Summary

Cranberries are mostly produced in the northern United States and Canada. Cranberries have numerous health benefits and can be found in many forms, most often as juice, canned, or in capsules. Most notably, cranberries can be used to prevent and cure urinary tract infections. They are also believed to be helpful in preventing cancer, healing wounds, and preventing stomach ailments. Cranberries also promote general hearth health. One half cup of cranberries contains 23 calories and more than 10 percent of your daily recommended intake of vitamin C. That said, consuming large quantities of cranberries may cause stomach upset. If you are taking warfarin, H2 blockers, or proton pump inhibitors use caution and ask a doctor before you consume cranberries in any form. Cranberry can be found in capsule, concentrate or juice form.

Description

Medicinal Parts

Fruit

Botanical Description

Cranberries are creeping, evergreen shrubs that spread by rhizomes. Upright shoots form from rhizomes after about 2 years, which produce the flowers and fruit. Uprights may grow 2-4 inches annually, with bases of the stems sagging down as the upright elongates—hence, only the terminal 5 to 8 inches remains in vertical position. Leaves are tiny (1/4′ to ½′ long), evergreen, thick, and oval/oblong in shape with entire margins. Leaves persist for 2 seasons and shed in late summer of the year after development. The plants yield pink flowers, followed by small, red-black edible berries from June to July. The flowers are hermaphrodite.

Habitat

Boreal forests of the world, especially Newfoundland, Nova Scotia, North Carolina, Minnesota, the Great Lakes region, and Scandinavia. In bogs, swamps and along lake shores.

Other Names

American cranberry, Arandano Americano, Arandano trepador, bear berry, black cranberry, bog cranberry, grosse Moosebeere, isokarpalo, Kranbeere, Kronsbeere, large cranberry, low cranberry, marsh apple, mountain cranberry, moosebeere, mossberry, pikkukarpalo, preisselbeere, ronce d'Amerique, trailing swamp cranberry, Tsuru-kokemomo.

Actions & Pharmacology

Compounds

Cranberry juice contains a variety of constituents. The berries contain about 88% water. The juice contains anthocyanin dyes, catechin, triterpenoids, approximately 10% carbohydrates, and small amounts of protein, fiber, and ascorbic acid (2 to 10 mg). Organic acids present are citric, malic, and quinic acids, with small amounts of benzoic and glucuronic acids. The glycoside leptosine and several related compounds have been isolated along with small amounts of alkaloids. Anthocyanin pigments obtained from cranberry pulp are used in commercial coloring applications.

Effects

The mechanism of action of cranberry has instigated a great deal of scientific debate. Initially, it was assumed that acidification of the urine contributed to an antibacterial effect. The currently proposed mechanism of action focuses primarily on cranberry's ability to prevent bacterial binding to host cell surface membranes. In vitro studies have observed potent inhibition of bacterial adherence of Escherichia coli and other gram-negative uropathogens. Cranberry has been found to specifically inhibit hemagglutination of E. coli by expression of types 1 and P adhesin through the component compounds, fructose and proanthocyanidins.

Clinical Trials

Urinary Tract Infections

A prospective, double-blind, placebo-controlled, crossover study was performed to determine the efficacy of cranberry at preventing urinary tract infections (UTIs) in 21 persons with neurogenic bladders secondary to spinal cord injury. Patients were randomly assigned to standardized, 400 mg cranberry tablets or placebo three times a day for 4 weeks. After 4 weeks and an additional 1-week washout period, participants were crossed over to the other groups. There was no statistically significant treatment effect for cranberry supplement, indicating that cranberry tablets were not effective at changing urinary pH or reducing bacterial counts, urinary white blood cell counts, or UTIs in individuals with neurogenic bladders (Linsenmeyer et al, 2004).

Cranberry extract in tablet form was not effective in reducing bacteriuria and pyuria in 48 persons with spinal cord injury. Each patient enrolled in this randomized, double-blind, placebo-controlled study ingested 2 g of concentrated cranberry juice or placebo in capsule form daily for 6 months. There were no differences or trends detected between participants and controls with respect to number of urine specimens with bacterial counts of at least 10(4) colonies per milliliter, types and numbers of different bacterial species, numbers of urinary leukocytes, urinary pH, or episodes of symptomatic urinary tract infection (Waites et al, 2004).

