Having the right balance of gut bacteria could be the secret to a long life, new research suggests.
U.S. researchers say age-related changes to gut bacteria, that result in an imbalance between 'friendly' and 'unfriendly' bacteria, are associated with cancer, diabetes and inflammatory bowel disease.
However, they admit there is currently no clear explanation as to why people go from having a young, healthy gut to one that is old and unhealthy.
Dr Heinrich Jasper from the Buck Institute for Research on Ageing, in California, said the findings could allow experts to find a way of intervening to prevent the age-related deterioration in gut bacteria quality.
He believes such a treatment could eventually lead to the extension of people’s lives.
Dr Jasper conducted his research using fruit flies.
He says the bacterial load in the flies' intestines increases dramatically with age, resulting in an inflammatory condition.
The imbalance, he explains, is driven by chronic activation of the stress response gene FOXO – this is something that happens with age.
Age-related changes in gut bacteria are associated with cancer and diabetes
It suppresses the activity of a type of molecule (PGRP-SCs, homologues of PGLYRPs) that regulates the immune system's response to bacteria.
This changes the behaviour of molecules (Rel/NFkB) that are important in the effectiveness of the immune system's response to gut bacteria.
This results in an immune imbalance which allows bacterial numbers to expand, triggering an inflammatory response that includes the production of free radicals.
Free radicals, in turn, cause over-production of stem cells in the gut. This can eventually result in cancer.
Dr Jasper said the most exciting result of their study occurred when his team increased the production of PGRP-SC in cells in the gut, which restored the bacteria balance and limited stem cell growth.
