Eating fish, as part of a balanced diet, offers several nutritional benefits. But, how do the mercury levels in fish impact your health?
Fish does a body good. It’s a low-calorie protein source that contains several nutrients, including omega-3 fatty acids that are beneficial for your heart and brain. But, can too much of a good thing be harmful?
First the facts: Americans ate an average of 16.0 pounds of fish and shellfish in 2017, according to the latest report from the National Oceanic and Atmospheric Administration (NOAA). Of that amount, 90% falls within the “best choices” for seafood, as defined by the Food and Drug Administration (FDA) and United States Environmental Protection Agency (EPA), meaning it has low levels of mercury. Fish and shellfish in this category, such as salmon, catfish, tilapia, lobster and scallops, are safe to eat two to three times a week, or 8 to 12 ounces per week, according to the FDA.
Halibut, grouper, mahi-mahi, albacore tuna and canned tuna fall under the FDA’s “good choices” category and should be eaten no more than once a week. Swordfish, orange roughy and bigeye tuna are best avoided, as they contain the highest levels of mercury.
“It’s a real concern, if you’re not careful about limiting the amount and frequency of eating fish known to have high levels of mercury,” says Jennifer Boozer, DO, a family medicine physician at Keck Medicine of USC and clinical associate professor of family medicine at the Keck School of Medicine of USC.
All fish contain some level of mercury, even fish in the “best choices” category. High levels of mercury do not usually cause health issues for most people, except for young children and women who are pregnant, planning to become pregnant or nursing. High mercury levels can damage a developing fetus or cause damage to the nervous system in young children. Mercury can also stay in your body for up to a year, so if you’re planning on getting pregnant, or even if you’re of childbearing age and may become pregnant, you should follow the recommended amounts of fish consumption.
If you’re not in an at-risk category and want to eat more than three servings of fish per week, stick to fish that are in the “best choices” category, and opt for farm-raised American fish, whenever possible. U.S. farmed fish and shellfish are required to meet state and federal standards; these are some of the most stringent in the world, according to NOAA.
And, rest assured, a diet that incorporates lower mercury fish is beneficial to your overall health, according to the FDA and EPA.