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Cranberry

Also listed as: Vaccinium macrocarpon

Overview
Plant Description
Parts Used
Medicinal Uses and Indications
Available Forms
 
How to Take It
Precautions
Possible Interactions
Supporting Research

Overview

Cranberry (Vaccinium macrocarpon) has been used as both a food and a medicine for centuries. It is native to North America and was used by Native Americans to treat bladder and kidney diseases. Early settlers from England learned to use the berry both raw and cooked for many ailments, including appetite loss, stomach problems, blood disorders, and scurvy, caused by not getting enough vitamin C.

Cranberry is best known for preventing urinary tract infections (UTIs), commonly caused by bacteria known as Escherichia coli (E. coli). At first, scientists thought cranberry worked by making urine acidic enough to kill the bacteria. Now, studies show that cranberry actually prevents bacteria from attaching to the walls of the urinary tract. Strong scientific studies support using cranberry, either in capsules or as juice, for preventing -- though not treating -- UTIs.

Plant Description

Found primarily in North America and grown in bogs, cranberry is an evergreen shrub related to blueberry, buckberry, huckleberry, and bilberry. The cranberry bush has upright branches with leaves that are speckled underneath by tiny dots. Pink flowers blossom and red-black fruits appear during June and July.

Cranberry fruit is high in antioxidants, partly from substances called proanthocyanidins, which give cranberries their vibrant color. Antioxidants neutralize particles in the body known as free radicals, which damage cell membranes, tamper with DNA, and even cause cell death.

Cranberries are also an excellent source of vitamin C, another important antioxidant. Scientists are researching to see if the antioxidant ability of cranberries will help protect against heart disease and cancer.

Parts Used

The ripe fruit of the cranberry is the part used in commercial and medicinal preparations.

Medicinal Uses and Indications

Urinary tract infections

Several studies indicate that cranberry helps prevent UTIs of the bladder and urethra (the tube that drains urine from the bladder), particularly for women who have frequent UTIs. In one study of older women, cranberry juice reduced the amount of bacteria in the bladder compared to placebo. Another study showed that younger women with a history of frequent UTIs who took cranberry capsules had fewer UTIs compared to those who took placebo.

However, studies suggest that cranberry doesn’t work once you have a UTI. That’s because in preventing UTIs, it helps keep bacteria from attaching to the urinary tract. But it’s less effective once the bacteria have already attached. For this reason, cranberry is more effective at preventing UTIs than treating them. UTIs should be treated with conventional antibiotics.

Ulcers

Two studies that cranberry may also prevent the bacteria Helicobacter pylori from attaching to stomach walls. H. pylori can cause stomach ulcers, so cranberries may play a role in the preventing stomach ulcers. More research is needed.

Other uses

Cranberry is also being studied for the following conditions, although there isn’t enough evidence yet to tell whether it helps prevent or treat them:

Alzheimer’s disease -- In laboratory tests, cranberry seems to protect somewhat against Alzheimer’s disease. Studies in people are needed.

Cancer -- Some test tube and animal studies suggest cranberry may help stop cancer cells from growing.

Inflammation -- In the laboratory, cranberry has anti-inflammatory effects.

High cholesterol -- One preliminary study found that drinking cranberry juice raised HDL “good” cholesterol levels.

Viruses -- Cranberry seems to fight some viruses in test tubes. Studies in people are needed.

Available Forms

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 very sour, so most cranberry juices contain a mixture of cranberries, sweeteners -- which may make the juice less healthy -- and vitamin C. Look for a brand of cranberry juice that has the lowest amount of added sugar or is sugar-free.

How to Take It

Pediatric

Cranberry juice is considered safe for children to drink. However, there is not enough evidence to establish a safe dose for children prone to UTIs. A child with a UTI should be seen by a doctor.

Adult

  • Juice: 3 or more fluid oz. of pure juice per day, or about 10 oz. of cranberry juice cocktail, for preventing UTIs. Ask your doctor about the right dose for you.
  • Fresh or frozen cranberries: 1.5 ounces

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider.

Cranberry juice is generally considered safe with no serious side effects, even for pregnant women. Cranberry supplements are considered safe for most people, although pregnant and breastfeeding women should ask their doctor before taking any supplement, including cranberry.

Cranberry contains relatively high levels of oxalate, chemicals that may raise the risk of kidney stones in some people. If you have kidney stones, talk to your doctor before taking cranberry supplements or drinking a lot of cranberry juice.

Don’t use cranberry if you already have a UTI. You should see a doctor for prescription antibiotics.

Because most cranberry juice contains added sugar, people who have diabetes should look for brands that are artificially sweetened or should be careful how much sweetened juice they drink.

People who are allergic to aspirin may also be allergic to cranberry.

