Fish oils are generally characterized by a rather large group of saturated and unsaturated fatty acids, which are commonly associated with mixed triglycerides.
Krill oil is extracted from Antarctic krill, Euphausia superba, a zooplankton crustacean rich in phospholipids carrying longchain omega-3 PUFAs, mainly EPA and DHA. Krill oil also contains various potent antioxidants, including vitamins A and E and astaxanthin.
Krill oil has a unique biomolecular profile of phospholipids (instead of triglycerides in fish oil) naturally rich in omega-3 fatty acids and antioxidant different from the usual profile of fish oils. The association between phospholipids and long-chain omega-3 fatty acids appears to facilitate the passage of fatty acid molecules through the intestinal wall, increasing bioavailability and ultimately improving the omega-3:omega-6 fatty acid ratio.
Dietary sources of omega-3 fatty acids include fish oil, krill oil and certain plant and nut oils. Fish oil and krill oil contains the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA); some nuts (English walnuts), seeds (flaxseed), and vegetable oils (canola, soybean, flaxseed, linseed, olive) contain alpha-linolenic acid (ALA), which may be converted to EPA and DHA in the body.
Omega-3 fatty acids have long been known to play critical roles in growth but have more recently been suggested as providing a wide range of health benefits, several of which are well supported in the literature, including reductions in the risk of coronary heart disease and regulating cholesterol and triglycerides.
- EPA and DHA contribute to the normal function of the heart
- DHA contributes to maintenance of normal brain function and normal vision
- DHA and EPA contribute to the maintenance of normal blood pressure
- DHA and EPA or only DHA contribute to the maintenance of normal blood triglyceride levels
- ALA contributes to the maintenance of normal blood cholesterol levels
- DHA maternal intake contributes to the normal brain development of the foetus and breastfed infants
- DHA maternal intake contributes to the normal development of the eye of the foetus and breastfed infants.
Sources of oil containing omega-3 fatty acids include krill, anchovy, black cod, bluefish, halibut, kipper, mackerel, menhaden, mullet, herring, pilchard, sable fish, salmon, sardine, seal blubber, sturgeon, trout, tuna, and whale blubber.