Drinking cranberry juice may fight that tummy bug

Jun 8 2005

A new study suggests that cranberry juice, a well documented remedy to help prevent urinary tract infections, may also work against gastrointestinal viruses.

Study co-author Patrice Cohen, a undergraduate researcher at St. Francis College in Brooklyn, says that so far, the results have been achieved only in the laboratory, and more study is needed to see if those results are creditable.

Cohen says if further tests in the field do prove successful it could in theory make a big difference, as hundreds of thousands of children die from gastroenteritis each year throughout the world.

Cohen and her team worked with cell cultures and focused in the laboratory on an intestinal monkey rotavirus which causes diarrhea, called SA-11 and a pool of goat intestinal reoviruses which cause inflammation of the small intestine. They exposed both of the cultures to cranberry juice.

They found that cranberry juice prevented the SA-11 virus from attaching to red blood cells or infecting host cells, and when they looked at the SA-11 cell cultures under high-magnification microscopes, there were no viral particles in those treated with juice, and says Cohen, the effect was immediate.

She says they also tried to determine if there was a dose response, and found that a dose of 1:16, cranberry juice to virus, was effective.

In order to determine if the effect had something to do with the pH of cranberry juice, they looked at two samples, one of virus was exposed to cranberry juice, and the other virus was exposed to an equivalent amount of liquid with the same pH as cranberry juice.

Cohen says in the one with the virus and cranberry juice, there was a 100 percent reduction in infectivity, but in the one with the liquid with the same pH as cranberry juice they saw only a 34 percent reduction. Which means that pH was not a factor and it was in fact some other component.

Other studies have found that cranberry juice was effective in preventing urinary tract infections because substances in the juice help prevent the adhesion of certain bacteria to the urinary tract wall.

Dr. Prabhakar Swaroop, an assistant professor of internal medicine at St. Louis University Hospital, called the new research "a very interesting study investigating the antiviral properties of cranberry juice."

But he agrees more study is needed, espeicially regarding how the findings can be translated to be of use in daily life.

He says in clinical practice, rotavirus, causes a self-limited diarrheal syndrome in infants and children, so it would be important to study whether the course of diarrhea is shortened after drinking cranberry juice.

He also thinks that it is important that the active ingredient which produces the anti-viral activity is identified.