D-mannose is a single sugar molecule also known as a monosaccharide, that is converted to glucose without insulin intervention. Because it is naturally assimilated, it quickly passes through the bloodstream and reaches the urinary tract unchanged, where it acts against the E Coli bacteria, which causes 90% of urinary tract infections. D-mannose is also found in some plants in the form of starch.
Various fruits and vegetables contain D-mannose, such as:
- Blueberries, cranberry (and cranberry juice), apples, oranges, peaches, broccoli, green beans.
D-Mannose is also found in a few nutritional supplements, available in capsules or powders. Some contain D-mannose by themselves, while others include additional ingredients, such as:
- Cranberry, probiotics, FOS, vitamin C, dandelion extract, hibiscus, rose hip, among others.
Many people take D-mannose to treat and prevent urinary tract infections (UTIs). D-mannose is believed to block E. coli growth in the urinary tract. But does it work?
What the science says
E. coli bacteria cause 90 percent of UTIs. Once these bacteria enter the urinary tract, they latch on to cells, grow, and cause infection. Researchers think that D-mannose might work to treat or prevent a UTI by stopping these bacteria from latching on.
After you consume foods or supplements containing D-mannose, your body eventually eliminates it through the kidneys and into the urinary tract.
While in the urinary tract, it can attach to the E. coli bacteria that may be there. As a result, the bacteria can no longer attach to cells and cause infection.
There isn’t much research on the effects of D-mannose when taken by people who have UTIs, but a few early studies show that it might help.
A 2013 study evaluated D-mannose in 308 women who had frequent UTIs. D-mannose worked about as well as the antibiotic nitrofurantoin for preventing UTIs over a 6-month period.
The rate of recurrent UTI was significantly higher in the group that did not receive prophylaxis (60%) compared with the groups receiving D‐mannose (15%) and nitrofurantoin (20%)
In a 2014 study, D-mannose was compared to the antibiotic trimethoprim/sulfamethoxazole for treatment and prevention of frequent UTIs in 60 women.
D-mannose reduced UTI symptoms in women with an active infection. It was also more effective than the antibiotic for preventing additional infections.
A 2016 study tested the effects of D-mannose in 43 women with an active UTI. At the end of the study, most women had improved symptoms.
D-mannose appears to be a promising nutritional supplement that may be an option for treating and preventing UTIs, especially in people who have frequent UTIs.
Most people who take it don’t experience any side effects, but higher doses may cause health issues yet to be discovered.
Talk with your doctor about appropriate treatment options if you have an active UTI. Although D-mannose might help treat a UTI for some people, it’s important to follow medically proven methods of treatment to prevent the development of a more serious infection.