New Studies Give Fish a Clean Bill of Health, Though Questions Remain

Two reports issued last week waded into whether seafood is safe to eat, addressing worries that our favorite fish might come laced with dangerous contaminants. They concluded that the health benefits of eating seafood outweigh any risks for both adults and children.

But plenty of Lean Plate Club members had questions about the reports. They e-mailed me about choosing wild vs. farm-raised fish, eating sushi and whether taking a fish oil supplement is as good as consuming those two meals of fish per week recommended by the reports. Here's a sampling of what they asked, along with answers from experts and from the new reports -- a federally funded study conducted by the Institute of Medicine and an investigation by scientists at the Harvard School of Public Health, whose findings were published Oct. 18 in the Journal of the American Medical Association.

What are these omega-3s, and do any foods besides fish have them?

Omega-3 fatty acids are healthy fats that come in two molecular lengths: short and long. Studies show that the long-chained omega-3s provide the most brain and heart benefits. Plenty of foods -- avocados, eggs, tofu and walnuts, to name just a few -- contain omega-3s. But they either provide mostly the short version or contain only small amounts of the long-chained omega-3s. Mother's milk and oily fish, such as salmon and tuna, pack the biggest omega-3 punch. Since mother's milk isn't really a food option for adults, that pretty much leaves fish and other seafood as the top choices.

Okay, so how much fish am I going to have to eat weekly to see any benefits?

Both reports suggest that you can cover the nutritional bases by eating about two servings of fish per week. Figure that a serving is about three ounces. The reports' advice is also consistent with recommendations from both the 2005 U.S. Dietary Guidelines and the American Heart Association.

There's so much conflicting information about farm-raised vs. wild fish. Which is better to eat?

This is a hotly debated issue, but most experts say that both are good choices. The point is to eat fish.

Harvard School of Public Health cardiologist Dariush Mozaffarian, co-author of the JAMA report, says that "farmed salmon has more than twice the amount of omega-3s as wild salmon, but both are very high." Wild fish are leaner, because they burn off some of their fat swimming in the ocean, while farm-raised fish spend their lives confined and well-fed.

As for other contaminants, dioxin and polychlorinated biphenyls can be lower in wild fish than in farmed, according to Mozaffarian, who notes that "overall the levels of dioxin and PCBs are low in all fish, and more importantly the magnitude of the omega-3 benefits of farm-raised salmon is so much greater than any risk from other contaminants."

A number of environmental groups, including Environmental Defense, a nonprofit research and advocacy group, support eating some farm-raised seafood to help avoid overfishing the oceans. Both Environmental Defense and the Monterey Bay Aquarium offer wallet-size cards with information on responsible seafood choices. Find links at http://www.leanplateclub.com/ .

I love sushi! Does it provide more or less mercury and omega-3s than cooked fish?