Can cranberry products prevent cystitis?

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Women who keep getting cystitis are sometimes advised to use cranberry products to try to prevent further infections. But research has shown that these products don’t have a preventive effect.

More than half of all women have cystitis at least once in their lives. The main symptoms are needing to go to the bathroom a lot and having a stinging or burning pain when passing urine.

Some women with recurrent cystitis use cranberry-based products to try to stop it from coming back again. These herbal products are sold in pharmacies and drugstores in the form of juices, syrups, powder, capsules and tablets. Cranberry juice in particular is supposed to prevent infections or even make them go away.

It is not clear how these cranberry products are supposed to work. Cranberries have substances called proanthocyanidins (PACs) in them. PACs are thought to prevent infections by keeping bacteria from sticking to the walls of the bladder.

Current research results

Researchers from the Cochrane Collaboration – an international network of researchers – wanted to find out whether cranberry products can prevent further infections in people with recurrent cystitis. To do so, they pooled and analyzed the results of all of the good-quality studies on this topic in a systematic review.

The researchers analyzed 24 studies involving about 4,500 participants in total, the vast majority of which were women. Most of the studies looked at whether cranberry products were better at stopping cystitis from coming back compared with a fake drug (placebo) not containing any active ingredients.

The cranberry products used in the studies were taken in various forms, including juice, tablets or capsules. One group, for example, was given a specific amount of cranberry juice every day, and the comparison group was given the same amount of colored, cranberry-flavored water. Most of the studies didn’t provide information about the amount of proanthocyanidins in the cranberry products.

Cranberry products do not prevent cystitis

When the researchers analyzed the results of the studies, they found that cystitis was just as common in people who had been given cranberry products as it was in people who had been given a placebo. This means that cranberry products are not effective in preventing cystitis.