D - mannose for recurrent UTIs

Last edited 11/2018 and last reviewed 01/2023

D-mannose for prevention and treatment of UTIs

  • D-mannose is a simple sugar, a monosaccharide extracted from larch rod, closely related to glucose
    • several fruits and vegetables contain D-mannose, including:
      • cranberries (and cranberry juice)
      • apples
      • oranges
      • peaches
      • broccoli
      • green beans
    • D-mannose is rapidly absorbed and in about 30 minutes reaches the peripheral organs, then is excreted by the urinary tract
    • D-mannose cannot be transformed into glycogen, therefore, is not stored in the body
    • long-term use of D-mannose, in concentrations up to 20%, has not shown any side effect on human metabolism (1)

  • the process of bacterial adhesion on the cell surface is a crucial factor for the onset of most infections
    • occurs because specific lectins on bacterial wall are able to bind molecules such as D-mannose and L-fucose distributed on the human cell surface
      • the bladder wall is coated with various mannosilate proteins, such as Tamm-Horsfall protein (THP) that interfere directly with the adhesion of bacteria on the mucosa
        • THP may fasten to E. coli with a specific bond, which may be inhibited by exogenous D-mannose
        • by inhibiting the adhesion of bacteria to the urothelium, D-mannose mimics urothelial barrier function
        • binding free D-mannose in the urine rather than proteins on the vescical cells surface, bacteria are trapped in the urinary flow and consequently eliminated by the urinary tract

  • NICE was aware of the mechanism of action of D-mannose, which is also in cranberry products
    • noted evidence suggesting that D-mannose was effective in reducing the risk of recurrent UTI in non-pregnant women, and noted the low NNT of 3 (range 2 to 3) over 6 months, compared with no treatment (2)
    • however, this was based on 1 small RCT (3)
      • D-mannose (200 ml of 1% solution once daily in the evening) used for up to 6 months significantly reduced the risk of recurrent infection in non-pregnant women compared with no treatment (14.6% versus 60.8%, NNT 3 [range 2 to 3]; high quality evidence)
        • based on 1 RCT in non-pregnant women presenting with a current UTI and a history of recurrent UTI
    • a study by Domennici et al suggest that D-mannose can be an effective aid in acute cystitis management and also a successful prophylactic agent in a selected population (4)

  • NICE made a recommendation that some women who are not pregnant may wish to try D-mannose, as a self-care treatment, noting the sugar content of this product which should be considered

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