Omega-3 lipids are an important type of polyunsaturated fat. There are three types of omega-3 fatty acids: EPA, DHA, and ALA.
Because EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are mostly found in fish, they are commonly referred to as marine omega-3s.
The most prevalent omega-3 fatty acid in most diets is ALA (alpha-linolenic acid). The human body primarily uses ALA for energy, with very little conversion to EPA and DHA.
Omega-3 Functions
Most of the types of fats that the body requires can be produced by it from other fats or basic materials. The case with omega-3 fatty acids is different. These are necessary fats that the body cannot produce on its own and must obtain from meals.
They are a crucial component of all cell membranes in the body and have an impact on how cell receptors work in those membranes. They serve as the precursor for the production of hormones that control inflammation, arterial wall contraction and relaxation, and blood clotting. Additionally, they bind to cell receptors that control genetic activity. Omega-3 fats have been demonstrated to help prevent heart disease and stroke may help manage lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other illnesses. These benefits are most likely the result of omega-3 fats.
Omega-3 Recommendation
Insufficient data were available to determine an EAR when the IOM last examined omega-3s, thus the IOM developed AIs for all ages based on omega-3 intakes in healthy populations.
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| 0 to 6 months | 0.5 g | 0.5 g | ||
| 7–12 months | 0.5 g | 0.5 g | ||
| 1–3 years | 0.7 g | 0.7 g | ||
| 4–8 years | 0.9 g | 0.9 g | ||
| 9–13 years | 1.2 g | 1.0 g | ||
| 14–18 years | 1.6 g | 1.1 g | 1.4 g | 1.3 g |
| 19-50 years | 1.6 g | 1.1 g | 1.4 g | 1.3 g |
| > 51 years | 1.6 g | 1.1 g |
Omega-3 Sources
Flaxseed, soybean, and canola oils are examples of plant oils that contain ALA. Walnuts and chia seeds also contain ALA.
The amount of omega-3 in fish varies greatly. Fish with higher fat content, like bass, tilapia, and cod, as well as shellfish, have lower levels of LC omega-3s than fish with a lower fat content, including salmon, mackerel, tuna, herring, and sardines.
| Food | gr per serving | ||
|---|---|---|---|
| ALA | DHA | EPA | |
| Flaxseed oil, 1 tbsp | 7.26 | ||
| Chia seeds, 1 ounce | 5.06 | ||
| English walnuts, 1 ounce | 2.57 | ||
| Flaxseed, whole, 1 tbsp | 2.35 | ||
| Salmon, Atlantic, farmed cooked, 3 ounces | 1.24 | 0.59 | |
| Salmon, Atlantic, wild, cooked, 3 ounces | 1.22 | 0.35 | |
| Herring, Atlantic, cooked, 3 ounces | 0.94 | 0.77 | |
| Canola oil, 1 tbsp | 1.28 | ||
| Sardines, canned in tomato sauce, drained, 3 ounces | 0.74 | 0.45 | |
| Mackerel, Atlantic, cooked, 3 ounces | 0.59 | 0.43 | |
| Salmon, pink, canned, drained, 3 ounces | 0.04 | 0.63 | 0.28 |
| Soybean oil, 1 tbsp | 0.92 | ||
| Trout, rainbow, wild, cooked, 3 ounces | 0.44 | 0.40 | |
| Black walnuts, 1 ounce | 0.76 | ||
| Mayonnaise, 1 tbsp | 0.74 | ||
| Oysters, eastern, wild, cooked, 3 ounces | 0.14 | 0.23 | 0.30 |
| Sea bass, cooked, 3 ounces | 0.47 | 0.18 | |
| Edamame, frozen, prepared, ½ cup | 0.28 | ||
| Shrimp, cooked, 3 ounces | 0.12 | 0.12 | |
| Refried beans, canned, vegetarian, ½ cup | 0.21 | ||
| Lobster, cooked, 3 ounces | 0.04 | 0.07 | 0.10 |
| Tuna, light, canned in water, drained, 3 ounces* | 0.17 | 0.02 | |
| Tilapia, cooked, 3 ounces | 0.04 | 0.11 | |
| Scallops, cooked, 3 ounces | 0.09 | 0.06 | |
| Cod, Pacific, cooked, 3 ounces | 0.10 | 0.04 | |
| Tuna, yellowfin, cooked 3 ounces | 0.09 | 0.01 | |
| Kidney beans, canned ½ cup | 0.10 | ||
| Baked beans, canned, vegetarian, ½ cup | 0.07 | ||
| Ground beef, 85% lean, cooked, 3 ounces | 0.04 | ||
| Bread, whole wheat, 1 slice | 0.04 | ||
| Egg, cooked, 1 egg | 0.03 | ||
| Chicken, breast, roasted, 3 ounces | 0.02 | 0.01 | |
| Milk, low-fat (1%), 1 cup | 0.01 |
Omega-3 Deficiency
Either an omega-3 or an omega-6 fatty acid deficit can result in dermatitis and rough, scaly skin. When there is a deficit in omega-3 fatty acids, DHA concentrations in the plasma and tissues fall. However, functional endpoints, such as those for visual or cognitive function or for an immunological response, do not have any known cut-off amounts of DHA or EPA beyond which they are affected.
Omega-3 Toxicity
EPA and/or DHA doses of 2-15 g/day may also increase the bleeding time by decreasing platelet aggregation. Long-term usage of EPA and DHA food supplements at combined levels of up to roughly 5 g/day appears to be safe, according to the European Food Safety Authority. It was stated that these doses have not been demonstrated to produce bleeding difficulties or to have an effect on immunological function, glucose homeostasis, or lipid peroxidation. Similarly, the FDA has determined that dietary supplements containing no more than 5 g of EPA and DHA per day are safe when used as directed.