Alchohol's diruretic effect?

Question

At what concentration (preferably in % volume) would the diruretic effect of alchohol be balanced by the increase in water intake in a beverage? Weak American beer seems to dehydrate so how much lower would the alcohol content have to be to avoid that?

Answer 1

There is, unfortunately, no simple answer to this. You suggest that the diuretic effect of ethanol is such that drinking so much alcohol will result in loosing so much water. Then, if you get the concentration right, you could drink all the alcohol you wanted and replenish the lost water at the same time.

This is not how the diuretic properties work for a few reasons. First, dosing curves are not linear. That is the second drink makes you lose more water than the first regardless of what the concentration is. Second, the diuretic effect of alcohol does not just make you lose water, it changes the way water balance in the body is regulated. As your blood-alcohol level goes up, the body is less sensitive to rising blood salinity, which normally causes the body to conserve water.

So, there is no magic concentration. Any concentration of alcohol, in sufficient quantity will eventually lead to dehydration. There is, of course, the practical matter that if the concentration gets extremely low, you may not be able to physically drink it fast enough to cause accumulation in your blood, but I don't think you meant that to count.

Answer 2

ETOH, alcohol, inhibits the bodies natural anti-diuretic hormone, thus causing the kidneys to diuresis more fluids than it otherwise would.
The % in volume is person dependent. One can not answer this without knowing ones natural level of the ADH, (anti-diuretic hormone). If this level was checked, you could figure out how much ETOH one would have to consume to inhibit the ADH to the point that the kidneys would over diuresis, thus leaving one dehydrated.
This inhibition of the ADH caused diuresis, which caused dehydration, which is what caused a hang-over, and the headaches associated. There are no otc's that really work in preventing a hang-over, however many millions of dollars are spent on such products.
The best way to avoid a hang-over is not drink too much, and whey you do, increase your PO (by mouth) intake of H2O, water, to compensate for the dehydration. One could measure the specific gravity of the urine to get a measure of dehydration, and give a rather inaccurate amount of water needed to correct the dehydration.