April 27, 2009
By Tammy Russell, R.D., Contributing Writer
For many, omega-3 fatty acids are kind of an afterthought. Popular magazines remind us to keep up our consumption of fish like salmon to ensure enough omega-3 fatty acid consumption. Vegetarians and vegans abstain from eating fish and shellfish, which is one way to avoid over-fishing our seas and polluting them with contaminants like PCBs, mercury and dioxins.
The real truth, though, is that most Americans don't get enough omega-3 fatty acids and even worse, over-consume another kind of fatty acid called omega-6. Although there are many healthy foods that contain omega-6 fatty acids, overeating vegetable oils and processed foods with high concentrations of omega-6 fatty acids imperils all of the potential benefits we could get from omega-3s.
What are omega-3 fatty acids anyway? Where do they come from and what do they do? Omega-3 fatty acids are plant-based and algae-derived fats that our bodies do not make on their own; thus they are considered essential to the diet. Omega-3 fatty acids play a crucial role in brain development/function as well as normal growth and development. The plant-based omega-3 fatty acid, alpha-linolenic acid (ALA) is found in flax seeds, walnuts, hemp seeds, dark green leafy vegetables and canola oil.
In the body, ALA is transformed via an enzymatic reaction to the highly unsaturated fatty acids (HUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA is used to make eicosanoids, which play a vital role in reducing inflammation, limiting cell proliferation and decreasing blood pressure. In this way, EPA helps to counteract the eicasonoids formed by arachidonic acid (found in meat, poultry and dairy products) which have the opposite effects of raising blood pressure and worsening the markers of heart disease when consumed in excess.
Two of the biggest issues with omega-3 fatty acid intake are that we consume too much omega-6 fatty acid compared to omega-3 fatty acid, and we need to eat more omega-3. This is especially true for vegans. The Joint World Health Organization/Food and Agriculture Organization (WHO/FAO) Expert Consultation on Diet, Nutrition and the Prevention of Chronic Diseases (2003) recommends 5 to 8 percent of calories from omega-6 fatty acids and 1 to 2 percent of calories from omega-3 fatty acids for the general population.
For vegetarians, this translates to about 12 to 18 grams of omega-6 fatty acids and 3 to 6 grams of omega-3 fatty acids every day. Vegans and vegetarians were found to be short of reaching this goal by having omega-3s make up only one-half percent to 1 percent of their daily calories. The best way to think about omega-3 fatty acids is that the ratio of omega-6 to omega-3s turns out to be very important for the good eicosanoids to do their job. The ideal ratio of these two types of fatty acids is 2:1 (omega-6 to omega-3) to 4:1 at the upper limit. Most vegetarian diets average 10:1 to 20:1, indicating way too much omega-6 fatty acids in relation to omega-3.
The best way to increase your consumption of omega-3 fatty acids without contributing to the disaster we call the fishing industry is by consuming ALA-rich flax seed oil, ground up flax seeds, walnuts, dark green leafy vegetables, canola oil and hemp seeds/hemp seed oil. Aim for 3 to 6 grams of omega-3 fats daily. This translates to a teaspoon of flaxseed oil per day, which has 2.7 grams, plus ALA-rich greens, walnuts, soybeans, hemp and other vegetarian foods. It is very important to not over consume omega-6 fatty acids, such as found in processed foods laden with cottonseed, soybean, corn, sunflower, and safflower oils. Too many omega-6 fatty acids in your diet can hinder ALA conversion to omega-3 fatty acids by 40-50 percent. Some people with increased requirements for omega-3 fatty acids, such as pregnant or lactating women, or those suffering from chronic illness, would fare better from direct EPA/DHA sources such as DHA-rich microalgae capsules sold over the counter providing 100 – 300 mg DHA per capsule and/or sea vegetables that are rich in EPA.
ALA (omega-3 fatty acids) in Foods
Flaxseed oil, 1 tablespoon: 8.0 grams
Hempseed oil, 1 tablespoon: 2.7 grams
Canola oil, 1 tablespoon: 1.6 grams
Soybean oil, 1 tablespoon: 1.0 gram
Walnuts, 1 ounce: 2.7 grams
Flaxseeds, 1 tablespoon: 2.6 grams
Soybeans, cooked 1 cup: 1.1 grams
Leafy greens raw, 1 cup: 0.1 gram
Wheat germ, 2 tablespoons: 0.1 gram
Source: The New Becoming Vegetarian by Vesanto Melina and Brenda Davis.