Cranberry is widely used to prevent urinary tract infection (UTI). It was initially believed to function by acidifying urine. However, the mechanism is now thought to be inhibition of adhesion of bacteria to uroepithelial cells by proanthocyanadin, a compound present in cranberry.
There is preliminary clinical evidence in support of the use of cranberry juice and cranberry supplements to prevent UTI, although most available studies are of poor methodologic quality. Most evidence has focused on effects against E. coli, although in vitro research suggests activity against Proteus, Pseudomonas and other species. There are no clear dosing guidelines, but given the safety of cranberry, it may be reasonable to recommend the use of moderate amounts of cranberry juice cocktail to prevent UTI in non-chronically ill individuals.
Cranberry has not been shown effective as a treatment for documented UTI. Although cranberry may be a viable adjunct therapy in a time when antimicrobial resistance of concern, given the proven efficacy of antibiotics, cranberry should not be considered a first line agent.
Cranberry has been investigated for numerous other medicinal uses, and promising areas of investigation include prevention of H. pylori infection and dental plaque.
Evidence
Uses based on scientific evidence
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Urinary tract infection (UTI) prevention
B
There are multiple studies of cranberry (juice or capsules) for the prevention of urinary tract infections in healthy women and nursing home residents. While no single study convincingly demonstrates the ability of cranberry to prevent UTIs, the sum total of favorable evidence combined with laboratory research tends to support this use. It is not clear what dose is best. Most research has focused on the bacteria E. coli, although laboratory research suggests possible effects against other bacteria such as Proteus or Pseudomonas.
Cranberry seems to work by preventing bacteria from sticking to cells that line the bladder. Contrary to prior belief, urine acidification does not appear to play a role. Notably, many studies have been sponsored by the cranberry product manufacturer Ocean Spray®. Additional research is needed in this area before a strong recommendation can be made.
Urinary tract infection (UTI) treatment
C
There are no well-designed human studies of cranberry for the treatment of urinary tract infections. Laboratory research suggests that cranberry may not be an effective treatment when used alone, although it may be helpful as an adjunct to other therapies such as antibiotics.
B12 absorption in people using antacids
C
Preliminary research suggests that cranberry juice may increase vitamin B12 absorption in patients taking drugs that reduce stomach acid, such as proton pump inhibitors like lansoprazole (Prevacid®). However, this effect may be due to the acidity of the juice rather than an active component of cranberry itself. Further study is needed before a recommendation can be made.
Antioxidant
C
Based on laboratory study, cranberry may have antioxidant properties. However, human study is lacking. Further study is needed before a recommendation can be made.
Antiviral and antifungal
C
Limited laboratory research has examined the antiviral and antifungal activity of cranberry. There are no reliable human studies supporting the use of cranberry in this area.
Cancer prevention
C
Based on a small amount of laboratory research, cranberry has been proposed for cancer prevention. Study is needed in humans before a recommendation can be made.
Dental plaque
C
Because of its activity against some bacteria, cranberry juice has been proposed as helpful for mouth care. However, many commercial cranberry juice products are high in sugar, and may not be suitable for this purpose. There is not enough research in this area to make a clear recommendation.
Stomach ulcers caused by H. pylori bacteria
C
Based on early research, cranberry may reduce the ability of H. pylori to live in the stomach. However, there are no reliable human studies in this area.
Kidney stones
C
Based on preliminary research, it is not clear if drinking cranberry juice increases or decreases the risk of kidney stone formation. Cranberry juice is reported to decrease urine levels of calcium, increase levels of urine magnesium and potassium and increase urine levels of oxalate.
Reduction of odor from incontinence/bladder catheterization
C
There is preliminary evidence that cranberry juice may reduce urine odor from incontinence or bladder catheterization. Further study is needed before a recommendation can be made.
Urine acidification
C
In large quantities, cranberry juice may lower urine pH. Contrary to prior opinion, urine acidification does not appear to be the way that cranberry prevents urinary tract infections.
Urostomy care
C
It is proposed that skin irritation at urostomy sites may be related to urine pH. Cranberry juice can lower urine pH, and has been tested for this purpose. Further study is needed before a recommendation can be made.
