Large review finds weak evidence of probiotics and vitamin D treating autism

A new review has found no strong evidence of treating autism with a set of complementary and alternative therapies. The study covered 19 assessments, including animal-assisted interventions, acupuncture, herbal medicine, music therapy, probiotics, and vitamin D.

The publication in Nature Human Behaviour is dubbed the “most comprehensive quantitative review” of alternative treatments for autism. It involves 248 meta-analyses, including 200 clinical trials involving over 10,000 participants.

These alternative treatments had “limited or low-quality evidence,” and most lacked safety assessments, according to researchers from France’s Paris Nanterre University and Paris Cité University and the UK’s University of Southampton.

The researchers explain that autistic people struggle with communication and understanding how others feel or think, and are susceptible to overwhelming and repetitive behaviors. These aspects can interfere with their quality of life.

“Many parents of autistic children, as well as autistic adults, turn to complementary and alternative medicines hoping they may help without unwanted side effects,” explains professor Richard Delorme, head of the Child and Adolescent Psychiatry Unit at Robert Debré Hospital, France.

“However, it is necessary to carefully consider evidence from rigorous randomized trials before concluding that these treatments should be tried.”

Meta-analyses over single studies

The first author, Dr. Corentin Gosling, an associate professor at Paris Nanterre University, explains that the team reviewed all the available meta-analyses instead of examining individual trials.

“Importantly, we also developed a free and easy-to-use online platform, which we will continue to test. Ultimately, we hope this tool will support autistic people and practitioners in choosing together the best treatment.”

Professor Samuele Cortese, National Institute for Health and Care Research professor at the University of Southampton and co-senior author, concludes: “This study shows that when people want to know whether a treatment is effective, they shouldn’t just look at one single study.” 

“It’s essential to consider all the available evidence and how good that evidence is. Drawing conclusions from one low-quality study can be misleading.”

Autism and nutrition link 

This month, researchers argued that the gut microbiota, rather than genetics, may be the leading cause of autism spectrum disorder (ASD). It revealed that the host immune system also impacts the condition’s progression in a genetic mouse model.

Other research has found that newborn babies with vitamin D deficiency are at greater risk of developing attention deficit/hyperactivity disorder, ASD, and schizophrenia. It suggests that mothers supplementing vitamin D during pregnancy could reduce these risks.

Also, research from last year suggests that eating any amount of fish during pregnancy was linked to a 16% lower likelihood of autism spectrum disorder diagnosis in offspring, specifically in girls, and a slight reduction in autism-related traits.