Cranberry Juice Protects Women Against Urinary Tract Infections

~ November 2001 No.136 ~

A recent report in the British Medical Journal provides strong evidence that drinking as little as 50 ml of cranberry juice a day can reduce the incidence of urinary tract infections (UFI) in women. This is good news for women who are susceptible to these painful infections, which usually require treatment with antibiotics.

The average adult passes about 1,500 millilitres of urine each day. The amount of urine varies, depending on the amount and type of food and fluids consumed. The volume formed at night is about half as much as that formed in the daytime. UTI occurs when microorganisms, usually bacteria from the digestive tract, cling to the opening of the urethra and begin to multiply. Most infections arise from one type of bacteria, Escherichia coli (E. coli), which normally lives in the colon. Several other conditions increase risk. Blockage in the urinary tract such as by a kidney stone or an enlarged prostate can cause abnormal urine flow and increase the risk of UTI. Disorders that suppressed the immune system such as diabetes also raise the risk of UTI.

Women are more at risk than men, although the reasons are not evident, and as women age the incidences of UTI increase. Researchers at Tulane University in New Orleans suggest that one factor behind recurrent UTI's may be the ability of bacteria to adhere to the mucous tissue of the urinary tract. Another may be that local immune responses in some women are less effective in preventing the growth of bacteria.

UTI sufferers may experience a frequent urge to urinate and a painful, burning feeling in the area of the bladder or urethra during urination. In spite of the urge to urinate, often very little urine is passed. UTI may result in an overall tired, rundown feeling. The urine itself may look milky or cloudy. If the kidney becomes infected, pain in the back or side below the ribs, nausea, or vomiting may occur.

UTI is traditionally treated with antibacterial drugs. Although the infection can often be cleared up in 1-2 days if there are no complications, patients are usually kept on the antibiotic treatment for 7-10 days to ensure no reoccurrence.

A Finnish group of doctors gave 150 women who had suffered from an occurrence of UFI either cranberry lingonberry juice concentrate, a drink that contained the live bacteria Lactobacillus GG or no treatment, and then followed the groups to observe the reoccurrence of any UFI. After the women had been on the experiment for six months, it was found that the group consuming the cranberry concentrate had statistically significantly few reoccurrences of UTI compared to the group which had received no treatment. The group receiving the live bacteria drink had a similar number of UTI as the group receiving no treatment.

The active ingredient in cranberry juice that appears to protect women against UTI has not been identified, but it is evident from the Finnish study that it doesn´t take much cranberry juice each day to help protect against UTI.

  1. Reference
    • Kontiokari, Sundqvist, Nuutinen, Pokka, Koskela and Uhari. 2001. Randomized trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. British Med. J. 322: 1571-15731

 

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Last modified

September 12 2015