Does Cranberry Juice Help Treat UTIs? Myth vs. Science

Cranberry juice contains proanthocyanidins (PAsCs) and a simple sugar called D-mannose, which are believed to treat UTIs in the same way antibiotics do.

One theory holds that proanthocyanidins (PACs) may help:

• Prevent UTI-causing bacteria from adhering to the bladder walls and the lining of other parts of the urinary system
• Inhibit bacteria from proliferating (multiplying)

According to the theory, this results in bacteria being flushed out of the bladder with urine, thus preventing infection.

Prevention

While cranberry juice cannot reverse or treat an active infection, it has been shown to be an effective preventative measure in some people. Cranberries may help make your urine more acidic, making it less hospitable for bacteria such as E. coli, which commonly cause UTIs. However, the results are mixed on whether cranberries can prevent UTIs from forming in the first place, and the specific mechanism through which they can help is unclear.

Research data are inconsistent as to whether the amount of D-mannose administered orally is enough to prevent a UTI. According to the studies so far, the amount of cranberry juice or supplements including their dosages and duration for UTI treatment is unknown. Thus, it is better to seek medical treatment for UTIs than to rely on cranberry juice.

Treatment

Unfortunately, there is no evidence that drinking cranberry juice or using a cranberry supplement helps cure active UTIs. If you already have an infection, you should seek medical treatment. 

Cranberry juice also promotes urination, flushing bacteria out of the bladder and alleviating the pain and burning associated with UTIs. However, the active compound in cranberry juice does not normally stay in the bladder long enough to heal the infection. As a result, cranberry juice can help reduce UTI symptoms, but cannot cure the infection.

Some studies suggest that there is a minor benefit of cranberry juice on UTIs, whereas the majority of studies show no benefit at all.

• A study of 24 major trials on the use of cranberry products for UTIs revealed that neither the juice nor supplements significantly lowered the risk of infection.
• A few smaller trials indicated that cranberry juice has had some effectiveness in preventing UTIs. However, many individuals in the trials dropped out or failed to comply. This implies that the frequency or volume of cranberry juice required to be effective may not be sustainable for many people.

The taste of cranberry supplements, such as pills and powders, may be more pleasant than cranberry juice, but the quantities of proanthocyanidins in these supplements vary and may be insufficient. A cranberry product is even less likely to prevent germs from adhering to the urinary system linings if the dose is not effective.

Even if the results of studies are unclear, there is probably no harm in drinking cranberry juice for the potential effects on UTI prevention. Make sure to buy unsweetened cranberry juice over varieties that contain added sugar. 

However, if you have health conditions such as diabetes or are taking any medications, consult your doctor about whether cranberry juice is safe for you.