|| Vaccinium macrocarpon
The medicinal properties of cranberry (Vaccinium macrocarpon) have
been recognized for centuries. Native Americans used raw cranberries as a wound
dressing. Early settlers from England learned to use the berry both raw and
cooked for a number of ailments including appetite loss, digestive problems,
blood disorders, and scurvy (vitamin C deficiency that causes weakness, gum
disease, and spontaneous bleeding in the skin).
In the early 1920s, American scientists discovered that people who eat large
amounts of cranberries have more acid in their urine than those who do not eat
high amounts of the berry. Because bacteria cannot survive in an acidic
environment, the researchers speculated that a diet rich in cranberries may help
prevent and treat urinary tract infections (UTIs), which are commonly caused by
bacteria known as Escherichia coli. In time, the popularity of cranberry
for UTIs soared and many women reported satisfactory results from drinking
cranberry juice. Although the scientific explanations for its purported benefits
have changed throughout the years, there is a significant amount of evidence
today to support the use of cranberries to prevent and treat
Found primarily in North America and grown in bogs, cranberry is an evergreen
shrub that is related to blueberry, buckberry, huckleberry, cowberry, and
bilberry. The cranberry bush has upright branches with leaves that are speckled
on the underside by tiny dots. Pink flowers blossom and red-black fruits appear
during June and July.
The cranberry fruit is high in antioxidants, partly from substances called
proanthocyanidins (which give cranberries their rich color). Antioxidants
scavenge damaging particles in the body known as free radicals. Free radicals
are natural by-products of normal metabolism. But, free radicals can alter cell
membranes, tamper with genetic material known as DNA, and even cause cell death.
Environmental toxins (including ultraviolet light, radiation, cigarette smoking,
and air pollution) can increase the number of free radicals in the body, which
are believed to contribute to the aging process as well as the development of a
number of health problems such as heart disease, cancer, and infections.
Antioxidants can neutralize free radicals and may reduce or even help prevent
some of the damage they cause.
Several studies have measured high levels of antioxidants in people after
drinking cranberry juice. Research is underway to determine if the antioxidant
ability of cranberries will translate into protection from heart disease.
Proanthocyanidins also help prevent microorganisms from causing infections
(such as UTIs) and appear to have cancer fighting properties. Cranberries are an
excellent source of vitamin C as well, another important antioxidant.
The ripe fruit of the cranberry is the part used in commercial and medicinal
|Medicinal Uses and Indications|
Cranberry is used to treat and prevent urinary tract infections of the
bladder and urethra (the tube that drains urine from the bladder).
In one study of 192 elderly women, those who drank 300 mL (approximately 1
1/3 cups) of cranberry juice cocktail every day for 6 months had significantly
less bacteria and infection in their urine than those who drank a placebo
beverage for the same period of time. In another study of sexually active
college students, regular consumption of cranberry juice was associated with a
50% reduction in UTIs.
Although used clinically for children with guidance from a qualified
healthcare practitioner, the benefits of cranberries for UTIs in this age group
are less clear. A preliminary study including only 15 children with neurogenic
bladder (a bladder that does not empty properly, putting the child at particular
risk for UTIs) found that cranberries were no more effective than placebo in
reducing either the symptoms of UTI or the amount of bacteria in the urine for
these children. Further studies are needed to best understand the application of
cranberry juice for preventing or treating UTIs in children.
Cranberry also appears to be more effective than certain probiotics in
preventing recurrent UTIs. (Probiotics are "friendly" bacteria that inhabit the
intestines and vagina and protect against the entrance and proliferation of
"bad" organisms that can cause disease. They are often used as a supplement to
try to prevent or fight UTIs.) Researchers in Finland randomly assigned 150
women with recurrent UTIs to receive either a combined juice made from
cranberries and lingonberries or a drink containing the probiotic Lactobacillus
GG for up to one year. Women who drank the berry juice developed substantially
fewer UTIs than those who consumed the probiotic beverage.
Interestingly, laboratory studies conducted in the mid 1990s revealed that
the effectiveness of cranberry juice is not due to its ability to acidify the
urine as originally thought, but to its ability to prevent E. coli (an organism
that causes most UTIs) from adhering to the cells lining the wall of the
bladder. Without adhering to the bladder, the researchers found, E. coli cannot
flourish and cause a UTI. Test tube studies also suggest that cranberry juice
may inhibit the adherence of other species of organisms that cause UTIs as well,
such as Proteus, Klebsiella, and Pseudomonas.
