Co-Supplementation of Zinc and Probiotic on Oxidative Stress Markers and Sleep Quality Index in Irritable Bowel Syndrome Patients: A Double-Blind Randomized Controlled Trial Publisher Pubmed

Summary: Can zinc and probiotics help people with IBS? A trial found improved oxidative stress markers with zinc, alone or combined, but no sleep benefit. #IBS #GutHealth

Rezazadegan M ; Saneei P ; Soheilipour M ; Rezazadegan N ; Amani R
Source: European Journal of Nutrition Published:2026

Abstract

Background: Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder that is related to impaired gut microbiota (GM) composition and sleep disorders. Zinc and probiotics play key roles in gut barrier integrity maintenance and microbiota modulation. Therefore, the current study investigated the effect of zinc and probiotic co-supplementation on oxidative stress biomarkers and sleep quality in IBS patients. Methods: In this parallel, randomized clinical trial, 84 participants with IBS were randomly allocated to three groups and received: 1- a zinc gluconate tablet (20 mg elemental zinc) and a probiotic placebo; 2- a zinc gluconate tablet and a probiotic capsule; 3- two placebos for a period of 90 days. After 10–12 h overnight fasting, serum zinc, total antioxidant capacity (TAC), total oxidant status (TOS), malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity as well as sleep quality were assessed by validated methods. Oxidative stress index (OSI) was also calculated. Results: Supplementation with zinc, without or with probiotic, enhanced serum zinc (mean change: 6.36 ± 0.80 and 13.03 ± 3.82, vs. -1.76 ± 1.82 µg/dL; p = 0.008) compared to placebo. Zinc supplement alone and in combination with probiotics significantly decreased serum TOS level (mean change: − 1.47 ± 0.38 and − 1.67 ± 0.60, respectively, p = 0.001) and OSI (mean change: -1.70 ± 0.28 and − 2.05 ± 0.63, respectively, p = 0.004) in comparison to the placebo group. However, no significant between-group effects were observed for serum MDA, TAC, SOD activity, and sleep quality. Conclusion: Zinc supplementation, alone or with probiotics, may improve serum zinc and TOS levels, and OSI in IBS patients. Future studies are warranted to confirm these findings and their clinical relevance. Trial registration: This study was registered on January 29, 2024, at the Iranian Registry of Clinical Trials (https://www.irct.ir) (registration number: IRCT20180818040827N5). © Springer-Verlag GmbH Germany, part of Springer Nature 2026.