TNF and irritable bowel syndrome: There are no differences in the IBS subtypes; however, in IBS‐C, malondialdehyde correlated with IL‐4, and TNF‐α with IL‐10, suggesting an interleukin‐mediated anti low‐grade inflammation mechanism, and in IBS‐D, GSH correlated with IL‐4, suggesting an antioxidant mechanism.