Cranberry, D-mannose, and NSAIDs, oh my! Are any useful for UTI? Original paper

The most common cause of an uncomplicated urinary tract infection or cystitis (i.e., inflammation localized to the bladder) is Escherichia coli bacteria. Antibiotics are the primary treatment, but due to rising rates of antibiotic resistance, it’s worth investigating whether nonantibiotic treatments are similarly effective.

This systematic review of 21 clinical trials investigated the effects of cranberry (12 studies), D-mannose (2 studies), cranberry + D-mannose (2 studies), and nonsteroidal anti-inflammatory drugs (NSAIDs; 5 studies) in women (average age of 21–53) with uncomplicated UTIs.

Most of the trials (16) focused on the prevention of recurrent UTIs, while the rest focused on treatment. Cranberry and/or D-mannose were used for prevention, while NSAIDs were used for treatment.

The participants in the cranberry trials supplemented with a capsule or juice, with a proanthocyanidin (the primary active ingredient in cranberries) content that ranged from 2 to 112 mg. In 3 of the cranberry trials, it was combined with other substances, such as propolis and zinc, lingonberry juice, or lactobacilli. The comparator was a placebo, with the exception of 4 studies, which used antibiotics (2 studies), a lactobacillus drink (1 study), or a lower dose of cranberry (1 study).

In the D-mannose trials, the participants supplemented with 2–3 grams of D-mannose. Both of the D-mannose trials used antibiotics as the comparator.

In the cranberry + D-mannose trials, other substances were added to the supplements, which may have influenced the results.

In the NSAID trials, 4 used ibuprofen (3 used a dose of 1.2 grams, and 1 used 1.8 grams). The comparator was antibiotics in 3 of the studies; the fourth used uva ursi, which is used to treat UTIs. One study tested the effect of an antibiotic combined with aceclofenac (an NSAID) versus the same antibiotic alone.

Half of the cranberry trials reported a statistically significant reduction in the number of UTIs during the study period. Of the 5 trials that assessed time to first UTI, 3 reported a significant difference between the groups, in favor of the cranberry group.

Both of the D-mannose trials found that D-mannose reduced the number of UTIs during the study period and reduced the time to first UTI.

Both of the cranberry + D-mannose trials found that the supplements reduced the number of UTIs during the study period.

Ibuprofen was not superior to the comparator in any of the trials. Combining an antibiotic with aceclofenac resulted in faster UTI symptom resolution.

The diagnostic criteria for UTI differed between the studies, and the trials did not report the participants’ fluid intake, which can influence the risk of recurrent UTIs.^[1] These issues reduce our confidence in the results.