Eat one to two 3-ounce servings of seafood every week, particularly fatty fish that aren’t overharvested, such as sardines or wild Alaskan salmon.

No fish story: Men who eat fish are less likely to develop aggressive prostate cancer.

RODALE NEWS, EMMAUS, PA—A new study published in the journal Clinical Cancer Research has found that polyunsaturated fatty acids may help reduce prostate inflammation that can lead to aggressive prostate cancer, the most severe form of the disease, which has high risks of the cancer spreading to the lymph nodes or bones. The omega-3s specific to dark-meat fish like salmon and sardines seem to be the most effective at cutting cancer risk, the study found, and they even seem to undo the risk for men who may be genetically predisposed to it.

THE DETAILS: The study analyzed two groups of men, 466 who had been diagnosed with prostate cancer (most with aggressive cancer) and a control group of 478 men with no history of the disease. The participants were asked to fill out food questionnaires that asked how frequently they ate dark-meat fish (such as salmon, mackerel, and bluefish), white-meat fish (such as sole, halibut, snapper, and cod), shellfish (shrimp, lobster, and oysters), tuna (canned tuna, tuna salad, and tuna casserole), and fried fish. Researchers also performed analyses for a specific gene linked to prostate inflammation that predisposes men to aggressive prostate cancer.

Based on survey results, they found that men who ate more dark-meat fish and shellfish had much lower risks of developing aggressive prostate cancer than men who ate fish only once or twice a month. But even men who ate dark-meat fish and shellfish one to three times per month had a 36 percent lower chance of developing prostate cancer compared with men who never ate fish. Among the men who had a genetic risk for prostate cancer, an increase in dark-meat fish intake was matched with a decrease in cancer risk.

WHAT IT MEANS: “Eating these fish that are rich in polyunsaturated fatty acids does appear to have an impact,” says study coauthor John S. Witte, professor of epidemiology and biostatistics at University of California-San Francisco’s Institute for Human Genetics. He adds that the specific subgroup of polyunsaturated fats called omega-3 fatty acids have anti-inflammatory properties that can actually counteract the prostate inflammation caused by a certain gene. “Even if you have this genetic variant that increases your risk, it’s like fish intake is competing with that and can overcome it,” he says.

The kinds of omega-3 fatty acids found in dark-meat fish and shellfish seem to be the most effective forms for preventing prostate cancer (as opposed to the omega-3s in walnuts, flaxseeds, and other plants). The Harvard School of Public Health recommends eating one to two servings of fish each week to reap the most benefits, which coincides with the study’s findings.

Here’s a list of fish and shellfish that are high in omega-3s, low in contaminants, and not overharvested, according to lists provided by the Monterey Bay Aquarium and Environmental Defense Funda:

• Alaskan Pollock
• Atlantic herring
• Canned light tuna (preferably troll-caught, like American Tuna brand, which minimizes impact on unintentionally caught species and aquatic ecosystems)
• Farmed rainbow trout
• Farmed oysters
• Lobster: either California spiny lobster or Caribbean spiny lobster from U.S.
• Shrimp: Canadian spot prawns and U.S. farmed or Oregon pink shrimp
• Wild Alaska salmon
• U.S. farmed catfish
• U.S. Pacific sardines

You can also boost your omega-3 intake with fish oils, but be sure to choose brands that refine the oils in a way that minimizes your exposure to environmental contaminants, and that actually deliver the amounts of omega-3s claimed on the label. Look for supplements certified by ConsumerLab.com, U.S. Pharmacopoeia, or the NSF.