Uncomplicated cystitis (commonly known as a urinary tract infection [UTI]) is very prevalent in women, but it does effect men, too. Nearly 11% of U.S. women report at least one UTI annually and half of them will experience an additional episode within the first year after initial infection, significantly impacting quality of life and health-care resources. 

Recurrent UTIs (rUTI) are defined as having at least three infections per year or two in the past 6 months. Oftentimes, most UTIs are caused by the pathogen Escherichia coli (E. coli) followed by Proteus, Klebsiella, Eneterocci, Streptococce, and Pseudomonas aeruginosa. Antibiotics are considered the first line of therapy for UTI treatment with conventional medicine. However, UTIs are becoming increasingly resistant to antibiotics, and therefore, adjuncts are needed for UTI prophylaxis.

According to a recent scope of literature review published in the journal Antibiotics, D-mannose is a well-tolerated, safe, and effective option for recurrent urinary tract infections in women. D-mannose is an inert monosaccharide that is approximately 100 times less abundant in human serum than glucose. It is a simple sugar that is metabolized and excreted in urine that inhibits bacterial adhesion to the urothelium. More specifically, D-mannose plays a competitive inhibitor role against the adhesion of several uropathogens to urothelial cell receptors by binding and blocking FimH adhesins on the tip of type 1 bacterial fimbriae. According to researchers, “D-mannose represents a promising nonantibiotic prevention strategy.” It has also been shown to be an effective intervention against inflammatory conditions through its ability to suppress macrophage interleukin-1β production and expression.

The researchers critically analyzed 13 human clinical studies regarding the efficacy and safety of D-mannose in the management of recurrent UTIs versus a placebo or other drugs or dietary supplements. Most of the studies included in this review showed that D-mannose plays a significant role in the prevention of recurrent UTIs and can be used as an adjunct to antibiotic treatment in some cases. Very few adverse events were reported; only 8% of participants who received 2 grams of D-mannose for 6 months experienced diarrhea. Researchers concluded, “D-mannose alone or in combination with several dietary supplements [including Lactobacillus probiotics] ... is safe and effective in the non-antimicrobial prophylaxis of recurrent UTIs in women.” Further well-designed studies are needed to definitively determine the optimal dose, frequency, and duration of treatment.  

Rapid and reliable enzymatic assays have been developed to readily detect urinary D-mannose. These sensitive assays may help assess susceptibility to UTIs and direct mannose therapy considering the scientific literature suggests that D-mannose ingestion and increased urinary D-mannose levels reduce UTI frequency. For patients who experience frequent or recurrent UTIs, supplemental D-mannose, in addition to probiotics, may help support a healthy microbial balance within the urinary tract and may help prevent recurrence.

By Caitlin H. Higgins, MS, CNS, LDN