Beerepoot MAJ, Riet GT, Nys S, et al. Cranberries vs Antibiotics to Prevent Urinary Tract Infections. A Randomized Double-blind Noninferiority Trial in Premenopausal Women. Arch Intern Med. 2011;171(14):1270-1278.
In this study, 221 premenopausal women with recurrent urinary tract infections (UTIs) were randomized to receive trimethoprim-sulfamethoxazole (TMP-SMX), 480 mg once daily, or cranberry capsules, 500mg twice daily for one year. The primary end points were the mean number of symptomatic UTIs, the proportion of patients with at least 1 symptomatic UTI, the median time to first UTI, and development of antibiotic resistance in indigenous Escherichia coli. Researchers observed the mean number and proportion of patients with at least 1 symptomatic UTI to be higher in the cranberry group. The median time to first symptomatic UTI was 4 and 8 months for the cranberry and TMP-SMX groups respectively. However, increased resistance was observed for TMP-SMX, trimethoprim, amoxicillin, and ciprofloxacin in the E.coli isolates in the TMP-SMX group. No such increases were seen in women who took cranberry.
TMP-SMX is more effective than cranberry capsules in preventing recurrent UTIs but antibiotic resistance is a major concern.
Barbosa-Cesnik C, Brown MB, Buxton M, et al. Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial. Clin Infect Dis. 2011 Jan;52(1):23-30.
In this double-blind, placebo-controlled trial 319 college-aged women with acute urinary tract infection (UTI) were randomized to receive 8 ounces of 27% cranberry juice twice daily or placebo for six months. The subjects were followed up for 6 months or until the occurrence of a second UTI. Researchers failed to find any significant differences in urinary symptoms between the treatment and placebo groups at follow-up. Although small studies have reported the benefits of cranberry juice for prevention of UTIs, large randomized studies are lacking. Further research is needed to determine the usefulness of cranberry juice.
Zhang L, Ma J, Pan K, Go VL, Chen J, You WC. Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial. Helicobacter 2005;10(2):139-45.
This randomized, double-blind, placebo-controlled trial was conducted to test the effectiveness of cranberry juice in the suppression of H. pylori in an endemically infected population. One hundred and eighty seven adults with H. pylori infection were randomly assigned to receive cranberry juice or a placebo for 90 days. The extent of H. pylori infection was determined using the 13C-urea breath test. The study concluded that significantly more subjects in the cranberry juice group (14.43%) than the placebo group (5.44%) yielded negative test results, suggesting that regular consumption of cranberry juice can suppress H. pylori infection in endemically infected populations.