Eating fish rich in essential fatty acids to help prevent heart disease and other chronic illnesses is indisputable. However, many people wonder if they should eat more fish to improve their health or avoid fish because pollutants such as mercury accumulate in the meat. A new study that compared the health benefits of eating fish with the risks should help people make that choice.
Mercury in fish
Although mercury occurs naturally in the environment, industrial pollution also adds it to streams and oceans. In the water the toxic metal turns into methylmercury, a health hazard. Fish and shellfish accumulate methylmercury in their bodies as they feed over time. That’s why larger predatory fish such as tuna, shark, king mackerel, tilefish, and swordfish contain the highest levels of methylmercury.
Should you eat fish?
Numerous studies have highlighted the benefits of omega-3 fatty acids for heart health, brain and eye function, skin conditions, and chronic inflammation. Fish are one of the best sources of omega-3s. Is it possible to eat more fish to lower the risk of chronic illness and minimize exposure to harmful levels of environmental pollutants?
To answer that question, researchers at Umeå University in Finland investigated the relationship between heart attack risk, omega-3 levels and methylmercury in the bodies of participants in Swedish and Finnish health studies.
Balancing mercury and omega-3
An analysis of blood and hair samples linked methylmercury to increased heart attack risk and omega-3 fatty acids to decreased heart attack risk. However, the increased risk from methylmercury was evident only if the toxin was present at high levels at the same time omega-3 levels were low.
In an article on the study published in the American Journal of Clinical Nutrition, the researchers simply concluded that eating fish is a good idea, as long as you avoid fish that accumulate the most environmental pollutants.
Recommended fish consumption
Tuna makes a lot of headlines as a health threat—primarily because people eat so much of it. Other fish have much higher levels of toxins such as methylmercury. The Environmental Protection Agency recommends going light on shark, king mackerel, tilefish and swordfish. Fish with lower levels of methylmercury include shrimp, salmon, catfish, pollock and canned light tuna, which has lower mercury levels than albacore tuna.
Regular consumption of fish high in methylmercury can accumulate the toxin in your blood over time. The body gets rid of methylmercury naturally, but it could take over a year to reach healthy levels. This is why women who plan on becoming pregnant should avoid eating certain types of fish.
To get the health benefits of eating fish while minimizing exposure to methylmercury, the EPA recommends eating up to 12 ounces (2 average meals) a week of fish and shellfish with lower levels of the toxin mentioned above. If you insist on albacore tuna, or if you’re uncertain about how much methylmercury is in the fish you’re eating, limit consumption to 6 ounces a week.