Cranberry: benefits, dosage, contraindications
Other name(s)
Cranberry
Scientific name(s)
Vaccinium macrocarpon Aiton
Family or group:
Plants
Active ingredients:
Resveratrol
Tannins
Organic acids
Polysaccharides
D-mannose
Oligo-Proanthocyanidins
Indications
Scoring methodology
EFSA approval.
Urinary tract infections ✪✪✪✪✪
Urinary tract infections (cystitis) are most often caused by an intestinal bacterium, Escherichia coli. This bacterium has the particular ability to remain attached to the bladder mucosa via fimbriae anchored by adhesins, which explains the recurrences. Cranberry contains specific molecules that block the adhesion of E. coli fimbriae and, after a few months, can lead to eradication of the organism and resolution of the condition. Cranberry juice inhibits adherence to urothelial cells by more than 75% for over 60% of the Escherichia coli strains tested. Indeed, several randomized, placebo-controlled clinical trials report that a concentrated cranberry juice rich in proanthocyanidins leads to a reduced frequency of urinary tract infections in women at high risk of recurrent UTIs, and in otherwise healthy children. In 2019, the American Urological Association published guidelines stating that, based on limited evidence, clinicians may offer cranberry tablets or juice as a preventive option for women suffering from recurrent urinary tract infections. In 2020, the U.S. Food and Drug Administration (FDA) approved qualified health claims indicating that consumption of cranberry juice at doses of at least 500 mg per day may help reduce the risk of recurrent urinary tract infections in healthy women. For prevention of recurrent E. coli cystitis: Drink 250 ml to 500 ml per day of a cranberry cocktail (equivalent to 80 ml to 160 ml of pure juice), or take one to six capsules of 300 mg to 500 mg concentrated cranberry extract twice a day. Most studies show that products that prevent recurrent urinary tract infections are standardized to provide 100 to 200 mg of proanthocyanidins per day.
Posologie
Oral: fruit
500 - 800 mg
Children, Women
Concentrated juice, dry extract
Cranberries and lower urinary tract infection prevention
Reduction of bacteriuria and pyuria after ingestion of cranberry juice
Reduction of Escherichia coli adherence to uroepithelial bladder cells after consumption of cranberry juice: a double-blind randomized placebo-controlled crossover trial
Enteric-coated, highly standardized cranberry extract reduces risk of UTIs and urinary symptoms during radiotherapy for prostate carcinoma
A randomized trial to evaluate effectiveness and cost-effectiveness of naturopathic cranberry products as prophylaxis against urinary tract infection in women
Cranberries for preventing urinary tract infections
Cranberry Reduces the Risk of Urinary Tract Infection Recurrence in Otherwise Healthy Women: A Systematic Review and Meta-Analysis
Cranberry juice for the prevention of recurrent urinary tract infections: a randomized controlled trial in children
Consumption of cranberry as adjuvant therapy for urinary tract infections in susceptible populations: A systematic review and meta-analysis with trial sequential analysis
Effectiveness of cranberry capsules to prevent urinary tract infections in vulnerable older persons: a double-blind randomized placebo-controlled trial in long-term care facilities
Can Cranberries Contribute to Reduce the Incidence of Urinary Tract Infections? A Systematic Review with Meta-Analysis and Trial Sequential Analysis of Clinical Trials
Randomized trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women
Cranberry juice for the prevention of recurrences of urinary tract infections in children: a randomized placebo-controlled trial
Inhibition of bacterial adherence by cranberry juice: potential use for the treatment of urinary tract infections
Cranberry juice for the prevention of pediatric urinary tract infection: a randomized controlled trial
A randomized trial of cranberry versus apple juice in the management of urinary symptoms during external beam radiation therapy for prostate cancer
Evaluation of a cranberry supplement for reduction of urinary tract infections in individuals with neurogenic bladders secondary to spinal cord injury. A prospective, double-blind, placebo-controlled, crossover study
Cranberry-containing products for prevention of urinary tract infections in susceptible populations: a systematic review and meta-analysis of randomized controlled trials
Oral and dental infections ✪✪✪✪✪
Weiss et al. report that one of the components of cranberry juice, NDM, is capable of preventing the aggregation of certain bacteria responsible for dental plaque and periodontal disease.nnOther clinical studies support that the many polyphenols present in cranberry juice also have a preventive and curative effect against dental plaque as well as the formation and acidification of biofilms formed by the strain Streptococcus mutans.nnA 2004 clinical study demonstrated that after daily treatment for 6 weeks with a mouthwash containing cranberry constituents, a significant decrease in the number of bacteria in saliva was observed. The NDMs extracted from cranberry therefore act as anti-biofilm agents without altering the oral flora.nnIt has been shown in vitro that cranberry prevents biofilm formation and reduces the adherence of Candida albicans and could therefore have a role in the prevention or treatment of oral candidiasis.nn
Posologie
Oral route: fruit
Children, Adults
concentrated juice, mouthwash
Polyphenol-Rich Cranberry Extracts Modulate Virulence of Streptococcus mutans-Candida albicans Biofilms Implicated in the Pathogenesis of Early Childhood Caries
A high molecular mass cranberry constituent reduces mutans streptococci level in saliva and inhibits in vitro adhesion to hydroxyapatite
Effect of a high-molecular-weight component of cranberry on constituents of dental biofilm.
