Question: on plastic water bottles they say that the water is natural and pure, i thought that only distilled water was pure and natural not bottled. Is this true?

Dr Hywel Jones answered on 24 Jun 2010:

Thats a very good Q. Next time you pay £1 for some water think about it. Most water derived from natural sources, whether it is from springs or rivers and reservoirs will have smalls amount of dissolved minerals from the rocks that the water has passed over. In fact this is the major selling point for “mineral waters”. Some people think the minerals are good for you but in fact the modern day diet is good enough that we don’t really need to worry about it. The VIctorians were really in to their Spas and mineral waters but its now generally regarded as not really that important.
Pure water is indeed the distilled type. In fact in our lab we have a special machine that produces very pure water, called de-ionised water, which we use in experiments. Even the stuff dissolved in tap water can affect our experiments.
Be warned though, if you drank enough very pure water quickly enough you could get ill as you dilute your bodies minerals to a dangerous level (we all need stuff like sodium and potassium for our cells to function). This is also true of normal water and some teenagers have died this way. http://en.wikipedia.org/wiki/Leah_Betts