In a randomized, placebo-controlled study, children (mean age 4.3 years) were randomized to receive either cranberry juice (n=171) or a placebo (n=170) for three months to evaluate the effect of cranberry juice on nasopharyngeal and colonic bacterial flora, and to determine how well cranberry juice is accepted by children and whether it affects infectious diseases and related symptoms. Bacterial samples were collected before and after intervention and analyzed for both respiratory bacterial pathogens and enteric fatty acid composition, reflecting changes in the colonic bacterial flora. Cranberry juice was well accepted by the children, but led to no change in either the bacterial flora in the nasopharynx or the bacterial fatty acid composition of stools (Kontiokari et al, 2005).

Infections

A prospective, randomized, double-blind, placebo-controlled trial was conducted with adults suffering from Helicobacter plyori infections. Subjects were randomly divided into two groups, one drinking two 250 ml cranberry juice boxes (n=97) and the other drinking matching placebo beverage (n=92) daily for 90 days. The researchers concluded that daily consumption of cranberry juice is capable of suppressing H. plyori infection in endemically afflicted populations (Zhang et al, 2005).

Cognitive Performance

In a 6-week, randomized double-blind, placebo-controlled, parallel-group trial, 50 volunteers were randomly assigned to receive either 32 ounces/day of a beverage containing 27% cranberry juice per volume or placebo. Aim was to investigate the efficacy of cranberry juice on the neuropsychologic functioning of cognitively intact older adults. No significant interactions were found between the cranberry and placebo groups and their pretreatment, baseline, and end-of-treatment neuropsychologic assessment. A non-significant trend was noted, however, on a subjective, self-report questionnaire; twice as many participants in the cranberry group rated their overall abilities to remember by treatment end as “improved” compared to placebo (Crews et al, 2005).

Indications & Usage

Unproven Uses

Anorexia, blood disorders, cancer treatment, diabetes, diuresis, nephrolithiasis prevention, radiation damage to urinary system, scurvy, stomach ailments, wound care.

Probable Efficacy

Cranberry is widely used to prevent urinary tract infection. There is clinical evidence in support of the use of cranberry juice and cranberry supplements to prevent urinary tract infections. Cranberry has also been investigated for numerous other medicinal uses, including prevention of H. pylori infection and dental plaque.

Contraindications

Aspirin allergy, atrophic gastritis, diabetes (when product is sweetened with sugar), hypochlorhydria, kidney stones.

Precautions & Adverse Reactions

Generally well tolerated. When consumed in large amounts, gastrointestinal upset and diarrhea may occur.

Pregnancy

Scientific evidence for the safe use of cranberry during pregnancy is not available.

Drug Interactions

Major Risk

Warfarin

Concurrent use may result in an increased risk of bleeding. Clinical Management: Patients receiving treatment with warfarin should be advised to avoid excessive use of cranberry products.

Moderate Risk

H2 Blockers

Concurrent use may result in a reduced effectiveness of the H2 blocker. Clinical Management: Advise patients to avoid regular use of cranberry juice while taking an H2 blocker. Occasional use of cranberry juice is not likely to have a clinical effect on H2 blocker. The effect of cranberry extract supplements on gastric acid is not known; caution is advised.

Proton Pump Inhibitors

Concurrent use may result in reduced effectiveness of proton pump inhibitors. Clinical Management: Advise patients to avoid regular use of cranberry juice while taking a proton pump inhibitor. Occasional use of cranberry juice is not likely to have a clinical effect on proton pump inhibitors. The effect of cranberry extract supplements on gastric acid is not known; caution is advised.

Dosage

How Supplied

juice, capsules (spray dried), concentrate

Daily Dose

To prevent urinary tract infections, 30-300g cranberry juice; in children 15mg/kg body weight is recommended. In type 2 diabetes, 200-400mg.

Literature