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#358: Any berry good solutions to preventing UTIs: Cranberries?

Do cranberry products prevent recurrent urinary tract infections (UTIs)?

Potential benefits of cranberry products for UTI prevention are at high risk-of-bias from potential publication bias, small studies, and unblinding. If biases disregarded, cranberry products might reduce the proportion of women with recurrent UTIs from 24% to 18% over ≤1 year. Results are inconsistent between patient populations; example children with recurrent UTIs may benefit but not institutionalized elderly or pregnant woman.

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  • 5 systematic reviews [7-50 randomized control trials (RCTs), 1498-8857 patients].1-5 UTI definition varied: Symptoms, bacteriuria, or both. Results statistically different unless stated.
  • Most recent/largest systematic review (50 RCTs, 8857 patients).1 “People-at-risk” subgroups included women (generally ≥2 UTIs/year) or children (1-18 years with ≥1 past UTI), adults with pelvic radiation/surgery/transplant or neuromuscular dysfunction, institutionalized elderly, and pregnant women. Any cranberry product versus placebo or no-treatment.  ≥1 UTI at 1-12 months (reporting subgroups, due to inconsistent results):
    • Women (8 RCTs, 1555 patients): 18% versus 24% placebo, Number Needed to Treat (NNT)=17.
    • Children (5 RCTs, 504 patients): 16% versus 34% placebo, NNT=6.
    • Adults following pelvic radiation/surgery/transplant (6 RCTs, 1434 patients): 11% versus 23% placebo, NNT=9.
    • Institutionalized adults, pregnant women, or neuromuscular dysfunction: No statistical difference.
  • Other systematic reviews: Women with recurrent UTIs2,3 and any “people-at-risk”4,5 report benefits.
  • Adverse events: No difference.1
  • Limitations:
    • Publication bias:5 UTI prevention Risk Ratio (RR)=0.68 [Confidence Interval (CI):0.57-0.80] worsens when adjusted for missing studies [RR=0.83 (CI:0.70-1.00)].
    • Systematic reviews1-5 did no analysis by quality. PEER performed quality analysis for study size and placebo-controlled (in women with recurrent UTI).1
      • Smaller RCTs RR=0.47 (CI:0.33-0.68) versus large RCTs RR=0.97 (CI:0.77-1.22), statistically different.
      • No-placebo (unblinded) RCTs RR=0.39 (CI:0.21-0.74) versus placebo RR=0.83 (CI:0.62-1.10), statistically different.

  • Proanthocyanidin (proposed active ingredient) studied dose varied 2.8-118 mg.
  • For women, typical cranberry intervention was juice (1/2-3 cups/day) or capsule (500mg/day).1
  • Cranberry juice versus capsules (1 RCT, 100 patients):6 No statistical difference.
  • Daily antibiotics reduce recurrence to 12% over 6-12 months versus 66% with placebo.7
  • Guidelines support antibiotic prophylaxis with conditional recommendation for cranberry.8
  • Costs:9 Juice/cup: ~$0.60; 110 calories (low-calorie: 10 calories).
  • Capsules: ~$0.15-0.63/capsule (doses vary).

Marlene Fuhrmann February 1, 2024

very interesting–such a common self treatment among patients

Ralph Suke March 30, 2024

Seems to confer some small benefit.

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  • Jennifer Young MD CCFP-EM
  • G. Michael Allan MD CCFP
  • Betsy Thomas BSc. Pharm

1. Williams G, Hahn D, Stephens JH, et al. Cochrane Database Syst Rev. 2023; 4(4):CD001321.

2. Valente J, Pendry BA, Galante E. J Herbal Med. 2022;36; 100602.

3. Fu Z, Liska D, Talan D, et al. J Nutr. 2017; 147(12):2282-2288.

4. Xia JY, Yang C, Xu DF, et al. PLoS One. 2021; 16(9):e0256992.

5. Luís Â, Domingues F, Pereira L. J Urol. 2017; 198(3):614-621.

6. Stothers L. Can. J Urol. 2002; 9(3):1558-62.

7. Finley C, Falk J, Korownyk T. Tools for Practice #322 (online publication), College of Family Physicians of Canada, 2022; Sept. 6. Available at: Accessed on: November 23, 2023.

8. Anger J, Lee U, Ackerman AL, et al. J Urol. 2019; 202(2):282-289.

9. Real Canadian Superstore website. Available at: Accessed on October 25, 2023.

Authors have no conflicts of interest to declare.