One nutrient that seems to be popping into all our foods these days is omega-3. Omega 3 refers to three fatty acids: ALA, EPA and DHA, which our body requires to function properly.
ALA is found naturally in walnuts, flaxseed, canola oil and soybean oil, whereas DHA and EPA are found primarily in fish oil and algae. The relative importance of each remains misunderstood, but most research focuses on the importance of fish sources, DHA and EPA. While the body can convert some ALA into EPA and DHA, it cannot be done efficiently or at therapeutic doses.
Omega-3 fatty acids are believed to enrich and stabilize cell membranes, reducing risk for cardiovascular disease. The strongest evidence exists for the role of EPA and DHA in preventing a coronary event or death, for those who already have established cardiovascular disease. There is also less clear evidence that Omega-3s aid in preventing neurological dysfunction, inflammation and incidence of some cancers.
The current recommendation for the general population is to eat eight ounces of fatty fish a week (two servings), which provides about 500 mg of EPA and DHA. Omega 3 persists in cell membranes for weeks after consumption therefore intermittent dosing (ie. eating fish twice a week) provides the same benefit as daily consumption at lower doses.
Considering the state of our fisheries these days, the sustainability of this recommendation is questionable. There is also concern of contaminants in fish such as dioxins and methylmercury. Shrimp, pollock, salmon and canned light tuna (not albacore) are all considered low-mercury fish. This is especially important for pregnant women, women who could become pregnant and young children.
For those needing higher doses of EPA and DHA, such as those with established heart disease or high triglycerides, fish oil capsules may be prescribed. Methylmercury is water-soluble and protein-bound, therefore not extracted into fish oil supplements. Some people complain that fish oil can cause stomach upset and “fishy” burps. To minimize this effect, take with meals or at bedtime, keep capsules in the freezer or buy enteric-coated products. Other Omega-3 products, such as eggs, come from chickens fed green algae, fish oils, canola seeds or flax seeds. Despite claims, omega content will vary depending on how efficiently individual hens grind flax seed, size of egg, etc. Furthermore, most research has been done on those who eat fish, not those who eat enriched products, so the effectiveness is uncertain.