October 10, 2007

Purdue nutrition expert: Pregnant women should know what kind of fish is safe

"Our best advice continues to be to eat eight to 12 ounces of fish per week if you are pregnant or nursing but also to select fish that is higher in omega-3 fatty acids and lower in pollutants," said Charles Santerre, a professor of foods and nutrition. "We don't want to scare people because many fish are safe to eat, but there are some fish that pregnant woman should not eat."

Santerre said research shows some fish, such as light tuna, tilapia and catfish, are low in omega-3 fatty acids. He said women can easily achieve the desired intake of healthy fats by eating eight ounces of fish that are low in mercury and higher in omega-3 fatty acids.

"Consuming more than 12 ounces of some species could cause a higher risk from some pollutants, like mercury, PCBs and flame retardants," Santerre said. "We know this from cases such as the one that occurred in Japan 50 years ago when people experienced extreme mercury toxicity after eating fish from Minemata Bay, where there was a great deal of industrial discharge of mercury."

Santerre said that studies showing that selenium can prevent mercury toxicity are encouraging but have yet to make it through human clinical testing. Therefore, he said, it is not appropriate to recommend unlimited fish consumption for pregnant or nursing women as suggested by a recent report by the Maternal Nutrition Group, in partnership with the National Healthy Mothers, Healthy Babies Coalition.

"There is a two-pronged message that can be confusing when it comes to eating fish," Santerre said. "Fish has valuable health benefits, such as omega-3 fatty acids that benefit brain development in babies and cardiovascular health in adults. However, eating too much of certain fish can lead to higher mercury exposure, which can harm your baby."

Salmon, farm-raised rainbow trout, herring, mackerel, sardines and whitefish are the best choices because they are lowest in mercury and highest in healthy fats, Santerre said. Childbearing-aged women should not eat swordfish, shark, king mackerel and grouper because of high mercury levels, he said.

If consumed at high levels, mercury can harm the developing nervous system of a fetus or nursing infant. Pregnant or nursing women should also use caution when eating fish that is caught locally, Santerre said.

Santerre created a "Fish for Your Health" card to help consumers know what fish is safe. It is available from the Indiana State Department of Health and its county offices: County Extension offices, the Family Nutrition Program and the Expanded Food and Nutrition Education Program.

The card is available at the Web site developed at Purdue. The site provides information regarding commercial fish that can help educate consumers all across the country.

Santerre said, "The message is clear: Eat fish, but be careful about some fish if you are pregnant, nursing or feeding the fish to a child."

Writer: Maggie Morris, (765) 494-2432, maggiemorris@purdue.edu

Source: Charles Santerre, (765) 496-3443, santerre@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

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