Cranberry: Benefits, Dosage, Contraindications

Urinary tract infections
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Urinary infections (cystitis) are most often linked to an intestinal bacterium, Escherichia coli. This bacterium has the peculiarity of remaining attached to the bladder mucosa via fimbriae fixed by adhesins, which explains the recurrences. Cranberry contains specific molecules that are anti-adhesive to the fimbriae of Escherichia coli and allows for the eradication of the germ and the cure of the pathology after a few months. Cranberry juice inhibits E. coli adherence to uro-epithelial cells by more than 75% in over 60% of the Escherichia coli bacteria tested. Indeed, several placebo-controlled randomized clinical studies report that a concentrated cranberry juice, rich in proanthocyanidins, results in a reduced frequency of urinary infections in women at high risk of recurrent urinary infections, as well as in children, who are otherwise in good health. In 2019, the American Urological Association published guidelines indicating that, based on low-quality evidence, clinicians may recommend cranberry tablets or juice as a preventive measure for women suffering from recurrent urinary infections. In 2020, the US Food and Drug Administration (FDA) approved qualified health claims that consuming cranberry juice in doses of at least 500 mg per day may help reduce the risk of recurrent urinary infections in healthy women. For preventing recurrent E. coli cystitis: Drink 250 ml to 500 ml per day of cranberry cocktail (equivalent to 80 ml to 160 ml of pure juice), or take one to six capsules of 300 mg to 500 mg of concentrated cranberry extract twice a day. Most studies show that products preventing recurrent urinary infections are standardized to provide 100 to 200 mg of proanthocyanidins per day.

Posologie

Oral route: fruit

500 - 800 mg

Children, Women

concentrated juice, dry extract

Oral Infections
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Weiss et al. report that a component of cranberry juice, NDM, can prevent the congregation of certain bacteria responsible for dental plaque and periodontal diseases. Other clinical studies support that the numerous 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 Streptococcus mutans strain. A 2004 clinical study demonstrated that after a 6-week daily treatment with a mouth rinse containing cranberry constituents, a significant reduction in the number of bacteria in saliva was observed. The NDM extracted from cranberry acts as an anti-biofilm agent without altering the oral flora. It has been demonstrated in vitro that cranberry prevents the formation of biofilms and reduces the adherence of Candida albicans and could thus have a role in the prevention or treatment of oral candidiasis.

Posologie

Oral route: fruit

Children, Adults

concentrated juice, mouth rinse

Helicobacter pylori Infection
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Cranberry fruits are used in the prevention of gastric ulcers due to Helicobacter pylori. Indeed, cranberries inhibit the adhesion of H. pylori to human gastrointestinal cells in vitro. Interestingly, a double-blind, placebo-controlled randomized clinical study published in 2007 reported the effectiveness of a triple therapy: cranberry juice, antibiotics (amoxicillin and clarithromycin), and proton pump inhibitor (omeprazole) to improve the eradication rate of a Helicobacter pylori infection in affected patients. A double-blind, multicenter randomized trial including 295 children revealed that regular consumption of cranberries or a probiotic inhibited H. pylori.

Posologie

Oral route: fruit

500 mL

90 - days

Children, Adults

concentrated juice

Gingivitis
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Gingivitis is the initial (early) stage of periodontal disease. This disease is notably characterized by gum inflammation caused by bacterial plaque, often associated with irritation and bleeding. According to several studies, cranberry could prove effective as an adjuvant treatment to heal or prevent this infectious disease, especially thanks to its antioxidants (particularly proanthocyanidins). Interestingly, treatment with a low concentration fraction containing NDM, high molecular weight molecules prepared from concentrated cranberry juice, is capable of inhibiting dose-dependent pro-inflammatory activity of major virulence factors of periodontal pathogens such as Actinobacillus actinomycetemcomitans. In a 2018 randomized controlled clinical study involving 50 patients suffering from gingivitis, a beneficial effect of cranberry beverage (750 mL/day) consumed over 8 weeks was reported. Indeed, gingival and plaque indices are significantly improved in treated subjects compared to the control group, without the risk of cavity development.

Posologie

Oral route: fruit

750 mL

Children, Adults

concentrated juice, mouth rinse, juice

Kidney Stones
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Cranberry juice may increase the risk of calcium oxalate nephrolithiasis while reducing the risk of calcium phosphate nephrolithiasis.

Posologie

Oral route: fruit

500 mL

Children, Adults

concentrated juice, juice

Prostate Health
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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. A double-blind, randomized, placebo-controlled study demonstrated the efficacy and safety of daily intake of FlowensTM at 250 or 500 mg in men suffering from lower urinary tract infections for 6 months. After 6 months, the decrease in the International Prostate Symptom Score was significant and dose-dependent.

Posologie

Oral: fruit

250 - 1500 mg

powder