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Omega-3 Fatty Acids and Our Health

What are they?

Omega-3 fatty acids are a type of essential fatty acid – they are necessary for human health, but our bodies cannot make them. Therefore, we need to get them through food sources, such as fatty fish (salmon, tuna, halibut), plants and nut oils, like flax seed and walnuts.

Omega-3 fatty acids are known as polyunsaturated fatty acids (PUFAs), a category of fats that are liquid at room temperature. They play a crucial role in brain function, as well as normal growth and development. They have also become popular due to their association with reducing the risk of developing heart disease. Omega-3 fatty acids initially grabbed the attention of scientists in the 1970s when they studied the diets and health of the Inuit population in Greenland in comparison to the people of Denmark. Compared to the Danish controls, the Inuit subjects suffered from heart attacks and diabetes one-tenth of the rate. The cause of this cardioprotective effect was attributed to the diet of the Inuits, which is heavy in marine-based foods. In comparison to the Danish diet, which provided 0.8 g/day of omega-3 fatty acids, the Inuit’s high intake of seafood provided them with 10.5 g/day of omega-3 fatty acids.

Since then more research studying populations in countries with high fish intakes has supported the observation that these fatty acids protect against heart disease. A 2008 review concluded that fish or fish oil providing approximately 250 mg of EPA + DHA (types of omega-3s) daily significantly lowers the risk of cardiovascular disease and death by 36% compared with not consuming these fats. Further studies have demonstrated health effects outside that of the heart, including its critical role in fetal brain development. Omega-3 fatty acids are highly concentrated in the brain and appear to be important in memory and cognitive performance as well.

How do I get them?

DHA and EPA can be synthesized in the body from plant-based omega-3 fatty acids in the diet (ie flax seeds, walnuts, vegetable oils). However, this process is very inefficient. It is recommended that the diet provide additional sources of DHA and EPA, either from seafood or a supplement. The amount of DHA and EPA in fish and seafood is well known (see Table 1), but it’s harder to determine the amount provided in supplements. Neither the FDA nor any other federal agency is required to routinely test fish or marine oil supplements for quality before being sold. The lack of quality control mechanisms makes it difficult to ensure that supplements are indeed safe and the labels are accurate.

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ConsumerLab.com is a privately held company that independently evaluates and reports the validity of dietary supplement products. Of the brands of omega-3 supplements tested on their site, most accurately contained the amount of DHA and EPA labeled on the containers. In addition, they disproved the commonly held belief that fish oil supplements become rancid over time. Some of the most-affordable ConsumerLab.com approved supplements include the following: 21st Century Fish Oil, NatureMade, LifeExtension Super Omega-3, and Swanson Omega-3 Fish Oil-Lemon Flavor. For a full list, see their website.

Bottom Line

There is no official recommendation for the intake of omega-3 fatty acids. The American Heart Association (AHA) and the Dietary Guidelines for Americans recommend eating two or more servings of fish or seafood per week (250 mg omega-3/week) to reduce your risk of cardiovascular disease. For those with documented coronary heart disease, the AHA recommends consuming 1g/day, preferably from oily fish, and up to 4 g/day for those with elevated triglycerides. Why not just take a supplement? Research does not support the use of fish oil supplementation for preventing heart attacks and stroke for those already at risk. The proven cardiovascular benefits from fish oil are strongest with the consumption of the actual food source – fatty fish.

References:

  1. http://www.umm.edu/health/medical/altmed/supplement/omega3-fatty-acids
  2. http://www.todaysdietitian.com/newarchives/040114p20.shtml
  3. http://www.todaysdietitian.com/newarchives/0317p18.shtml

By Jillian Klemm, Dietetic Internal