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CRANBERRY
Cranberries (Vaccinium macrocarpon, the American cranberry) have been valued for their healing abilities for centuries and were favored by the Native Americans, who used them to treat bladder and kidney conditions. Cranberries are related to blueberries, buckberries, and huckleberries and are an excellent source of antioxidants, including substances called proanthocyanidins (PACs), as well as vitamin C..
Cranberries are not the only food that contains PACs; apples, chocolate, green tea, grapes, and maritime pine bark (Pycnogenol) are also good sources of the phytonutrient. However, the main type of PACs in cranberries is called A-type PACs, which differs from those found in other foods, which are called B-type PACs. Only the PACs in cranberries have the ability to prevent bacteria from adhering to the walls of the urinary tract, which is the essential characteristic that makes cranberries so helpful in managing urinary tract infections.
French scientists measured the PACs in cranberries using a method called the 4-dimethylaminocinnamaldehyde (DMAC). Then in 2004, France became the first country to approve a health claim for the American cranberry, noting that use of at least 36 mg of proanthocyanidins can “help reduce the adhesion of certain E. coli bacteria to the urinary tract walls.” Numerous studies since then have demonstrated the ability of cranberries to help manage urinary tract infections, supporting the use of cranberry supplements or juice (unsweetened) for this purpose. The dose found to be most beneficial in supporting urinary tract health and managing urinary tract symptoms is 500 mg daily.
Cranberry and Urinary Tract Health
A new study (March 2011) published in Current Bioactive Compounds reported on the success of a whole cranberry powder product (PACran from Decas Botanical Synergies) that significantly reduced the recurrence of urinary tract infections when administered in two different doses. The 90-day randomized clinical trial involved 60 women aged 18 to 40 years who had a history of recurrent urinary tract infection, the presence of E. coli, and mild symptoms of urinary tract infection. The women were randomly assigned to receive no treatment, 500 mg of whole cranberry powder daily, or 1,000 mg of whole cranberry powder daily.
After 10 days and at the end of 90 days, all the women underwent a urine culture analysis. The women who did not receive any treatment showed no changes in the concentrations of E. coli, while those in the two cranberry treatment groups showed reductions of E. coli of between 25 and 45 percent after 10 days of taking whole cranberry powder. This reduction persisted over 90 days.
Forty percent of the women in the two cranberry treatment groups also reported complete relief and remission from urinary tract symptoms such as frequent urination, as well as from itching and burning during urination. Based on all of these findings, the study’s authors concluded that “proanthocyanidins standardized whole cranberry powder was effective in safely reducing the number of E. coli positive subjects at both the 500 mg and 1000 mg dose levels and in ameliorating the symptoms of UTI in these subjects. Therefore, a daily dose of 500 mg or 1000 mg of proanthocyanidins standardized whole cranberry powder may be considered as an adjunct to antibiotic prophylactic therapy against recurrent UTIs.” (Sengupta 2011)
The 500-mg dose used in this study reportedly provides the same amount of anti-adhesion activity against E. coli over 24 hours as does 300 milliliters of Cranberry Juice Cocktail that contains 36 mg proanthocyanidins, based on the earlier French health claim.
Another recent study was published in the BMC Infectious Diseases. (Howell 2010) The researchers noted that cranberry powder standardized to deliver 72 mg proanthocyanidins per day was effective in preventing adhesion. Several earlier studies by Howell at the Marucci Center for Blueberry and Cranberry Research and Extension, Rutgers, The State University of New Jersey, isolated and studied the effects of A-type PACs from cranberry and their antiadhesion activity against E. coli. (Howell 2007; Howell 2002) The ability of cranberry to treat urinary tract infections, however, has not been proven.
Cranberry and Prostate Health
Two other studies indicate that cranberry may be helpful in managing prostatitis and BPH. One was conducted in the Czech Republic and included 42 men at risk of prostate disease because they had lower urinary tract symptoms (LUTS), elevated prostate-specific antigen (PSA), negative prostate biopsy, and chronic nonbacterial prostatitis. The participants were given either 1,500 mg of dried powdered cranberries per day for six months or no cranberry supplement. Compared with the control group, men who had taken the cranberry supplement had statistically significant improvement in International Prostate Symptom Score (IPSS), quality of life, urination factors (e.g., rate of urine flow, average flow, total volume, post-void residual urine volume), and lower total PSA levels at the end of the six-month study.
Cranberry had no effect on blood testosterone or serum C-reactive protein levels. Men in the control group showed no statistically significant improvement. The authors noted that their results were “the first firm evidence that cranberries may ameliorate LUTS, independent of benign prostatic hyperplasia or C-reactive protein level.”. (Vidlar 2010)
In the second study, 48 rats with chronic bacterial prostatitis (CBP) were administered E. coli extract, cranberry, ciprofloxacin, or no intervention. After four weeks, the scientists analyzed the results of microbiological culture of prostate and urine samples along with histological findings for the prostate for each group of rats. They found that the infection rate in the ciprofloxacin group was significantly lower than the rate in the control group, and that the E. coli and cranberry groups showed significantly reduced bacterial growth and prostatic inflammation when compared with the control group. Based on these observations, the authors concluded that “E. coli extract has a potential preventive effect on the development of CBP, and cranberry also exhibits promising activity in this context.” (Kim 2010)
Based on the 2011 study of whole cranberry powder discussed earlier, Dan Souza, director of sales and marketing for Decas Botanical Synergies said the study results “have shown that a daily consumption of 500 mg of PACran helps support urinary tract health.” (Sengupta 2011) Cranberry is considered safe with no serious side effects. However, because cranberry contains high levels of oxalate, chemicals that can increase the risk of kidney stones, consult your doctor before taking cranberry if you have had kidney stones. Cranberry may also interfere with the effects of blood-thinning drugs.
More reading
BPH, Prostatitis and Urinary Tract Infections in Men
References
Howell AB et al. Dosage effect on uropathogenic Escherichia coli anti-adhesion activity in urine following consumption of cranberry powder standardized for proanthocyanidin content: a multicentric randomized double blind study. BMC Infect Dis 2010 Apr 14; 10(1): 94
Howell AB. Bioactive compounds in cranberries and their role in prevention of urinary tract infections. Mol Nutr Food Res 2007 Jun; 51(6): 732-37
Howell AB, Foxman B. Cranberry juice and adhesion of antibiotic-resistant uropathogens. JAMA 2002 Jun 19; 287(23): 3082-83
Kim SH et al. Do Escherichia coli extract and cranberry exert preventive effects on chronic bacterial prostatitis? J Infect Chemother 2010 Nov 2
Sengupta K et al. A randomized, double-blind, controlled, dose dependent clinical trial to evaluate the efficacy of a proanthocyanidin standardized whole cranberry (Vaccinium macrocarpon) powder on infections of the urinary tract. Current Bioactive Compounds 2011 Mar; 7(1): 39-46
University of Maryland Medical Center:
http://www.umm.edu/altmed/articles/cranberry-000235.htm
Vidlar A et al. The effectiveness of dried cranberries (Vaccinium macrocarpon) in men with lower urinary tract symptoms. Br J Nutr 2010 Oct; 104(8): 1181-89
Updated June 1, 2011
