According to the food conglomerate Danon: “Evidence is increasing that even mild dehydration plays a role in the development of various diseases.” It’s a campaign, sponsored by the producers of Volvic, Evian, and Badoit bottled waters, to get us all to drink more water.
But what and where is this evidence? A doctor replies: “This is not only nonsense, but is thoroughly debunked nonsense.”
The right approach
Worried by the fact that European guidelines classified almost all older people as being at high risk of cardiovascular disease, Norway has developed its own guidelines that use differential risk thresholds according to age.
Compared with the European guidelines, the total sum of life gained is about the same, but the number of patients treated is considerably lower.
How does clinical evidence work?
Ben Goldacre's Moment of Genius on BBC4 radio:
"Clinical trials in medicine are designed to be free from bias. They test, as objectively as possible, the effectiveness of a particular intervention.
When you bring the results of all these individual trials together, however, how do you weigh up what evidence is relevant and what is not? In 1993, a method of "systematic review" was introduced that enables us to get the clearest possible view of the evidence."
Don’t just swallow, check the evidence first. Godlee 343. BMJ, 2011.
Image source: Plastic bottles before processing. Wikipedia, dierk schaefer, Creative Commons Attribution 2.0 License.