Cranberry (Vaccinium macrocarpon)

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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.

H. pylori infection
Based on early research, cranberry may reduce the ability of Helicobacter pylori bacteria to live in the stomach and cause ulcers. Further research is needed to confirm these results. 		B
Urinary tract infection (prevention)
There are multiple studies of cranberry (juice or capsules) for the prevention of urinary tract infections in healthy women, pregnant women, individuals with spinal cord injuries, 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. 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. 		B
Achlorhydria and B12 absorption
Preliminary research suggests that cranberry juice may increase vitamin B12 absorption in patients taking drugs that reduce stomach acid (antacids), 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. 		C
Antibacterial
Study results of cranberry as an antibacterial show conflicting results. Further study is needed before a conclusion can be drawn. 		C
Antioxidant
Based on laboratory study, cranberry may have antioxidant properties. However, human study is lacking. Further study is needed before a recommendation can be made. 		C
Antiviral and antifungal
Limited laboratory research has examined the antiviral and antifungal activity of cranberry. There is a lack of reliable human studies supporting the use of cranberry in this area. 		C
Cancer prevention
Based on a small amount of laboratory research, cranberry has been proposed for cancer prevention. Study is needed in humans before a strong recommendation can be made. 		C
Dental plaque
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. 		C
Kidney stones
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. 		C
Memory improvement
Preliminary study results show that cranberry juice may increase overall ability to remember. Further well-designed clinical trials are needed to confirm these results. 		C
Radiation therapy side effects (prostate cancer)
There is preliminary evidence that cranberry is not effective in preventing urinary symptoms related to pelvic radiation therapy in patients with prostate cancer. 		C
Reduction of odor from incontinence/bladder catheterization
There is preliminary evidence that cranberry juice may reduce urine odor from incontinence or bladder catheterization. Further study is needed before a firm recommendation can be made. 		C
Urinary tract infection (treatment)
There is a lack of 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. 		C
Urine acidification
In large quantities, cranberry juice may lower urine pH, making it more acidic. Contrary to prior opinion, urine acidification does not appear to be the way that cranberry prevents urinary tract infections. More research is needed in this area. 		C
Urostomy care
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. 		C
Chronic urinary tract infection prophylaxis: children with neurogenic bladder
There is preliminary evidence that cranberry is not effective in preventing urinary tract infections in children with neurogenic bladder. 		D

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)

Grading rationale

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.

Alzheimer's disease, anorexia, anti-inflammatory, antiparasitic, blood disorders, blood thinner, cancer treatment, heart disorders, decontamination (of meats), gum disease, hardening of the arteries, improving urine flow, gall bladder inflammation, gall bladder stones, high cholesterol, influenza, ischemic stroke, liver disorders, neurodegenerative diseases, rheumatoid arthritis, scurvy, stomach ailments, urinary tract inflammation, vomiting, wound care.

Dosing Related terms
NS_patient-cranberry Portions of this document last updated: Sept. 1, 2012

THIS EVIDENCE-BASED MONOGRAPH WAS PREPARED BY
THE NATURAL STANDARD RESEARCH COLLABORATION
(www.naturalstandard.com)

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