Omega-3 fatty acids are “essential fatty acids” that are required by the body in order to perform a variety of metabolic functions, but which bodies can not produce. Our body must get them from the food we eat. They are classified as polyunsaturated fatty acids (PUFAs) and are considered to be “the good fats.”

There are three important omega-3s: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). EPA and DHA are primarily found in fish, krill, and calamari, and in algae (algal oil). They are present in the highest concentrations in fatty fish such as salmon, tuna, sardines and mackerel. ALA is commonly found in plant sources like flax seed, soy, walnuts and canola oil.

While the function of omega-3s is not fully understood, these fatty acids definitely play a definite role in our health. Their role is the subject of intensive ongoing research, and even controversial.

People at risk for heart disease and stroke, and those who already have one or both conditions, do better when they consume fatty fish several times a week. Eating the fish may be more effective than taking supplementary fish oil, because because the fish contains other helpful substances, but the jury is still out on this one.

People with inflammatory diseases may benefit from an increased consumption of omega-3s. The list is long, and includes rheumatoid arthritis, inflammatory bowel disease (Crohn's disease and ulcerative colitis), lupus, and some forms of immune kidney diseases.

Fish oil may play a role in the prevention of a variety of cancers, age related eye disease, dry eye symptoms (keratoconjunctivitis sicca), anxiety, depression aggression, age-related cognitive function, and even Alzheimer's.

Much of the beneficial effect of omega-3s is thought to be due to its ani-inflammatory function. The reasoning is that many diseases are either caused by or made worse by inflammatory processes in the body, and the less inflammation there is, the easier it is to bring the condition under control.

There is no agreement about how much omega-3 is enough, and how much is too much. Some permissions place the minimum daily requirement for healthy women and men at 1,000 mg and 1600 mg a day, respectively. A prescription drug, Lovaza (used to treat high triglycerides, a cardiac risk), provides more than 3,000 mg of omega-3s a day.

Recommended doses for different conditions vary through a wide range of doses.

A reasonable-size portion of salmon, approximately 6 ounces, contains a little more than 800 mg of EPA and more than 1,100 mg of DHA.

So what's the bottom line?

Two to three portions a week of salmon or another fatty fish a week, plus a variety of ALA-foods (walnuts, soy, and flax seed) should suffice for most healthy people.

If you are not a fish or ALA-food eater, you may want to take a fish oil and flax seed oil supplement.

If you feel that you have a condition that can be appreciated, at least in part, with fish oil, do not do it on your own. The subject is very complicated and in a state of flux. It may involve consideration of other supplements, dietary changes and prescriptions. Above all, it requires a thorough understanding of your condition and the potential benefits of omega-3s, and knowledge of its limitations. Discuss it with your doctor!