You’ve probably heard of omega-3s, and their role in a healthy diet. Maybe you’ve heard that these fatty acids can be found in abundance in some seafoods, or that they are “heart healthy.” But have you ever wondered what makes this super-lipid so important in our bodies?
The chemistry of omega-3 fatty acids
Omega-3 fatty acids are polyunsaturated. Polyunsaturated fats are so named because they have more than one double bond within their chemical structure. This differentiates polyunsaturated fats from their cousins, saturated and monounsaturated fats.1 Saturated fats have no double bonds (they are “saturated” with hydrogen atoms and thus cannot carry a double bond), while monounsaturated fats have one double bond.
There are three common members of the omega-3 family: ALA, EPA and DHA. The differences between these omega-3 fatty acid chains are the number of carbon atoms and the number of double bonds; ALA has 18 carbon atoms and 3 double bonds, EPA has 20 carbon atoms and 5 double bonds, and DHA has 22 carbon atoms and 6 double bonds. The length of the chain (dependent upon the number of carbon atoms) and the number of hydrogen atoms influences the flexibility of the structure, thus affecting how it functions within cells.2
Why is this important?
Your body needs omega-3s! They cannot be synthesized within the human body, and yet are necessary for its function. It’s also notable that while saturated and monounsaturated fats can be used by the body for energy, polyunsaturated fats are the only type of fat that is essential to the body.3
They’re essential for your brain. Omega-3s are needed to form prostaglandins, which initiate the brain’s self-repair system and are basic structural components of the brain. Indirectly, DHA is a major component of the retina of your eye. People who eat a lot of the DHA form of omega-3 are more likely to be able to see better and therefore learn better.4 There have also been studies that suggest omega-3s can reduce symptoms of depression, rheumatoid arthritis and ADHD, and can reduce inflammation.1
They’re essential for your heart. Omega-3s have been shown to improve cardiovascular health in multiple studies. They first attracted the attention of researchers studying the diet of the Inuit in the 1970s. Their research showed that compared with the Danish population, the Inuit suffered from diabetes and heart attacks at one-tenth the rate. The Inuit diet, rich in seafood, provided 10.5 grams of omega-3s in the form of EPA and DHA daily, which provided the cardio-protective benefit.1
They’re essential for your baby. Research has shown that EPA and DHA are essential for fetal brain and retina development.1 DHA constitutes 10 to 15 percent of the baby’s cerebral cortex and 50 percent of the weight of the retina. It is so critical to the baby during late pregnancy that the placenta extracts it from the mother’s blood and creates a higher concentration of DHA within the baby’s circulatory system.2
I’ve only mentioned EPA and DHA here, as these are the most important forms of omega-3 for your body. EPA and (especially) DHA are longer chains of molecules that have more double bonds between their atoms than ALA. Where a double bond is present, a hydrogen atom is absent, creating the potential for flexibility within the molecular chain. All omega-3s have surprisingly flexible chemical structures, and DHA in particular has been shown to have a wide range of conformations.5 While EPA and DHA can be synthesized in your body from ALA, the conversion rate is very low (less than 1 percent).1
The Benefits of Salmon
One of the best sources of omega-3s is salmon, particularly Copper River salmon. The reason? The marine food chain, and the incredible life story of Copper River salmon.
Copper River salmon typically spend between two and four years in the ocean after leaving fresh water. They gain about 99 percent of their body mass in the ocean, eating small invertebrates and fish. These tiny creatures have been eating plankton, an excellent source of ALA omega-3 fatty acid. When they eat plankton, some of the ALA is converted to EPA and DHA within the predators’ bodies. As those predators are eaten by the Copper River salmon, EPA and DHA accumulate to high concentrations within each salmon’s body.4
While all wild salmon follow a close version of this lifecycle, there is something that makes Copper River salmon shine above even their wild cousins: the Copper River. Copper River salmon must store larger amounts of precious omega-3 fat to swim 300 miles or more to their natal stream to spawn. They need every bit of the energy for their journey, simply to procreate. Not only is the Copper River long, but it is one of the most turbid rivers in Alaska. Hundreds of miles of strong current requires that these salmon be the hardiest of them all, and that means storing up plenty of healthy fat.
It’s worth noting that farmed salmon can’t compare to wild salmon (and especially Copper River salmon) when it comes to omega-3s. Farmed salmon don’t experience their natural life cycle of gathering healthy nutrients over years in the ocean when they are fed processed food (which may include scraps from fish processing, wild forage fish and synthetic supplements, and comes in the form of pellets, much like dog food6) and don’t live nearly as long.4 The diet of a wild salmon varies by species and region. Wild Alaska sockeye salmon often feed on small prey such as zooplankton and krill. In contrast, wild Alaska coho salmon are voracious, opportunistic predators and tend to feed on fish or other available prey in their environment.
Omega-3 fatty acids are essential for your brain, your heart, and your well-being. If you’d like to incorporate more of these healthy fats into your diet, wild salmon is nature’s perfect source.
1. Weisenberger J. “The Omega Fats.” Today’s Dietitian. http://www.todaysdietitian.com/newarchives/040114p20.shtml.
2. Brewer S. “DHA – Brain food.” Healthspan. 21 Sep 2005. http://omega3forchildren.co.uk/articles/article_details.aspx?id=231.
3. Holford P. (1999). The optimum nutrition bible. Freedom, CA: Crossing Press.
4. Sears W. The Family Nutrition Book: Everything You Need to Know About Feeding Your Children – From Birth through Adolescence. Little Brown, 1999.
5. Gawrisch K, Eldho NV, Holte LL. “The structure of DHA in phospholipid membranes.” Lipids. 38.4 (2003): 445–52.
6. “Feeds for Aquaculture.” NOAA Fisheries. http://www.nmfs.noaa.gov/aquaculture/faqs/faq_feeds.html#17how