Effects of kefir on symptoms, sleep, and gut microbiota in children with ADHD: a randomised controlled trial
Abstract
Background: Evidence indicates the gut microbiome may be altered in ADHD, suggesting that targeting gut bacteria could alleviate symptoms. This study examined the effects of kefir supplementation on ADHD symptoms, sleep, attention, and gut microbiome composition in children diagnosed with ADHD.
Methods: A six-week, randomised, double-blind, placebo-controlled trial was conducted in UK children aged 8-13 years with ADHD. Participants were assigned either to a daily kefir or placebo drink group. The primary outcome was ADHD symptom severity measured by the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour (SWAN) scale. Secondary outcomes included gut microbiota composition (analysed using shotgun metagenomic sequencing), gastrointestinal symptoms, sleep (actigraphy, parent/self-report), attention and impulsivity.
Results: Fifty-three participants (mean age = 10.2 years, SD = 1.7) completed the study. Kefir had no significant overall effect on parent or teacher-rated ADHD symptom severity. A non-significant interaction was observed between baseline symptom severity and group for teacher-rated SWAN scores, with children in the kefir group who had the highest baseline ADHD symptoms showing lower scores at week six (M = 2.03, SE = 0.33 vs. 2.86, SE = 0.34), p = 0.088. Actigraphy revealed the kefir group spent fewer minutes awake during the down period at week six (M = 70.10, SE = 0.09) than the placebo group (M = 89.72, SE = 0.07), p = 0.04. However, the kefir group…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.
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