Cranberries and UTIs are often in the news, with both positive and negative reports. Headlines have ranged from “Cranberry Juice does not prevent UTIs” to “Cranberry juice reduces UTI recurrence in women.” Cranberry controversy abounds.
So, what is the real story? Does drinking cranberry juice or taking cranberry capsules help prevent Urinary Tract Infections (UTIs)? We’ll answer these questions, and more, in this article.
Let’s start with some basics about UTIs.
What is a UTI?
The Mayo Clinic defines a UTI as an infection in any part of your urinary system (bladder, kidneys, ureters, or urethra). Most UTIs occur in the bladder or urethra. Some people refer to UTIs as bladder infections or cystitis.
What causes a UTI?
Bacteria from the colon and rectal area cause most UTIs. These bacteria enter the urinary tract through the urethra, the tube that carries urine out of the body. Bacteria use special hair-like structures called P-fimbria to stick to the wall of the urinary tract. Once the bacteria are attached, they can multiply and cause a UTI. E.coli is the type of bacteria that most commonly causes UTIs. According to the National Kidney Foundation, E.coli is responsible for 80-90% of all UTIs.
What are some UTI risk factors?
There are a number of UTI risk factors. Women are more likely to have a UTI than men. According to Dr. Martha Boone, Board Certified Urologist, about 95% of UTIs among people under 50 years of age occur in women. Women have higher UTI rates because a woman’s urethra is shorter than a man’s urethra. Therefore, bacteria have less distance to travel to reach a woman’s bladder.
Women are at higher risk for a UTI during pregnancy, and also after menopause. Decreased estrogen levels after menopause can allow the overgrowth of bacteria at the urinary opening.
Sexual activity is a UTI risk factor in women. During intercourse, bacteria from the rectal and vaginal area can enter the urethra, potentially causing an infection. Therefore, it is important for women to urinate after sex, to help flush the bacteria out of the body. Also, be sure to wipe from front to back after urinating, which helps keep bacteria from getting into the urethra.
Some other potential UTI risk factors include:
- Poor personal hygiene
- Holding urination for too long
- Not emptying the bladder completely
- Enlarged prostate, narrowed urethra, or anything that blocks urine flow
- Having a urinary catheter
- Bowel incontinence
- Prolonged immobilization
- Kidney stones
Symptoms of UTIs can include:
- Frequent, painful, or burning urination
- Urgency to urinate
- Cloudy urine
- Blood in urine
- Foul-smelling urine
- Pressure or pain in the lower back or abdomen
If not treated, a bladder infection can spread from the bladder to the kidneys. A kidney infection can cause fever, chills, fatigue and other symptoms. If you think you have a UTI, contact your doctor.
Cranberries and UTIs
Cranberry has been a long-standing folk remedy for various bladder issues. Researchers used to think cranberries were beneficial because of their acidity. However, drinking normal amounts of cranberry juice hasn’t been shown to make urine more acidic.
In recent years, research has revealed that cranberries naturally contain a specific group of compounds called proanthocyanidins (PACs). Lead cranberry researcher Amy Howell, Ph.D. first isolated cranberry PACs. She determined that these PACs could bind to E. coli bacteria, preventing them from sticking to the urinary tract cells and causing an infection. When the E. coli bacteria bind to PACs, it is easier for them to be flushed out in the urine before a UTI can start. PACs are now considered the active ingredients in cranberries.
While other foods contain PACs, cranberry PACs are unique in their structure. Cranberries contain A-type PACs, while apples, grapes, green tea, and chocolate contain B-type PACs. Only A-type PACs have proven bacterial anti-adhesion activity (AAA), meaning only cranberries can block E.coli bacteria from adhering to urinary tract cells.
Does cranberry help with UTIs?
There is a fair amount of research that suggests that cranberry helps with UTIs. A 2012 meta-analysis of 13 cranberry trials found that overall, cranberry decreased the risk of UTIs by 38%. This study also looked at how effective cranberry was in specific groups. In adults with recurrent UTIs, cranberry reduced the risk of infection by 47%. In females, cranberry reduced the risk of UTIs by 51%, and in children, cranberry reduced the risk 67%.
A 2017 review and meta-analysis also found that cranberry products reduced UTIs in people prone to having them. In this study, cranberry decreased UTI recurrence by 33%.
A randomized, placebo-controlled study published in 2015 showed that cranberry capsules reduced catheter-associated UTIs by 50% among women having gynecological surgery. In this study, women took cranberry capsules providing 36 mg of PACs per day, for six weeks after their surgery. According to lead author Betsy Foxman, this reduction in infection was similar to when patients take antibiotics as a preventative measure. Dr. Foxman advises that antibiotics should be saved for UTI treatment, in order to help avoid antibiotic resistance.
Why is there any controversy regarding the benefits of cranberryin UTI prevention?
Well, not every cranberry study has shown benefit. One example is a study published in 2017, which received a lot of media attention. This study tested a cranberry supplement in nursing home patients and showed no benefit in decreasing asymptomatic bacteriuria (bacteria in the urine, with no symptoms). Although this study showed no overall benefit, the cranberry group had to take fewer antibiotics, had fewer symptomatic UTIs, fewer hospitalizations, and lower mortality (death) rate.
Reasons for mixed results among cranberry studies, in general, include not assessing UTI recurrence, and not evaluating the right population. Lack of consistency in the amount, form, and quality of cranberry products used in the various studies also contributes to mixed findings.
Also, remember that cranberry products cannot treat a current UTI. Once bacteria have attached to the urinary tract and caused an infection, cranberry cannot help. If you currently have a UTI, contact your healthcare provider. Do not attempt to treat it yourself. The only reliable treatment for a current urinary tract infection is an antibiotic. You can begin taking a cranberry product along with an antibiotic to help reduce your risk of future infections.
How much cranberry for UTI protection?
Often people want to know how much cranberry for UTI protection. Whether choosing cranberry juice or a cranberry supplement, the amount you drink or take each day is crucial. Cranberry researchers have determined that at least 36 mg of PACs per day are needed to help prevent UTI recurrence. There are several ways to get this amount. You can drink 8-10 ounces of cranberry juice cocktail, eat 1 ounce of dried or 1 ½ cups of fresh cranberries, or take a cranberry supplement providing 36 mg of PACs each day.
A cranberry supplement can provide a low-calorie alternative to sugary cranberry juice cocktail, but there are things to be aware of when choosing one. Cranberry supplements vary widely in their content, labeling, and marketing claims.
Choose a cranberry supplement that is standardized to contain 36 mg of PACs. Read the Supplement Facts label carefully. Most products do not list PAC content on their label, and likely contain a very low dose of PACs per capsule. If a product does not list PAC content or does not provide 36 mg of PACs, it probably will not be effective in decreasing your risk of UTIs.
If you have had a UTI, you are at a higher risk of having another one. Taking a high-quality cranberry supplement, or drinking cranberry juice daily can be an effective way to decrease your chance of having another infection. Always remember to tell your doctor about any new supplements you start taking.
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