Although the condition most commonly sought is the opposite one, namely urinary alkalinization, in some cases acidifying the urine can prove to be a useful behavior for maintaining the state of health.
Urine and pH
Urine is the product of renal excretion, through which metabolic or catabolic products dissolved in the blood stream are expelled from the body (harmful waste, especially urea, ketone bodies, creatinine, etc.).
Monitoring urinary pH means evaluating and measuring the kidney's ability to acidify urine; the latter, together with breath (pulmonary ventilation), are responsible for the acid-base balance of the blood by expelling the non-volatile acids (hydrogenions) normally produced and daily by the metabolism (about 60mEq). Hydrogen ions, if not expelled, cause the lowering of blood pH and metabolic acidosis; any difficulty in producing and eliminating acid urine in conditions of metabolic acidosis almost always gives rise to renal failure.
As can be easily guessed from the above, the pH of urine can fluctuate significantly and represents an indispensable condition for maintaining blood homeostasis (preventing acidification or systemic alkalosis); normally, the pH of the urine is between 4.4 and 8, with normality at 6/7.
Acidify the Urine
Urine acidification is useful in the prevention and treatment of cystitis (bladder infection), urethritis (urethra infection) and uretrocystitis (bladder + urethra). It is also used in pharmacology to modulate the effect of some drugs, favoring the elimination of weak bases (useful practice eg in case of an amphetamine overdose) and hindering the excretion of weak acids (in this case urinary acidification reduces drug elimination by prolonging the half-life).
The bacteria that infect the urinary epithelium are generally belonging to the coliforms and more commonly it is Escherichia coli, a microbial strain particularly sensitive to the surrounding pH. In acidic conditions, Escherichia coli is NOT able to reproduce effectively, therefore, in case of urinary tract infections it is however useful to try to acidify the urine.
The most used food (and the only one subjected to clinical trials) in the treatment of urinary infections (by virtue of its power to acidify urine and above all to prevent bacterial adhesion to the urinary mucosa) is cranberry juice. The latter constitutes a drink obtained from the fruits of the American marsh cranberry and it seems that if consumed in portions of 500-750 ml / day it can favor the prevention and remission of the aforesaid pathologies; however, as often happens, the experimental results are still controversial but it is nevertheless necessary to specify that it is a food and not a drug; therefore, being characterized by the TOTAL absence of contraindications, it is always advisable to use it.
Other foods useful for acidifying urine are all those containing an abundant acid residue deriving from chlorine (Cl), phosphorus (P) and sulfur (S). In particular, the foods useful for acidifying the urine are: cheese, egg yolk, white and red meat, fish; followed by dried fruit, legumes and cereals.
Other methods: Contraindications
Acidification of urine can occur following inappropriate feeding behaviors such as ketogenic (or generally hyperproteic) diets, but also in post-exercise physical activity. In both cases, also due to dehydration, the pH of the urine undergoes acidification due to:
- Chetonic bodies
- Nitrogen residues
Although they also contribute to the acidification of urine, from my point of view it is absolutely inadvisable to take advantage of these obsolete and generally unwanted conditions; the negative aspect that precludes its use in therapy against urinary tract infections is the potentially fatiguing effect they exert on the renal filtering system (see ketogenic diet) ... without considering that both the ketone bodies and the nitrogen residues, in addition to acidifying the urine, lead to a systemic impairment which, in some cases (as in renal insufficiency) can lead to severe metabolic acidosis.
NOTE: regardless of the method chosen, in people with hyperuricosuria (high levels of uric acid in the blood) or hypercystinuria (high urinary levels of cystine), acidifying the urine means favoring the formation of stones in the urinary tract; for these categories of patients, urinary alkalinization is therefore recommended and it is strongly advised not to acidify the urine. A similar speech in the prevention of osteoporosis, given that a CHRONIC diet rich in acid residues promotes bone mineral loss.
