Cranberry

The cranberry is a plant native to North America. It produces red berries that are used for food and as medicines. Cranberry plants grow low, producing vertical branches that are approximately two to ten inches high. The fruit is harvested between September and October.

The berries are used to produce beverages and many other food products, as well as dietary supplements in the form of extracts, teas, and capsules or tablets.

Coastal Washington cranberry bog. Source: USDA Agricultural Research Service

Other Names

Common Names

• Cranberry
• American cranberry
• Bog cranberry

Latin Name

• Vaccinium macrocarpon

Cranberries are a source of polyphenol antioxidants. Source: FreeDigitalPhotos.net

How it Works

Free radicals are reactive atoms or molecules that damage cell membranes and disrupt the function of proteins. Cranberries are a source of polyphenol antioxidants. Antioxidants reduce the amount of free radicals. In this way, antioxidants are believed to aid the cardiovascular and immune systems. They are also thought to act as anti-cancer agents.

Research shows that components found in cranberry may prevent bacteria, such as E. coli, from clinging to the cells along the walls of the urinary tract and causing infection. ^[1] However, the mechanism of action of cranberry is not fully understood.

Sources

Cranberries can be dried and sweetened, made into juice (usually mixed with sweetener and water to enhance palitability), capsules or a tincture (alcoholic extract).

Benefits

Historically, cranberry fruits and leaves were used for a variety of problems, such as wounds, urinary disorders, diarrhea, diabetes, stomach ailments, and liver problems. Cranberry products have been used for the following purposes:

• Prevention or treatment of urinary tract infections. The proanothcyanidins found in cranberries can likely prevent urinary tract infections by inhibiting E. coli bacteria from attaching to the urinary tract wall. ^[2]
• Prevention of Helicobacter pylori infections that can lead to stomach ulcers. Research suggests that compounds found in cranberries may keep these bacteria from sticking to the walls of the stomach and causing ulcers. ^[3]
• Prevention or treatment of certain types of cancer. Cranberry has also been reported to have anticancer activity. The flavonoids in cranberry are believed to inhibit certain types of cancer. However, there is insufficient research regarding the use of cranberries for this purpose, and it is advisable to consult a physician for any concerns about cancer prevention and treatment.
• Treatment of high cholesterol. Preliminary research shows that cranberries have the ability to decrease total cholesterol and LDL (bad cholesterol), and increase blood flow. ^[4]
• Prevention of memory loss and coordination problems. Polyphenol compounds are believed to have anti-aging benefits, which can help protect against these problems. ^[5]

Recommended Daily Intake

Typical doses for :

• Juice: cranberry juice cocktail: 3 to 16 oz (90 to 480 ml) twice/day; cranberry juice concentrate: 15 to 30 ml/day (one and one half ounces twice/day)
• Capsules: one to six capsules containing 300 to 400 mg of cranberry juice extract in gelatin twice daily by mouth, given with water one hour before meals or two hours after meals.
• Tincture: 4 to 5 ml of cranberry tincture three times/day by mouth.

Risks

Side Effects

Eating cranberry products in traditional amounts appears to be safe. Side effects may include:

• Nausea
• Gastrointestinal upset
• Diarrhea
• Bitter taste in the mouth

Drinking excessive amounts of cranberry juice (greater than a liter/day) may cause gastrointestinal upset, diarrhea, and an increased risk of kidney stone formation. ^[6]

Interactions

Several interactions between cranberry juice and warfarin have been documented. These reports have prompted some physicians to warn that drinking cranberry juice or consuming products containing cranberries while taking warfarin may increase the risk of severe bleeding ^{[7] [8]}

Complications

An untreated urinary tract infection can cause significant illness. If symptoms of a urinary tract infection are present (burning or pain with urination, passing small amounts of urinary frequently, a persistent urge to urinate, blood in the urine or flank pain), a health care provider should be contacted, as antibiotics may be needed.

Research

Recent News

Some studies testing cranberry products for their ability to prevent urinary tract infections have shown promise. These studies have generally been small in size, and some were not well-designed. As research has progressed, however, the data suggest that cranberry products may prevent urinary tract infections in some individuals. ^[6] One review of 10 studies of patients with urinary tract infections found that cranberry products reduced the risk of developing an infection by 35% after 12 months of use. ^[9] These products were more effective in women susceptible to infections compared with elderly men and women. More research is needed to evaluate long-term benefit and side effects.

Cranberry products have not been adequately tested to see if they can be used to treat an existing urinary tract infection.

Current research

The National Center for Complementary and Alternative Medicine (NCCAM), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), and the National Institute for Dental and Craniofacial Research are funding studies to understand whether and how cranberry might work to prevent urinary tract infection and the formation of dental plaque. With respect to the latter, cranberry-containing mouthwash has been shown to reduce the amount of bacteria in the mouth, but not to reduce the amount of dental plaque.

Clinical Trials

There are a number of ongoing studies involving the use of cranberries to prevent urinary tract infections, treat premature rupture of membranes in pregnancy and the effect of cranberry juice on risk factors for cardiovascular disease. For more information, see ClinicalTrials.gov: Open Studies: cranberry

Interesting Fact

Cranberries were named because of the shape of the plant. Pilgrims thought that the stem and flower resembled the head, neck, and beak of a crane.

References

1. ↑ DiMartino P, Angniel R, David K, Templer C, Gaillard JL, Deniys P, et al. Reduction of Escherichia coli adherence to uroepithelial bladder cells after consumption of cranberry juice: a double-blind randomized placebo-controlled cross-over trial. World J Urol. 2006 Feb;24(1):21-7. Epub 2006 Jan 6. Abstract
2. ↑ Howell AB. Bioactive compounds in cranberries and their role in prevention of urinary tract infections. Mol Nutr Food Res. 2007 Jun;51(6):732-7. Abstract
3. ↑ Zhang L, Ma J, Pan K, Go VL, Chen J, You WC. Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial. Helicobacter. 2005 Apr;10(2):139-45. Abstract
4. ↑ McKay DL, Blumberg JB. Cranberries (Vaccinium macrocarpon) and cardiovascular disease risk factors. Nutr Rev. 2007 Nov;65(11):490-502. Abstract
5. ↑ Crews WD Jr, Harrison DW, Griffin ML, Addison K, Yount AM, Giovenco MA. A double-blinded, placebo-controlled, randomized trial of the neuropsychologic efficacy of cranberry juice in a sample of cognitively intact older adults: pilot study findings. J Altern Complement Med. 2005 Apr;11(2):305-9. Abstract
6. ↑ ^{6.0 6.1} Lynch DM. Cranberry for prevention of urinary tract infections. Am Fam Physician. 2004 Dec 1;70(11):2175-7. Abstract | Full Text
7. ↑ Suvarna R, Pirmohamed M, Henderson L. Possible interaction between warfarin and cranberry juice. BMJ. 2003 Dec 20;327(7429):1454. Abstract | Full Text
8. ↑ Aston JL, Lodolce AE, Shapiro NL. Interaction between warfarin and cranberry juice. Pharmacotherapy. 2006 Sep;26(9):1314-9. Abstract
9. ↑ Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD001321. Abstract

External Links

Cranberry Institute

Complementary and Alternative Medicine: Cranberry for the prevention of urinary tract infection