Taner Buğra Tan

Background: Irritable bowel syndrome (IBS) is a disorder of gut–brain interaction frequently accompanied by anxiety, depression, and low‐grade systemic inflammation. Intestinal dysbiosis and vitamin D deficiency may contribute to disease severity. This study evaluated the effects of probiotic supplementation, vitamin D replacement, and their combination on inflammatory biomarkers, IBS symptom severity, and psychological outcomes. Methods: In this single‐center retrospective cohort study, 120 adults with IBS diagnosed according to the Rome IV criteria (January 2023–December 2025) received probiotic monotherapy, vitamin D monotherapy, or combined therapy. Clinical characteristics, inflammatory biomarkers, serum 25‐hydroxyvitamin D levels, Hospital Anxiety and Depression Scale (HADS) scores, and IBS Severity Scoring System (IBS‐SSS) scores were assessed before and after treatment. Correlation and multivariable logistic regression analyses were performed. Results: The mean age was 41.8 ± 12.6 years, and 62% of participants were female. Combined therapy achieved the greatest reductions in C‐reactive protein, neutrophil‐to‐lymphocyte ratio, platelet‐to‐lymphocyte ratio, anxiety, depression, and IBS symptom severity. Serum 25‐hydroxyvitamin D levels were inversely correlated with depressive symptoms ( r = −0.31, p = 0.01). Combined therapy independently predicted psychological improvement after adjustment for age, sex, body mass index, and IBS subtype (OR 1.92, 95% CI 1.14–3.26, p = 0.01). Conclusions: Combined probiotic and vitamin D supplementation was associated with greater improvements in psychological symptoms and inflammatory biomarkers than either monotherapy. These findings support targeting the gut–brain axis and vitamin D deficiency as complementary therapeutic strategies for IBS. Prospective randomized multicenter studies are warranted.

Background/Aims: Gastroesophageal reflux disease (GERD) is a common gastrointestinal disorder that negatively impacts individuals' quality of life.Methods: This study investigates the effect of circadian preferences on the quality of life in patients with GERD. A total of 152 participants (80 patients diagnosed with GERD and 72 healthy controls) were included in the study. Participants' circadian preferences were assessed using the morningness‐eveningness questionnaire (MEQ), quality of life was evaluated with the SF‐36 scale, and the severity of GERD symptoms was measured using the gastroesophageal reflux disease quality of life scale (GERD‐QOL).Results: The study's findings indicate that the quality of life and circadian preferences of GERD patients differ significantly from those of the control group. Correlation analyses revealed a positive relationship between SF‐36 and MEQ, but no direct relationship was found between GERD‐QOL and SF‐36 or MEQ. Mediation analyses demonstrated that the effect of GERD‐QOL on SF‐36 is entirely mediated by circadian preferences.Conclusions: These results highlight the significant impact of circadian preferences on the quality of life in GERD patients, suggesting that individuals with an evening chronotype may have lower quality of life. Our study contributes to the literature as one of the first to suggest that circadian preferences should be considered in the management of GERD.