Chronic urinary tract infection prevention: children with neurogenic bladder
D
There is preliminary evidence that cranberry is not effective in preventing urinary tract infections in children with neurogenic bladder.
Radiation therapy side effects (prostate cancer)
D
There is preliminary evidence that cranberry is not effective in preventing urinary symptoms related to pelvic radiation therapy in patients with prostate cancer.
*Key to grades: A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Anorexia, blood disorders, cancer treatment, diuresis (increasing urine flow), gall bladder stones, liver disorders, scurvy, wound care, stomach ailments, vomiting.
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Dosing
The below doses are based on scientific research, publications, traditional use or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Standardization
Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. There is no widely accepted standardization for cranberry juice products, although some cranberry preparations are standardized to 11% to 12% quinic acid per dose.
Adults (18 years and older)
Urinary tract infection prevention: Recommended doses range from 90 to 480 milliliters (three to 16 ounces) of cranberry cocktail twice daily, or 15 to 30 milliliters of unsweetened 100% cranberry juice daily. Three hundred milliliters per day (10 ounces) of commercially available cranberry cocktail (Ocean Spray®) has been used in well-designed research.
Other forms of cranberry used include capsules, concentrate and tinctures. Between one and six 300 to 400 milligram capsules of hard gelatin concentrated cranberry juice extract, twice daily by mouth, given with water one hour before meals or two hours after meals has been used. Soft gelatin capsules may contain vegetable oil and less of the cranberry compound. One and a half ounces of frozen juice concentrate twice daily by mouth has been used, as well as four to five milliliters of cranberry tincture three times daily by mouth. One study suggests that 500 milliliters of cranberry juice with 1500 milliliters of water was sufficient in helping prevent the formation of oxalate kidney stones.
Children (younger than 18 years)
There is not enough scientific evidence to recommend cranberry supplementation in children (beyond amounts found in a normal balanced diet). Cranberry has been used safely in doses of 15 milliliters per kilogram of body weight in one study, or 300 milliliters per day of cranberry juice for three months.
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Safety
The U. S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
Cranberry should be avoided by people with allergy/hypersensitivity to Vaccinium species (cranberries and blueberries).
Side Effects and Warnings
Patients with diabetes or glucose intolerance may want to drink sugar-free cranberry juice to avoid a high sugar intake. Doses greater than three liters per day of cranberry may cause stomach distress and diarrhea. Drinking more than one liter per day of cranberry juice may increase the risk of kidney stones in people with a history of oxalate stones. Some commercially available products are high in calories. On average, six ounces of cranberry juice contains approximately 100 calories. One study shows the possibility for occurrence of vaginal yeast infections in those women who often consume cranberry juice, although this has not been proven.
Pregnancy and Breastfeeding
Safety has not been determined in pregnancy and breastfeeding, although cranberry juice is believed to be safe in amounts commonly found in foods. Many tinctures contain high levels of alcohol and should be avoided during pregnancy.
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Interactions
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments or traditional use. You should always read product labels. If you have a medical condition or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
In theory, due to its acidic pH, cranberry juice may counteract antacids. Cranberry juice theoretically may increase the effects of antibiotics in the urinary tract and increase the excretion of some drugs in the urine. Cranberry juice may increase absorption of vitamin B12 in patients using proton pump inhibitors such as esomeprazole (Nexium®).
Some cranberry tinctures may have high alcohol content and lead to vomiting if used with the drug disulfiram (Antabuse®) or metronidazole (Flagyl®).
Studies have shown that taking the prescription blood thinner warfarin (Coumadin®) and cranberry products at the same time can elevate the INR which could increase the risk of bleeding.
Interactions with Herbs and Dietary Supplements
In theory, cranberry juice may increase the excretion of some herbs or supplements in the urine.
Theoretically cranberry products may increase the risk of bleeding in people taking other herbs or supplements like garlic or danshen.
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Updates
Last updated: September 2005.
This patient information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration.
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Selected References
Natural Standard developed the above evidence-based patient information based on a systematic review of more than 100 scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to Natural Standard on the Web. Selected references about effectiveness are listed below.
Avorn J, Monane M, Gurwitz J, et al. Reduction of bacteriuria and pyuria using cranberry juice. JAMA 1994;272(8):588-590.
