Cranberry products in the prevention of urinary tract infections: examining the evidence

Abstract:

Cranberry (Vaccinium macrocarpon) juice and extracts are widely used and recommended as folk remedy for prophylaxis of urinary tract infections (UTIs). Its putative mechanism is an anti-adhesive effect that prevents docking of bacteria on host tissues. The anti-adhesion quality is attributed to A-type proanthocyanidins (PACs), a group of polyphenols that has a restricted occurrence in cranberries and a few related plants. Clinical trials with cranberry have provided a mixed evidence on behalf of UTI prophylaxis. In some trials, a benefit could not be detected due to lower than calculated UTI recurrence rates, in others failure had retrospectively been blamed on underdosing of cranberry products. To circumvent such problems, cranberry products need to be standardized for the bioactive principle of PAC and administered at a sufficient dose. Further characterization of PAC bioavailability, improvement of the currently inconvenient prescriptions, and above all of the palatability for patients is strongly recommended. Larger staged trials should then be carried out in patients with relevant UTI risks.

Keywords::

• cranberry (Vaccinium macrocarpon Aiton)
• urinary tract infection
• proanthocyanidins
• anti-adhesion
• p-fimbriae

Disclosure

The authors report no conflicts of interest in this work.