Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), precursors of certain eicosanoids that are known to reduce inflammation throughout the body, and are thought to have many health benefits.
Marine foods are rich sources of the n-3 long-chain polyunsaturated fatty acids (LCPUFA) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). These are bioactive LCPUFA that influence the regulation of biological processes such as eicosanoid synthesis and gene expression. Intake of marine oils could influence synthesis of bioactive molecules such as prostaglandins, which in turn influence timing of parturition.
Omega-3s have been found to be essential for both neurological and early visual development of the baby. However, the standard western diet is severely deficient in these critical nutrients. This omega-3 dietary deficiency is compounded by the fact that pregnant women become depleted in omega-3s, when the fetus uses omega-3s for its nervous system development
Although EPA and DHA naturally occur together and work together in the body, studies show that each fatty acid has unique benefits. EPA supports the heart, immune system, and inflammatory response. DHA supports the brain, eyes, and central nervous system which is why it is uniquely important for pregnant and lactating women.
Research shows that omega-3 fatty acids reduce inflammation and may help lower risk of chronic diseases such as heart disease, cancer, and arthritis. Omega-3 fatty acids are highly concentrated in the brain and appear to be important for cognitive (brain memory and performance) and behavioral function.
In fact, infants who do not get enough omega-3 fatty acids from their mothers during pregnancy are at risk for developing vision and nerve problems. Symptoms of omega-3 fatty acid deficiency include fatigue, poor memory, dry skin, heart problems, mood swings or depression, and poor circulation.
Fish oil is the best source of two long-chain essential fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)--the omega-3 fats we hear so much about. Essential in this context means our body cannot synthesize them, so we must get them from food or supplements. Food is usually preferable to supplements, but in this case fish oil, in capsule or liquid form, may be a better source than the fish that produce it because it is purified to be free of mercury and organic toxins.
The health-promoting effects of EPA and DHA have little or nothing to do with preventing abnormal cardiac rhythms. Their most important actions are reducing inflammation, reducing the clotting tendency of the blood, improving the profile of fats circulating in the blood, optimizing brain function (DHA is a major constituent of cell membranes in the central nervous system) and inhibiting abnormal cell proliferation, thereby reducing cancer risks. All of this translates into significant disease protection.
There is evidence from multiple studies supporting intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides, reduces the risk of death, heart attack, dangerous abnormal heart rhythms, and strokes in people with known cardiovascular disease, slows the buildup of atherosclerotic plaques ("hardening of the arteries"), and lowers blood pressure slightly. However, high doses may have harmful effects, such as an increased risk of bleeding.
Dietary sources of omega-3 fatty acids include fish oil and certain plant/nut oils. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while some nuts (English walnuts) and vegetable oils (canola, soybean, flaxseed/linseed, olive) contain alpha-linolenic acid (ALA).
Cod liver oil became popular in 19th century England as a vitamin D supplement for sun-deprived children. In the 1950s, a German scientist named Johanna Budwig, PhD, discovered essential fatty acids and developed a diet that she said would fight cancer. Dr. Budwig claimed that many of her patients experienced tumor reduction within 3 months, and she stated that some experienced even more dramatic results.
In 1996, the American Heart Association released a report stating that eating foods containing omega-3 fatty acids is reasonable and possibly helpful in reducing risk of heart disease. More recent recommendations have suggested eating 2 or more servings of fatty fish per week and eating foods that are high in alpha-linolenic acid such as flaxseed, canola oil, soybeans, and walnuts to reduce cardiovascular disease risk. People who already have cardiovascular disease are recommended to eat more of these products or take supplements.
Fish oil comes from the fatty tissues of oil-rich fish. These fish, however, do not create the oils themselves for which they are so prized. Vegetarian fish such as sardines and herring obtain these super omega 3 rich oils from the algae they consume, and carnivorous fish such as swordfish, tuna, and shark, obtain their oils from the consumption of other vegetarian fish that are rich in oils due to the algae they have consumed.