Microbes causing a ‘leaky gut’ may be triggering ADHD in children

TAOYUAN CITY, Taiwan — Higher levels of some microbes in the gut put children at greater risk of developing attention-deficit/hyperactivity disorder (ADHD), a new study suggests. Researchers in Taiwan say that children with ADHD had higher levels of some species of fungus and lower levels of others — pointing to a link between the condition and gut health.

They explain that the human gut hosts large numbers of microorganisms such as bacteria, viruses, and fungi. However, the amount of each one varies from person to person. After studying fecal samples from 35 children with ADHD and 35 without, the Taiwanese research team found that those with ADHD had higher levels of certain species of fungi and lower levels of others.

The presence of a fungus called Candida albicans was more common in those with the disorder and also created a “leaky gut” that allows bacteria into the bloodstream. This leak leads to inflammation throughout the body and the brain, potentially triggering ADHD.

“The human body is home to a complex and diverse microbial ecosystem, and findings from this study suggest that dysbiosis of the fungal mycobiome in ADHD can influence patient health,” the study authors write in a media release.

ADHD is a common neurodevelopmental disorder that affects people’s behavior. Those with the condition are often restless, struggle with concentration, and sometimes act impulsively. ADHD affects around one in 16 children and teenagers worldwide.

“ADHD may develop from a multidimensional pathophysiology, including the bidirectional signaling pathways between the brain and the gut,” the researchers say, according to SWNS.

“The ‘gut–brain axis’, referring to the link between intestinal function, gut microbiota and the central nervous system, has been proposed to be related to several neuropsychiatric disorders.”

Gut microbiome and digestive system concept
(© sdecoret – stock.adobe.com

Which microbes may be leading to ADHD onset?

Participants in this study were around the age of 10 and just over half were boys. First, the team collected total DNA samples from each fecal sample. Next, they used ITS amplicon sequencing and fungal taxonomic classification to reveal the microorganisms living in the gut.

In the healthy participants, the dominant phylum was Ascomycota. This was followed by Basidiomycota and Mucoromycota. Ascomycota and Basidiomycota were also present in those with ADHD, but the levels of Ascomycota was significantly higher, while the amount of Basidiomycota was much lower.

Candida albicans was the most abundant fungus in the gut and its levels were much higher in those with ADHD. It was this fungus that was able to dampen the human intestinal barrier, leading to gut leakage.

“The current study is the first to explore altered gut mycobiome dysbiosis using the NGS platform in ADHD,” researchers conclude. “The findings from this study indicated that dysbiosis of the fungal mycobiome and intestinal permeability might be associated with susceptibility to ADHD.”

The study is published in the Journal of Child Psychology and Psychiatry.

South West News Service writer Alice Clifford contributed to this report.

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