Nutrispeak Vesanto Melina with Angelina Lam, Gloria Ho & Kelly Bogh
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HEALTH
Getting your omega-3s
esearch suggests omega-3s can reduce the risk of cardiovascular and autoimmune diseases. Fortunately, products with omega-3s – such as margarine, eggs and supplements – are commonly found in grocery stores. Omega-3s are a family of fatty acids that includes a-Linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is a shorter-chain fatty acid while EPA and DHA are examples of longchain, polyunsaturated fatty acids (LC-PUFAs). LC-PUFAs are more active in biological processes than shorter-chain fatty acids. For example, compounds derived from LC-PUFAs enhance the immune system through anti-inflammatory processes and help regulate blood clotting and blood flow. Omega-3 fatty acids are also required for the utilization of genetic information in cells, communication among cells and proper functioning of the brain and nervous system. Recommended intakes ALA is an essential fatty acid, meaning it cannot be synthesized in the body and, therefore, must be obtained from one’s diet. Once consumed, ALA can be lengthened into LC-PUFAs such as EPA and DHA. However, on average, only about 5% of ALA is converted to EPA and less than 0.5% is converted to DHA. Therefore, consumption of foods or supplements containing preformed EPA and DHA can help individuals whose ability to convert to long-chain forms may be compromised – for example, people with type 2 diabetes or hypertension. An adequate intake of ALA is 1.6 grams per day for adult men and 1.1 grams per day for adult women. In addition to ALA, suggested daily intakes of preformed EPA and DHA are 160 milligrams for men and 110 milligrams for women. Individuals who don’t consume preformed EPA and DHA are advised to double their ALA intake (3.2 and 2.2 grams per day for men and women, respectively).
Sources of omega-3s Fish, particularly cold-water, oily fish like salmon, are the most common sources of preformed EPA and DHA. However, fish don’t make EPA and DHA; these originate from the microalgae these fish feed upon. Therefore, microalgaebased supplements containing both EPA and DHA are a plant-based alternative to fish. It may be beneficial for certain vegan populations, pregnant women and those with type 2 diabetes or hypertension to take a supplement with 200–300 milligrams of DHA (and possibly EPA) two to three times weekly. Microalgae and certain types of seaweed (wakame, for example) are the only plant sources of EPA. However, foods containing ALA are abundant in plant-based diets; nuts and seeds are particularly rich sources. For instance, 1/4 cup walnuts or two tablespoons ground flaxseeds or chia seeds will supply at least 3.2 grams of ALA. ALA is also found in oils: 2.5 tablespoons of unrefined canola oil, 1.5 tablespoons of hempseed oil or 1.5 teaspoons of flaxseed oil will provide more than 3.2 grams of ALA. Because these oils can be damaged by heat, use them in salad dressings or drizzle them on cooked vegetables, pasta or soup. Don’t cook with them! To ensure high-quality sources of ALA, purchase unprocessed nuts, seeds and oils and store them in airtight containers in your refrigerator or freezer. j Vesanto Melina is a local registered dietitian (www.nutrispeak.com, www.becoming vegan.ca) For more on fats, see Becoming Vegan: Comprehensive Edition (or the Express Edition) both with Brenda Davis. Angelina Lam, Gloria Ho and Kelly Bogh are third-year UBC dietetics students. Augus t 2 0 15
common ground
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