Fasting blood specimens will be taken from the patients with IBS that have inclusion criteria. First, the objectives and method of study will be explained to the patients and informed consent form will be taken from them. They will be divided into 4 groups by an adjusted randomized blocking and the clinical outcomes, quality of life, emotional stress questionnaires will be completed before and after intervention. During 6 weeks, they will receive 2 capsules of soy isoflavones per day, 50000IU vitamin D biweekly in addition to the other placebo form, both of them and placebo of both. At the end, body mass index ( BMI), serum TNF-Alpha, TAC, gene expression of GATA3, ROR gamma, FOXP3 in lymphocytes and gut permeability will be measured. The quantity of polymorphisms of vitamin D and estrogen receptors will be determined.