CUTI: Cranberries for Urinary Tract Infections
Urinary tract infections (UTIs) are the commonest bacterial infections affecting women, and are usually treated with antibiotics. Because of frequent and sometimes inappropriate use of antibiotics, many bacteria have adapted so that they are no longer killed by antibiotics (antibiotic resistance). As a result, there has been increasing interest in using non-antibiotic treatments, such as cranberry extract. The sugars in cranberries are believed to prevent bacteria from sticking to the wall of the bladder, thus reducing the ability of bacteria to cause a UTI. Cranberries might also make it easier for antibiotics to surround and kill bacteria.
Women with a suspected UTI were invited to take part in this trial and were assigned at random to one of three groups:
- Group 1 - Usual treatment with antibiotics.
- Group 2 - Treatment with antibiotics AND cranberry capsules.
- Group 3 - Initial treatment with cranberry capsules. Women in this group were also given an antibiotic prescription that they could take to the chemist at a later date if they didn’t get better with cranberry capsules alone (‘back-up antibiotics’).
The cranberry capsules were supplied by an Italian company called Indena S.p.A. Each capsule contains 60 mg of cranberry extract and 18 mg of proanthocyanidins (‘PAC’ for short – this is believed to be the active ingredient).
The main aim of this small-scale study was to test whether the study design described works and was acceptable to participants (called a ‘feasibility’ study). This will help in the planning of a subsequent, similar, but much larger study. By comparing the information from different treatment groups on a larger scale, we will be able to tell whether cranberries actually treat UTIs and help reduce the need for antibiotics.
The protocol was published in Trials and the findings have been published in BMJ Open:
Does cranberry extract reduce antibiotic use for symptoms of acute uncomplicated urinary tract infections (CUTI)? A feasibility randomised trial.
Gbinigie O, Allen J, Williams N, Moore M, Hay AD, Heneghan C, Boylan AM, Butler CC.
BMJ Open. 2021 Feb 22;11(2):e046791. doi: 10.1136/bmjopen-2020-046791. PMID: 33619202.
Does cranberry extract reduce antibiotic use for symptoms of acute uncomplicated urinary tract infections (CUTI)? Protocol for a feasibility study
Gbinigie O, Allen J, Boylan AM, Hay A, Heneghan C, Moore M, Williams N, Butler C Trials. 2019 Dec 23;20(1):767. doi: 10.1186/s13063-019-3860-z. PMID: 31870413; PMCID: PMC6929469.
Here is a video explainer of the findings: