Differences in intestinal flora of patients with autism may be related to dietary preferences

Previous studies have shown that autism spectrum disorder (ASD) may be partly due to differences in the composition of the intestinal flora.
This is mainly based on the observation that certain types of microorganisms are more common in patients with autism
.

But on November 12, a paper published in Cell Press, a journal called Cell ("Cell"), suggested that this connection may actually be the other way around: the flora found in the intestines of children with autism.
The difference may be related to the restrictive diet associated with autism, rather than the cause of its symptoms
.

"A lot of people are interested in the role of gut microbes in autism, but there is not a lot of conclusive evidence
.
" said Jacob Gratten of the Mater Institute and the corresponding author of the paper.
"Our research is by far the largest and aims to Overcome some of the limitations of previous research
.
"

In the past 10 years, with the development of next-generation gut microbial sequencing technology, microbiome analysis has become more automated and less time-consuming.
Many studies have examined the connection between specific gut microbes and mental health
.
Scientists have discovered that the gut-brain axis is not only related to ASD, but also to anxiety, depression and schizophrenia
.
Research on new therapies targeting the microbiota is a growing field
.

In the study, the researchers analyzed the stool samples of 247 children between the ages of 2 and 17
.
The samples came from 99 children diagnosed with ASD and their 51 healthy siblings, and 97 unrelated children without ASD
.
The analysis objects come from the Australian Autism Biobank and the Queensland Twin Adolescent Brain Project
.

The researchers analyzed the samples through metagenomic sequencing, which looked at the entire genome of the microbial species, rather than short genetic barcodes
.
The researchers said that it provides information at the gene level, not only at the species level, but also enables a more accurate characterization of the microbiome composition than 16S analysis
.
16S analysis is a technique used in many early studies of the association between the microbiome and autism
.

"In the analysis, we also carefully considered diet, age and gender
.
" Dr.
Chloe Yap of Gratten's team and the first author of the paper said, "The microbiome is strongly influenced by the environment, which is why we designed two control groups.
Research
.
"

Based on the analysis, the researchers found that there is limited evidence for autism and the microbiome directly related, but autism is highly correlated with diet, and the diagnosis of autism is related to dietary diversity and poor diet quality
.
In addition, measures of the degree of characteristics of autism (including restricted interest, social difficulties, and sensory sensitivity) and ASD polygenic scores (representing genetic factors), as well as impulsive/compulsive/repetitive behaviors, are also related to lower dietary diversity
.

"In general, these data support a very simple and intuitive model that autism-related characteristics promote restrictive diets,
" Yap said.
"This in turn leads to a decrease in microbial community diversity
.
"

The researchers acknowledge that the current work has several limitations
.
One is that the design of the study cannot rule out the contribution of the microbiome before ASD diagnosis, nor can it rule out the possibility that changes in the microbiome related to diet affect behavior
.
In addition, it is difficult for them to completely rule out the possible impact of antibiotics on the gut microbiota of the sample population
.
Finally, there is currently no comparable data set to confirm these findings
.

"We hope this discovery will encourage others in the autism research community to regularly collect metadata in omics research to explain important but often underestimated potential confounding factors, such as diet
.
" Gratten said, "Our findings It also focuses on the nutritional problems of children with autism, which is an important but not fully understood factor in the clinic
.
"

The researchers plan to generate new data in a larger sample to replicate their findings
.
(Source: Tang Yichen of Science Net)

Related paper information: http://dx.
doi.
org/10.
1016/j.
cell.
2021.
10.
015