Urine Acidification

The first theory proposed to explain why drinking cranberry juice seemed to help some patients was based on the idea that the naturally tart cranberry juice contained acids that lowered the pH of urine. Normal urine pH is close to neutral (7.0); a pH of 5.5 or lower is necessary to retard development of UTIs. An early clinical study found that 53% of 60 patients with acute UTIs showed some improvement after consuming 16 ounces of cranberry juice daily for three weeks; 27% had no change in symptoms (Papas et al., 1966). The researchers suggested that cranberry juice aided the drug methenamine by keeping urine pH sufficiently low for the drug to have enhanced antibacterial activity. They concluded that cranberry juice was a helpful, well-tolerated, and inexpensive adjunct to traditional antibiotic therapy.

Sweetened, diluted cranberry juice (about 80% juice) was provided along with meals to 40 healthy young adults (Kinney and Blount, 1979). Each treatment group (150, 180, 210, or 240 mL cranberry juice per meal) had significantly lower urine pH than the control group. There was no apparent dose relationship; i.e., it did not appear to matter how much juice each person drank. However, incidence of urinary tract infections was not monitored, and it is unlikely that most people would drink a product containing 80% cranberry juice, even if sweetened, due to the strong bitter and sour flavor. In a double-crossover experiment with 21 elderly men, no cranberry juice cocktail was provided for 4 weeks, followed by 4 weeks in which two 118.3 mL servings were consumed daily; then the experiment concluded with another 4-week period with no cranberry juice (Jackson and Hicks, 1997). Urine pH was significantly lower during the juice phase of the program.

0 0

Post a comment