It's only water

Ok so help me out here.

Last week the talk of the office has been about R.O water. For the benefit of those who aren't in the know (me included until last week) R.O. is referring to the process known as reverse osmosis

If you remember your science, osmosis refers to the movement of a solvent through a semi-permeable membrane into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane.

Hmmm perhaps that didn't come off right. Let's take the look at the picture (right) and see if I can explain it in plain and simple English. On the left is a beaker filled with water where a tube has been half-submerged in the water. Notice the water level in the beaker is the same as the water level in the tube. You with me so far? Next the end of the tube in the middle beaker has been sealed with the supposed semi-permeable membrane (examples being the lining of our intestines, a cell wall and Gore-tex fabric..basically a semi permeable membrane is membrane..think saran/cling wrap..which allows some atoms or molecules to pass through BUT not others) and half-filled with a salty solution and submerged. Now if you look closely, both the salt solution and water are equally levelled at first. But after some time, as represented by the last beaker, the water in the tube actually rises. This rise is attributed to "osmotic pressure". So what really happened is that the semi-permeable membrane allowed the water molecules to pass but not the salt molecules.

Do you know why drinking salt water i.e. ocean water is a no-no? Osmosis. When we put salty water in our body, the osmotic pressure begins drawing body out of our body as a means of trying to dilute the salt in our tummy...which explains why we eventually dehydrate and die.

Reverse Osmosis, on the other hand, refers to the process where the membrane is used to act like an extremely fine filter to create drinking water from salty water. The salty water is put on one side of the membrane and pressure is applied to stop and reverse the osmotic pressure. And voila! We have R.O. water.

Now water, to me, is still water. R.O, distilled, mineral, tap..makes no difference to me. Alright perhaps I'm lying there..there's something about distilled water which doesn't work for me. But what I'd like to know is, what are the benefits of drinking R.O. water? Yes, I have seen all the 'dirt' that comes with tap water and mineral water..trust me, they're not a pretty sight. Will it make me live longer? Will my body be cleaner by drinking R.O water? How is it that our elders have managed to live longer when R.O water wasn't even around, oh say, 50 years ago?

So until someone can show me some proof that I should spend $1K on getting R.O water (or is it equipment? or chemical?) then I'm more than happy to have a l'il bit of 'dirt' in my water..