The relationship between sleep and GI function is well known. We know that in shift workers the disruption of sleep leads to an increase in gastrointestinal disorders such as gastroesophageal reflux, peptic ulcers, and irritable bowel disease. However, it is now becoming apparent that altered sleep can modify the immune system and as a result influence the course of inflammatory bowel diseases (IBDs) as well. The two major types of IBDs being Crohn’s disease and ulcerative colitis.
In a study published this past year in the journal Clinical Gastroenterology and Hepatology done at Massachusetts General Hospital, 3,173 patients with IBD were studied concerning sleep disorders. Among the 1,291 patients with Crohn’s disease in remission, those with impaired sleep were twice as likely to have a flare-up of active disease when followed for six months. While this study did not show a similar relationship of sleep to ulcerative colitis, other studies have.
Sleep disorders are very common in the United States. NIH studies have estimated that 50–70 million Americans currently suffer from sleep disorders, and intermittent sleep disorders can adversely affect people’s health. So what might be the link between poor sleep and IBD? IBD is a waxing and waning disease characterized by diarrhea, abdominal pain, and weight loss. Sleep loss is associated with an increase in inflammatory cytokines such as TNF-alpha, IL-6, and elevated C-reactive protein, all of which have been implicated in the inflammatory process characteristic of IBD.
These same inflammatory mediators alone can severely disrupt sleep. As a result, a vicious cycle can arise with the chronic inflammation of IBD worsening sleep, and decreased sleep increasing the production of the very mediators of inflammation that exacerbate IBD.
Just as interesting is the role of melatonin. Melatonin is the hormone that drives circadian rhythms. It is present in the gastrointestinal tract in amounts 400 times higher than in the gland that produces it, the pineal gland. Melatonin is a powerful antioxidant and free radical scavenger. In animal experiments, it has been found to be capable of preventing experimentally induced colitis. As a result, there are experts in the field calling for studies to determine whether melatonin supplementation might be effective in treating IBD.
It is becoming clear that disordered sleep can have a major impact on colitis. It would appear that both insufficient sleep and possibly abnormal melatonin production might play a significant role by increasing the activity of the inflammatory system. Consequently, much more attention needs to be paid to underlying sleep disturbances in those with IBD. It would appear that as in heart disease, diabetes, and stroke, the importance of sleep can never be underestimated.