Further laboratory studies indicated that cranberries also prevent another
microorganism known as Helicobacter pylori from adhering to cell walls. H.
plyori is a bacteria that can cause stomach ulcers, so it is possible that
cranberries may eventually prove to play a role in the prevention of this
condition. Studies also suggest that cranberries may help prevent bacteria from
adhering to gums and around the teeth, but researchers caution that cranberry
juice is high in sugar and should not be used for oral hygiene.
Cranberries are available fresh or frozen and in juice and concentrate forms.
Dried berries are also available in tablet or capsule form. Pure cranberry juice
is acidic and quite sour. Most commercial cranberry juices contain a mixture of
cranberries, sweeteners (which may reduce the immune-boosting effects associated
with the berry), and vitamin C. The addition of sweeteners to cranberry
beverages may explain why cranberry juice cocktail and concentrate are not
always effective in improving symptoms of UTI.
|How to Take It|
For minor urinary infections, the average recommended dosage for a 50 lb (20
to 25 kg) child is 0.5 L per day (16 ounces) of cranberry juice. Given that more
research is needed regarding the specific effects of cranberries on UTIs in this
age group, a child with a suspected or confirmed UTI should have his or her care
directed by a qualified healthcare practitioner.
- Juice: 3 or more fluid ounces per day
- Capsules: 6 per day (equivalent to 3 fluid ounces of cranberry juice
- Fresh or frozen cranberries: 1.5 ounces (equivalent to 3 fluid ounces
of cranberry juice cocktail)
The use of herbs is a time-honored approach to strengthening the body and
treating disease. Herbs, however, contain active substances that can trigger
side effects and interact with other herbs, supplements, or medications. For
these reasons, herbs should be taken with care, under the supervision of a
practitioner knowledgeable in the field of botanical medicine.
Cranberry contains relatively high levels of oxalate, a substance that may
increase the risk of kidney stones in people who are at risk for this condition.
Individuals who are at risk for developing kidney stones, therefore, should
consult a healthcare provider before taking cranberry supplements or drinking
excessive amounts of cranberry juice.
Cranberry should not be used as a substitute for antibiotics during a serious
There are no known scientific reports of interactions between cranberry and
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Bomser J, Madhavi DL, Singletary K, Smith MA. In vitro anticancer activity of
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Burger O, Ofek I, Tabak M, Weiss EI, Sharon N, Neeman I. A high molecular
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Foster S, Tyler VE. Tyler's Honest Herbal. 4th ed. New York: The
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Foxman B, Geiger AM, Palin K, et al. First-time urinary tract infection and
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Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for
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Terris MK, Issa MM, Tacker JR. Dietary supplementation with cranberry tablets
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|Review Date: April 2002|
|Reviewed By: Participants in the review process include: Jacqueline A. Hart, MD,
Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University
and Senior Medical Editor Integrative Medicine, Boston, MA; Gary Kracoff, RPh
(Pediatric Dosing section February 2001), Johnson Drugs, Natick, MA; Enrico
Liva, ND, RPh (August 2000), Vital Nutrients, Middletown, CT; Steven Ottariono,
RPh (Pediatric Dosing section February 2001), Veteran's Administrative Hospital,
Londonderry, NH. All interaction sections have also been reviewed by a team of
experts including Joseph Lamb, MD (July 2000), The Integrative Medicine Works,
Alexandria, VA; Brian T Sanderoff, PD, BS in Pharmacy (March 2000), Clinical
Assistant Professor, University of Maryland School of Pharmacy; President, Your
Prescription for Health, Owings Mills, MD; R. Lynn Shumake, PD (March 2000),
Director, Alternative Medicine Apothecary, Blue Mountain Apothecary &
Healing Arts, University of Maryland Medical Center, Glenwood, MD; Ira Zunin,
MD, MPH, MBA (July 2000), President and Chairman, Hawaii State Consortium for
Integrative Medicine, Honolulu, HI.|
Copyright © 2004 A.D.A.M., Inc
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