Not All Fish is Heart Healthy, Study Says

Is there something fishy about the latest studies on heart disease and seafood consumption? Yes, fish can be a heart-healthy food choice, if you’re eating the right kinds. If not, you may actually be increasing your heart attack risk, a new study shows.

It turns out that eating fish may not be as healthy for the heart as first thought, according the study, which found that high mercury levels in some fish negate the ability of the seafood’s fatty acids to help prevent heart attacks.

Fish species such as swordfish, shark, and king mackerel, contain methylmercury levels high enough to counteract the heart-friendly benefits of DHA, an omega-3 fatty acid found in fish that the U.S Food and Drug Administration says promotes cardiac health.

“People should continue to eat fish because it’s a good source of omega-3 acids and protein,” said Jerry Glassman, MD, medical director of the Heart Care Center at Scripps Mercy Hospital. “However, fish consumers should be cautious about what types they eat.”

According to Dr. Glassman, fish species such as tuna, salmon and trout all have low or moderate levels of methylmercury, and are safe to eat. Dr. Glassman added that tofu, walnuts and canola oil are also significant sources of omega-3 fats – without the risk of methyl mercury.

The study, which appeared in The New England Journal of Medicine, examined mercury levels in the toenail clippings of more than 1,400 men. The researchers found that men with the highest levels of mercury in their system had about twice the risk of a heart attack as those with the lowest levels.

Patients concerned about eating a heart-healthy diet should consult their physician or a licensed dietitian.