Effects of a Gluten-Free Diet on Gastrointestinal Symptoms and Quality of Life in Non-celiac Gluten-Related Disorders: A Systematic Review and Meta-Analysis

Non-celiac gluten sensitivity (NCGS) is a gastrointestinal and extraintestinal condition characterized by symptoms triggered by the ingestion of gluten, but it does not involve celiac disease (CD) or an allergic reaction to wheat. This meta-analysis and systematic evaluation were intended to determine the impact of a gluten-free diet (GFD) on gastrointestinal symptom reduction and quality of life (QoL) in NCGS patients. We filtered studies published from 2010 to 2025, focusing on randomized controlled trials and observational studies. The findings showed that GFD significantly promoted gastrointestinal signs and symptoms and QoL, and the pooled effect was 0.88 (95% CI = 0.20-1.55), which showed a marginal effect. Nonetheless, significant heterogeneity was observed (I² = 97.77%), suggesting that variability in effects may be attributed to differences in study design, participant characteristics, and adherence to the diet. Subgroup analysis suggested a larger pooled effect among participants with NCGS (pooled effect size = 0.93) than among participants with CD or less clearly defined gluten-related sensitivity (pooled effect size = 0.74). However, high heterogeneity within the NCGS subgroup indicates the need for further well-designed studies. The evaluation indicates that adherence and baseline symptom severity are key factors influencing the efficacy of diet. Publication bias was not identified as a major concern, as suggested by the relatively symmetrical funnel plot and the non-significant results of the statistical tests. Overall, this meta-analysis suggests that a GFD may be a useful intervention for patients with NCGS; however, individualized dietary management is needed because responses may vary across patients.