People Encouraged To Eat More Fish

The Minnesota Department of Health (MDH) has revised its fish consumption advisory to include a large new body of data on contaminants in fish from Minnesota lakes and rivers. The advisory is also in a new format designed to make it easier to understand while encouraging people to eat more fish.

For more than 20 years, the fish consumption advisory has helped Minnesotans choose which species of fish to eat and how often in order to minimize their risks from contaminants in fish while gaining the many health benefits from eating fish.

Health experts, including MDH, recommend eating one to two meals of fish per week. Fish are a good low-fat source of protein and eating fish may help protect adults against cardiovascular disease. Pregnant women and women who may become pregnant should also eat fish because it promotes eye and brain development in fetuses.

This year's edition of the advisory includes a substantial amount of new data collected from numerous species of fish from more than 250 lakes and rivers. The advice for specific lakes and rivers in the advisory has been redesigned to include information on three contaminants instead of the previous two: perfluorooctane sulfonate (PFOS) joins mercury and polychlorinated biphenyls (PCBs) as one of the contaminants that can affect how much fish people should eat. The tables also include changes in how meal advice is displayed.

"The changes to this year's guide represent the biggest change in the advisory format since it was first published in 1985. It reflects a great amount of cooperative work among MDH, the Minnesota Pollution Control Agency (MPCA), the Department of Natural Resources (DNR), and the Department of Agriculture (MDA)," said Commissioner of Health Dr. Sanne Magnan.

For this advisory, MDH staff analyzed and interpreted laboratory results from approximately 4,500 samples of fish tissue, more than twice the usual amount. The data came from field collections in 2006 and 2007 by DNR and the subsequent analysis of PCBs and mercury in fish tissue by MDA. The increased collections and analysis were made possible in part by funding from the Clean Water Legacy Act of 2006.

In addition, the 2008 advisory includes data on perfluorochemicals (PFCs) in fish taken from 33 lakes in the metro area and the Mississippi and St. Croix rivers. Fish sampling for PFCs in metro lakes was begun in 2006 after PFOS was discovered in bluegill sunfish from Lake Calhoun in Minneapolis. PFOS is the compound from the PFC family that accumulates most abundantly in fish.

One surprise finding in the new data is that Cedar Lake in Minneapolis has a much lower level of PFOS in bluegill than Lake Calhoun. Because Cedar Lake is connected to Calhoun in the Minneapolis Chain of Lakes, it was expected that Cedar would have similar levels of PFOS in fish, so it received the same advisory as Calhoun in 2007. Since then, the levels in fish from Cedar have been found to be lower than from Calhoun, so the advisory for Cedar Lake bluegill has been relaxed from one meal per month to one meal per week.

To make information for specific lakes and rivers easier to understand, two major changes were implemented. Symbols are no longer used to represent the meal advice and meal advice categories are now listed at the top of the advice table. While for some species of fish, contamination concentration increases with size, for many species the concentration does not change significantly with size. Therefore, more of the meal advice is now for "all sizes" of a particular species of fish, rather than categorized by length of fish.

"The symbols required interpretation," said Pat McCann, an MDH environmental health researcher and coordinator of the fish consumption advisory (FCA). "We believe the new approach is less complicated and more accurately reflects the relationship between fish size and contaminant concentration. Also, changes in the format were needed to add another contaminant, PFOS."

The advisory is also aimed at encouraging people to eat more fish. Previous guides advised consumers that they could eat fish that had a once-per-week recommendation OR a meal of fish from the once-per-month category, but not both. Now, MDH is advising consumers that they may eat fish from the once-per-week category AND the once-per-month category. "The health benefits of eating more fish are clear," McCann said. "Additional data and a thorough analysis show that this slight change will still be safe for people eating fish."