November 2013 Issue
Beneficial Plant-based Omega-3s
Everyone knows that omega-3 fatty acids are good for you. Hundreds of studies have linked omega-3s to such benefits as lowering inflammation, blood lipids, and blood pressure levels; reducing the risk of type 2 diabetes, and lowering the risk of heart attacks and sudden death for people with coronary heart disease. These healthy polyunsaturated fats may even protect your brain—they’ve been found to help prevent Alzheimer’s disease and to treat depression.
Two types of omega-3s. While the good news about omega-3s is widespread, what many people don’t realize is that there are two major types: the long chain omega-3s eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish and fish oil; and the short-chain form alpha-linolenic acid (ALA), found in walnuts, flax, and some vegetable oils. What is the difference between long-chain and short-chain? Most of the research linking health benefits to omega-3s comes from studies on EPA and DHA intake from fish. But there also are benefits linked to the plant-based variety, ALA.
ALA has benefits, too. Don’t underestimate the health potential of plant omega-3s. Researchers have found that ALA has its own anti-inflammatory and heart health benefits, and, in addition, your body can convert ALA into EPA and DHA—albeit at low levels.
Studies show that people who consume a diet high in ALA-rich foods have a lower risk of heart disease deaths. And a 2009 study published in the American Journal of Clinical Nutrition compared the effects of an ALA-rich walnut diet with an EPA- and DHA-rich salmon diet and a control diet. Subjects who followed the ALA-rich walnut diet for four weeks had lower total cholesterol and LDL cholesterol and better ratios of cholesterol compared to those on the salmon diet and control diet. However, the fish diet showed improved effects on HDL cholesterol and triglycerides compared with the walnut and control diets. The results of the study suggest that consuming plant-based omega-3s, in addition to fish-based omega-3s, may offer the most cardiovascular benefits.
Eat a variety of omega-3s. It’s definitely a good thing to boost your intake of all types of omega-3s, with the priority of getting this nutrient from real food sources rather than supplements. While there is no established DRI (Dietary Reference Intake) for omega-3s, the World Health Organization and governmental health agencies of several countries recommend consuming 0.3 – 0.5 grams (g) of EPA plus DHA, which you can achieve through about two servings a week of fatty fish, such as salmon and sardines, and 0.8 – 1.1 g of alpha-linolenic acid (ALA), through daily intake of walnuts, flax and vegetable oils, daily. The American Heart Association (AHA) echoes this recommendation for EPA and DHA for heart health, suggesting that patients with documented heart disease should consume even higher levels—about 1 g per day. In addition, AHA suggests that everyone should eat foods rich in ALA, whether you eat fish or not. It’s easy to get plenty of ALA in your diet every day, just sprinkle some flax (ground) or chia seeds over you morning cereal, munch on a handful of walnuts at snack time, and use moderate amounts of vegetable oils in cooking. —Sharon Palmer, RD