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

By Sally Squires
Tuesday, October 24, 2006

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?

Omega-3s and any contaminants are about the same in sushi as in cooked fish. But sushi -- or any other raw seafood -- could come with some unwanted bacteria or viruses. "There's no question that raw fish is a risk," notes Rebecca Goldburg, senior scientist for Environmental Defense. Even so, Goldburg and her family still occasionally enjoy sushi. Her advice to help reduce risks of getting sick: "Don't be cheap about where you eat sushi."

Does grilling fish take away any of the health benefits?

Grilling, broiling, steaming, baking, stir-frying or sauteing are all fine to do. Skip the deep-fat fried fish or seafood, since in restaurants and fast-food establishments it's often fried with unhealthy oils that add trans fat and saturated fats. Plus, deep-fat frying adds calories, and the species most often used for deep-fried fish are generally very low in omega-3s.

Can you also get health benefits by taking an omega-3 supplement instead of eating fish?

Yes, but you'll miss the selenium and protein found in fish. Plus, by substituting fish for red meat or poultry twice a week you can reduce calories and saturated fat. There's also no guarantee that fish oil capsules have the amount of omega-3s claimed on the label, since dietary supplements are not as closely regulated by the Food and Drug Administration as medications. If you opt for supplements, aim for about 0.25 grams per day of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), typically the amount of omega-3s found in a one-gram fish oil capsule and what research suggests protects the heart.

What about squid, oysters, octopus, shrimp, crab and lobster? Do they contain the omega-3 fatty acids, too?

They all have moderate or higher amounts of omega-3 fatty acids, but not as much as deep-water, oily fish such as salmon. They're also generally low in mercury. Another good option: clams.

If a woman isn't pregnant or planning to get pregnant, is it really so bad to eat albacore tuna and swordfish?

The warnings to avoid swordfish, tilefish, king mackerel and shark don't apply to men or to women who are past childbearing age. Ditto for the government advice to limit total fish intake to 12 ounces per week. Of that, albacore tuna should be six ounces or less. But experts stress that it's wise to eat a variety of foods, including fruits and vegetables as well as seafood.

Fresh fish and seafood are pretty pricey. Are there any low-cost options?

You bet! Canned sardines, anchovies, salmon and tuna are just some of the bargains, and they cost less than a dollar per serving. The frozen food section has others. Fish that are flash-frozen at sea may taste far fresher than "fresh" seafood that spends at least a week getting to the local market.