View Full Version : Diuretic effect of coffee

09-26-2002, 02:55 PM
We all know coffee dehydrates you but does it dehydrate you more than the liquid it contains?

ie when you are counting your fluid intake should coffee counted be as:

1. zero
2. -1 cup
3. less than 1 cup but still positive
4. other (please explain)

09-26-2002, 04:11 PM
Caffeine mucks about with anti-diuretic hormone (ADH) hence, the diuretic effect.

Basically, ADH is released when you don't drink much water and it tells the kidneys not to allow as much water out through to the bladder for excretion and to reabsorb some so the body doesn;t dehydrate.

I can't remember the exact mechanism, but caf messes about with ADH so it lets more water through than it really should.

Whether this is more than the water in the cup with the coffee is anyone's guess, but i imagine it will be.

I'm also not sure how long the diuretic effect actually lasts, so the net loss of water will probably be much greater overall than the water in the cup with the coffee.

Just to avoid dehydration, drink more water if you're gonna drink coffee.