Truth on Tuesday

Fishy Recommendations about Seafood...

You often read about the many health benefits of fish, mainly due to their omega-3 fatty acid profile.  You've likely also read that pregnant women or those looking to conceive should avoid fish due to worries over toxins like mercury  that might be dangerous to the baby. In the past, both the American Dietetic Association and the Environmental Protection Agency cautioned women to limit fish consumption to no more that 12 oz. per week, which led most pregnant women to avoid seafood altogether (1).



However, limiting seafood during pregnancy is actually doing a disservice to your baby. Fatty fish provide EPA and DHA, two essential fatty acids that are key in fetal brain development (2). In fact, the new 2010 Dietary Guidelines for Americans now recommend that pregnant and breast-feeding women include 8 to 12 oz of fish and seafood low in mercury as part of a healthful diet.


According to the FDA, consumption of fish with methyl mercury levels of one part per million (ppm), such as shark and swordfish, should be limited to approximately 7 ounces per week. The FDA also states that this advice does not apply many of the most popular seafood species like canned tuna, shrimp, salmon, cod, crabs, and scallops.  For these varieties, the methyl mercury levels are less than 0.2 parts per million You would have to eat 2.2 pounds of fish per week to be at risk for high mercury consumption (3).


The other issue of concern with seafood consumption has to do with polychlorinated biphenyls (PCBs) and dioxins, or DDT. However, concentrations of these substances have been found to be well below established maximum intake levels. Mercury appears to stand out as the contaminant of concern in fish (4).

Even still, the dangers associated with the consumption of large amounts of methylmercury accumulated in seafood are well recognized from past poisoning incidents, in which fishwith mercury burdens in the range of 9 - 24 parts per million(5).



Takeaways:

• The nutritional benefits of consuming fish during pregnancy outweigh the risks as long as women are smart about the type and quantity of fish consumed.
• Both the FDA and ADA advise avoiding species of fish that are traditionally higher in mercury
• According to recent reports from the Natural Resources Defense Council, the fish with the highest mercury content were King Mackerel, Shark, Swordfish, Orange Roughy, Marlin, Ahi Bigeye Tuna, and Tilefish (6)
• Be sure to purchase your seafood from reputable vendors and markets to avoid contaminants and risks of foodbourne illness
• Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas
• Advisories in Texas

Want to be sure you're safe? You can use this Mercury Calculator to find our how much mercury is in the fish you commonly consume.



1) Oken E, Kleinman KP, Berland WE, Simon SR, Rich-Edwards JW, Gillman MW. Decline in fish consumption among pregnant women after a national mercury advisory. Obstet Gynecol. 2003;102(2):346-351.

2) Coletta JM, Bell SJ, Roman AS. Omega-3 fatty acids and pregnancy. Rev Obstet Gynecol. 2010;3(4):163-171.

3) Rigby, A. (2004). Omega-3 Choices: Fish or Flax? Today's Dietitan, 6(1), 27.


4) Seher, C. (2011). Shifting Tide — Experts Reassess Risks of Eating Fish During Pregnancy. Today's Dietitian, 13(7), 22.

5)Balshaw, S., Edwards, J. Daughtry, B., & Ross, K. (2007). Mercury in seafood: mechansims of accumulation and consequences for consumer health. Reviews on Environmental Health, 22(2), 91-113.

6) Consumer guide to mercury in fish. National Resource Defense Council. http://www.nrdc.org/health/effects/mercury/guide.asp