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Pregnant People Should Eat More Seafood, New Guidelines Say

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Key Takeaways

  • New guidelines suggest people who are planning on getting pregnant, are pregnant, or breastfeeding eat 8 to 12 ounces of seafood weekly.
  • Seafood has numerous benefits, including improving cognitive function in babies and lowering hypertension.
  • When considering what to choose, you should still keep mercury levels in mind.

New U.S. dietary guidelines suggest individuals who are planning on having children, are pregnant or have recently given birth should eat at least 8 to 12 ounces of seafood per week, particularly from fish higher in omega-3 fatty acids that have less risk of containing mercury.

The U.S. Department of Agriculture (USDA) recently published the Scientific Report of the 2020 Dietary Guidelines Advisory Committee. The report highlights two major themes that will inform how the 2020-2025 Dietary Guidelines for Americans are developed. One is that people should consider all life stages—pregnancy, lactation, birth to age 24 months, childhood, adolescence, and adulthood—when choosing healthy foods.

The other is that there should be a focus for individuals and public health efforts to emphasize the fact that a high-quality dietary pattern can:

  • Promote health
  • Achieve nutrient adequacy and energy balance
  • Reduce the risk of diet-related chronic illnesses

With those two themes in mind, the Dietary Guidelines Advisory Committee made the seafood suggestion based on evidence that fish consumption before pregnancy as part of a healthy diet may reduce risk of gestational diabetes and hypertensive issues, while seafood during pregnancy could lower risk of premature birth.

Seafood may confer benefits to the baby as well, the guidelines state, including potentially better development of cognitive function, language, and communication skills. For example, a 2019 study found an average 7.7 IQ point gain in children whose mothers ate seafood during pregnancy, compared to people who didn't eat fish when pregnant.

What About Mercury?

In recommending seafood, the report does address the sometimes problematic issue of methylmercury levels in some types of seafood.

"In terms of neurocognitive development, fish is the primary dietary source of long-chain polyunsaturated omega-3 fatty acids, which are needed for brain development," the report states. "Thus, the benefits of seafood need to be weighed again the potential for negative health consequences due to possible contamination with heavy metals, chiefly methylmercury."

The presence of mercury has likely steered many pregnant individuals away from fish completely, but not all seafood is an equal risk. The U.S. Food and Drug Administration (FDA) categorizes fish based on mercury levels and reports the following as the safest for women who are pregnant, may become pregnant, or are breastfeeding:

Safest Fish to Consume

  • Anchovies
  • Catfish
  • Cod
  • Crab
  • Haddock
  • Herring
  • Lobster
  • Oyster
  • Pollock
  • Salmon
  • Sardines
  • Scallops
  • Shrimp
  • Tilapia
  • Tuna, canned light (including skipjack)

That said, it's important for people to be aware of the potentially harmful health effects of eating high-mercy fish on a regular basis, according to dietitian Julie Cunningham, RD, LDN. "Mercury can accumulate in the body and become toxic to the brain and nervous system over time," she says.

Fish to Avoid

  • King mackerel
  • Marlin
  • Orange roughy
  • Shark
  • Swordfish
  • Tilefish (Gulf of Mexico)
  • Bigeye tuna

Omegas and Vitamin D

Incorporating more low-mercury seafood choices into a regular rotation is important for increasing omega-3 fatty acids, according to certified nutritionist Aimee Aristotelous, CN, who specializes in prenatal dietetics.

Aimee Aristotelous, CN

"We all know folate as the main pregnancy nutrition superstar since it prevents neural tube defects, however, omega-3 fatty acids are just as important as they are the key players in fetal eye and brain development. Your body cannot manufacture these fats so one must get them food.

— Aimee Aristotelous, CN

There are three important types of omega-3 fatty acids and they come from two primary dietary sources:

  • Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are mostly found in fatty seafood such as salmon, tuna, anchovies, mussels, and oysters.
  • Alpha-linolenic acid (ALA) comes from vegetable oils, nuts, flaxseeds and flaxseed oil, and leafy vegetables.

The vital health benefits attributed to omega-3 fatty acids come from EPA and DHA, says Aristotelous.

"Seafood, by leaps and bounds, is the best dietary source of DHA and is really the only food which will give adequate amounts of the fatty acid," she notes. "The body converts ALA into EPA, but in very little amounts; the conversion is usually less than 5 percent."

Another health boost, she adds, is that choices like salmon, sardines, and tuna are the best dietary sources of vitamin D. Research suggests that pregnant people who get higher amounts of this vitamin reduce the chances of complications from preterm birth, gestational diabetes, and infection.

"Between the fatty acids and vitamin D found in fish, it truly is a superfood which should be taken seriously during pregnancy,” Aristotelous says.

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Article Sources
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  1. U.S. Department of Agriculture, Agricultural Research Service. Dietary Guidelines Advisory Committee. Scientific Report of the 2020 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Agriculture and the Secretary of Health and Human Services. July 2020.

  2. Hibbeln JR, Spiller P, Brenna JT, et al. Relationships between seafood consumption during pregnancy and childhood and neurocognitive development: Two systematic reviews. Prostaglandins Leukot Essent Fatty Acids. 2019;151:14-36. doi:10.1016/j.plefa.2019.10.002

  3. U.S. Food & Drug Administration. Advice About Eating Fish. Updated July 2, 2019.

  4. Antunes dos santos A, Appel hort M, Culbreth M, et al. Methylmercury and brain development: A review of recent literature. J Trace Elem Med Biol. 2016;38:99-107. doi:10.1016/j.jtemb.2016.03.001

  5. Harvard T.H. Chan School of Public Health. Omega-3 Fatty Acids: An Essential Contribution.

  6. Dovnik A, Mujezinović F. The Association of Vitamin D Levels with Common Pregnancy Complications. Nutrients. 2018;10(7). doi:10.3390/nu10070867