Flaxseed and fish oil both contain essential omega-3 fatty acids, but while one of these two is a superstar home run hitter, the other should probably remain as a bench warmer. Omega-3s help keep your heart healthy and your immune system strong. Choosing the source of your dietary omega-3s is an important decision, with nutrition, safety and palatability being key factors.
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As an adult woman, the U.S. Department of Agriculture recommends that you eat 1.1 grams of omega-3 fatty acids per day to prevent deficiency and optimize health. Eight grams -- 1 tablespoon -- of ground flaxseed will give you your daily dose, providing 1.8 grams of omega-3s, 36 calories, 3.3 grams of fat, 1.6 grams of protein, 2.2 grams of fiber and no cholesterol. While 8 grams of fish oil -- just under 2 teaspoons -- provides more omega-3s at 2.74 grams, it also provides 72 calories, 8 grams of fat, 39 milligrams of cholesterol and is devoid of protein and fiber. Gram for gram, flaxseed has a superior nutritional profile.
Your safety is one of the biggest reasons to avoid fish oil supplements. The Environmental Protection Agency notes that nearly all fish and shellfish contain mercury. Toxic pesticides like DDT and industrial chemicals like PCBs are also commonly found in seafood. These contaminants build up in the fatty tissue, liver and skins of fish, which are used to produce commercial fish oils. Even purified, distilled and refined fish oils can contain pollutants. With flaxseed, you don’t have to worry about these health risks.
Consider yourself lucky if you have never had the misfortune of burping up the taste of a fish oil capsule that you took earlier in the day. If you have had this experience, you know that flavor is another reason flax is preferable to fish oil. While fish oil tastes like the smell of the seafood department at your local grocery store, flax has a mild, pleasant flavor that is nutty or seedy. You can easily and tastelessly incorporate it into smoothies, oatmeal, baked goods, cereal, doughs, batters or casseroles.
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The best way to get your omega-3 fatty acids is through whole plant-based foods. Purchase ground or milled flax because it is more digestible than the whole seeds. Other plant foods with high omega-3 content include walnuts and soybeans. Flax, walnut, soybean and canola oils are also good sources but are more refined and therefore not as nutrient-dense. If you really prefer to take a supplement, you are off the hook as long as you look for a product that is derived from algae, which is where the fish get its omega-3s.
- Flax Council of Canada: Flax Nutrition
- USDA: National Nutrient Database
- EPA: What You Need to Know About Mercury in Fish and Shellfish
- NutritionFacts.org: Fish Oil in Troubled Waters
- NutritionFacts.org: Is Distilled Fish Oil Toxin Free?
- NutritionFacts.org: DDT in Fish Oil Supplements
- Nutrition Concepts and Controversies 10th Edition; Frances Sizer and Ellie Whitney
Tara Martine is a registered dietitian and licensed dietitian/nutritionist based in North Carolina. She specializes in sports nutrition, plant-based nutrition and weight loss. Martine holds a Master of Science in nutrition from the University of North Carolina at Greensboro.