Can cranberry juice help UTI?

Published 2021/09/23

What is the nutritional
composition of cranberry?

Can Cranberry Juice Help UTI? Let’s take a look at the nutritional composition of cranberry. Fresh cranberries contain nearly 86~87% water, 4~5% fructose, 2% insoluble fiber, 1.4% soluble fiber, 2.4% organic acid, water-soluble vitamins B and C and are very rich in antioxidants like phytochemicals compared to other berry fruits.

What are Phytochemicals?

Phytochemicals are secondary metabolites produced by plants in order to survive or increase their adaptive capacity. To be more specific, these secondary metabolites can help plants avoid biological (some metabolites have an odor to repel insects) or non-biological hazards (strong sunlight exposure- and assist in the production of UV-absorbing substances).

There are many types of phytochemicals, and their health effects are different, but the general benefit is to have anti-oxidation and anti-inflammatory effects. Phytochemicals can be divided into six categories according to the structure:


  1. flavonoids
  2. phenolic acids
  3. plant-based females.
  4. Hormone (phytoestrogens)
  5. Organosulfur compound (carotenoid)
  6. Others

Research shows among these phytochemicals, TypeA Proanthocyanidins (PACs) is considered to be the most effective ingredient for improving urinary tract infection (UTI), and cranberry is rich in such phytochemicals.

What are the functions
and benefits of cranberry?

In addition to the benefits mentioned above, phytochemicals have an antibacterial effect. Although they will not directly kill bacteria, they can affect the performance of the fimbriae of bacteria. The fimbriae are like hooks. Generally speaking, bacteria use fimbriae to bind to the cells of various tissues. After binding to the cells, the bacteria begin to multiply and proliferate around them, then attack the cells




Preventing UTI

Urinary tract infection is one of the most common bacterial infections aside from respiratory tract infections. UTI is more common in women. Statistics show that UTI may happen to ¼ of all women.


So what causes UTIs? Usually, it is Escherichia coli (E-coli), a strain of bacteria, that causes UTIs.

that causes UTIs.



Among the two types of Proanthocyanidins (PACs), only type A can effectively prevent urinary tract infection because type-A proanthocyanidins can prevent E. coli fimbria from binding to the bladder epithelial cell receptors and reduce the attachment of E. coli. The way it reduces the binding is particularly obvious in women with repeated urinary tract infections.



However, preventing is not equal to curing or stopping UTI.


In Beerepoot et al.’s study, the antibiotics group has a higher drop-down rate in UTI compared to cranberries group for premenopausal women. However, the antibiotic resistance rises for antibiotics group as well. Therefore, for people who suffered from recurrent UTI and showing resistance for antibiotics, cranberries pill or supplement may be another option.



Dr. Pamela J. Levin, Assistant Professor of Clinical Obstetrics and Gynecology explains that “though studies have demonstrated potential ability to decrease symptomatic UTIs, there isn’t sufficient data to determine the duration of therapy or the dose of cranberry necessary to achieve the effect.”

The best and most common practice is to visit a doctor and take antibiotics for curing UTI.

Possible side effects of
eating cranberries and who should
avoid eating cranberries?

Moderate intake of cranberry and its supplement is safe for most people. However, excessive consumption may cause stomach upset and diarrhea. In this case, cranberry supplements are great alternatives for people who need the nutrition from cranberries but don’t want to irritate their digestion system.

In addition, people with kidney diseases like kidney stones should be cautious of their cranberry intake. Most patients with kidney stones are caused by calcium oxalate and excessive oxalate in urine is one of the main etiological agents. Unfortunately, berries are relatively high in oxalate. Taking a lot of berries may increase the risk of having kidney stones. Therefore, people with a family history of urinary tract stones should avoid excessive intake of cranberry. 


(Current research data on the effects of kidney stones from cranberry is not consistent. We choose to err on the side of caution by making the above recommendation.)


Finally, people who take anticoagulant drugs like Warfarin should avoid eating cranberries and the drug at the same time because some components in the cranberry will interfere with the effect and efficacy of the drug.

In addition, people who have been allergic to Aspirin should also avoid eating cranberries, because cranberries contain salicylic acid, which has a similar chemical structure to that of Aspirin.

How much cranberry juice should I take?

According to research, the recommended minimum A-type proanthocyanidin should be no less than 36 mg per day . For people with diabetes, it is best to choose the fresh cranberry juices without added sugar because sugars will affect the blood sugar level. If you don’t like the sourness of cranberry juice, add some diabetic-friendly sweetener if needed.


Khomych, G., Matsuk, Y., Nakonechnaya, J., Oliynyk, N., & Medved, L. (2017). Study of the сhemical composition of cranberry and the use of berries in food technology. Eastern-European Journal of Enterprise Technologies6(11 (90), 59–65. https://doi.org/10.15587/1729-4061.2017.117315

Foo LY, Lu Y, Howell AB, Vorsa N. A-Type proanthocyanidin trimers from cranberry that inhibit adherence of uropathogenic P-fimbriated Escherichia coli. J Nat Prod. 2000 Sep;63(9):1225-8. doi: 10.1021/np000128u. PMID: 11000024.

Howell AB, Reed JD, Krueger CG, Winterbottom R, Cunningham DG, Leahy M. A-type cranberry proanthocyanidins and uropathogenic bacterial anti-adhesion activity. Phytochemistry. 2005 Sep;66(18):2281-91. doi: 10.1016/j.phytochem.2005.05.022. PMID: 16055161.

Howell AB, Botto H, Combescure C, Blanc-Potard AB, Gausa L, Matsumoto T, Tenke P, Sotto A, Lavigne JP. Dosage effect on uropathogenic Escherichia coli anti-adhesion activity in urine following consumption of cranberry powder standardized for proanthocyanidin content: a multicentric randomized double blind study. BMC Infect Dis. 2010 Apr 14;10:94. doi: 10.1186/1471-2334-10-94. PMID: 20398248; PMCID: PMC2873556.

Fu Z, Liska D, Talan D, Chung M. Cranberry Reduces the Risk of Urinary Tract Infection Recurrence in Otherwise Healthy Women: A Systematic Review and Meta-Analysis. J Nutr. 2017 Dec;147(12):2282-2288. doi: 10.3945/jn.117.254961. Epub 2017 Oct 18. PMID: 29046404.

McHarg T, Rodgers A, Charlton K. Influence of cranberry juice on the urinary risk factors for calcium oxalate kidney stone formation. BJU Int. 2003 Nov;92(7):765-8. doi: 10.1046/j.1464-410x.2003.04472.x. PMID: 14616463.

Hamann GL, Campbell JD, George CM. Warfarin-cranberry juice interaction. Ann Pharmacother. 2011 Mar;45(3):e17. doi: 10.1345/aph.1P451. Epub 2011 Mar 1. PMID: 21364039. 
Vinson JA, Su X, Zubik L, Bose P. Phenol antioxidant quantity and quality in foods: fruits. J Agric Food Chem. 2001 Nov;49(11):5315-21. doi: 10.1021/jf0009293. PMID: 11714322.

Beerepoot MA, ter Riet G, Nys S, van der Wal WM, de Borgie CA, de Reijke TM, Prins JM, Koeijers J, Verbon A, Stobberingh E, Geerlings SE. Cranberries vs antibiotics to prevent urinary tract infections: a randomized double-blind noninferiority trial in premenopausal women. Arch Intern Med. 2011 Jul 25;171(14):1270-8. doi: 10.1001/archinternmed.2011.306. PMID: 21788542.

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