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Background

Fish intake during pregnancy was associated with a reduction in the likelihood of an autism diagnosis and autism-related traits according to findings from a study recently published in The American Journal of Clinical Nutrition. In contrast, supplementation with omega-3 was not associated with this reduction.¹

According to the investigative team, prenatal fish intake is a key source of omega-3 polyunsaturated fatty acids needed for brain development. Despite this, intake is considered to be generally low. This, paired with the lack of studies addressing autism spectrum disorder (ASD) associations, prompted investigators to create a study further examining the association.¹

Previous evidence demonstrated that the fish and omega-3 polyunsaturated fatty acid (PUFA) intake in the United States is low, with nationally representative data suggesting that 95% to 100% of pregnant and childbearing-age females consumed less than the recommended amounts of fish and docosahexaenoic acid (DHA).¹

"A large number of studies have examined associations between maternal prenatal fish intake and child neurodevelopmental outcomes, with many suggesting that prenatal fish intake is generally associated with higher developmental and cognitive scores among offspring," stated the study authors. "However, not all studies have shown benefits, and few have addressed associations with autism."¹

Study details and results

Comprised of 69 individual cohorts across the United States, the Child Health Outcomes (ECHO) Program is a large collaborative consortium focused on early life factors that can impact mental health. In the study, investigators analyzed data available from ≤32 cohorts that enrolled children born before 2019, to allow time for symptom development and reporting of diagnosis, which typically occurs after age 3, they stated. Included in analysis were 3939 individuals for fish intake and 4537 individuals for omega-3 supplement use. Analyses of autism traits included 3609 individuals for fish intake and 3925 individuals for ω-3 supplement use.¹

Outcome measures included parent report of clinician-diagnosed ASD and parent-reported autism-related traits, measured by the Social REsponsiveness Scale (SRS), second edition. Fish and seafood intake, along with omega-3 supplement intake were collected via questionnaires, as was all covariate information.¹

Fish intake during pregnancy, compared to no fish intake, was associated with reduced odds of autism diagnosis in adjusted regression models (odds ratio: 0.84; 95% confidence interval [CI]: 0.77, 0.92). Results also demonstrated a reduction in raw total SRS scores (β: −1.69; 95% CI: −3.3, −0.08). Across categories of fish consumption (none or <once a month; >once per month but <weekly; weekly; and 2 or more servings per week), estimates were similar from "any" or "less than once per week" to "more than twice per week."¹

"We did not observe an association between omega-3 supplement use and autism diagnosis (adjusted OR: 1.14; 95% CI: 0.83, 1.57)," stated the study authors.¹

"This study provides yet more evidence for the safety and benefit of regular fish consumption during pregnancy," said Emily Oken, MD, MPH, Harvard Medical School, ECHO cohort researcher, in an article published by Environmental Influences on Child Health Outcomes NIH. "Other proven benefits include lower risk for preterm birth and improved cognitive development.”²

Conclusion

Investigators noted this study adds to a growing body of evidence that supports the role of prenatal diet and offspring autism-related outcomes.¹

"In particular, the results from this national study suggest that maternal fish intake, but not omega-3 supplement use, during pregnancy is associated with reductions in the likelihood of autism and autism-related traits," stated the authors. "Our findings are consistent with current dietary guidelines that support fish intake during pregnancy and support continued public health efforts to encourage fish intake, accounting for types of fish with the lowest risk of toxicants."¹

This article was published by our sister publication Contemporary Pediatrics.

References:

1. Lyall K, Westlake M, Musci RJ, et al. Association of maternal fish consumption and ω-3 supplement use during pregnancy with child autism-related outcomes: results from a cohort consortium analysis. The American Journal of Clinical Nutrition. Volume 120. Issue 3. 2024. Pages 583-592. ISSN 0002-9165. doi:/10.1016/j.ajcnut.2024.06.013.
2. ECHO study shows fish consumption and omega-3 supplement use uncommon during pregancy. Environmental influences Child Health Outcomes. Accessed September 5, 2024. https://echochildren.org/research-summaries/echo-study-shows-fish-consumption-and-omega-3-supplement-use-uncommon-during-pregnancy/