Eating Fish: Health Benefits and Risks

The foods we eat influence our health. Besides containing protein and other nutrients such as vitamin D and selenium, fish (either finfish or shellfish) contain a specific type of fat, omega-3 fatty acids, that may reduce the risk of developing heart disease and other medical problems. However, fish may also contain mercury and other contaminants that may have risks for health.

Researchers from the Harvard School of Public Health (HSPH) tackled that question by undertaking the single most comprehensive analysis to date of fish and health. In the first review to combine the evidence for major health effects of omega-3 fatty acids, major health risks of mercury, and major health risks of PCBs and dioxins in both adults and infants/young children, the results show that the benefits of eating a modest amount of fish per week—about 3 ounces of farmed salmon or 6 ounces of mackerel—reduced the risk of death from coronary heart disease (CHD) by 36%. Notably, by combining results of randomized clinical trials, the investigators also demonstrated that intake of fish or fish oil reduces total mortality—deaths from any causes--by 17%.

Some fish contain mercury. For men and women not of childbearing age, it is not clear that mercury exposure from typical levels of fish intake has any adverse health effects. In contrast, fish intake has significant benefits for reducing the risk of death from heart disease, the number one cause of death. So, mercury exposure from fish intake should not be a major concern for men or for women not of childbearing age. The benefits of fish intake can be maximized by consuming a variety of different seafood.

However, when it comes to a healthier heart, the benefits of eating fish usually outweigh the possible risks of exposure to contaminants. Find out how to balance these concerns with adding a healthy amount of fish to your diet.