Possible Interactions

Warfarin (Coumadin) -- Cranberry may raise the risk of bleeding, especially if you already take medications to thin the blood such as warfarin. The evidence is mixed and not completely clear, so it’s best to ask your doctor before you take cranberry or drink a lot of juice.

Aspirin -- Like aspirin, cranberries contain salicylic acid. If you take aspirin regularly -- as a blood-thinner, for example -- or if you are allergic to aspirin, you should not take cranberry supplements or drink a lot of juice.

Other medications -- Cranberry may interact with medications that are processed by the liver. If you take any medications, ask your doctor before taking cranberry.

Supporting Research

Ahuja S, Kaack B, Roberts J. Loss of fimbrial adhesion with the addition of Vaccinum macrocarpon to the growth medium of P-fimbriated Escherichia coli. J Urol. 1998;159:559-562.

Aston JL, Lodolce AE, Shapiro NL. Interaction between warfarin and cranberry juice. Pharmacotherapy. 2006 Sep;26(9):1314-9.

Avorn J, Monane M, Gurwitz JH, Glynn RJ, Choodnovskiy I, Lipsitz LA. Reduction of bacteriuria and pyuria after ingestion of cranberry juice. JAMA. 1994;271:751-754.

Bailey DT, Dalton C, Joseph Daugherty F, et al. Can a concentrated cranberry extract prevent recurrent urinary tract infections in women? A pilot study. Phytomedicine. 2007 Feb 10; [Epub ahead of print].

Bomser J, Madhavi DL, Singletary K, et al. In vitro anticancer activity of fruit extracts from Vaccinium species. Planta Med. 1996;62(3):212-216.

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 Dec;29(4):295-301.

Caton PW, Pothecary MR, Lees DM, Khan NQ, Wood EG, Shoji T, Kanda T, Rull G, Corder R. Regulation of vascular endothelial function by procyanidin-rich foods and beverages. J Agric Food Chem. 2010 Apr 14;58(7):4008-13.

Côté J, Caillet S, Doyon G, Sylvain JF, Lacroix M. Analyzing cranberry bioactive compounds. Crit Rev Food Sci Nutr. 2010 Oct;50(9):872-88.

Dugoua JJ, Seely D, Perri D, Mills E, Koren G. Safety and efficacy of cranberry (vaccinium macrocarpon) during pregnancy and lactation. Can J Clin Pharmacol. 2008;15(1):e80-6.

Howell AB, Vorsa N, Der Marderosian A, et al. Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial-cell surfaces by proanthocyanidin extracts from cranberries. N Engl J Med. 1998;339(15):1085-1086.

Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008;1: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. 2002;322:1571-1573.

Maclean MA, Scott BE, Deziel BA, Nunnelley MC, Liberty AM, Gottschall-Pass KT, Neto CC, Hurta RA. North American Cranberry (Vaccinium Macrocarpon) Stimulates Apoptotic Pathways in DU145 Human Prostate Cancer Cells In Vitro. Nutr Cancer. 2010 Dec 15:1. [Epub ahead of print]

McKay DL, Blumberg JB. Cranberries (Vaccinium macrocarpon) and cardiovascular disease risk factors. Nutr Rev. 2007;65(11):490-502.

Paeng CH, Sprague M, Jackevicius CA. Interaction between warfarin and cranberry juice. Clin Ther. 2007;29(8):1730-5.

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.

Prasain JK. Effect of cranberry juice concentrate on chemically-induced urinary bladder cancers. Oncol Rep. 2008;19(6)1565-70.

Rossi R, Porta S, Canovi B. Overview on cranberry and urinary tract infections in females. J Clin Gastroenterol. 2010 Sep;44 Suppl 1:S61-2. Review.

Ruel G, Pomerleau S, Couture P, Lemieux S, Lamarche B, Couillard C. Low-calorie cranberry juice supplementation reduces plasma oxidized LDL and cell adhesion molecule concentrations in men. Brit J Nutr. 2008;99(2):352-9.

Schlager TA. Effect of cranberry juice on bacteriuria in children with neurogenic bladder. J Pediatr. 1999;135:698-702.

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 tablets may increase the risk of nephrolithiasis. Urol. 2001;57:26-29.

Weiss EI, Lev-Dor R, Kashamn Y, et al. Inhibiting interspecies coaggregation of plaque bacteria with a cranberry juice constituent. J Am Dent Assoc. 1998;129(12):1719-1723.

Zafriri D, Ofek I, Adar R, et al. Inhibitory activity of cranberry juice on adherence of type 1 and type P fimbriated Escherichia coli to eucaryotic cells. Antimicrob Agents Chemother. 1989;33: 92-98.


Review Date: 1/2/2011
Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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