Healthy Prenatal Dietary Pattern Linked to Lower Odds of Child Having Autism

Catherine Friel, PhD

Credit: LinkedIn

A new study found an association between an expecting mother following a healthy prenatal dietary pattern and their child having lower odds of an autism diagnosis and social communication difficulties—but not for autism-associated traits of restrictive and repetitive behaviors.¹

“This inconsistency related to differential associations with the subdomains and at different ages,” wrote investigators led by Catherine Friel, PhD, from MRC/CSO Social and Public Health Sciences Unit at the University of Glasgow in Scotland. “More consistent results were observed for social communication difficulties.”

Research suggests prenatal diet may be causally related to autism. A previous study found an autism diagnosis was inversely linked to prenatal multivitamins, folic acid supplement use, adequate vitamin D status, and high prenatal fish intakes.² However, findings on this subject are inconsistent and limited by the small sample sizes and retrospective study designs.¹

Investigators sought to investigate the link between prenatal dietary patterns with autism diagnosis and autism-associated traits. The team leveraged data from the large perspective studies of The Norwegian Mother, Father, and Child Cohort (MoBa) Study and the Avon Longitudinal Study of Patients and Children (ALSPAC), conducted across Norway and the Southwest of England, respectively. Participants from the former cohort were recruited between 2002 and 2002, and the latter cohort was recruited between 1990 and 1992.

The primary outcome for MoBa was offspring autism diagnosis and elevated social communication questionnaire score at 3 years old and 8 years old; the study also examined social communication difficulties and restrictive and repetitive behaviors. The ALSPAC focused on offspring outcomes of elevated social communication difficulties checklist score at 8 years old.

Participants from both studies had singleton pregnancies with self-reported food frequency questionnaire responses. Both the studies MoBa and ALSPAC followed the children of the participants until ≥ 8 years old.

MoBa had 84,548 pregnancies with a mean age of 30.2 years and 51.2% male offspring, and ALSPAC had 11760 pregnancies with a mean age of 27.9 years and 51.3% male offspring. Friel and colleagues analyzed this data from February 1, 2022, to August 1, 2023.

Investigators created a healthy prenatal dietary pattern using a factor analysis. The score was adjusted for total energy intake and categorized as high, medium, and low adherence to a healthy prenatal dietary pattern. The dietary patterns were high for fruits, vegetables, fish, nuts, and whole-grain foods, and low for red and processed meats, soft drinks, and foods high in fats or refined carbohydrates. Recommended nutrient intakes were consistent for Norway and England.

Adjusted models showed a high adherence to a healthy dietary pattern, compared with low adherence, was linked to reduced odds of autism diagnosis (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.66 – 0.92) and social communication difficulties at 3 years old in MoBa (OR, 0.76; 95% CI, 0.70 – 0.82) and 8 years old in ALSPAC (OR, 0.74; 95% CI, 0.33 – 0.98).

Sensitivity analysis of food subgroups showed mothers on a plant-based dietary pattern reduced the likelihood of their offspring having a high score on Social Communication Questionnaire at 8 years old (OR, 0.92; 95% CI, 0.86 – 0.99) and Social Communication Questionnaire (SCQ) about autism-associated social communication difficulties at 8 years old (OR, 0.89; 95% CI, 0.82 – 0.96). A fish-based dietary pattern was also associated with a reduced likelihood of a high score on the Social Communication Questionnaire about restrictive and repetitive behaviors at 8 years old (OR, 0.93; 95% CI, 0.88 – 0.99).

“…although nutrients are distributed across multiple foods, there are key food sources of specific nutrients,” investigators wrote. “Further studies are required to clarify if plant-based foods have clearer associations with social communication difficulties.”

Investigators saw the association between a healthy dietary pattern and offspring outcome was greater depending on the offspring sex. On a healthy dietary pattern, female offspring were more likely to have reduced social communication difficulties at 8 years and 12-item Social and Communication Disorders Checklist at 8 years. Male offspring were more likely to have reduced social communication difficulties at 3 years.

“We observed inconsistent evidence that female offspring, compared with male offspring, had a greater reduction in the likelihood of social communication difficulties at age approximately 8 years if their mothers had consumed an [healthy prenatal dietary pattern],” investigators wrote.

Ultimately, the study found a high adherence to a healthy prenatal dietary pattern was associated with a 22% reduced likelihood of an offspring autism diagnosis.

“At present, we remain uncertain as to whether the associations observed are causal,” investigators wrote. “Further research should substantiate our findings, especially given the inconsistency in the previous literature and across our measures of autism-associated traits. It would be advantageous to measure the subdomains combined and separately and explore whether associations differ by food group.”

References

1. ^{Friel C, Leyland AH, Anderson JJ, Havdahl A, Brantsæter AL, Dundas R. Healthy Prenatal Dietary Pattern and Offspring Autism. JAMA Netw Open. 2024;7(7):e2422815. doi:10.1001/jamanetworkopen.2024.22815}
2. ^{Zhong C, Tessing J, Lee BK, Lyall K. Maternal dietary factors and the risk of autism spectrum disorders: a systematic review of existing evidence. Autism Res. 2020;13(10):1634-1658. doi:10.1002/aur.2402}