Inhibitory effect of cranberry polyphenol on cariogenic bacteria
Inhibiting interspecies coaggregation of plaque bacteria with a cranberry juice constituent
Antimicrobial traits of tea- and cranberry-derived polyphenols against Streptococcus mutans
Antimicrobial Effect of Natural Berry Juices on Common Oral Pathogenic Bacteria
Inhibitory effects of cranberry juice on attachment of oral streptococci and biofilm formation.
Helicobacter pylori infection ✪✪✪✪✪
Cranberry fruits are used in the prevention of gastric ulcers caused by Helicobacter pylori. Indeed, cranberry inhibits the adhesion of H. pylori to human gastrointestinal cells in vitro. Interestingly, a randomized, double-blind, placebo-controlled clinical study, published in 2007, reported the effectiveness of a triple therapy: cranberry juice, antibiotics (amoxicillin and clarithromycin), and a proton pump inhibitor (omeprazole) in improving the eradication rate of a Helicobacter pylori infection in affected female patients. A multicenter randomized double-blind trial including 295 children found that regular consumption of cranberries or a probiotic inhibited H. pylori.
Posologie
Oral: fruit
500 mL
90 days
Children, Adults
concentrated juice
Effect of cranberry juice on eradication of Helicobacter pylori in patients treated with antibiotics and a proton pump inhibitor
Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial.
Gingivitis ✪✪✪✪✪
Gingivitis represents the initial (early) stage of a periodontal condition. This disease is characterized in particular by inflammation of the gums, caused by bacterial plaque and often associated with irritation and bleeding. According to several studies, cranberry may prove effective as an adjunctive treatment to manage or prevent this infectious disease, notably thanks to its antioxidants (in particular proanthocyanidins). Interestingly, treatment with a low-concentration fraction containing NDM, high-molecular-weight molecules, prepared from concentrated cranberry juice, is able to dose-dependently inhibit the pro-inflammatory activity of the main virulence factors of periodontal pathogens such as Actinobacillus actinomycetemcomitans. In a randomized, controlled clinical study from 2018 including 50 patients suffering from gingivitis, a beneficial effect of the cranberry beverage (750 mL/day) consumed for 8 weeks was reported. Indeed, gingival and plaque indices are significantly improved in treated subjects compared with the control group, without increased risk of caries development.
Posologie
Oral: fruit
750 mL
Children, Adults
concentrated juice, mouthwash, juice
Green tea polyphenol epigallocatechin-3-gallate and cranberry proanthocyanidins act in synergy with cathelicidin (LL-37) to reduce the LPS-induced inflammatory response in a three-dimensional co-culture model of gingival epithelial cells and fibroblasts
Cranberry components inhibit interleukin-6, interleukin-8, and prostaglandin E production by lipopolysaccharide-activated gingival fibroblasts
Consumption of cranberry functional beverage reduces gingival index and plaque index in patients with gingivitis
Inhibition of interleukin 1β-stimulated interleukin-6 production by cranberry components in human gingival epithelial cells: effects on nuclear factor κB and activator protein 1 activation pathways
Anti-inflammatory and macrophage polarization effects of Cranberry Proanthocyanidins (PACs) for periodontal and peri-implant disease therapy
Kidney stone ✪✪✪✪✪
Cranberry juice may increase the risk of calcium oxalate stones while decreasing the risk of calcium phosphate stones.
