Not All Fish Is Heart Healthy, Study Says

Scripps cardiologist recommends fish low in methylmercury

Scripps cardiologist recommends fish low in methylmercury

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 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 to avoid

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 Poulina Uddin, MD, a cardiologist at Scripps' Women's Heart Center. “However, fish consumers should be cautious about what types they eat.”

Heart-healthy fish

According to Dr. Uddin, fish species such as tuna, salmon and trout all have low or moderate levels of methylmercury, and are safe to eat. Dr. Uddin recommends choosing wild salmon instead of farm raised, and also added that tofu, walnuts and canola oil are also significant sources of omega-3 fats — without the risk of methylmercury.

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.