Just to give a heads up, most of the articles on this story (there's about 25 that all 'independently' popped up about 8 months after the actual decision. weird...) are complete bunk. The Guardian published a good explanation of what's actually going on here.
RisingDown, when you laugh that 'it required highly paid scientists to figure this out', you're missing what was actually being discussed. It was a test case regarding advertising rules in the EU. The product that made controversial claims was completely bogus; it was never meant for market, it was simply made to test the legal system.
Here's a few excerpts from the commentary at the Guardian:
"I was in a pub in Farringdon last night when a picture of the front page of The Express materialized on a TV screen, screaming semi-literately that, "EU SAYS WATER IS NOT HEALTHY." We swiftly neutralized the offending appliance, but stupidity is highly contagious, and this morning an newborn EU myth oozed from the presses, that the EU's European Food Standards Authority have ruled water to be unhealthy. Youcouldntmakeitup. Or maybe you could, because The Express headline is made up."
"The specific health claim tested is outlined in the ruling: "The regular consumption of significant amounts of water can reduce the risk of development of dehydration and of concomitant decrease of performance." The claim wasn't submitted for a genuine product, but was created as a deliberate 'test' exercise... there are two major problems with the claim: drinking water doesn't prevent dehydration, and drinking-water doesn't prevent dehydration."
Surprisingly, those two major problems are actually correct. I already knew this, but the Guardian does a decent job explaining the physiology to an audience that lacks much medical knowledge:
"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."
The latter is actually a real problem. Hyponatremia is a deadly condition and kills quite a lot of people. Binge water drinking can cause it and you'll see it quite a bit in marathon runners for similar reasons. In the town where I live we've had a couple people die from hyponatremia over the past few years (when will the frats figure out that binge drinking water is a bad idea).
The Guardian finishes on a great point:
"the ruling seems pretty sensible to me, or at least as sensible as a ruling can be when the claim being tested is vexatious in the first place. It's accurate advice, and it prevents companies selling bottled water from making exaggerated claims for their products, which is a good thing. They even have the support of the British Soft Drinks Association, who tweeted just as this piece was going live with the following statement: "The European Food Safety Authority has been asked to rule on several ways of wording the statement that drinking water is good for hydration and therefore good for health. It rejected some wordings on technicalities, but it has supported claims that drinking water is good for normal physical and cognitive functions and normal thermoregulation."
It's also an great opportunity to challenge received wisdom, and to make the point that keeping the human body hydrated is about much more than just drinking tap water when you're thirsty. Unfortunately, it seems a lot of journalists are more interested in promoting second-hand hysteria than informing their readers. Which is a bit sad."