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The Dangers Of Using Antibiotics To Prevent Urinary Tract Infections

June 2014

By Alex Johnson

Clinical Studies Validate Cranberry Effectiveness

Clinical Studies Validate Cranberry Effectiveness 

Cranberries have been used for generations to help boost urinary tract health. It’s only in the past dozen or so years, however, that scientists have come to a better understanding of how cranberry products work to combat bacterial adhesion, reduce oxidant stress, and fight inflammation. The most compelling studies are those that directly examine how cranberry products reduce the frequency or severity of urinary tract infections.

An early pilot study evaluated women between 25 and 70 years old who took 200 mg of a concentrated cranberry extract twice a day.39 All of these women had a history of at least six urinary tract infections in the past year. During the 12-week course of the study, not a single woman had a urinary tract infection.39 Even better, two years later, all of those who continued to take the cranberry supplement remained free of urinary tract infections. That’s 100% protection for a group of people who previously had averaged one urinary tract infection every two months.

A large meta-analysis study of 10 individual clinical trials involving 1,049 patients showed that cranberry products significantly reduced the incidence of urinary tract infections at 12 months, lowering the risk of an infection by 35% compared with control groups.40

Still more recently, several studies have compared the effect of cranberry extracts with the most commonly used antibiotics in preventing recurrent urinary tract infections. These studies have demonstrated good efficacy of the cranberry treatment in comparison to standard antibiotics.41,42

One study showed that cranberry extract had similar effectiveness to the antibiotic trimethoprim at preventing urinary tract infections.41

uropathogenic E.coli

Another study found that the antibiotic combination of trimethoprim and sulfamethoxazole was only slightly more effective at preventing urinary tract infections than cranberry capsules. (Patients took 500 mg twice daily of cranberry capsules, or once-daily doses of the antibiotic combination.42) However, patients treated with antibiotics had a 62% greater amount of antibiotic-resistant organisms during the study, compared to those receiving cranberry. This study has been widely cited as an example of the reasonable trade-offs between cranberry and antibiotic treatment; over the long term, it seems likely that the cranberry recipients will develop fewer infections with dangerous multiple antibiotic-resistant strains of organisms.

As with any therapy directed against microorganisms, the question arises whether cranberry supplements might in some way alter the normal bacterial population of the intestinal or vaginal tracts. Certainly antibiotics do this, as we’ve seen, and with often devastating effects.

Research shows that not only do cranberry products not unfavorably affect normal bacteria, but in fact they also help eliminate certain disease-causing germs living in the genito-urinary tract in up to 42% of patients.18 Similarly, studies show that cranberry supplementation does not have any negative interactions with existing antibiotics.43

What To Look For In A Cranberry Supplement
What To Look For In A Cranberry Supplement

Cranberry products, especially those in capsule form and made from whole fruit, provide undoubted protection against recurrent urinary tract infections, especially in older women who are at the greatest risk of infection. The strong research proving cranberry’s benefits for treating and preventing urinary tract infections led the European Urological Association to recommend the use of cranberry preparations containing not less than 36 mg of proanthocyanidins per day as a preventive strategy against urinary tract infections.38

It’s important to do your research before choosing a cranberry supplement. A 2012 study surveying cranberry supplements found that only four of 19 products studied actually provided 36 mg of total proanthocyanidins per day; some provided none at all.46

In order to take advantage of cranberry’s benefits, make sure you’re taking a cranberry supplement that’s derived from whole fruit, and that will deliver the recommended 36 mg/day of the proanthocyanidins that prevent bacteria from sticking.


Urinary tract infections afflict millions of Americans, overwhelmingly women.1 Nearly 20% of women who have had one urinary tract infection will have another and this risk increases with each infection so that a woman who has had three urinary tract infections in her lifetime has an 80% chance of developing a fourth.44 Those women (and the few men with similar problems) are often placed on antibiotic preventive therapy to reduce the chance of another recurrence.

But antibiotic treatment poses major risks to the individual and to the health of the public. Repeated treatment produces drug-resistant organisms, which are much more difficult to treat as time goes by.

A new family of drugs is under development that will block the first step in urinary tract infections, binding of the bacteria to the bladder lining. But those drugs are still far in the future, and their safety and effectiveness profiles are as yet unknown.

Whole-fruit cranberry supplements, on the other hand, are already recognized to block bacterial binding to the urinary tract linings, and their safety profile is well-established. Concentrated supplements avoid the excess sugar load and occasional stomach upset that can be caused by cranberry juice.

Supplements with at least 36 mg of cranberry proanthocyanidins are recognized by international agencies as being appropriate for use in prevention of urinary tract infections.38 Capsule preparations of these supplements minimize the risk of stomach upset.

If you have or are concerned about recurrent urinary tract infections, you owe it to yourself to start supplementing with a whole-fruit cranberry product today. You’ll be benefiting yourself and your entire community by doing so, as you lower your risk for contributing to the epidemic of antibiotic resistance.

If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.


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