The Skinny on Fat

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The Skinny on Fat

Before we start to look at how different types of fat might affect prostate cancer risk, let's review what fat is, where it comes from, and what it does.

Fat is one of three main types of nutrient molecules used by the body in its everyday processes. (The other two are carbohydrates and proteins.) After fat is ingested, the body breaks it down into smaller components, uses what it needs, and stores the rest for future use.

Although saturated and trans fats have been targeted in the fight against cardiovascular disease, more studies in prostate cancer have zeroed in on omega-3 fatty acids, found primarily in fatty fish, fish oils, and certain vegetable oils, including walnut and canola oils.

A number of years ago, the omega-3 fatty acids were studied for their beneficial effects on memory and depression, and particularly on the risk of cardiovascular disease. While the effects on memory and depression are questionable, the benefits of the omega-3 fatty acids in minimizing heart disease seem to have held true, and the American Heart Association continues to promote omega-3 fatty acids as "heart healthy."

In studies of prostate cancer, however, the equation is not so simple.

Using blood samples collected during one study, researchers found that men with the highest levels of the omega-3 fatty acid ALA (alpha-linolenic acid) in their bloodstreams were three times as likely to develop prostate cancer compared with those in whom the fatty acid could not be detected. Similarly, another study found that men who consumed the highest amounts of ALA were nearly twice as likely to develop advanced prostate cancer. In both of these studies, as in the typical American diet, the primary source of ALA was animal and dairy products, particularly red meat.

At the same time, however, consumption of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), two omega-3 fatty acids found mostly in fatty fish, was associated with a lower risk of developing advanced prostate cancer. In fact, eating the equivalent of 3 servings of fish per week cut the risk of developing advanced prostate cancer in half.