By the way, doctor: Is there an environmentally friendly way to get omega-3s?
Q. Omega-3 fats may be good for you, but I worry about overfishing. Is there a way of getting omega-3s without contributing to this problem?
A. Fish contains two omega-3 fats, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). There's good evidence that consuming these "marine" omega-3s lowers the risk of heart disease and perhaps some other conditions as well. But your worry about declining fish stocks is well-founded. Many are already in trouble, and if everyone were to eat the recommended amount of fish, which is about seven ounces per week, the harvestable fish supply couldn't meet the demand.
Fish farming, especially of salmon, has become more common, and it's one way to meet the growing demand for fish. But salmon farming depends on fish and other creatures further down the food chain for feed (salmon are carnivores). There's growing concern that those populations are being overfished to support fish farms, and imperiling ocean ecosystems in the process.