Is coffee diuretic?

[rppa]

rppa-- I'm not convinced that your observations show that coffee causes dehydration in you.

Nor am I. I note that the symptoms are the same, but I don't believe it's the caffeine, as tea does not have seem to any such effect. Or at least so my memory tells me. In this forum, I guess I need not point out the impressions and memories can be surprisingly unreliable. See Randi's recent column on the unreliability of memory.

Coffee has lots of other things in it besides caffiene and water. Perhaps your feeling of thirst has something to do with its acidity?

Thirst is only one of the symptoms. See the opening post for the others.

Now this gets really subjective, but I believe I can tell the difference between a dehydration headache (which actually is a new thing for me, just in the last few years) and a caffeine-withdrawal headache (something that used to hit me a lot on weekends, as I drink a lot of coffee on weekdays and then would tend not to have any till quite late, if at all, on Saturday). My habits haven't changed but I no longer seem to be bothered by caffeine withdrawal, even after an abrupt shift in caffeine intake.

If you put sugar in your coffee, does that have any effect on how you feel?

I wouldn't know, as I consider sugar in coffee a crime against nature. Anything for science, though...

A headache the day after may be unrelated, or not related to dehydration, at least.

It might be if it wasn't also coincident with all of the other symptoms typical (for me) of dehydration. See opening post.

Maybe you're allergic to some trace chemical in coffee. Do better quality coffees make you feel the same way? Etc. etc. etc.

Off the top of my head? Yes, I think so.

But this gets dangerously anecdotal. Time for a controlled experiment, I think.

IOW, your personal experiences may not be evidence of what you think they are, and can't confirm or deny the hypothesis that cofee causes you to become dehydrated without ruling out countless other factors.

Sure. Hence my opening this thread instead of just declaring "coffee dehydrates me". Personal experience seems to suggest that, but it's not a controlled experiment.

Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause?

In my personal experience, coffee used to cause me great....gastrointestinal distress, let's just say. Then, around late high school sometime (yes, I started early!), I switched over to "gourmet" coffee from Folger's.

I'm not real snooty about coffee, but most of my coffee these days is better quality (I'll spend $8 for a pound, sometimes, but it bugs me to spend $10 or more). And after coming back from Italy last summer, my wife and I have taken to frequently making coffee in the Italian style, using an Italian stovetop percolator. That's strong stuff.

 

[Phaycops]

Originally posted by rppa Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause? [/B]

Ooh, this could be fun!

First, though, as to your other symptoms, I get those kinds of symptoms (cough, thirst) in the morning during the winter when the air in my house is much dryer. I also tend to just feel really crappy in the morning anyway

Ok, experiment. We don't want to deliberately dehydrate anyone, because that may be unsafe.

How about something like, for several days drink x amount of coffee, then for several days drink 2x amount of coffee, and rate your symptoms each morning? Does anyone else want to help? I drink two cups of coffee every morning, but I'm sure I can manage to drink an extra two cups when I get home, you know, for science

 

[El Greco]

If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant.

 

[Phaycops]

If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant.

I agree with everything you said, but I thought the idea was to evaluate, to the extent possible, whether rppa's symptoms are caused by coffee.

Let's start over. What are we trying to prove?

 

[El Greco]

Let's start over. What are we trying to prove?

I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ?

 

[Phaycops]

Ok....

Hypothesis: drinking coffee makes you dehydrated.

Now, how can we investigate this hypothesis considering the following facts:
1. We can't afford laboratory services.
2. Nobody wants to bottle up their urine every day, anyway.
3. We're all in different areas.
4. We'll presumably be making our own coffee, so we'll know if it's decaf or regular, as well as what we put in it.
5. We may not all be able to drink the same kind of coffee.
6. We have different coffee makers, and preferneces as far as how strong we make the coffee.
7. Many of the indicators of dehdration or increased urine production are very subjective -- for example, I tend to urinate frequently anyway, so a small increase may not be noticeable.

This is why I suggested we can measure our subjective responses to more or less coffee. Volunteers would be good because even though I personally don't notice an increase or decrease in certain symptoms with coffee usage, maybe I would if I tried. I dunno. It's not perfect, so any suggestions?

 

[El Greco]

Hypothesis: drinking coffee makes you dehydrated.

I would rephrase this as "rppa's usual coffee and fluid intake may cause a net water loss". We cannot say that any coffee drinking can cause dehydration. For example I'm pretty sure that even if one drinks 4-5 mugs of coffee each day, one extra glass of water after each mug would be enough to prevent water loss.

 

[rppa]

I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ?

What he said, but about more than my own personal habits.

I want to pin down the connection (or lack of one) between coffee and hydration. I'd rather do it with more subjects than just myself.

We have a claim in at least one cited source that the water content of coffee balances the diuretic effect. I think that's flat wrong.

As a rough guess, I consume somewhere in excess of 36 ounces (1.1 liter) of coffee per day, almost always caffeinated. This may be qualititatively different from drinking 2-3 cups, caffeinated or not. This needs to be tested.

Edited to add: On reflection, 36 oz is probably a significant underestimate for those days I wake up feeling dehydrated.

I *suspect* that it's not the caffeine content of coffee, and that decaf would have much the same effect on me. But this needs to be tested as well.