Is eating fish healthy or a cause for worry?

Is eating fish good for you? That’s not as easy a question to answer as it once was. Evidence continues to mount that consuming fish is beneficial for the heart, brain, and inflammatory conditions. On the other hand, many fish have been found to con-tain chemical contaminants that may harm health and even pose a risk of causing cancer. So, what’s the bottom line?

Many benefits

First, various positive effects on the heart have been reported from studies of fish eating. One possible explanation is that eating fish in place of meat means consuming less saturated fat, thereby reducing the risk of atherosclerosis, the beginnings of cardiovascular disease. Another explanation lies in the omega-3 fatty acids in fish. This type of fat is believed to help prevent blood clots, inflammation, and irregular heart rhythms. With these benefits in mind, the American Heart Association advises people to eat fish 2 or more times a week to ward off heart disease. Those who already have heart disease should eat fish more frequently.

Omega-3s also help brain development in babies and young children. In addition, they may tamp down chronic inflammation in conditions such as rheumatoid arthritis.

Something’s fishy

On the other hand, almost all fish contain mercury, a toxic heavy metal—in part due to industrial pollution. The larger the fish, the more mercury it’s likely to have absorbed. Mercury can dam-age the nervous system of fetuses, infants, and young children. For this reason, pregnant women, nursing mothers, and young children are advised to avoid certain kinds of fish, such as swordfish, shark, tilefish, and king mackerel.

Other pollutants in fish may also pose a health threat. These include the industrial chemicals PCBs (polychlorinated biphenyls) and organic pollutants such as DDT and dioxin, which may be a cancer hazard. PCBs are worrisome because they accumulate in the body.

If you think that eating farmed fish will protect you from these chemicals, think again. Farmed salmon generally have more PCBs than wild salmon do. Most canned salmon is wild.

The bottom line

A recent study concluded that, based on the strength of the evidence and the size of the effects, the benefits of fish eating clearly outweigh the risks. Almost everyone—the exception is pregnant women—should eat fish 2 to 3 times a week. It’s wise to steer clear of raw or undercooked seafood. And to minimize exposure to PCBs, remove the fish skin and the fat just beneath it.

From the UC Berkeley Wellness Letter and The Journal of the American Medical Association