Many have wondered whether being exposed to bacteria may have a detrimental effect on our life-spans, and that we would live longer in a bacteria-free environment. Scientists have pondered for decades whether the immune system response to bacteria accelerates the ageing process.
According to scientists from the University of Southern California, a sterile environment does not seem to extend life at all. You can read their report in the journal Cell Metabolism.
The researchers carried out a study with fruit flies – some were kept in a sterile environment, while others weren’t. Fruit flies in the sterile environment did not live any longer, or less time, than those in the other group. The scientists stressed that fruit flies are much simpler organisms than humans – humans need bacteria for digestion and other purposes.
Nevertheless, they explained that the results of their findings might be relevant to research into ageing in humans. As humans and fruit-flies age, so do the number of bacteria inside them – both have a weaker and weaker immune response to bacteria the older they get. The study, on the other hand, indicates that this has nothing to do with ageing.
Team leader Dr Steven Finkel said “I think a lot of people would just assume that if you’re increasing bacterial load in an ageing human, it must be bad. It might not just be bad, it just might be. Prior to this study, I would not have thought that.”
The team members said they were surprised with what they found. Even though the flies were accumulating so much bacteria and a robust immune response to that bacteria, it was not limiting how long they lived. If it is the wrong question to ask (does bacteria reduce life span) – then what is the right question to ask?
Increased Internal and External Bacterial Load during Drosophila Aging without Life-Span Trade-Off
Chunli Ren, Paul Webster, Steven E. Finkel, and John Tower
Cell Metabolism, Vol 6, 144-152, 08 August 2007
Click here to see abstract online
Written by: Christian Nordqvist