Study links pregnant women's diet to autism risk in children
Researchers from Norway and Scotland have identified a possible link between a mother’s diet before and during pregnancy and the likelihood of her child developing autism.
While previous studies have shown that diet, genetic, and environmental factors can influence the development of autism during the foetal stage, many questions remain, especially regarding the role of parental lifestyle and nutrition.
Researchers from the Norwegian Institute of Public Health (NIPH) and the University of Glasgow in Scotland have looked more closely at the importance of diet. They collected data from over 95,000 pregnancies across two large population studies: the Norwegian Mother, Father and Child Cohort Study (MoBa) and the British Avon Longitudinal Study of Parents and Children (ALSPAC). The findings were recently presented in JAMA Network Open.
Women's diets were scored based on the consumption of healthy versus unhealthy foods during pregnancy. The researchers found that children born to mothers who followed a healthy diet were about 22 per cent less likely to be diagnosed with autism compared to those born to mothers with less healthy diets.
Additionally, children of mothers who ate healthily during pregnancy had roughly a 24 per cent lower chance of developing social and/or communication difficulties.
What is healthy?
Clinical nutritionist and senior researcher Anne Lise Brantsæter at NIPH is a co-author of the study. She explains that the research team adhered to international guidelines and national dietary recommendations when defining what constitutes a healthy diet and creating a scoring system:
“A healthy diet includes regular consumption of fruits, vegetables, and berries, as well as fish, nuts, and whole grains. Points were also awarded for low consumption of sugary drinks, meat products, and foods high in refined carbohydrates, fats, or salt,” Brantsæter tells NTB.
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She notes that the foods contributing to a positive diet score reflect long-term eating habits, not just those during pregnancy.
Controlling for other factors
Previous studies have suggested that an unhealthy diet might correlate with various other parental factors, such as socioeconomic background, lifestyle, and general health. In this study, the researchers accounted for these variables, including the mother's age, level of education, mental health, whether the pregnancy was planned, and the mother's habits related to smoking, alcohol, and vitamin intake before and during pregnancy.
“Additional analyses confirmed the consistency of the results. For instance, we checked whether the father's age, BMI, education, and income had any impact on the outcomes, which they did not,” says Brantsæter.
Annette Drangsholt, the leader of the Autism Association in Norway, emphasises the importance of research on autism, while also cautioning against narratives that could cause those with autism and their families to feel blamed.
“Our priority at the Autism Association is that research leads to better understanding and competence regarding autism within the support system. This way, appropriate help can be provided at the right time,” she says.
Significant increase in diagnoses
The number of autism spectrum diagnoses made in Norway has increased sharply in recent years. In July, the Autism Association surpassed 10,000 paying members. This increase in diagnoses and membership is likely due to greater awareness and understanding of autism among professionals and the general public, though underlying causative factors could also play a role.
The diet study utilised data from the Autism Study, a large sub-study within MoBa that aims to increase knowledge about the prevalence, development, and causes of autism. New insights from this research could improve understanding, detection, and support for those affected.
“It’s not yet clear if the relationship between diet during pregnancy and autism in children is causal,” says Alexandra Havdahl.
She is the project leader for the Autism Study.
Havdahl explains that researchers in the Autism Study are continuing to explore the relationship between diet and genetics, a development welcomed by Drangsholt.
“There’s a need for research that addresses the entire autism spectrum. We also want more research on follow-up and long-term outcomes to understand what is needed for a good life with autism,” she says.
Reference:
Friel et al. Healthy Prenatal Dietary Pattern and Offspring Autism, JAMA Network Open, 2024. DOI: 10.1001/jamanetworkopen.2024.22815
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Translated by Alette Bjordal Gjellesvik
Read the Norwegian version of this article on forskning.no
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