Women have long been drinking cranberry juice for prevention of urinary tract infections (UTIs), but medical studies have had variable results (some say cranberry juice and products help, while some others say they don't). A recent review of studies found that YES, cranberry juice and cranberry products help with prevention of UTIs.
The review was published in Cochrane Reviews, which is viewed as a gold standard in medical evidence. Fifty studies were reviewed, with the data supporting the use of cranberries (in juice, tablets, or capsules) in reducing the risk of developing UTIs.
Why do cranberries work? Cranberries contain proanthocyanidins (PACs), which inhibit E. coli from adhering (attaching) to the urothelial cells lining the bladder.
Another good treatment and preventative for the majority of UTI, is D-mannose (capsules or powder). D-mannose is effective for urinary tract infections caused by E. coli bacteria (up to 90% of UTIs), even infections that keep recurring (30 to 50% of infections). A study first found D-mannose effective in 2015, and since then there have been several studies finding D-mannose results to be "favorable".
From Medical Xpress: A myth no more: Cranberry products can prevent urinary tract infections for women
Drinking cranberry juice has long been a mythical prevention strategy for women who develop a urinary tract infection—and new medical evidence shows consuming cranberry products is an effective way to prevent a UTI before it gets started.
A global study looking at the benefits of cranberry products published in Cochrane Reviews has determined cranberry juice, and its supplements, reduce the risk of repeat symptomatic UTIs in women by more than a quarter, in children by more than half, and in people susceptible to UTI following medical interventions by about 53%.
Cranberry juice and healthcare supplements that commonly include the fruit, such as capsules and tablets, have long been promoted as a readily available solution to ward off the infection but the most recent review in 2012, with evidence from 24 trials, showed no benefit from the products.
The medical scientists behind this updated review from Flinders University and The Children's Hospital at Westmead aimed to update these findings, as an important step in determining the effectiveness of cranberry products by looking at 50 more recent trials that included almost 9000 participants.
Flinders University epidemiologist Dr. Jacqueline Stephens, a co-author of the study, says if the UTI persists untreated it can move to the kidneys and cause pain and more complications, including sepsis in very severe cases, so prevention is the most effective way to reduce risks.
"Most UTIs are effectively, and pretty quickly, treated with antibiotics, sometimes as little as one dose can cure the problem. Unfortunately, in some people UTIs keep coming back. Without being sure if or how it works, some healthcare providers began suggesting it to their patients. It was a harmless, easy option at the time. Even centuries ago, Native Americans reportedly ate cranberries for bladder problems, leading somewhat more recently, to laboratory scientists exploring what it was in cranberries that helped and how it might work."
The data also doesn't show any benefit for elderly people, pregnant women or in people with bladder emptying problems.