Gluten-Free Diet in Children with Autism Spectrum Disorders: A Randomized, Controlled, Single-Blinded Trial.

Piwowarczyk et al. (2020) ran a six-month randomized trial. One group of preschoolers with autism ate a gluten-free diet. The other group ate the same meals with gluten. Parents and testers did not know which child got which diet.

Doctors checked autism symptoms, behavior problems, and IQ every month. They wanted to see if removing gluten helped kids feel or act better.

After six months both groups looked the same. Kids on the gluten-free diet showed no extra progress in language, play, or daily living skills. Their GI complaints also stayed level with the control group.

IQ scores and problem behaviors did not budge either. The diet was safe but added no clear benefit.

Lu et al. (2025) pooled 19 studies and saw that probiotic or synbiotic supplements do ease tummy pain in autistic kids. Their positive result is not a true clash with Piwowarczyk et al. (2020); the meta-analysis tested live bacteria, not wheat removal, and many trials tracked GI pain directly while Anna’s team looked at broader autism symptoms.

Andreo-Martínez et al. (2022) found lower good gut bacteria in autistic children. That pattern hints that diets targeting the microbiome could matter, yet Anna’s gluten-free meals did not replace those missing bugs, so the null finding makes sense.

Matson et al. (2009) tried oral immunoglobulin for GI trouble and also saw no change, backing the idea that simple dietary tweaks rarely fix autism-related gut issues on their own.

You can now tell parents that skipping gluten is unlikely to shrink autism traits or GI upset. Save their time, money, and stress. If gut problems persist, probe for specific Rome-IV subtypes or try a probiotic with solid evidence instead.