September 27, 2023


Future Depends on What You Do

Environmental Component – June 2023: Eating fish while pregnant: rewards outweigh harms

The nutritional added benefits of having fish for the duration of being pregnant seem to outweigh the probable harms of mercury contamination, Emily Oken, M.D., discussed through her May well 8 NIEHS Keystone Science Lecture. Conflicting messages about fish intake, however, have prompted lots of expecting females to consume much less than the suggested servings required to support healthful brain development.

Oken explained her very first R01 grant was funded by NIEHS to examine this topic of fish consumption, mercury exposure, and nutrition through pregnancy. (Photograph courtesy of Emily Oken)

“It is a sophisticated and appealing tale to check out to tease out what is the greatest factor that we ought to be advising men and women to do, and how to give the very best advice,” said Oken, a medical doctor and epidemiologist at Harvard Health-related University.

Her operate facilities on improving upon the wellbeing of females for the duration of being pregnant to advertise their prolonged-expression health and that of their offspring.

“Dr. Oken is an excellent medical professional-scientist tackling intricate inquiries concerning the harmony of risks and gains to pregnant girls and their little ones,” explained Abee Boyles, Ph.D., a health and fitness scientist administrator at NIEHS who hosted the lecture.

Possible harms

Clinicians and scientists treatment what foodstuff expecting women of all ages consume to advertise healthful pregnancies and mainly because it is the key source of vitamins for the creating infant. But food is far more than nourishment, Oken mentioned. It can also be a big car or truck of exposure to environmental contaminants, these kinds of as metals, pesticides, and per- and polyfluoroalkyl substances.

Methylmercury, for illustration, is released into the ecosystem via coal burning, volcanic eruptions, and industrial output. It settles into the sediment of lakes and rivers right before transferring up the maritime food stuff chain, accumulating to its greatest stages in larger, predatory fish.

In 2001, the U.S. Food and Drug Administration (Food and drug administration) and the Environmental Protection Company (EPA) issued an advisory for expecting girls to avoid eating several kinds of predatory fish — these kinds of as shark, swordfish, and mackerel — and also to restrict how much fish they eaten in general.

Oken’s earliest operate evaluated the impact of this federal mercury advisory on pregnant women’s having patterns. She located that the advisory was adopted by a precipitous drop of a lot more than a serving a thirty day period of complete fish usage.

“That led us to surprise irrespective of whether that is basically what we want,” stated Oken.

The 2001 advisory did not issue in the added benefits of eating fish, which is a supply of omega-3 prolonged-chain polyunsaturated fatty acids like docosahexaenoic acid (DHA).

“These are vital vitamins, which suggests we are unable to make them, we have to try to eat them,” she mentioned. “They are required for mind and eye progress of the fetus.”

Messaging matters

Oken and other scientists in the Countrywide Institutes of Health–funded Job Viva have been subsequent mothers and their youngsters for more than two decades to have an understanding of how diet in being pregnant has an effect on children’s health. They uncovered no proof of hurt, and, in some circumstances, proof of reward from bigger fish usage on neurocognitive results.

In 2004, the Food and drug administration and the EPA revised their advisory based on rising facts to say pregnant ladies could try to eat a most of two servings of fish a 7 days. At the same time, maternal health organizations recommended a bare minimum of two servings, preferably additional.

“There has been ongoing confusion among women of all ages about what they should really be ingesting through being pregnant,” claimed Oken.

To explore regardless of whether they could translate the science into much more helpful general public wellbeing messages, Oken and her staff executed a pilot review termed Foodstuff for Imagined. They found that by providing pregnant girls simple and precise tips about maximizing intake of very low-mercury fish, they had been equipped to raise their intake of DHA. Of note, they observed no evidence of an increase in mercury publicity in those people girls.

Woman eating fish
Oken said suggestions for fish intake in the course of pregnancy need to consider the nutritional positive aspects of fish in addition to the prospective harms from environmental exposures. (Photograph courtesy of Shutterstock)

In 2019, the Food and drug administration and the EPA issued the most current information on ingesting fish, which prioritized the nutritional benefits of fish.

“If you lead with the harms, which is how the outcomes were being introduced in 2001, persons will hear the hurt and stay clear of it,” Oken explained. “If you lead with the added benefits, folks listen to the profit and assume it is handy even if the information is the same.”

Bloomingdale A, Guthrie LB, Selling price S, Wright RO, Platek D, Haines J, Oken E. 2010. A qualitative study of fish intake in the course of pregnancy. Am J Clin Nutr 92(5):1234–1240.

Oken E, Guthrie LB, Bloomingdale A, Platek DN, Cost S, Haines J, Gillman MW, Olsen SF, Bellinger DC, Wright RO. 2013. A pilot randomized controlled demo to market healthful fish intake for the duration of being pregnant: the Food items for Assumed Study. Nutr J 12:33.

Oken E, Kleinman KP, Berland WE, Simon SR, Wealthy-Edwards JW, Gillman MW. 2003. Drop in fish intake between pregnant females immediately after a national mercury advisory. Obstet Gynecol 102(2):346–351.

Oken E, Wright RO, Kleinman KP, Bellinger DC, Amarasiriwardena CJ, Hu H, Abundant-Edwards JW, Gillman MW. 2005. Maternal fish usage, hair mercury, and infant cognition in a US cohort. Environ Well being Perspect 113(10):1376–1380.

(Marla Broadfoot, Ph.D., is a contract author for the NIEHS Office environment of Communications and Public Liaison.)