An initiative to reduce mercury levels among pregnant women living in northeastern Minnesota by getting them to change their fish consumption habits has been effective and is being expanded to include women throughout the state, the Minnesota Department of Health (MDH) announced on Monday.
North Shore women who took part in the initiative successfully lowered their mercury levels by being more careful about which types (species) of fish they ate — and how often they ate them.
“We don’t want to discourage women from eating fish, but we want to encourage them to eat fish that is low in mercury,” said Pat McCann, a research scientist for MDH, in a phone interview with MinnPost.
For the North Shore women, that often meant eating less walleye and lake trout, she said, but not eating less fish overall.
A source of lasting health problems
McCann and her colleagues launched the initiative, called the Fish are Important to Superior Health (FISH) project, after a 2011 MDH study found that 1 in 10 newborns in the North Shore/Arrowhead region had unhealthy levels of mercury in their blood.
Mercury is a toxic metal. Babies who are exposed to too much of it in the womb may experience neurological damage that can lead to long-term learning difficulties, as well as vision and hearing problems.
Contaminated fish are the primary source of high mercury levels in the United States. The mercury gets into the fish through airborne pollution — often from the burning of fossil fuels — which settles in the water and eventually makes its way into the food chain. Both fish and humans easily absorb a type of mercury known as methylmercury, making it especially dangerous. The larger and older the fish, the more methylmercury they are likely to have in their bodies — and the greater the threat to human health.
Yet, while fish can be a source of unhealthful levels of mercury, they are also a source of healthful fatty acids.
“Studies have shown that babies whose mothers have eaten low-mercury fish during pregnancy do better developmentally,” said McCann.
An educational project
The 499 women of childbearing age from Cook County, the Grand Portage reservation and the surrounding area who participated in the FISH project were therefore not told to stop eating fish. Research has shown, said McCann, that when women are informed about the dangers of mercury in fish, they often eliminate all fish — including healthy fish — from their diet.
Instead, the women’s health-care providers counseled them about what species of fish to eat and how often to eat them.
Walleye, northern pike, lake trout, bass and catfish, for example, should be eaten no more than once a month, according to the MDH, while other Minnesota favorites, such as lake herring (also known as Cisco), crappie, bullhead and lake whitefish, can be eaten once a week.
When the women were enrolled in the FISH project (between June 2014 and June 2015), their blood was tested for mercury and healthy fatty acids. Data from the study revealed that the women in the project ate more fish than women nationally — not surprising, given the North Shore’s strong cultural connection to fishing, said McCann. They also tended to have higher fatty acid levels and blood mercury levels than women nationally.
Only 3 percent of the women in the project had mercury levels above the level of concern. That’s much lower than the 10 percent found in the 2011 study, and it’s the same percentage seen in women nationally. That finding suggests that in recent years many women in northeastern Minnesota have been following health officials’ recommendations regarding fish consumption, said McCann.
Some of the women in the FISH project, including 15 with concerning levels of mercury in their blood, were re-tested six months later. That follow-up data revealed positive changes. The women’s mercury levels had declined, undoubtedly because they had reduced — as counseled — their consumption of walleye, lake trout and other fish species high in mercury.
“We also found that participating in the project didn’t cause the women to eat less low-mercury fish, and that was good,” said McCann.
The MDH, in partnership with HealthPartners, has published a fish-consumption brochure — customized for different regions of the state and translated into several languages — which will be distributed to women and families in all health-care systems across Minnesota.
They’ve also launched a website, ChooseYourFish.org, to help inform Minnesotans about how often different types of fish can be eaten to minimize exposure to mercury. The website also offers recipes, videos and tips for selecting and cooking fish.
“How much fish you can eat and how often depends on who you are,” said McCann.
Pregnant women and kids need to be particularly careful about the fish they eat, she stressed, but people should not be afraid to eat fish.
“The benefits outweigh the risks — if you eat fish low in mercury,” she said.
FYI: At the ChooseYourFish.org website, you’ll find helpful lists of the fish to eat and the fish to avoid — from Minnesota lakes and rivers as well as from stores and restaurants. Among the fish-related cooking tips on the website is a helpful video from British chef Gordon Ramsey on what to look for when buying fish. The MDH also has information at its Fish Consumption Guidance website.