A campaign to reduce the number of babies in northeastern Minnesota born with elevated mercury levels in their blood appears to be working.
The Minnesota Department of Health reported Monday that mercury levels have declined in a study group of women living along the North Shore of Lake Superior, where studies have found widespread mercury contamination in freshwater fish. The women’s mercury levels came down even though they continued to eat fatty fish that offer dietary and health benefits.
The findings were welcomed by doctors and public health officials on the North Shore, where a 2011 study had found that 10 percent of newborns had risky levels of mercury — which among other things increases the danger of learning disabilities. Officials had worried that overcorrecting for the problem would cause women to miss out on the benefits of fish, such as fatty acids for their personal health and nutrients that support fetal development during pregnancy.
Monday’s report showed that women in the region were eating more fish on average than women nationally and had higher mercury levels. But only 3 percent of the North Shore women had mercury levels that were considered troubling, which matches the national rate and suggests they have been following the latest guidance on the proper amount and type of fish to eat.
“Now we know we can eat fish wisely and give birth to healthy babies!” said Rita Plourde, chief executive of Sawtooth Mountain Clinic, based in Grand Marais, which participated in the study and education campaign.
The project, known as Fish are Important to Superior Health (FISH), consisted of educational materials presented to 500 women of childbearing ages in Cook County. Their blood mercury levels also were tested.
Fifteen women with troubling mercury levels in their blood were then selected for a follow-up study, along with 30 healthy women for comparison. Six months later, none of the women had mercury levels that were concerning.
Presumably, reducing mercury levels in women of childbearing age will also reduce levels in newborns. However, the latest study did not examine blood levels in newborns.
“We wanted to focus on it in women, because we wanted to prevent it in the babies,” said Pat McCann, the lead state health researcher on the project.
Also participating were Grand Portage Health Service, North Shore Health and the Grand Portage Band of Lake Superior Chippewa Trust Lands. Partial funding came from the U.S. Environmental Protection Agency Great Lakes Restoration Initiative.
Clinics in the region now include screening for mercury levels in prenatal visits.
The HealthPartners Institute also reacted to the results with a new website, chooseyourfish.org, to help women make healthy fish consumption choices.
Lake trout and walleye caught in Minnesota tend to have higher mercury content, for example, and should be consumed only once a month by women who are pregnant or likely to become pregnant. The guidance also applies for children younger than 15.
Farm-raised catfish and Atlantic or Pacific salmon tend to have low mercury levels by comparison and can be consumed by these higher-risk groups twice per week.
“We want women and children to eat fish,” McCann said, adding that benefits outweigh risks if proper choices are made.