Kefir e ADHD

In recent years, interest in the role of the gut microbiota in the pathophysiology of ADHD has grown significantly. Alterations in microbial composition, sleep disturbances, and dysregulation of the microbiota-gut-brain axis are frequently reported in ADHD subjects, suggesting possible targets for nutritional intervention.

A study published in 2025 in BMC Psychiatry evaluated the effects of kefir, a complex fermented food, on ADHD symptoms, sleep, and gut microbiota in children aged 8 to 13 years. The study was conducted with a randomized, double-blind, placebo-controlled design, considered one of the most robust in the clinical field.

Participants consumed 125 ml of kefir or a placebo daily for six weeks. The main outcomes included ADHD symptom severity (SWAN scale), sleep parameters assessed by actigraphy and questionnaires, and analysis of gut microbiota composition via metagenomics.

The results did not show a significant reduction in core ADHD symptoms in the kefir group compared to placebo. However, in exploratory analyses, a trend toward improvement was observed in children with greater initial symptom severity, though not statistically significant. Regarding sleep, actigraphy showed a reduction in minutes of nighttime wakefulness in the kefir group, while questionnaires reported a subjective increase in sleep problems, suggesting a possible discrepancy between objective and perceived measures.

From the perspective of the gut microbiota, no significant changes in overall diversity emerged, but an increase in the relative abundance of certain taxa was observed, particularly species of the genus Bifidobacterium, indicating biologically relevant microbial modulation.

Overall, the study suggests that kefir is able to modify the composition of the gut microbiota and may influence some aspects of sleep, but does not provide sufficient evidence to consider it a therapeutic intervention for ADHD. These data reinforce the idea that the microbiota-gut-brain axis plays a role in neurodivergence, but that nutritional interventions should be included in multidimensional, personalized strategies based on solid clinical evidence.

https://link.springer.com/article/10.1186/s12888-025-07568-8