Omega-3 fatty acids may keep heart disease at bay.(Knight Ridder Newspapers)

The product: Zone Perfect's Omega 3 Molecular Distilled Fish Oil and Vitamin E Supplement.

The claim: Omega-3 class fats have long been billed as a way to keep heart disease at bay. More recently they have cropped up as effective preventers of depression, asthma, stroke and arthritis.

Key ingredient: Omega-3, long-chain polyunsaturated fatty acids.

Price: $16.95 for 120 one-gram capsules, with a recommended daily dose of four to six capsules.

Other sources: Many other companies market omega-3 supplements, available in drug or health-food stores. This brand comes with Vitamin E to keep the omega-3 from becoming rancid. You can also stock up on fish oil by eating fatty fish such as salmon and tuna.

How it works: Two oils, EPA and DHA, found in omega-3 appear to be responsible for most of its salutary effects on the body. We do not make these compounds on our own, relying on our diet for sufficient amounts. EPA is thought to help lower cholesterol and prevent clotting, while DHA is considered to promote healthy development of the central nervous system.

Scientific evidence: Study after study supports the claims that omega-3 fatty acids confer myriad health benefits. Earlier this month a study showed that Omega-3 ameliorated the symptoms of depressed people who did not respond to other medication. A few months ago an Italian study with more than 10,000 participants found omega-3 stalled death in people who had had a heart attack. An April study found men with high levels of omega-3 fatty acids in blood had an 81 percent lower chance of dying from a sudden heart attack than those with ...