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Coffee isn't diuretic

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Woot, another myth laid to rest!

Of course, I'm quite a lot behind on this news, cos this was all over the place back in August:
"Black tea – helpful or harmful? A review of the evidence". E J Gardner, C H S Ruxton and A R Leeds, European Journal of Clinical Nutrition, 19 July 2006.
It's not indexed in PubMed, dunno why not.

BBC (among others) picked up the story and ran with it:
"Tea not only rehydrates as well as water does, but it can also protect against heart disease and some cancers, UK nutritionists found."
"Studies on caffeine have found very high doses dehydrate and everyone assumes that caffeine-containing beverages dehydrate. But even if you had a really, really strong cup of tea or coffee, which is quite hard to make, you would still have a net gain of fluid."

This bit: "Tea drinking is most common in older people, the 40 plus age range. In older people, tea sometimes made up about 70% of fluid intake so it is a really important contributor," made me snigger. Older people, eh? How the world changes. 20 years ago I, too, thought that 40 plus people were old ...

Anyway, it's nice to get some Tea Council -sponsored proof that yep, tea is good for you.


May not make you pass more water but it can make some people want to go more urgently

Aye. Coffee will also turn on the defecation urge ... while making the stools harder.

I don't understand your headline about coffee not being a diuretic, with the linked article being about tea. I did read the article about how they've done studies on caffeine, and -high- doses of caffeine can dehydrate. But the article didn't state what the caffeine amount needs to be before the diuretic effects start.

Here's my reason for the interest: About six years ago I had what I considered to be a bad hear flutter. I called my insurance company and spoke to their triage nurse, who questioned me, then advised me to go to the ER. I wore a holter monitor for 24 hours after discharge, and then my primary ordered blood tests for cardiac, renal, and liver functions.

All tests had good results, so after my primary questioned me further, I told him I'd drank a lot of caffeine that day, even more than usual for me. So he said to cut my caffeine back as much as possible, without getting headaches. So I cut back to one morning coffee, and no diet coke.

Two or three days later I couldn't get any of my shoes on, including adjustable clogs! Primary saw me that day, and reviewed my test results while I chatted on about how I hadn't done anything differently except to dramatically reduce my caffeine intake. That was when he decided I had some sort of rebound effect to cause the swelling.

After a day or so, I normalized on my own. I quit diet coke altogether (that was incredibly difficult), and now have 1-2 coffees in the mornings I work. I told this story to another lady, who told me she had a similiar experience after dramatically cutting back caffeine.

So, I worry that articles telling us that caffeine isn't a diuretic, unless consumed in large amounts (that they fail to provide information on what is a 'large amount'), will fool people into thinking coffee is fine to drink, especially with so many coffee-addicts (at least in the USA, not sure if other countries are as addicted as we are).

Same experience is with me. I noticed lately that I pee a lot after drinking coffee. So I was wondering if coffee is diurectic.

Thanks for that, Sherri.

coffee not a diuretic?
i have a cup of coffee in the morning (on an empty stomach) and the effects are dramatic!
i have to go to the bathroom within 30 minutes or so, and have to ake frequent trips every 10 minutes there after.
none of these symptoms occur if i don't have the cup of coffee.

i guess it depends on ones physiology whether coffee is a diuretic or not

You're having an extreme reaction to coffee; perhaps your kidneys (or urinary tract) doesn't agree with it?

This article you speak of is not on Pubmed because it is not true and has no scientific basis. Coffee (as well as tea to a lesser extent) are both diuretics. A diuretic is defined as any substance that when ingested, increases urine output (i.e. makes you pee more). In this sense, even water can be considered a diuretic because drinking water increases your blood volume and causes your kidneys to produce more urine. Coffee and tea both contain caffeine (unless you are drinking decaf), which increases the diuretic effect of these drinks because of the fact that caffeine inhibits sodium reabsorption and therefore also reduces the effects of ADH (Anti-diuretic hormone), a hormone that causes your kidneys to reabsorb water. It seems like you are confused about this topic and therefore should not be posting information about it that other people may read and use to make decisions about their own health.

I think you missed the irony in my "tea council" remark ...