Reply #25: Daft hysteria over the EU's ruling on water and dehydration

[fishwax]

http://www.guardian.co.uk/science/the-lay-scientist/2011/nov/18/1?newsfeed=true

The claim wasn't submitted for a genuine product, but was created as a deliberate 'test' exercise by the two professors, who were apparently already unhappy with the European Food Standards Authority. The panel were well aware of it's absurdity too, noting drily that "the proposed risk factors," the conditions addressed by the hypothetical product, in this case water loss, "are measures or water depletion and thus are measures of the disease (dehydration)."

Leaving that aside, there are two major problems with the claim: drinking water doesn't prevent dehydration, and drinking-water doesn't prevent dehydration.

Firstly, "regular consumption" of water doesn't reduce the risk of dehydration any more than eating a pork pie a day reduces the risk of starvation. If I drink half a pint of bottled water while running through a desert in the blistering sun, I'll still end up dehydrated, and if I drink several bottles today, that won't prevent me from dehydrating tomorrow. The key is to drink enough water when you need it, and you're not going to get that from any bottled water product unless it's mounted on a drip.

Secondly, dehydration doesn't just mean a lack of water, or 'being thirsty'; electrolytes like sodium are important too. If salt levels fall too far, the body struggles to regulate fluid levels in the first place. That's why hospitals use saline drips to prevent dehydration in patients who can't take fluids orally, and why people with diarhhoea are treated with salt-containing oral rehydration fluids. Presumably the next big investigation at the Express will expose the shocking waste of NHS money on needless quantities of saline solution, when jolly old tap water would work just as well.