Scientists have carried out the first detailed study of how our intestinal tract changes as we age, and how this determines our overall health. The study was published in the journal Clinical Science.
As well as digesting food, the gut plays a central role in programming our immune system, and provides an effective barrier to bacteria that could make us ill. In particular, immune cells that line the gut work to maintain the integrity of the barrier, as well as maintaining a balance that provides a healthy environment for beneficial bacteria, but reacts to combat invasion by pathogenic microbes.
It's known that our immune system declines with age, not only making us more susceptible to infections, but also increasing our risk of other diseases, including cancer. But until now, we haven't known how changes to the gut barrier's structure and function contribute to this.
To address this, the researchers studied samples taken from healthy volunteers, comparing the samples from people of different ages undergoing routine endoscopy examinations. They found that the aging gut had a characteristic increase in one specific immune system regulator called interleukin 6 (IL-6). Cells of the immune system release IL-6 to trigger inflammation. Chronic low-grade inflammation is seen to increase as we age.
Further experiments showed that the increased levels of IL-6 directly lead to making the gut barrier 'leaky' to small, soluble molecules, although no physical differences in its structure were seen. And the scientists also showed that aging is associated with a reduced immune response to microbes, which might contribute to our increased susceptibility to infection as we age.
The next steps are to work out what triggers these changes in gut permeability, immune response and IL-6, the researchers said. "Understanding the triggers will help us better understand what caused the changes observed in this study, and find ways of preventing them."
Based on material originally posted by Norwich BioScience Institutes.