Aspartame in pregnancy and autism in boys
What it found
In a study of 356 children, boys with autism were more likely to have mothers who consumed at least one diet soda or 177 mg of aspartame daily during pregnancy or breastfeeding.
No such link was found in girls.
What they found
Studies in people
Autism in boys
Boys with autism were more than three times as likely to have been exposed daily to at least one diet soda during pregnancy or breastfeeding, compared with neurotypical boys. The link was even stronger for boys with non-regressive autism.
Aspartame in boys
Boys with autism were also more than three times as likely to have been exposed daily to at least 177 mg of aspartame from diet drinks and packets. For non-regressive autism, the odds were nearly four times higher.
No link in girls
No statistically significant links were found between diet soda or aspartame exposure and autism or ASD in girls. The authors note that girls made up only a small part of the autism cases.
Total ASD in boys
When all autism spectrum disorders were combined, the link with diet soda or aspartame was not statistically significant in boys. The association was specific to autism, not the broader category.
Lower doses
Daily exposure to lower amounts of aspartame or other non-nutritive sweeteners was not linked to autism status in this study. The authors suggest a possible threshold effect at higher daily doses.
What the authors conclude
“These associations do not prove causality.”
Also in their conclusions
- They say their findings do not prove that aspartame causes autism.
- They call for more research with larger groups and prospective measurements to confirm the link.
- They advise women to exercise caution when considering diet sodas and aspartame during pregnancy and breastfeeding.
How it was done
The authors wanted to test whether daily exposure to diet soda or aspartame before birth and during breastfeeding increases the risk of autism. They noted that autism diagnoses have risen sharply and that diet products are widely used by pregnant women.
They asked mothers of 235 children with autism spectrum disorder and 121 neurotypically developing children to recall their diet soda and aspartame intake during pregnancy and breastfeeding. They compared the odds of daily exposure between the groups, separately for boys and girls.
What it can’t tell you
- This was a case-control study, so it can show a link but not prove that aspartame causes autism.
- Mothers recalled their diet soda and aspartame intake years later, which may not be accurate.
- The study did not account for other factors like maternal weight, diabetes, or mental health.
Who paid
- Funding
- Funded by NIEHS NIH HHS; NIOSH CDC HHS; ACL HHS; Autism Speaks (from the PubMed record).
- Conflicts
- The authors declare no conflict of interest. The funding institutions had no role in either the design or the execution of the study; in the collection, analysis, and interpretation of the data; or in the writing or reviewing of the manuscript.
- Authors work at
- The University of Texas Health Science Center at San Antonio, USA; The University of Texas Health Science Center at Houston, USA; Universitat Pompeu Fabra, Spain
The paper
- Title
- Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Fowler SP, Gimeno Ruiz de Porras D, Swartz MD, Stigler Granados P, Heilbrun LP, Palmer RF (2023). Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study. Nutrients. doi:10.3390/nu15173772Free full textPubMed 37686804DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error