Effect of Vitamin D3 Supplementation in Treatment of Irritable Bowel Syndrome

This randomized double blind clinical trial will be performed on 90 patients (45 in intervention and 45 in control group) diagnosed with IBS. The intervention group will receive 50000 IU vitamin D3 and the control group will receive placebo contains edible paraffin once every 2 weeks for six months. Variables including biomarkers of inflammation and oxidative stress, serum levels of calcium and vitamin D, anthropometric indicators and blood pressure will be measured at baseline and end of the study. The investigators will use Rome III questionnaire for evaluating the clinical signs of the disease. The questionnaires will be filled out at baseline and every 2 weeks by the patients for six months.

Inclusion criteria

• The patients who are diagnosed with Irritable Bowel Syndrome (IBS) according to ROME III criteria; Signed consent by the patient.

Exclusion criteria

• Patients who have celiac disease (diagnosed by a duodenal biopsy or celiac serological tests)
• Any other diseases of the gastrointestinal tract such as Inflammatory Bowel Disease (IBD)
• Any kind of abdominal surgery
• Chronic disease such as diabetes
• Cardiovascular, hepatic
• Kidney and severe infection
• Pregnancy
• Breastfeeding
• Smoking
• Alcohol consumption
• Use of dietary supplements
• Use of vitamin D and calcium supplement during the last year before the study
• Use any medication for signs improvement during the study period.