Nutrition 411: The Use of Cranberry Products for Urinary Tract Infection Prevention

  Urinary tract infections (UTIs) are the most prevalent infection in long-term care (LTC), accounting for at least 40% of all infections and more than 8% of total nursing home costs.^1,2 UTIs are the most prevalent source of bacteremia, the most common cause for hospital transfers, and the most common condition for which antibiotics are prescribed. Although patients usually respond to antimicrobial treatment, the recurrence rate is high and associated with side effects. It is estimated that more than 50% of elderly patients in LTC will have a recurrence, usually within 6 months, despite antibiotic therapy.^3,4 The frustration of repeated cycles of antibiotic agents with diminished effects due to microbial resistance has a significant impact on the patient’s quality of life (QoL).

Antibiotic Usage

  UTIs alone account for 30% to 56% of all prescriptions for antibiotics in LTC facilities.^5,6 Escherichia coli is the most common cause of UTIs in older adults. E. coli strain resistance is now approximately 40% to 50% to ampicillin, approximately 20% to trimethoprim-sulfamethoxazole, and in just the last few years resistance has gone from 1% to 5% to more than 20% to fluoroquinolone.⁷ This reduces treatment options for UTIs and can add significant costs when newer, more expensive antibiotics are needed. Additionally, every antibiotic regimen fosters resistant subpopulations of bacteria that can later re-infect that same patient or their caregivers or be passed around to other patients, particularly in the LTC environment. Side effects of antibiotics also must be considered and include allergic reactions, nausea, interactions with foods or other drugs, and depletion of beneficial bacteria in the colon that can lead to diarrhea, stomach or intestinal upset, changes in mental status, yeast infections, and Clostridium difficile (C. diff).

Development of UTIs

  Urine is normally sterile, so in order for a UTI to occur, E. coli from a fecal or vaginal source must migrate upward, enter the urethra, attach, and begin to multiply. As the bacteria multiply, they ascend up the urethra into the bladder. E. coli have finger-like projections (fimbriae) on their cell surface that allow them to attach to receptors on epithelial cell walls using a Velcro-like effect that can resist the cleansing action of urine flow. Because E. coli are living, they continue to move after adherence, irritating and destroying the urethral or bladder wall and causing inflammation. The inflammation causes a painful burning sensation. In some cases, these pathogens will rupture underlying blood vessels, resulting in visible blood in the urine. Inhibiting E. coli from attaching to the urinary tract wall is one of the most important ways to prevent UTIs.

  Older adults are at increased risk for UTIs due to age-related changes. Decreased estrogen as part of menopause leads to thinning and weakening of the mucosa, reducing its ability to resist bacteria. A decrease in estrogen also leads to pH changes in the vagina, favoring E. coli colonization. An aging immune system decreases antibody response to pathogens. Changes in microbiota (microflora) include an increase in harmful bacteria and a decrease in beneficial bacteria. Plus, as we age, the ability to concentrate urine decreases. To help counteract these changes, daily consumption of cranberry products is recommended.

Cranberries

  Proanthocyanidins (PACs) — flavonoids found in cranberries — can prevent E. coli from attaching to the urinary tract wall. PACs from cranberries target E. coli cells in three ways: 1) they alter E.coli cell membranes, 2) they compress fimbriae, greatly reducing E.coli’s ability to remain in place long enough to launch an infection, and 3) they change E. coli shape from rods to spheres, affecting its activity. All of these effects inhibit the bacteria’s ability to attach to cells lining the bladder wall, prevent the bacteria from making contact with cells, and disrupt bacterial communication. The E. coli can be flushed out in the urine instead of causing an infection.

  Provision options. Cranberry tablets/capsules have the ability deliver concentrated doses of PACs but the amounts vary considerably from brand to brand. For example, the source of the cranberry powder in the tablets can be derived from freeze-dried cranberry juice, cranberry juice concentrate, whole cranberry, cranberry concentrate, and cranberry extract, all with varying amounts of PACs and recommended doses ranging from two to six pills per day. Cranberry tablets/capsules typically contain 300 to 500 mg of cranberry (concentrate, extract, juice) per tablet (~6 to 10 mg PACs). Many older adults have difficulty tolerating several tablets per day and nursing administration can be cumbersome, particularly if a patient is tube fed.

