You've probably heard two things about omega-3 fatty acids:

1. They're good for you
2. They're mostly found in fish

Scientists have known about the benefits of omega-3s since the 1930s, and in the last few years, they have been one of the most sought after ingredients for nutritional supplementation. These essential fatty acids are necessary for human health, but your body cannot produce them - you have to get your omega-3s from the foods you eat.

Researchers have discovered that omega-3s are good for:

Prevention of cardiovascular disease. Studies show that a diet full of omega-3 fatty acids may help lower fat deposits in the body (triglycerides) and increase good cholesterol (HDL cholesterol). Research also shows that omega-3s help prevent blood from clotting (by acting as an anticoagulant) and may help in lowering high blood pressure.

Fighting Alzheimer's Disease. Omega-3s, found in tuna, salmon, and other fatty fish, show some benefit in protecting against Alzheimer's disease. Omega-3s help prevent the accumulation of a protein that has been linked to this disease - a result that many scientists find very encouraging. Testing is still in its preliminary stages.

Slowing Down Cellular Aging. Scientists are still researching the connection between higher levels of omega-3s in the blood and slower aging, but evidence suggests that more fatty fish in your diet may keep your cells a little younger for a little longer. Studies have shown that shrinkage rates in cell structure are a little slower in patients with higher levels of omega-3s. In other words, patients with higher levels of omega-3 fatty acids in their bodies experienced slower cell aging.

Reduced Incidence of Stroke. For people who have suffered a stroke, a diet rich in oily fish may help reduce the onset of a second one. Eicosapentaenoic acid, or EPA, is an essential omega-3 polyunsaturated fatty acid that scientists have found to lower the chance of a recurrent stroke among patients who were taking a cholesterol-lowering drug.

Although there are risks associated with a diet high in the kinds of oily fish containing omega-3 fatty acids - elevated mercury levels, being one of them - it is still a good idea to add these essential-fatty-acid-rich foods to your diet. The benefits of omega-3s in fighting heart and cardiovascular disease outweigh the potential risks, so it's worth it to add salmon, tuna, mackerel or herring to your meal plan.

To minimize risk, buy fish low in mercury. The bigger the fish, the more mercury it contains; smaller, low mercury fish include shrimp, salmon, pollock, and catfish. To be safe, know which fish are typically associated with high mercury levels. Freshwater fish located in areas with little pollution also have much less mercury in their tissues.

If you're allergic to seafood or just don't like the taste of fish, you can still get omega-3 fatty acids from certain oils and nuts, such as flaxseeds, pumpkin seeds, walnuts and soybeans.

Deborah is the Health Director for Organic Liaison, has been a Registered Dietitian for over 16 years, counseling clients on nutrition and fitness, and is the author of 200 Superfoods That Will Save Your Life published by McGraw-Hill, Inc. Her mission is to educate Organic Liaison members to achieve optimal wellness through balanced eating and exercise. For more on Deborah - click here.