Women need to hear about healthy benefits of fish

Prior studies have shown that omega-3 fatty acids – found abundantly in fish – are important for the health of developing fetuses. However, because women are also advised to limit fish due to contaminants such as mercury, which may harm the fetus, many pregnant women avoid fish entirely.

In this study, 22 pregnant women who ate less than two servings of fish per week were surveyed in focus groups about their knowledge of the health effects and risks of eating fish, advice they had received about eating fish, how much and what types of fish they ate, and other questions about their knowledge and dietary behaviors. Results showed:

• Women were more aware of the health risks from fish contaminants than the potential health benefits from eating fish during pregnancy
• Many of the women did not know how often they could eat fish, how much to eat, or which fish types are more likely to be low in mercury and higher in fatty acids
• Not knowing which types of fish might be safer caused women to eat less fish

The study results suggest that women should be counseled about the risks as well as the benefits of eating fish and participants suggested that a ready source of information, such as a wallet card with which type of fish to eat and which to avoid. “Pregnant women who infrequently consume fish might be willing to eat more fish if they received advice to eat some fish from their obstetrician or other sources and if they had a clear, readily accessible source of information regarding which fish types are safe to eat during pregnancy,” said Arienne Bloomingdale, lead study author, and her colleagues from the Department of Population Medicine at Harvard Medical School, Boston, MA.

Moderation is important

The American Congress of Obstetricians and Gynecologists states that “fish and shellfish are good sources of protein, omega-3 fatty acids, and other nutrients” but also warns against eating too much fish and eating fish that is higher in mercury, which may harm the fetus. They offer the following guidelines:

• Pregnant women or women who are trying to become pregnant may eat up to 12 ounces, or two average meals a week, of fish and shellfish that are considered to be lower in mercury, and they should avoid fish that is considered to be higher in mercury content.
• Types of fish considered higher in mercury include: shark, swordfish, king mackerel, albacore tuna, and tilefish.
• Types of fish considered lower in mercury include shrimp, canned light tuna (not albacore), salmon, pollock, and catfish. They state that if a woman wants to include albacore tuna as part of her two fish meals per week then she should limit the amount of albacore tuna she eats to no more than 6 ounces for that week.
• With fish caught in local rivers or streams, women should check local advisories and if there is no advice about them, it may be safe to eat up to 6 ounces (about one meal) per week of fish from local waters and during that week women should not eat any other fish.

New information about the benefits and risks of eating fish continues to appear in the scientific literature, so women who are pregnant or planning a pregnancy should discuss emerging information with an informed physician.

(Am J Clin Nutr doi:10.3945/ajcn.2010.30070; “Nutrition During Pregnancy,” American Congress of Obstetricians and Gynecologists: www.acog.org/publications/patient_education/bp001.cfm, accessed on September 26, 2010)