  Another example of a concentrated product is UTI-Stat® with proantinox® (Medical Nutrition USA Inc, Englewood, NJ), a novel urinary tract cleansing complex clinically proven to help prevent recurrent UTIs (rUTI). This ready-to-drink liquid contains a proprietary blend of cranberry concentrate, vitamin C, D-mannose, fructooligosaccharides (FOS), and bromelain. The ingredients work by counteracting the effects of E. coli: cranberry concentrate inhibits the ability E. coli to adhere to the urinary tract wall; bromelain, a proteolytic enzyme from the stem and juice of pineapples, has an anti-inflammatory effect that can be beneficial in reducing symptoms caused by E. coli; vitamin C helps maintain adequate urine acidity, creating a less tolerable environment for E. coli; D-mannose reduces adhesion of E.coli to the urinary tract wall; and FOS stimulate the growth of beneficial bacteria in the colon, reducing the number of E. coli. Each serving (1 oz, 30 mL) of this product provides as much cranberry PACs as 16 8-oz glasses of cranberry juice cocktail but without the sugar and with only 2 calories per serving compared to 150 calories per glass of cranberry juice. This makes the product appropriate for patients with diabetes as well as patients on fluid restriction, with renal insufficiency, or older adults who have trouble consuming large fluid volumes. The higher the concentration of PACs, the greater their impact on E. coli, suggesting that concentrated products that have not been highly diluted have the greatest effects.

  Cranberries in the literature. Several recent studies have shown cranberry juice consumption can reduce bacteriuria and prevent symptomatic recurrences of UTIs.^8-14 The anti-adhesion activity of PACs is evident in the urine within 2 hours and persists for up to 10 hours following ingestion of cranberry juice.¹⁵ This suggests that in order to get protection from cranberry products, they must be consumed prophylactically on a daily basis. However, some studies with high dropout rates have indicated that the prolonged consumption of cranberry juice is not feasible for many because of its cost, highly acidic taste, volume required to consume, and caloric load.^9,10,14,16 In this respect, concentrated cranberry products high in PACs may be a better alternative to cranberry juice in terms of patient compliance and tolerability.¹⁷

  A recent clinical study determined the safety, tolerability, QoL, and efficacy of UTI-Stat® in female patients with a history of rUTIs.¹⁸ Subjects had an average of 2.78 ± 0.73 UTIs at baseline. The product was administered daily for 12 weeks. Blood, urinary dipstick testing, and urinalysis were completed at baseline and at weeks 4 and 12. Safety variables — ie, adverse events and clinical laboratory test results (hematology and urinalysis) — were assessed. Safety was monitored continuously during the 12-week study period and the study participants were interviewed and examined by a study physician at the beginning and end of the study. Adverse events were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.019 according to the severity (mild, moderate, severe, or life-threatening) and the relationship to the study medication (unlikely related, possibly related, or probably related). QoL was measured using the American Urologic Association20 (AUA) Symptom Index and the Medical Outcomes Study Short-Form, 36-item Questionnaire21 (SF-36). Most (91%) subjects remained UTI-free over 3 months taking doses up to 60 mL/day; 9% reported a rUTI, results markedly better than historical data (36%). QoL and AUA were significantly improved (P = 0.0097 and P = 0.045, respectively). The product showed a good safety profile, tolerability, and demonstrated effectiveness in reducing rUTIs and increasing QoL in both pre- and post-menopausal females with history of rUTI.

Practice Points

  Table 1 lists tips for educating patients on UTI prevention. Considering the emerging resistance to antibiotics used to treat UTIs, the development of new treatment and prevention strategies has become critical. Administering concentrated cranberry products to patients and residents in LTC along with encouraging proper hygienic measures and hydration may help decrease the occurrence and recurrence of UTIs. Furthermore, due to the prevalence of UTIs, nonantibiotic treatment options can play an important role in alleviating the public health issue of antibiotic resistance.

Coming next month: the bariatric patient

Jennifer Sallit, PhD, RD, serves as Scientific Director for Medical Nutrition USA, a division of Nutricia, where she conducts research in gerontological nutrition, manages the science programs, and aids in the development of medical nutrition products. Her current research focus is on improving the nutritional status of older adults through specialized medical foods. Nancy Collins, PhD, RD, LD/N, FAPWCA, is founder and executive director of RD411.com and Wounds411.com. For the past 20 years, she has served as a consultant to healthcare institutions and as a medico-legal expert to law firms involved in healthcare litigation. Correspondence may be sent to Dr. Collins at NCtheRD@aol.com. This article was not subject to the Ostomy Wound Management peer-review process.

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