Why does Iced Tea and coffee make me go to the bathroom more often than other beverages? If I drink a bunch of coke or pepsi I don’t have to go. Fruit Juices don’t make me go. However, a cup of coffee or a glass of iced tea and I’m at the john within 15 minutes.
Both contain caffeine, which is a diuretic.
Tea also has theobromine and theophylline, which are closely related to caffeine and are diuretics. I think the theophylline in tea is what gives it such a diuretic effect.
AND, many sodas have salt, which helps the body to RETAIN fluids.
Just to add a bit. Caffeine, IIRC, inhibits ADH (Anti-Diuretic Hormone) which normally acts at the last stage of urine production in the nephron to allow H[sub]2[/sub]O to be reabsorbed. (Reabsorbing H[sub]2[/sub]O prevents it from going out in the urine so it prevents diuresis (high volume of pee).) By blocking ADH, caffeine keeps the nephron impermeable to H[sub]2[/sub]O so it comes out in the urine.
So when I drink 16oz coffee and a bottle of water to counter dehydration (something else that caffeine can do), its not all that effective?
Well, I’m a little rusty on my water balance physiology, but depending on the amount of caffeine (and maybe your tolerance, but I haven’t heard specifically of tolerance to that aspect of caffeine) you’ll end up peeing more for longer the more caffeine you have. The bottle of water is probably helping, but you may want to drink some more later, too.
Basically, the more blood that flows through the kidneys, the more fluid gets filtered out, and (with inhibited ADH) the more urine you make. I’m just not sure how much the water you drink would affect that.
P.S.- It’s the diuresis that makes you dehydrated.
P.P.S.- One theory of the cause of hangovers is dehydration of a number of sites in the brain. (The H[sub]2[/sub]O is replaced by EtOH.) So dinking a lot of H[sub]2[/sub]O (w/o caffeine) while you drink alcohol should help prevent a hangover, and drinking it afterwards should limit the extent of the hangover. (That’s one theory I was taught in med school, and anecdotally, I’ve found it works.:))
From the Snopes page on the “8 glasses of water a day” rule:
However as a prime consumer of iced tea (approximately 12 8 oz. servings per day), I can tell you that the “pee every 15 minutes” rule applies no matter how great your tolerance becomes.
I didn’t realize that. Do you mean sodium, or other salts?
Good points SpoilerV. Maybe people in the studies drank a few 6 oz glases rather than an impressive 12 8oz servings. Maybe you’re above tolerance threshold or are taking longer to become tolerant? Then again, if there’s one thing they keep telling us, it’s that the “text book” presentation is rarely seen. Implying that there is a lot of variablility among people and how their bodies behave.
Keep in mind, SpoilerV that anyone who drinks three quarts of any liquid is going to pee a lot.