Long touted as a folk remedy for cystitis, recent research explains why cranberry juice helps both treat and prevent bladder infections. Cranberries block E. coli, the most common bacterial cause of bladder infections, from attaching to the bladder wall.1,2 Elderly women given 300 ml (approximately 1 cup) of cranberry juice per day had fewer bacteria in their urine3, which may explain why cranberry juice can help prevent as well as treat bladder infections. Cranberries and other berries of the Vaccinium family (e.g. low bush blueberry, bilberry, and lingonberry) also have other health-promoting benefits: they can help reduce periodontal disease4 and may have anti-cancer activity5 as well.
Most of these studies used cranberry juice cocktail, with sugar and dextrose added. The results probably would have been even more dramatic had the researchers used unsweetened cranberry or blueberry juice. Any simple sugar feeds the bacteria, thereby prolonging the bladder infection.
For best results, drink unsweetened cranberry juice or use freeze-dried cranberry capsules. The juice also has the added benefit of increasing your fluid intake.
1 Ahuja, S., B. Kaack, J. Roberts. Loss of fimbrial adhesion with the addition of Vaccinum macrocarpon to the growth medium of P-fimbriated Escherichia coli. J Urol 159, no. 2 (February 1998): 559-62.
2 Ofek, I, J. Goldhar, N.Sharon. Anti-Escherichia coli adhesion activity of cranberry and blueberry juices. Adv Exp Med Biol 408 (1996): 179-83.
3 Avorn, J., M. Monane, J.H. Gurwitz, R.J. Glynn, I. Choodnovskiy, L.A. Lipsitz. Reduction of bacteriuria and pyuria after ingestion of cranberry juice. JAMA 271, no. 10 (March 9, 1994): 751-4.
4 Weiss, E.I., R. Lev-Dor, Y. Kashamn Y, J. Goldhar, N. Sharon, I. Ofek. Inhibiting interspecies coaggregation of plaque bacteria with a cranberry juice constituent. J Am Dent Assoc 129, no. 12 (Decemeber 1998): 1719-23.
5 Bomser, J., D.L. Madhavi, K. Singletary, M.A. Smith. In vitro anticancer activity of fruit extracts from Vaccinium species. Planta Med 62, no. 3 (June 1996): 212-6.