Cranberry Juice and Health

Cranberry Juice and Health

If new research data supports earlier findings, for some people the key to preventing a urinary tract infection may be as simple as a visit to the grocery store.

Millions of people suffer yearly from these painful infections, says Cibele Barbosa-Cesnik, a research investigator in the Department of Epidemiology. In fact, only respiratory infections are more prevalent. And women are especially vulnerable. According to a study by SPH Professor Betsy Foxman, 11 percent of women over the age of 18 suffer from UTIs, and many of these infections are recurrent.

What’s more, says Barbosa-Cesnik, in the past 15 years UTIs have become increasingly resistant to common antibiotics, so researchers are looking for new ways to prevent infections. Barbosa-Cesnik is focusing on one potential solution: cranberry juice.

Most UTIs, she explains, stem from one type of bacteria, Escherichia coli (E. coli), which typically inhabits the colon but often adheres to the bladder, causing infections to develop. A number of in vitro studies suggest that proanthocyanidins, or PAC, a component of ordinary cranberry juice, inhibits the adherence of E. coli bacteria to the bladder. “If it can’t adhere,” says Barbosa-Cesnik, “it’s washed out.”

In a four-year study funded by the National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health, Barbosa-Cesnik is studying the ability of cranberry juice to inhibit UTIs in college-aged women, a population that is particularly prone to UTIs, in part because the infections can be sexually transmitted. Foxman is a co-investigator on the study.

For a period of six months, the 400 participants in Barbosa-Cesnik’s randomized study will drink either eight ounces of cranberry juice or a placebo juice twice daily. Researchers will monitor relevant symptoms in the participants and ultimately analyze the data they collect. Barbosa-Cesnik is seeking to determine whether cranberry juice reduces UTI recurrence within six months, whether it helps UTI patients heal faster, and whether it selects for a less-virulent bacteria. Morton Brown, professor of biostatistics, directs the study’s Data Coordinating Center.

If cranberry juice turns out to be an effective means of preventing UTIs and of halting recurrent infections, she says, at-risk patients could begin drinking more juice as a preventive measure, and doctors could begin prescribing the juice as part of a daily diet regimen.

The study is one of several throughout the nation that are looking at the effect of cranberry juice in populations susceptible to UTIs, including pregnant women. “There’s a lot of interest in this,” Barbosa-Cesnik says.

Send correspondence about this or any Findings article to the editor at sph.findings@umich.edu. You will be contacted if your letter is considered for publication.

Studies suggest that a component of ordinary cranberry juice inhibits the adherence of E. coli bacteria to the bladder.