Posologie
Oral route: fruit
500 mL
Children, Adults
concentrated juice, juice
Prostate health ✪✪✪✪✪
Forty-two participants received either 1500 mg of dried cranberry powder per day for 6 months (cranberry group; n = 21), or no cranberry treatment (control group; n = 21). The cranberry group had a lower total prostate-specific antigen level than the control group and showed a statistically significant improvement in their International Prostate Symptom Score on day 180 of the study.nnA double-blind, randomized, placebo-controlled study demonstrated the efficacy and safety of daily FlowensTM at 250 or 500 mg in men with lower urinary tract infections for 6 months. After 6 months, the decrease in the International Prostate Symptom Score was significant and dose-dependent.nn
Posologie
Oral: fruit
250 - 1500 mg
powder
The effectiveness of dried cranberries ( Vaccinium macrocarpon) in men with lower urinary tract symptoms
A randomized trial of cranberry versus apple juice in the management of urinary symptoms during external beam radiation therapy for prostate cancer
Properties
Antibacterial
It was first believed that the antibacterial effect of cranberry was due to its acidifying the urine, but it was later discovered that this effect was minimal. Its effect is instead attributable to the fact that cranberry contains components that prevent bacteria from adhering to the walls of the urinary tract, and consequently from growing there. Following two clinical studies, ANSES considers that cranberry leads to a decrease in the frequency of urinary tract infections caused by certain uropathogenic E. coli presenting P-fimbriae (P-type pili) in adult women. In vivo and in vitro, cranberry reduces the adhesion of the bacterium Helicobacter pylori (responsible for ulcers) to the gastric mucosa, hence its use in the prevention of gastric ulcers. This property is due to certain cranberry components, the NDM (Non-Dialyzable Material), high molecular weight molecules. NDM has the ability to prevent the aggregation of certain bacteria responsible for dental plaque and periodontal disease. Further studies followed, showing that cranberry NDMs inhibit the adhesion of a large number of bacterial species. One study confirmed that cranberry polyphenols inhibited the adhesion of H. pylori to human gastric mucus. These in vitro studies are supported by the 2004 clinical study showing that after a daily 6-week treatment with a mouthwash containing cranberry constituents, there was a significant decrease in the number of bacteria in saliva. NDMs extracted from cranberry therefore act as anti-biofilm agents without altering the oral flora. Research on human bronchial cells revealed a 90% inhibition of adhesion for Streptococcus pneumoniae (a frequent cause of pneumonia, meningitis, and otitis media) with cranberry juice. Two studies examined the effect of cranberry extracts on biofilm production, which can cause infections when catheters are used and corneal infections caused by contact lens use. Both studies found a reduction in biofilm growth with Gram-positive bacteria, particularly Staphylococcus spp. Cranberry juice inhibits adhesion to uroepithelial cells by more than 75% for over 60% of the Escherichia coli strains tested.
