A double-blind, randomized, placebo-controlled trial of cranberry supplements in multiple sclerosis.

Abstract: Cranberry cocktail has been reported to reduce bacteriuria and pyuria in elderly women and self-reported urinary tract infection (UTI) in young female undergraduates, but commercially prepared cranberry concentrate supplements have never been evaluated in multiple sclerosis (MS) patients

with neurogenic bladder. The purpose of this study was to determine whether one 8,000-mg cranberry concentrate supplement daily could prevent UTI in MS participants with bladder symptoms. We conducted a double-blind, randomized, placebo-controlled longitudinal trial of cranberry supplement versus placebo with participants who have MS. After informed consent had been obtained from the participants, baseline data were collected and participants were randomized to receive either one cranberry supplement or placebo daily for 6 months. The sample consisted of 135 participants. In the cranberry group 34.6% of participants failed (i.e., developed a UTI) versus 32.4% in the control group (p = .849). Not all cranberry supplements have been found to contain proanthocyanidins, the active ingredient of cranberries. Because there is no way for the consumer to distinguish supplements that contain proanthocyanidins from those that do not, taking juice or whole cranberries may be preferable.

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The reported prevalence of urinary tract infection (UTI) in people with multiple sclerosis (MS) varies from 20% to 74% depending on the sample selected for study, and some 12% to 25% are recurrently infected (Edich, Westwater, Lambordi, Watson, & Howards, 1990; Gonor, Carroll, & Metcalfe, 1985; Koldewijn, Hommes, Lemmens, Debruyne, & Van Kerrebroeck, 1995; Surls, Zimmern, & Leach, 1994). Incomplete bladder emptying with urinary stasis is probably the leading cause of UTI in people with MS. Spinal cord lesions, interrupting spinal pathways between the pontine micturition center and the sacral spinal cord, are the most common cause of disordered bladder function and result in detrusor hyperreflexia. The loss of normal inhibitory pathways also results in unsustained detrusor contractions, detrusor-sphincter dyssynergia, or both. In this population, UTI is associated with significant morbidity. UTI temporarily worsens neurologic impairment, and there is some evidence to suggest that UTI might trigger MS relapses (Edich et al., 1990; Metz, McGuinness, & Harris, 1998). In the only randomized trial reported in the literature, cranberry cocktail reduced bacteriuria and pyuria in a sample of 153 elderly women who consumed at least 300 ml daily (Avorn et al., 1994). Foxman, Gieger, Plain, Gillespie, and Koopman (1995) found that cranberry cocktail reduced the risk of self-reported UTI in young female undergraduates. However, the efficacy of cranberry cocktail has never been studied in MS patients with neurogenic bladder.