Maternal Dietary Fat Intake in Association With Autism Spectrum Disorders

Kristen Lyall; Kassandra L. Munger; Éilis J. O'Reilly; Susan L. Santangelo; Alberto Ascherio


Am J Epidemiol. 2013;178(2):209-220. 

In This Article

Abstract and Introduction


Our goal in this study was to determine whether maternal fat intake before or during pregnancy was associated with risk of autism spectrum disorder (ASD) in the offspring. Our primary analysis included 317 mothers who reported a child with ASD and 17,728 comparison mothers from the Nurses' Health Study II (index births in 1991–2007). Dietary information was collected prospectively through a validated food frequency questionnaire. Binomial regression was used to estimate crude and adjusted risk ratios. Maternal intake of linoleic acid was significantly inversely associated with ASD risk in offspring, corresponding to a 34% reduction in risk in the highest versus lowest quartiles of intake. Mothers in the lowest 5% of ω-3 fatty acid intake had a significant increase in offspring ASD risk as compared with the remaining distribution (risk ratio = 1.53, 95% confidence interval: 1.00, 2.32); this association was also seen in the subgroup of women (86 cases and 5,798 noncases) for whom dietary information during pregnancy was available (risk ratio = 2.42, 95% confidence interval: 1.19, 4.91). Thus, variations in intake of polyunsaturated fats within the range commonly observed among US women could affect fetal brain development and ASD risk. Because the number of women with diet assessed during pregnancy was small, however, these results should be interpreted cautiously.


Autism spectrum disorders (ASDs) are defined by significant deficits in communication and social functioning and by the presence of repetitive behaviors. Less than 25% of cases can be accounted for by known causes; for the remainder, multifactorial etiology, including both genetic and environmental factors, is likely.[1,2] Research indicates structural and functional brain differences in children with autism and points to the perinatal and neonatal periods as etiologically relevant time frames.[3,4] Several maternal prenatal factors also have been shown to influence risk of ASD.[5]

Although maternal nutrition is essential to fetal development, relatively little research has been dedicated to the topic of maternal diet in association with ASD. Maternal intake of fatty acids has been associated with birth weight, gestational age and length, and offspring intelligence quotient,[6–8] but no prior report has specifically addressed maternal intake of these fats in association with ASD. Maternal fish intake, a source of ω-3 fatty acids, has been examined in association with broader child developmental outcomes, though results are somewhat conflicting.[9–11] Given the known importance of fatty acids in brain development and the correlation between maternal intake and availability to the developing fetus, determination of whether maternal fatty acid intake alters ASD risk is a logical and potentially informative next step for ASD research.

In this study, we examined maternal intake of fats and risk of having a child with ASD. We used data from a large national cohort, the Nurses' Health Study II (NHS II), to address whether women with high and low intakes of fats and fatty acids differ in risk of having a child with ASD. In particular, we hypothesized that high maternal intakes of ω-3 and other polyunsaturated fats might be protective against ASD because of their role in brain development, and conversely, that low intakes would increase risk.