Is fish a regular part of your diet? If not, maybe it should be. Including seafood in your diet a few times a week could have long-lasting health benefits.

Question: What makes seafood healthful?

Answer: There are many reasons to include seafood as a regular part of your diet. All fish are a good source of protein, perhaps the most important nutrient for the body after water. A modest 4-ounce portion of most types of fish provides 20 to 30 grams of high quality protein, providing about a third of the daily protein needed by the average adult.

But, it’s mostly the fat in fish that makes it nutritionally special. Yes, clearly this is a type of fat you can feel good about. The fats or oils in fish provide two omega-3 fatty acids that are known for several health benefits.

The two key omega-3 fatty acids in fish are: eicosapentaenoic acid (DHA) and docosahexaenoic acid (DHA). An adequate intake of these two fatty acids by pregnant women is essential for brain and retina development during fetal and infant stages of life. Throughout life, EPA and DHA continue to be needed for the health of these and other parts of the body. Adequate dietary intake of EPA and DHA is associated with reduced risks of cardiovascular disease, prostate cancer and macular degeneration of the retina. In addition, a proper dietary balance of EPA and DHA in relation to other fats helps to reduce inflammation and reduce the symptoms in some inflammatory conditions such as arthritis, psoriasis and asthma.

Q: Does the omega-3 fatty acid in flax, canola and soybean oils have the same effects as EPA and DHA?

A: No, the plant oil omega-3 fatty acid is called alpha linolenic acid (ALA). This fatty acid is mainly used as a source of calories in the body. It is estimated that less than 1 percent of it is converted into EPA that has multiple functions in the body. Consequently, the body is likely to function better when it can obtain EPA and DHA directly in adequate amounts from the oils in fish.

Interestingly, some research indicates that a high intake of ALA is associated with an increased risk of health problems such as prostate cancer and macular degeneration in the retina. In contrast, adequate intake of EPA and DHA is associated with reduced risk of these conditions.

Q: What about the risk of too much mercury in fish?

A: Mercury accumulates in some types of fish, and too much mercury is toxic. However, most fish have what is sometimes called a "mercury shield," a high level of beneficial selenium that greatly exceeds the amount of mercury in the fish. In the body, selenium plays a role in blocking and neutralizing the otherwise detrimental effects of mercury.

Seafood is the richest source of selenium in most people’s diets. The mineral, in appropriate amounts, plays a major role in the body’s antioxidant systems, is essential for thyroid hormone production, and is associated with decreased risk of developing various types of cancer.

Perhaps you have found the "5-A-Day" promotion for daily servings of fruits and vegetables difficult to accomplish. For fish, the recommendation is easier – only two to three servings a week. Hawaii’s location in the middle of the Pacific Ocean makes it a great center for a wide variety of fresh local seafood and seafood from around the Pacific. Take advantage!

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Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.