Interesting report, Marilyn, thanks. It does call into question the
acidifying effect of cranberries, but notice that the reports' authors don't
think it was the water that acidified the urine--they pointed to possible
"subtle dietary changes when subjects were drinking the fluids." In other
words, the assumption is that other foods had an acidifying effect, so the
dietary acidification hypothesis is still accepted by the report's authors.
And even if it was the water that acidified the urine, that would still mean
the acidification was caused by diet (though it would more likely mean the
study was flawed, since water has a neutral pH).

> -----Original Message-----
> From: Paleolithic Eating Support List
> [mailto:[log in to unmask]] On Behalf Of Marilyn Harris
> Sent: Tuesday, March 13, 2007 7:09 AM
> To: [log in to unmask]
> Subject: Cranberry Juice
> 
> FYI: Some information about urinary pH and cranberry juice consumption
> and
> its anti-bacterial effect. It's possible that it may not in fact
> increase
> blood pH. Apparenlty in the study ordinary water also increased urinary
> pH.
> 
> Marilyn
> 
> * * *
> 
> http://www.blackwell-synergy.com/links/doi/10.1046/j.1464-
> 410X.2003.04472.x/full/?cookieSet=1
> 
> Early studies claimed that cranberry juice caused a decrease in urinary
> pH
> [29,30]. Quinic and benzoic acids in cranberries are presumably
> precursors
> of the hippuric acid that is excreted by the kidneys, and thereby
> acidify
> the urine [30]. Recently, claims about the ability of cranberry juice
> to
> acidify urine have been disputed [13,17]. A study of the effect of
> cranberry
> juice on bacteriuria and pyuria found that a group drinking cranberry
> juice
> had a higher urinary pH than the placebo group [13], while there were
> no
> significant changes in urinary pH in the study with cranberry tablets
> [17].
> In the present study, the pH increased after drinking cranberry juice
> (relative to the control) but drinking water also caused an increase in
> urinary pH. Similarly, calcium excretion decreased relative to the
> control
> after drinking juice or water. These results are puzzling but may have
> arisen as a result of subtle dietary changes when subjects were
> drinking the
> fluids.

...