[thedoc (OP)]

Christina Simon  asked the Naked Scientists:
   
If you keep your hands clean all the time, can it make you less healthy and more susceptible to colds? Are there any ways to be safely exposed to germs?

   

What do you think?

[evan_au]

There are bacteria on all external surfaces of our bodies. We don't really know what most of them do, except that most of them don't do us much harm if they stay in their normal location (and don't get into our bloodstream, for example).

The "Hygiene hypothesis" suggests that exposure to a "healthy" mix of bacteria in infancy is important for development of a healthy immune system, and prevention of future problems.

It has been observed that if our normal "benign" bacterial ecosystem gets disturbed (eg due to excess doses of antibiotics), sometimes a pathological bacteria strain gains a foothold, and causes considerable problems.

So, in theory, excess hand-washing could cause us medical problems.

To keep this in balance, medical staff are always exposed to pathogenic microorganisms from sick patients, and failure to do thorough handwashing could be bad for the doctor and all of their patients! (To a lesser extent, this applies to school teachers and anyone who rides public transport or visits public places, or who knows someone who does...)

So a sensible amount of handwashing is recommended for the general public.