More people are trying to add omega-3s to their diet – for good reason. Research suggests that omega-3s reduce inflammation and may lower the risk of some health problems including heart disease. In addition, they may have benefits for brain health and, possibly, mental health as well. The problem is not all omega-3s are created equal. Some sources say you can get the benefits of omega-3s by eating more flaxseed and walnuts. Not necessarily so. Here’s why.
Short-Chain versus Long-Chain Omega-3s: What’s the Difference?
Omega-3s exist in nature in two forms: short-chain and long-chain omega-3s. Short-chain omega-3s include alpha-linolenic acid. Alpha-linolenic acid is found primarily in plant-based food with the best sources being flaxseeds, walnuts, soybeans, canola oil, chia seed, and hemp. Short-chain omega-3s haven’t been proven, as of yet, to have the same health benefits as the long-chain fatty acids, DHA and EPA, that are anti-inflammatory and have benefits for heart and brain health. Long-chain fatty acids like DHA and EPA in their natural form are most abundant in fatty fish like wild salmon, mackerel and sardines. Some foods are also fortified with omega-3s but it’s in the form of short-chain omega-3s or alpha-linolenic acid.
The good news is alpha-linolenic acid can be converted to long-chain omega-3s. The problem is this conversion isn’t very efficient. In fact, the amount of dietary alpha-linolenic acid converted to DHA and EPA (the more beneficial long-chain fatty acids) is usually less than 10%. One study even showed that conversion was less than 0.1% in healthy males. Women appear to be slightly more efficient converters than men. This means you’re not getting a significant amount of the more beneficial long-chain omega-3s when you depend on plant-based omega-3 sources like flaxseed and walnuts. Not that these foods aren’t good for you, but the short-chain omega-3s they contain haven’t been as extensively studied as the long-chain omega-3s.
What Does This Mean?
Enjoy walnuts and flaxseed for their other health benefits. They’re a good source of fiber, and flaxseed has natural lignans that may offer protection against breast cancer. On the other hand, don’t count on them, or any other plant-based source of omega-3s, to provide the same cardioprotection as the long-chain omega-3s in fatty fish. The conversion is simply not efficient enough to give you the quantity you need. Also, don’t depend on products with added omega-3s to supply significant amounts of DHA and EPA. Again, these products are fortified with alpha-linolenic acid, plant-based omega-3s, which doesn’t yield significant amounts of DHA or EPA. Fatty fish is still your best source for long-chain omega-3s. If you choose to take fish oil capsules rather than eat fatty fish, choose a brand that’s molecularly distilled since this process removes virtually all of the heavy metals and other impurities that make some fish unhealthy.
References:
Men’s Health. “The Truth about Omega-3s”
Int. J. Vitam. Nutr. Res. 68 (3): 159–173.
American Journal of Clinical Nutrition 84 (1): 44–53.
