A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Fall, 2021 | Number 4, Volume 35

Microbiome differences may be due to restricted diets

While researchers are examining the possibility that differences in the gut microbiome may contribute to autism spectrum disorders (ASD), a new study suggests that these microbiome differences may actually arise from the restricted diets of children with ASD. 

In the study, Chloe Yap and colleagues analyzed stool samples from 247 children, all between 2 and 17 years of age. Subjects included 99 children diagnosed with ASD, 51 paired undiagnosed siblings, and 97 unrelated, undiagnosed children. 

The investigators analyzed the samples using a technique called metagenomic sequencing, which they note provides a more accurate representation of microbiome composition than the technique used in many of the earlier studies linking microbiome anomalies to autism. 

“We also carefully accounted for diet in all our analyses, along with age and sex,” Yap says. “The microbiome is strongly affected by the environment, which is why we designed our study with two comparison groups.” 

The researchers found only limited evidence for a direct association of autism with the microbiome. However, they did detect a highly significant association of autism with diet. Their analysis showed that an ASD diagnosis was associated with a less diverse diet and poorer dietary quality. A higher degree of autistic traits was also associated with a less diverse diet. 

They conclude that the findings of their study “support a model whereby ASD-related restricted interests are associated with less diverse diet[s], and in turn reduced microbial taxonomic diversity and looser stool consistency.” 

However, the researchers note that their study could not rule out microbiome contributions prior to ASD diagnosis or the possibility that diet-related changes in the microbiome could have a feedback effect on behavior. In addition, while they excluded individuals taking antibiotics at the time of stool collection, they could not account for prior antibiotic use. 


Citations

“Autism-related dietary preferences mediate autism-gut microbiome associations,” Chloe X.Yap, Anjali K. Henders, Gail A. Alvares, David L.A. Wood, Lutz Krause, Gene W. Tyson, Restuadi Restuadi, Leanne Wallace, Tiana McLaren, Narelle K. Hansell, Dominique Cleary, Rachel Grove, Claire Hafekost, Alexis Harun, Helen Holdsworth, Rachel Jellett, Feroza Khan, Lauren P. Lawson, Jodie Leslie, Mira Levis Frenk, Anne Masi, Nisha E. Mathew, Melanie Muniandy, Michaela Nothard, Jessica L. Miller, Lorelle Nunn, Gerald Holtmann, Lachlan T. Strike, Greig I. de Zubicaray, Paul M. Thompson, Katie L. McMahon, Margaret J. Wright, Peter M. Visscher, Paul A. Dawson, Cheryl Dissanayake, Valsamma Eapen, Helen S. Heussler, Allan F. McRae, Andrew J.O. Whitehouse, Naomi R. Wray, and Jacob Gratten, Cell, November 11, 2021 (online). Address: Jacob Gratten, [email protected]

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“Gut microbiota differences seen in people with autism may be due to dietary preferences,” news release, Cell Press, November 11, 2021.