly the same as for marine omega-3 fatty acids. This study also points out that the source of ALA may be relevant when it comes to its cholesterol-lowering properties, with whole food sources the greatest benefit. [3] So, if your goal is to improve your cardiovascular health, you may want to eat whole chia seeds rather than use chia oil.

Cardioprotective effects aside, the omega-3 fatty acid ALA in chia seeds may also help improve asthma in some people, reduce chronic inflammation, reduce the risk of breast cancer (see chia seeds and breast cancer), and keep your bones strong and healthy. Thanks to the ALA and other nutrients they contain, chia seeds may also be good for pregnant women.

So, to sum up, if you are trying to reap the much-touted health benefits of the long-chain omega-3 fatty acids DHA and EPA, go for marine sources because the omega-3 in chia seeds is not easily converted to DHA and EPA. Here's a list of fish that are high in omega-3 and low in mercury so you can get your marine omega-3s while minimizing your exposure to one of the most harmful heavy metals found in fish. On the other hand, if your goal is to maintain a healthy, balanced diet, it is a good idea to include both marine-based and plant-based sources of omega-3 such as chia seeds in your diet because different types of omega-3 fatty acids have different health benefits.

Sources:
1. HealWithFood.org. Chia Seed Nutrition Facts.
2. J. Greenberg et al (2008). Omega-3 Fatty Acid Supplementation During Pregnancy. Reviews in Obstetrics and Gynecology, 1(4): 162-169.
3. S. Rajaram (2104). Health benefits of plant-derived alpha-linolenic acid. The American Journal of Clinical Nutrition, 100, Supplement 1, 443S-448S.