What are omega 3 fatty acids?
You've probably been hearing about omega 3 fatty acids in recent years. The reason? A growing body of scientific research indicates that these healthy fats help prevent a wide range of medical problems, including cardiovascular disease, depression, asthma, and rheumatoid arthritis.
Unlike the saturated fats found in butter and lard, omega 3 fatty acids are polyunsaturated. In chemistry class, the terms "saturated" and "polyunsaturated" refer to the number of hydrogen atoms that are attached to the carbon chain of the fatty acid. In the kitchen, these terms take on a far more practical meaning.
Polyunsaturated fats, unlike saturated fats, are liquid at room temperature and remain liquid when refrigerated or frozen. Monounsaturated fats, found in olive oil, are liquid at room temperature, but harden when refrigerated. When eaten in appropriate amounts, each type of fat can contribute to health. However, the importance of omega 3 fatty acids in health promotion and disease prevention cannot be overstated.
The three most nutritionally important omega 3 fatty acids are
- alpha-linolenic acid
- eicosapentaenoic acid (EPA)
- docosahexaenoic acid (DHA)
Alpha-linolenic acid is one of two fatty acids traditionally classified as "essential." The other fatty acid traditionally viewed as essential is an omega 6 fat called linoleic acid. These fatty acids have traditionally been classified as "essential" because the body is unable to manufacture them on its own and because they play a fundamental role in several physiological functions. As a result, we must be sure our diet contains sufficient amounts of both alpha-linolenic acid and linoleic acid.
Dietary sources of alpha-linolenic acid include flaxseeds, walnuts, hemp seeds, soybeans and some dark green leafy vegetables. Linoleic acid is found in high concentrations in corn oil, safflower oil, sunflower oil, and canola oil. Most people consume a much higher amount of linoleic acid than alpha-linolenic acid, which has important health consequences.
The body converts alpha-linolenic acid into two important omega 3 fats, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). These fats can also be derived directly from certain foods, most notably cold-water fish including salmon, tuna, halibut, and herring. In addition, certain types of algae contain DHA. EPA is believed to play a role in the prevention of cardiovascular disease, while DHA is the necessary for proper brain and nerve development.
| World's Healthiest Foods ranked as quality sources of: omega 3 fatty acids |
||||||
|---|---|---|---|---|---|---|
| Food | Serving Size |
Cals | Amount (g) |
DV (%) |
Nutrient Density |
World's Healthiest Foods Rating |
| Flaxseeds | 2 tbs | 95.3 | 3.51 | 146.3 | 27.6 | excellent |
| Cloves, dried, ground | 2 tsp | 14.2 | 0.20 | 8.3 | 10.6 | very good |
| Walnuts | 0.25 cup | 163.5 | 2.27 | 94.6 | 10.4 | excellent |
| Oregano, dried, ground | 2 tsp | 9.2 | 0.12 | 5.0 | 9.8 | very good |
| Salmon, chinook, baked/broiled | 4 oz-wt | 261.9 | 2.09 | 87.1 | 6.0 | excellent |
| Cauliflower, boiled | 1 cup | 28.5 | 0.21 | 8.8 | 5.5 | very good |
| Mustard seeds | 2 tsp | 35.0 | 0.20 | 8.3 | 4.3 | very good |
| Cabbage, shredded, boiled | 1 cup | 33.0 | 0.17 | 7.1 | 3.9 | very good |
| Romaine lettuce | 2 cup | 15.7 | 0.08 | 3.3 | 3.8 | good |
| Broccoli, steamed | 1 cup | 43.7 | 0.20 | 8.3 | 3.4 | very good |
| Brussel sprouts, boiled | 1 cup | 60.8 | 0.26 | 10.8 | 3.2 | good |
| Winter squash, baked, cubes | 1 cup | 80.0 | 0.34 | 14.2 | 3.2 | good |
| Tofu, raw | 4 oz-wt | 86.2 | 0.36 | 15.0 | 3.1 | good |
| Summer squash, cooked, slices | 1 cup | 36.0 | 0.15 | 6.3 | 3.1 | good |
| Halibut, baked/broiled | 4 oz-wt | 158.8 | 0.62 | 25.8 | 2.9 | good |
| Collard greens, boiled | 1 cup | 49.4 | 0.18 | 7.5 | 2.7 | good |
| Spinach, boiled | 1 cup | 41.4 | 0.15 | 6.3 | 2.7 | good |
| Kale, boiled | 1 cup | 36.4 | 0.13 | 5.4 | 2.7 | good |
| Soybeans, cooked | 1 cup | 297.6 | 1.03 | 42.9 | 2.6 | good |
| Shrimp, steamed/boiled | 4 oz-wt | 112.3 | 0.37 | 15.4 | 2.5 | good |
| Turnip greens, cooked | 1 cup | 28.8 | 0.09 | 3.8 | 2.3 | good |
| Cod, baked/broiled | 4 oz-wt | 119.1 | 0.32 | 13.3 | 2.0 | good |
| Strawberries | 1 cup | 43.2 | 0.11 | 4.6 | 1.9 | good |
| Green beans, boiled | 1 cup | 43.8 | 0.11 | 4.6 | 1.9 | good |
| Snapper, baked/broiled | 4 oz-wt | 145.2 | 0.36 | 15.0 | 1.9 | good |
| Scallops, baked/broiled | 4 oz-wt | 151.7 | 0.35 | 14.6 | 1.7 | good |
| Tuna, yellowfin, baked/broiled | 4 oz-wt | 157.6 | 0.33 | 13.8 | 1.6 | good |
| Raspberries | 1 cup | 60.3 | 0.12 | 5.0 | 1.5 | good |
| Miso | 1 oz | 70.8 | 0.14 | 5.8 | 1.5 | good |
| World's Healthiest Foods Rating |
Rule | ||||
|---|---|---|---|---|---|
| excellent | DV>=75% | OR | Density>=7.6 | AND | DV>=10% |
| very good | DV>=50% | OR | Density>=3.4 | AND | DV>=5% |
| good | DV>=25% | OR | Density>=1.5 | AND | DV>=2.5% |
