It seems drinking cranberry juice daily really does reduce the odds of getting urinary tract infections.

According to research presented at the American Chemical Society meeting in Boston on Monday, drinking cranberry juice not only prevents women from getting urinary infections but its benefits last up to 24 hours, said Terri Camesano, a professor of chemical engineering at Worcester Polytechnic Institute.

Camesano and her students followed the impact of drinking cranberry juice on 20 healthy female college students. But they ended up with complete data for 11 volunteers. Some were asked to drink 16 oz glass of cranberry juice, the others had a placebo drink that looked like cranberry juice, Camesano said in an interview with the Star.

Then after the very first dose, the women were asked to give a urine sample. Then they were asked again 2 hours after taking the drink, 8 hours after taking the drink, 24 hours later and then 48 hours.

After that the urine was taken to the lab and the scientists began testing the specimens. “We wanted to know if there are compounds in cranberry juice that prevent bacteria from being able to form a biofilm,” she said. A biofilm is a community of bacteria attached to a surface and is usually the first step in the development of an infection.

And, Camesano said, that turned out to be the case.

The team grew forms of E coli and staphylococcus aureus in urine from the volunteers, she said. The results were astonishing. In the urine of volunteers who had drunk cranberry juice there was a reduction in the ability of the bacteria to form a biofilm. But when bacteria was in the urine from a volunteer who had drunk a placebo there was no reduction.

Researchers also found it took about eight hours for the benefit of the cranberry juice to show up and lasted usually 24 hours. In the odd case the benefit even persisted for 48 hours.

Camesano’s conclusion: “If someone wants to prevent urinary tract infections they should drink cranberry juice every day. By the next day the effect may already be gone.”

The chemical engineering professor has been studying the relationship between cranberries and urinary tract infections for the past four years. One of the reasons she began the research was because, while people believed drinking cranberry juice helped prevent urinary tract infections, no-one understood why.

In some of her earlier work Camesano found that the compounds in cranberry juice makes proteins on the surface of a bacteria like E coli collapse when they come in close contact. “Cranberry juice binding to these proteins makes them collapse and then the E coli can no longer attach itself to urinary tract cells,” she explained.

Next up for Camesano is a look at why some people respond “well” to cranberry juice while others respond “very well.” And she also hopes to collect cells from women who suffer from chronic urinary tract infections and compare them to cells from women who only get infections occasionally.

Camesano’s study looked at a female sample only but she said earlier studies have found the benefits of cranberry juice apply to men as well, reducing urinary tract infections. It’s just that women tend to get urinary tract infections more frequently, she said.