Usages associés
Diuretic
Cranberry contains proanthocyanidins, also known as condensed tannins, and a high-molecular-weight compound that has not yet been identified. These constituents appear to interfere with the adherence of bacteria to the epithelial cells of the urinary tract. For example, proanthocyanidins appear to be able to prevent Escherichia coli (E. coli), which is the cause of most urinary tract infections, from adhering to the wall of the urinary tract. Cranberry, however, does not seem to have the ability to release bacteria that are already attached to the epithelial cells of the urinary tract. nnCranberry (a 330 ml dose) would also increase the excretion of oxalic acid and uric acid according to an open study.nn
Usages associés
Antioxidant
Ruel and colleagues showed a significant decrease in oxidized LDL (responsible for the development of atherosclerosis) in men who took cranberry juice supplementation for 14 days.nnThe effect of cranberry consumption on plasma antioxidant capacity was evaluated in 9 healthy female volunteers. After an overnight fast, on different occasions they consumed 500 mL of cranberry juice and 500 mL of blueberry juice. The results showed that consumption of cranberry juice significantly increased plasma antioxidant capacity, due to an increase in vitamin C concentration.nn
Anti-inflammatory
Cranberry contains significant amounts of salicylic acid. Salicylic acid, the active metabolite of aspirin, has anti-inflammatory, antiplatelet, and antitumor effects. Cranberry juice contains about 7 mg of salicylic acid per liter. Drinking three 250 mL servings of cranberry juice per day for two weeks increases serum salicylate levels. Moreover, cranberry has shown some anti-inflammatory activities, notably inhibition of cyclooxygenases. nnConsumers who drank an average of 404 mL (14 fl oz) of V. macrocarpon juice for 2 days had significantly lower levels of C-reactive protein and total serum cholesterol.nn
Usages associés
Gastroprotective
The phenolic substances in cranberry may have antibacterial activity against Helicobacter pylori. Cranberry can prevent the adhesion of Helicobacter pylori (H. pylori) in the stomach and reduce the risk of associated gastrointestinal issues.nn
Usages associés
Uricosuric effect
Ingestion of 1 L of cranberry juice for 7 days was shown to decrease urinary pH from 5.97 to 5.67; a significant increase in urinary calcium and oxalate and a slight increase in urinary magnesium and ammonium ion concentrations. Cranberry juice would therefore increase the risk of calcium oxalate stone formation while it would decrease the risk of calcium phosphate stone formation.nn
Usages associés
Antiviral
In vitro, cranberry has antiviral properties against viruses of different species: primate rotavirus SA-11 and bacteriophages T2 and T4. Weiss et al. showed that NDMs extracted from cranberry inhibit the adhesion of the influenza virus to host cells, thereby preventing infection.nnA-type proanthocyanidin dimers and trimers from cranberry extracts are capable of inhibiting, in vitro, influenza virus replication.nn
Antifungal
An in vitro study of cranberry proanthocyanidin fractions on human fungi, such as Candida spp. and Cryptococcus neoformans, revealed antifungal activity.nn
Usages associés
Anticancer
There is preliminary evidence that the cranberry proanthocyanidin fraction may have anticarcinogenic activity. Cranberries may induce apoptosis in tumor cells. Proanthocyanidin oligomers, flavonols, and anthocyanin glycosides and triterpenoids are all likely contributors to the observed anticancer properties and may act additively to block carcinogenesis.nn
Safe dosage
Adults 18 years and older: 300 mL - 750 mL (juice)
Drink 300 mL to 750 mL per day of cranberry cocktail (which is equivalent to 80 mL to 160 mL of pure juice).nnMost studies show that products that prevent recurrent urinary tract infections are standardized to provide 72 mg to 200 mg of proanthocyanidins per day.nn
Adults 18 years and older: 200 mg - 800 mg (standardized extract)
Take between 200 mg and 800 mg of standardized cranberry extract. nnMost studies show that products that prevent recurrent urinary tract infections are standardized to provide 72 mg to 200 mg of proanthocyanidins per day.nn
Children up to 18 years: 300 mL (juice)
5 ml/kg per day were used for 6 months.
Interactions
Médicaments
Cytochrome P450 3A4: moderate interaction
Theoretically, cranberry juice may inhibit CYP3A4 enzymes and increase the risk of side effects from drugs metabolized by these enzymes. Drugs metabolized by CYP3A4 include lovastatin, ketoconazole, itraconazole, fexofenadine, and others.
Warfarin: moderate interaction
Patients taking warfarin with cranberry juice should monitor for symptoms of bleeding.
Proton pump inhibitor: low interaction
Cranberry juice increases vitamin B12 absorption when taken concurrently with proton pump inhibitor medications.
Precautions
Kidney stones: avoid
Urine acidification caused by cranberry could promote the formation of kidney stones. People with a history of oxalate-based kidney stones should therefore limit their consumption of cranberry juice.
Pregnant women: use with caution
Women more frequently experience urinary tract infections during pregnancy. A systematic review of the literature on the evidence of use, safety, and pharmacology of cranberry, focusing on issues related to pregnancy and breastfeeding, found that there is no direct evidence of harm or contraindication to the mother or the fetus following cranberry consumption during pregnancy. A survey of 400 pregnant women did not find any adverse effects when cranberry was consumed regularly.
Breastfeeding: use with caution
Likely safe when consumed in recommended amounts.
