title: Effect of vitamin D on gastrointestinal symptoms and health-related quality of life in irritable bowel syndrome patients: a randomized double-blind clinical trial.
abstract: BACKGROUND
  Low-grade mucosal inflammation and immune activation are involved in the pathogenesis of irritable bowel syndrome (IBS). Furthermore, IBS symptoms are associated with a significantly higher prevalence of psychological distress, which in itself results into an impaired quality of life (QoL). Vitamin D could ameliorate the symptoms of patients suffering from IBS through its beneficial effects on psychological factors and inflammation.
  
  
  METHODS
  A total of 90 IBS patients participated in this double-blind, randomized, placebo-controlled study. Participants were randomly selected to receive either 50 000 IU vitamin D3 or a placebo fortnightly for a period of 6 months. Patients reported their IBS symptoms at the baseline and monthly during intervention periods. The IBS severity score system (IBSSS) and IBS-specific QoL questionnaires were used at the baseline and postintervention.
  
  
  RESULTS
  Over the 6-month intervention period, a significantly greater improvement in IBS symptoms such as abdominal pain and distention, flatulence, rumbling, and overall gastrointestinal (GI) symptoms (except dissatisfaction with bowel habits) was observed in the patients receiving vitamin D as compared to the placebo group. The IBSSS and the IBS-QoL scores in the vitamin D group significantly improved compared to the placebo group postintervention (mean IBSSS score change: -53.82 ± 23.3 vs -16.85 ± 25.01, p < 0.001, respectively; mean IBS-QoL score change: 14.26 ± 3 vs 11 ± 2.34, p < 0.001, respectively).
  
  
  CONCLUSIONS
  Vitamin D seems to be an effective and safe option to improve QoL and symptoms of IBS. ClinicalTrials.gov (NCT02579902).
authors.affiliation: Nutrition and Metabolic Diseases Researcher Center, Department of Nutrition, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Abbasnezhad
authors.affiliation: Diabetes Research Center, Health Research Institute, Department of Nutrition, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. amani-r@ajums.ac.ir.
authors.forename: R
authors.initials: R
authors.lastname: Amani
authors.affiliation: Research Center for Infectious Diseases of the Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: E
authors.initials: E
authors.lastname: Hajiani
authors.affiliation: Research Center for Infectious Diseases of the Digestive System, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: P
authors.initials: P
authors.lastname: Alavinejad
authors.affiliation: Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: B
authors.initials: B
authors.lastname: Cheraghian
authors.affiliation: Research Center for Infectious Diseases of Digestive System, Department of Biostatistics and Epidemiology, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Ghadiri
mesh_terms: D000328:Adult; D003967:Diarrhea / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D004311:Double-Blind Method; D005260:Female; D005414:Flatulence / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D005500:Follow-Up Studies; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014807:Vitamin D / Q000097:blood* / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D
keywords: IBS severity score; gastrointestinal symptoms; health-related quality of life; irritable bowel syndrome; vitamin D