Actually, when you're on the move a lot it's quite sensible to take along a bottle of water, because it flushes out the immune system, although I admit there's this inverted snobbery thing attached to 'branding'. When I'm in Africa I'm never without one.
It's always amusing when 'scientists' rubbish common ideas. Like the test they did about taking vitamins not being of any benefit. I know any wounds I get heal much quicker because I take multi-vits etc.
But bearing in mind to conduct a scientific 'test' you only need two groups; the experimental group and the control group. And there will always be a 'bias' towards the experimenter/s theory even though they claim to be impartial.
If you're drinking tea etc as part of your recommended daily liquid intake also bear in mind tea is a diuretic, so the water loss is quicker than by taking plain water. If you're drinking alcohol the loss is much greater than the intake (hence hangovers).
I have lived and worked in many 'hot climate' countries, and I can never recall seeing the 'locals' walking around, attached to bottles of Avian type drinks. The occasional stop for a odd Fanta, Cola or fresh fruit was more than likely.
The same applied to working in 'cold climate' countries, I can never recall people walking about clutching thermos flasks.
And as for taking bottles of vitamin supplements!!.
Wrong termonology, my naive mistake. I would have been more careful and exact. Flushing out the 'system' to boost the immune system. Flushing out all the nasty bits and pieces that can adhere to the lower intestine and bowels click here. The resulting conditions can occur if there's a poor intake of proper fluids like; flatulence, dryness, constipation, and poor absorption of the nutrients that are needed to build healthy skin, hair, bones, nerve sheaths, reproductive fluids, and brain tissue. and bad breath.
Spuds, yes it's something I've noticed too, especially in Africa. The locals aren't aware of the western type of health benefits that we go by. Usually it's to do with ensuring they have something to eat instead of starving so it's probably just a question of priorities. Their's being different to ours.