One of our reader's wrote in with this question: A friend of mine tells me I should eat more salmon because scientists have shown it's good for you. Another friend says I should eat less salmon because scientists have shown it's bad for you. What's the deal?

Well, both your friends have a little bit of the picture. Salmon is indeed good for you; researchers believe it's something called Omega-3 fatty acids that do the trick. Though "fatty" may sound like a bad thing, Omega-3 fatty acid is a good thing --especially for your ticker.

Now comes the other half. Just recently, researchers have found that a lot of the salmon you buy at supermarkets is contaminated with PCBs and pesticides. "PCB" stands for polychlorinated biphenyls. These are chemical contaminants used in industry and agriculture that can leak into the environment and create a cancer risk.

Wild salmon, it turns out, are a better bet. Farm-raised fish from Europe and North America have far more PCBs and other cancer-risk chemicals in them than salmon just out swimming in the Pacific. Unfortunately, however, most of the stuff you get in supermarkets is farm-raised.

Researcher Ronald Hites of Indiana University suggests that, if it's farm raised or if you don't know where it came from, you might want to limit your salmon munching to once a month. If you know its wild Pacific salmon, two to four times a month is the recommended limit.