Neuroscience Blog

Article Author: Brett J. Weiss

Highlights

• The percentage of boys with autism who had mothers consuming at least one diet soda daily was dramatically higher than boys without autism — 19.3% compared to 7.4%, respectively.
• Boys with autism have triple the odds of having mothers with daily consumption of at least one diet soda or comparable amounts of aspartame during their early lives compared to boys without autism.
• Girls with autism didn’t show significantly higher odds of having maternal exposure to aspartame during their early lives.

Over the last 40 years, the prevalence of autism spectrum disorder (ASD) has risen dramatically, affecting fewer than 0.3 per 1,000 children before 1980 and rising to 27.6 per 1,000 children diagnosed in 2020. Diagnostic criteria changes and increased testing availability may help explain the substantial upsurge in ASD diagnoses. However, mothers’ exposure to dietary contributors like aspartame — approved by the FDA in 1983 as a sugar substitute in diet sodas — may help explain the uptick in ASD diagnoses.

Published in Nutrients, Palmer and colleagues from the University of Texas Health Science Center at San Antonio show that the percentage of boys with autism whose mothers consumed at least one diet soda or equivalent amounts of aspartame daily were significantly higher than boys without autism. Moreover, the researchers uncovered a statistical association where boys with autism have triple the odds of having mothers who consumed at least one diet soda or equivalent amounts of aspartame per day during their early lives. In contrast, females with autism didn’t show a higher likelihood of having mothers who consumed diet sodas or high levels of aspartame regularly. Although the study doesn’t show causation between maternal aspartame consumption and autism risk, it reveals a statistical association between mothers who consume aspartame and autism in male offspring.

Maternal Aspartame Consumption During Early Development Linked to Male Autism Diagnosis

Intriguingly, boys have a fourfold increased probability of receiving an ASD diagnosis compared to girls. For this reason, Palmer and colleagues divided 356 children based on sex (257 boys and 99 girls) and ASD diagnoses (203 ASD boys and 32 ASD girls). The researchers found that the percentage of boys with autism who underwent exposure to daily aspartame through their mothers’ wombs or breastfeeding was 19.3% compared to 7.4% for boys without autism. These significant findings only applied to boys, possibly due to boys theoretically having more neurodevelopmental vulnerabilities than girls. Thus, these results suggest that exposure to aspartame through maternal diet is linked to autism risk for boys.

Because higher percentages of boys with autism had mothers consuming aspartame during their early lives, Palmer and colleagues sought to find the odds of boys with autism having mothers consuming aspartame. Through statistical analyses, Palmer and colleagues found that boys with autism were about three times more likely to have mothers who consumed at least one diet soda per day than boys without autism. Again, these significant findings didn’t apply to girls. These data provide more evidence for the connection between maternal aspartame consumption and male offspring with autism.

“Compared with male controls, males with autism in our study had more than tripled odds of having been exposed daily—gestationally and/or through breastfeeding—to either diet soda itself or comparable doses of aspartame from multiple sources,” said Palmer and colleagues.

Aspartame Possibly Confers Neurodevelopmental Complications in Males Due to Inflammation

The study doesn’t prove causality; it merely provides a statistical association between maternal aspartame consumption and male offspring with autism. Aspartame has been shown to reduce levels of glutathione, an antioxidant present in cells, in rodents. If these findings translate to humans, they could mean that by inhibiting neuronal glutathione concentrations, aspartame induces neuroinflammation that potentially interferes with brain development. Given the study’s association between maternal aspartame consumption and male ASD diagnosis, mothers should take extra precaution with aspartame, especially if pregnant with a male.

The study used a limited number of participants with and without ASD. This factor may explain why maternal aspartame consumption wasn’t linked to autism in female offspring. Future studies potentially associating maternal aspartame consumption to offspring ASD diagnoses should include more participants.

Story Source

Fowler SP, Gimeno Ruiz de Porras D, Swartz MD, Stigler Granados P, Heilbrun LP, Palmer RF. Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study. Nutrients. 2023 Aug 29;15(17):3772. doi: 10.3390/nu15173772. PMID: 37686804.