The newly released 2020-2025 Dietary Guidelines for Americans took a life span approach, including a new consideration of the first 1000 days of life. To support this new focus, the 2020 Dietary Guidelines Advisory Committee conducted systematic reviews to examine the relationships between aspects of the maternal diet consumed before and/or during pregnancy and lactation and maternal and child outcomes, including neurodevelopment. The 2020 Dietary Guidelines Advisory Committee report provides evidence that seafood intake during pregnancy is associated favorably with cognitive development in young children and may be associated favorably with language and communication development as well. Accordingly, the 2020-2025 Dietary Guidelines for Americans recommends that women who are pregnant or breastfeeding should consume at least 8 and up to 12 ounces of seafood per week. Yet, there is limited evidence to ensure that omega-3 fatty acid supplementation provides similar benefits.
As long-chain polyunsaturated fatty acids are particularly important for the formation of a fatty sheath around nerves and for the development of vision during the perinatal period, Julie Nevins (Nutritionist at the Center for Nutrition Policy and Promotion, USDA) and colleagues conducted a systematic review of the literature to examine the relationship between omega-3 fatty acid supplementation during pregnancy and/or lactation and neurodevelopment in children. The initial literature search resulted in 1393 articles. Their study, published in The Journal of Nutrition, identified 33 relevant articles from 15 randomized controlled trials and 1 prospective cohort study, published between 2006 and 2019.
Of the 8 randomized controlled trials that delivered omega-3 fatty acid dietary supplements during pregnancy alone, 5 studies reported >1 finding that supplementation improved measures of cognitive development in the infant or child by 6%–11%. All 8 studies reported >1 nonsignificant result. There was inconsistent or insufficient evidence for other outcomes (language, social-emotional, physical, motor, or visual development; academic performance; risks of attention deficient disorder, attention deficit/hyperactivity disorder, autism spectrum disorder, anxiety, or depression) and for supplementation during lactation alone or both pregnancy and lactation.
The authors concluded that omega-3 fatty acid supplementation during pregnancy may result in favorable cognitive development in the child, although the evidence was graded as limited. There was insufficient evidence to evaluate the effects of omega-3 fatty acid supplementation during pregnancy and/or lactation on the development outcomes listed above. Less evidence was available to evaluate the effects of supplementation during lactation than during pregnancy.
The importance of omega-3 fatty acids for brain development in utero is not disputed. However, based on the evidence in this review, the 2020 Dietary Guidelines Advisory Committee was unable to make a specific recommendation about routine supplementation with omega-3 fatty acids before and/or during pregnancy and lactation. In a companion editorial, Susan Carlson and John Colombo (University of Kansas) offer insights on reasons why the randomized clinical trials of omega-3 fatty acid supplementation in pregnancy might have led to the conclusion of limited evidence despite their importance in brain development.
Julie E H Nevins, Sharon M Donovan, Linda Snetselaar, Kathryn G Dewey, Rachel Novotny, Jamie Stang, Elsie M Taveras, Ronald E Kleinman, Regan L Bailey, Ramkripa Raghavan, Sara R Scinto-Madonich, Sudha Venkatramanan, Gisela Butera, Nancy Terry, Jean Altman, Meghan Adler, Julie E Obbagy, Eve E Stoody, Janet de Jesus, Omega-3 Fatty Acid Dietary Supplements Consumed During Pregnancy and Lactation and Child Neurodevelopment: A Systematic Review, The Journal of Nutrition, Volume 151, Issue 11, November 2021, Pages 3483–3494, https://doi.org/10.1093/jn/nxab238.
Susan E Carlson, John Colombo, DHA and Cognitive Development, The Journal of Nutrition, Volume 151, Issue 11, November 2021, Pages 3265–3266, https://doi.org/10.1093/jn/nxab299.
Images via canva.com.