Omega-3 polyunsaturated fatty acids (PUFAs), also known simply as omega-3 fats are essential dietary fats which the body cannot make on its own, so they have to be consumed regularly via the diet. Omega-3 fats play a crucial role in brain function as well as in normal growth and development during childhood. They have also been shown to reduce the risk of cardiovascular disease. For example, over 30 years ago, researchers noted that Inuit Eskimos have a very low incidence of heart attacks, most likely because the Eskimo diet - which relies heavily on whale blubber - contains a high amount of omega-3 fats. It is partly due to these published studies that many health-conscious people have started taking omega-3 supplements on a regular basis.

Indeed, these essential fats offer multiple health benefits to the cardiovascular system, including:

Lowering blood pressure (BP) - An analysis of 17 clinical studies found that taking 3 or more grams of fish oil daily reduces BP in people with untreated hypertension. However, it is important to note that doses this high should only be taken under the careful supervision of a physician.

Achieving a better cholesterol balance - people who follow a Mediterranean style and other similar diets tend to have higher HDL (good) cholesterol levels, which promote heart health. Inuit Eskimos tend to have increased HDL cholesterol and decreased triglycerides (which are fats in the blood). Several studies have shown that fish oil supplements reduce triglyceride levels. Also, walnuts - which are rich in alpha linolenic acid or ALA, which converts to omega-3 fats in the body - have been reported to lower total cholesterol and triglycerides in people with high cholesterol levels.

Reducing risk of heart disease - consuming a diet rich in omega-3 fats reduce risk factors for heart disease, including high cholesterol and high BP. Most trials reported that fish oil significantly reduced death from all causes including myocardial infarction, cardiac and sudden death or stroke. Not only that, fish oil has been shown to lower the risk of death, heart attack, stroke and abnormal heart rhythms in people who have already had one heart attack - a very high risk population. These effects appear to be because of increased consumption of omega-3 fats from fish or fish-oil supplements, but not ALA. The evidence for the benefits of fish oil is stronger in secondary than in primary prevention settings. Fish oil also appears to prevent the formation of atherosclerosis by slowing the development of plaque and blood clots, which can clog arteries. It may even be effective in the treatment of atherosclerosis that has already taken place. For example, a recently concluded meta-analysis examined 11 studies with over 39,000 patients with various cardiovascular problems who were administered omega-3 dietary supplements for a year. These supplements were found to significantly reduce risk of death due to cardiovascular disease and all other causes. Not only that, omega-3 fats have been shown to be more effective than statin drugs in reducing heart disease-related deaths, with only minor adverse effects.

Protection against stroke - large population studies show that dietary omega-3 fats protect against stroke caused by plaque buildup and blood clots in the arteries that lead to the brain. Eating at least 2 servings of fish per week can reduce the risk of stroke by as much as 50%. However, consuming too high doses of fish oil and omega-3 fatty acids may increase the risk of bleeding.

Omega-3 fats are made mainly by cold water algae and krill. They also occur in oily fish such as sardines, wild salmon, herring, mackerel and tuna that feed on these plants. Eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) are the long-chain forms of omega-3 fats found in fish, fish and krill oil supplements and algae extract. Our body can readily use these forms, so these are our best dietary sources. Alpha-linolenic acid or ALA is the short-chain form of omega-3 fats found in walnuts, flaxseed, flaxseed oil, canola (rapeseed) oil, soybeans, soybean oil, pumpkin seeds, walnuts and green leafy vegetables. Our body needs to chemically convert ALA into longer chain forms of omega-3 fats before it can be used.

The health effects of omega-3 fats come from EPA and DHA, so when looking for an omega-3 supplement, the issue is not so much omega-3 fats but EPA and DHA and making sure to get plenty of long-chain omega-3 fats. Similarly, dosing for fish oil supplements should be based on the amount of EPA and DHA, both of which can be taken as fish oil capsules. Supplements may vary in the amounts and ratios of EPA and DHA. Flaxseed, flaxseed oil, fish and krill oils should be kept refrigerated. Always buy omega-3 fat supplements made by established companies who certify that their products are free of heavy metals such as mercury, lead, and cadmium. Also, different types of fish contain variable amounts of omega-3 fats, and different types of nuts or oil contain variable amounts of ALA. Omega-3 fat supplements of up to 1 gram per day are recommended for cardio-protection.