Cranberries: Are There Health Benefits?

cranberry juice

Do cranberries play roles in Urinary tract infection (UTI) prevention, as a urinary deodorizer for incontinent patients, reducing type 2 diabetes, chronic fatigue syndrome, scurvy, pleurisy, or have other potential benefits?

  • UTI: Some (but not all) studies show significant reduction in the risk of recurrent UTI’s in the elderly, hospitalized patients, and pregnant women. However, we have no reliable evidence shows effectiveness for treating UTI, once it is established. Suggested doses are as follows: Cranberry juice cocktail (26% cranberry juice) 10-16 ounces per day, or cranberry juice 15 mL twice daily by mouth.
  • Urinary odor: Preliminary research shows there may be a reduction in urinary odor in patients receiving oral cranberry.
  • Diabetes: Clinical studies show NO improvement in fasting blood glucose (sugar), HbA1c, fructosamine, triglyceride, HDL cholesterol, or LDL cholesterol levels in patients with type 2 diabetes.

A Counter View: A meta-analysis (collection of studies, combined) showed that compared with placebo, water, or no treatment, cranberry products were not associated with significant reductions in the occurrence of symptomatic UTI overall (RR, 0.86; 95% confidence interval [CI], 0.71 – 1.04). Cranberry products also had no apparent protective effect in any subgroups, including women with recurrent UTIs, older people, pregnant women, children with recurrent UTI, patients with cancer, and patients with neuropathic bladder or spinal injury.

Compared with antibiotics, cranberry was not significantly different in efficacy for women or for children, based on 3 small studies. Gastrointestinal adverse effects were similar for cranberry products and for placebo or no treatment (RR, 0.83; 95% CI, 0.31 – 2.27).

But… Compliance was low and dropout rate high in many studies, which may have resulted from poor acceptability of cranberry juice and of other cranberry products to a lesser extent. Also, doses were not consistently provided in the studies.

Careful: Cranberries may interact with warfarin, so check with you valued healthcare provider. They can also cause gastrointestinal upset, diarrhea, or even kidney (or other urinary tract site) stones at higher doses.

Did You Know? Cranberries are native to North America and are farmed on approximately 40,000 acres across the northern United States and Canada. Fresh cranberries are harvested in September and October, so fall is the best time to get them in season. They can be refrigerated for up to two months before using and can also be frozen for later use. Choose cranberries that are firm to the touch and unwrinkled.

Cranberries can also be enjoyed dried or in a can, but watch out for added sugars. Check the ingredient label and make sure that the product contains cranberries only. If you choose to drink cranberry juice, it is often mixed with other fruits and added sweeteners. Look for juice with cranberries as the first ingredient.

I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

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References:;; Cochrane Database Syst Rev. Published online October 16, 2012.

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Harvard AB Yale MD UPenn Radiation Oncology Radiation Oncologist, Seattle area

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