I ran into an interesting question today that examined the science around alkaline water and its advertised 'generalized health benefits' assumed to be (but incorrectly) stemming from a rise in blood pH. Logic behind the misassumption itself stemming from a rise in urine pH.

What I'm trying to figure out, is would deionized water (slightly acidic water) actually improve short term metabolic blood acidosis and ironically raise pH levels? Proposed ideas are 1) an acidic water stimulated elevation in bicarbonate secretion (kidneys and exocrine pancreas ) and reabsorption (to circulation), 2) elevated mineral resorption or 'leaching' from cells. These don't sound all that great in themselves, but regarding a short-term net effect on pH (either on urine or a hypothetical blood ph), could not deionized water have a net alkaline effect due to bicarbonate regulation and cellular reabsorption of minerals being inherently 'slower' than the near instantaneous acid-base reaction?

Alkaline metabolic products of an acidic source that may be included in water (ie lemon) do not count as justifications to an answer. Only looking at water.

If anyone has any relevant studies, feel free to share them, I can't seem to find anything outside of fish.

  • $\begingroup$ I'm no expert in blood pH regulation, but it seems highly unlikely that you can treat acidosis by attempting to lower the pH further. The normal treatment of (acute) acidosis is to give alkaline fluids, usually a bicarbonate solution. Also, I wouldn't trust any information from the alkaline water peddlers -- it looks like a typical scam. See for example quackwatch.org/01QuackeryRelatedTopics/DSH/coral2.html $\endgroup$ – Roland May 27 '17 at 8:46
  • $\begingroup$ Absolutely, as a scientist of metabolism I'm fully aware of the quackery in alkaline water. But, my question really is based in the idea: if bicarbonate water increases urine pH, this logically indicates an elongated systemic shift to lower blood pH. Perhaps, by causing a quick decrease in urine pH, an elongated shift towards increasing blood pH wouldn't be out of the question? (As you can guess I'm no expert in blood pH regulation either) $\endgroup$ – Aaron43 May 27 '17 at 13:53
  • $\begingroup$ I don't think increased urine pH generally indicates a decrease in blood pH. It seems more likely that urine pH goes up when drinking alkaline fluids precisely because regulatory systems act to keep blood pH constant. Also, this is not a closed system, due to respiration CO2 exchange; and urine pH does not affect blood pH -- it's the other way around. Just some points to think about! $\endgroup$ – Roland May 27 '17 at 14:43
  • $\begingroup$ You're absolutely right in this regard, but I do feel there would be a window of a lower blood pH, as compared to baseline, following elevated excretion of alkaline minerals/chemicals/metabolites ect. And just by logic, an opposite effect in which increasing acidity of urinary pH may consequently cause systemic overcompensation leading to a more alkaline blood pH. All theory though, I can't find any definitive proof of this concept anywhere in any manner ("blood pH compensation causing or following a change in urinary pH") $\endgroup$ – Aaron43 May 27 '17 at 16:12

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