Avorn J, Monane M, Gurwitz JH, et al. Reduction of bacteriuria and pyuria after ingestion of cranberry juice. JAMA 1994;271(10):751-754.
Burger O, Ofek I, Tabak M, et al. A high molecular mass constituent of cranberry juice inhibits helicobacter pylori adhesion to human gastric mucus. FEMS Immunol Med Microbiol 2000;29(4):295-301.
Campbell G, Pickles T, D'yachkova Y. A randomised trial of cranberry versus apple juice in the management of urinary symptoms during external beam radiation therapy for prostate cancer. Clin Oncol (R Coll Radiol) 2003;15(6):322-328.
Carson CF, Riley TV. Non-antibiotic therapies for infectious diseases. Commun Dis Intell. 2003;27 Suppl:S143-6.
Cavanagh HM, Hipwell M, Wilkinson JM. Antibacterial activity of berry fruits used for culinary purposes. J Med Food 2003;6(1):57-61.
Dignam R, Ahmed M, Denman S, et al. The effect of cranberry juice on UTI rates in a long term care facility. J Amer Ger Soc 1997;45(9):S53.
Ebringer A, Rashid T, Wilson C. Rheumatoid arthritis: proposal for the use of anti-microbial therapy in early cases. Scand J Rheumatol 2003;32(1):2-11. Review.
Fleet JC. New support for a folk remedy: cranberry juice reduces bacteriuria and pyuria in elderly women. Nutr Rev 1994;52(5):168-170.
Foda M, Middlebrook PF, Gatfield CT, et al. Efficacy of cranberry in prevention of urinary tract infection in a susceptible pediatric population. Canadian J Urol 1995;2(1):98-102.
Foxman B, Geiger AM, Palin K, et al. First-time urinary tract infection and sexual behavior. Epidemiology 1995;6(2):162-168.
Gibson L, Pike L, Kilbourne J. Effectiveness of cranberry juice in preventing urinary tract infections in long-term care facility patients. J Naturopath Med 1991;2(1):45-47.
Goodfriend R. Reduction of bacteriuria and pyuria using cranberry juice. JAMA 1994;272(8):588-590.
Haverkorn MJ, Mandigers J. Reduction of bacteriuria and pyuria using cranberry juice. JAMA 1994;272(8):590.
Hopkins WJ, Heisey DM, Jonler M, et al. Reduction of bacteriuria and pyuria using cranberry juice. JAMA 1994;272(8):588-589.
Howell AB, Foxman B. Cranberry juice and adhesion of antibiotic-resistant uropathogens. JAMA 2002;287(23):3082-3083.
Jepson RG, Mihaljevic L, Craig J. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev 2000;(2):CD001321.
Kontiokari T, Sundqvist K, Nuutinen M, et al. Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. BMJ 2001;322(7302):1571-1573.
Lee YL, Owens J, Thrupp L, et al. Does cranberry juice have antibacterial activity? JAMA 2000;283(13):1691.
Papas PN, Brusch CA, Ceresia GC. Cranberry juice in the treatment of urinary tract infections. Southwest Med 1966;47(1):17-20.
Pedersen CB, Kyle J, Jenkinson AM, et al. Effects of blueberry and cranberry juice consumption on the plasma antioxidant capacity of healthy female volunteers. Eur J Clin Nutr 2000;54(5):405-408.
Schlager TA, Anderson S, Trudell J, et al. Effect of cranberry juice on bacteriuria in children with neurogenic bladder receiving intermittent catheterization. J Pediatr 1999;135(6):698-702.
Schmidt DR, Sobota AE. An examination of the anti-adherence activity of cranberry juice on urinary and nonurinary bacterial isolates. Microbios 1988;55(224-225):173-181.
Terris MK, Issa MM, Tacker JR. Dietary supplementation with cranberry concentrate tablets may increase the risk of nephrolithiasis. Urology 2001;57(1):26-29.
Walker EB, Barney DP, Mickelsen JN, et al. Cranberry concentrate: UTI prophylaxis. J Fam Pract 1997;45(2):167-168.
2006-07-23 22:37:57
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answer #10
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answered by Anonymous
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