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American Cranberry, vaccinium macrocarpon, is a plant that grows wild from the mountains of Georgia to the Canadian Maritimes, and as far west as Minnesota. It has been reported that Native Americans were the first group to use cranberries for food, fabric dye and as a healing agent.
Cranberry was one of the main ingredients in Pemmican, a mixture of meat, animal fat and cranberries made by the Native Americans to provide nourishment on long journeys. The acidity of the cranberries acted as a preservative and prevented the growth of bacteria, allowing the Native Americans to store Pemmican for months at a time.
Native Americans were the first to use cranberry as a treatment for bladder and kidney ailments. In addition to traditional usage, cranberry has a long history of scientific research studying its benefits on the urinary tract.
Cranberry supports the health of the urinary tract by inhibiting the adhesion of bacteria to the epithelial lining of the urethra, which is typically how bacteria enter the urinary tract. One of the primary beneficial compounds in cranberries are proanthocyandins (PACs), they help protect against bacteria by collecting in the urine relatively intact and also by binding to pathogenic bacteria from the colon and decreasing their harmfulness (1).
Cranberry supports the health of the urinary tract by inhibiting the adhesion of E. coli to the epithelial cell lining of the urethra. One study found that cranberry extract can reduce the ability of E.coli to adhere to the urinary epithelial cells by roughly 50% (2).
A dose dependent study found that women given 500 mg cranberry extract standardized to 1.5% PACs reduced urinary E. coli adherence by 36%. Women given 1000 mg daily showed even further reduction of E. coli at 65% (3).
Science has established that proanthocyanidins (PACs) in cranberries are important inhibitors of E.coli. A study looked at varying doses of PACs and found that there was a significant dose-dependent reduction in the bacterial adherence to human epithelial cells 24 hours after ingestion compared to placebo. The study participants were given doses of PACs ranging from 0 to 72 mg (4).
A second study had similar findings. Participants who consumed 108 mg of cranberry in capsule form, had a significant decrease in bacterial adherence to human uroepithelial cells 12 hours after consumption when compared with placebo (5).
Monograph of Vaccinium macrocarpon
Shaheen G, Ahmad I, Mehmood A, Akhter N et al., n. Journal of Medicinal Plants Research. 2011. October. Vol. 5(22). 5340-46. , 2011
Inhibitory activity of cranberry extract on the bacterial adhesiveness in the urine of women: an ex-vivo study.
Tempera G, Corsello S, Genovese C, Caruso F, IJIP, 2010
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
Sengupta K, Alluri K, GolakotiT, Gottumukkala G, Raavi J et al. , Current Bioactive Compounds, 2017
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
Howell A, Botto H, Combescure C, Blanc-Potard A, Guasa L et al. , BMC Infectious Diseases, 2010
In-vitro and in-vivo evidence of dose-dependent decrease of uropathogenic Escherichia coli virulence after consumption of commercial Vaccinium macrocarpon (cranberry) capsules
Lavigne JP, Bourg G, Combescure C, Botto H, Sotto A. , Clin Microbiol Infect, 2008