Anyone who has experienced a urinary tract infection is familiar with the discomforts that come along with it. The urgency, burning and rush of the experience are enough to make the trip to the doctor’s office a long one for anyone. For that matter, a remedy that could prevent a urinary tract infection (UTI) is of interest to many, especially to those who are at a higher risk or those who tend to get a UTI more frequently. Cranberry products have got a reputation in prevention and even treatment of urinary tract infections. We’d like to set the record straight on where cranberries stand based on the most recent evidence.
A urinary tract infection is a common event that can happen to anyone at some point in life. Adult females are 50 times more at risk than adult males. Infants, pregnant women, the elderly, people with catheters, those affected by diabetes or individuals with a weakened immune system are also at a higher risk of acquiring UTIs1 .
How Could Cranberries Prevent UTIs?
Cranberries, more specifically cranberry juice, have been used for many years in treatment and prevention of UTIs 1. In vitro studies (experiments in test tubes) have shown that cranberry juice can prevent the bacteria from sticking to the cells that line the bladder2,3. By doing so, cranberries are thought to reduce the likelihood of bacterial colonization and subsequent infection 1. Cranberries contain many different ingredients and discovering the active ingredient responsible for this effect has been a difficult task. Proanthocyanidins (PACs) in cranberries are thought to be responsible for their anti-adhesion property1,2,3.
What Do the Studies Tell Us?
Up until very recently, the studies were showing that cranberry products could help prevent recurrent infections in women. Recently, in 2012, 24 studies on this topic were analyzed in what is called a meta-analysis, which altogether included a total of 4473 participants1. The goal was to figure out how effective cranberries would be in preventing UTIs in various groups (i.e. children, women with recurrent UTIs, people with bladder dysfunction and the elderly). Although some smaller studies have suggested that a benefit may exist, analysis of these 24 trials showed that overall there is no substantial reduction in risk of a UTI with associated symptoms in various groups of individuals when using cranberry products.
As for the treatment, cranberries have not been shown to be effective in treatment of a UTI either5.
What Are Some of the Gaps?
Even though there isn’t enough evidence to make us recommend routine use of cranberry products for prevention of UTIs, some may argue that there is little to lose in trying. It’s true that cranberry supplements or juice are generally safe. Other than the sugar content (which is important to consider if affected by diabetes), the calories and possibly a bit of heartburn, it’s not likely for one to suffer from any major side effects from taking cranberry products 2. Regardless of one’s decision, we’d like to bring to your attention the following points:
1. Limitations of some of the studies:
Some of the studies’ findings are insignificant due to small sample sizes. Another important limitation in some of the trials is the fact that the subjects that were initially included in the study were not included in the final analysis of the outcomes as these subjects dropped out throughout the course of the study. These limitations amongst other study design issues make the outcomes of some of the studies too weak for consideration.
The small benefit that may come from taking cranberry products would require daily and routine use of the product for an indefinite period of time. Here is an important limitation: adherence. Most of the studies done on cranberries and UTIs have shown large dropout rates 1. Evidently committing to drinking two glasses of juice or taking the tablet or capsule twice a day everyday may not be as practical as it may seem.
3. Lack of product standardization
The dose that has been studied is 36 mg of proanthocyanidin (PAC), whether it is in the form of juice, tablets or capsules. This dose is usually divided into two portions taken once in the morning and once in the evening.
As you know, there are a large variety of cranberry juices and cocktails available on the market. It is therefore not unlikely for one to be taking a product that isn’t concentrated enough to provide the required dose. Many prefer taking a supplement to drinking a juice. The problem rises from lack of standardization when it comes to the content of the commercial supplements 4. Much of the PAC content of cranberries is lost as they get processed into tablets or capsules. Therefore, it is important to know the actual PAC content of the supplement or juice. It is definitely worthwhile to pay extra attention to product labels and ingredients.
When one’s affected by a urinary tract infection, cranberry products cannot treat the infection; a visit to doctor’s office becomes necessary. As for the prevention, studies on the effectiveness of cranberry juice or supplements in prevention of urinary tract infections have had important shortcomings and variable results. The most recent compilation of available information suggests a lack of effectiveness of these products in most populations. Having said that, there is little harm that can result from trying. It is recommended to consult your health care professional regarding preventative options that would be appropriate for you.
For those who are considering a trial of cranberries, it is important to adhere to a regular daily treatment at an optimal dose. For those who are disappointed by now, we do hope you enjoy cranberries in your diet with reasonable expectations as they not only taste great but are also a great source of vitamins, fiber and antioxidants.
The Health Aisle Team – 2013
- Jepson RG, Williams G, Craig JC (2012). Cranberries for preventing urinary tract infections (Review). Cochrane Database of Systematic Reviews. Issue 10. Art. 10.1002/14651858.CD001321.pub5.
- Recurrent Urinary Tract Infections in Women. UpToDate. www.uptodate.com. Accessed in 2013.
- Guay DR (2009). Cranberry and urinary tract infections. Drugs. 69(7):775-807.
- Sánchez-Patán F, Bartolomé B, Martín-Alvarez PJ, Anderson M, Howell A, Monagas M (2012). Comprehensive assessment of the quality of commercial cranberry products. Phenolic characterization and in vitro bioactivity. J Agric Food Chem. 60(13): 3396-408.
- Cranberry (Vaccinium macrocarpon). Natural Standard – The Authority on Integrative Medicine. www.naturalstandard.com. Accessed in 2013.