D-mannose is thought to prevent certain bacteria from sticking to the walls of the urinary tract. Mannose receptors are part of the protective layer that’s found on cells that line the urinary tract. These receptors are able to bind to E. coli and washed away during urination, thereby preventing both adhesion to and invasion of urothelial cells.
In a 2014 study published in the World Journal of Urology, 308 women with a history of recurrent UTI, who had already received initial antibiotic treatment, were divided into three groups. The first group received two grams of D-mannose powder in 200 milliliters of water daily for six months. The second group received 50 milligrams of Nitrofurantoin (an antibiotic) daily, and the third group did not receive any additional treatment.
Overall, 98 patients had recurrent UTI. Of those women, 15 were in the D-mannose group, 21 were in the Nitrofurantoin group and 62 were in the no treatment group. Of the patients in the two active groups, both modalities were well-tolerated. In all, 17.9 percent of patients reported mild side effects, and patients in the D-mannose group had a significantly lower risk of side effects compared to patients in the Nitrofurantoin group.
Researchers concluded that D-mannose powder significantly reduced the risk of recurrent UTI and may be useful for UTI prevention, although more studies are needed to validate these results.
In a randomized cross-over trial published in the Journal of Clinical Urology, female patients with acute symptomatic UTIs, and with three or more recurrent UTIs in the preceding 12-month period, were randomly assigned to either an antibiotic treatment group (using trimethoprim/sulfamethoxazole) or to a regime including one gram of oral D-mannose three times daily for two weeks, following one gram twice daily for 22 weeks.
At the end of the trial period, the mean time UTI recurrence was 52.7 days with the antibiotic treatment group and 200 days with the D-mannose group. Plus, mean scores for bladder pain, urinary urgency and 24-hour voidings decreased significantly. Researchers concluded that mannose appeared to be safe and effective for treating recurrent UTIs and displayed a significant difference in the proportion of women remaining infection-free compared to those in the antibiotic group.
Why might mannose be such an effective agent for preventing recurrent UTIs? It really comes down to microbial resistance to traditional antibiotics. This is an increasing problem, with one study showing that more than 40 percent of 200 female college students with UTI symptoms were resistant to first-line antibiotics.
The study, published in Antimicrobial Agents and Chemotherapy, concludes with this warning: “Given the frequency with which UTIs are treated empirically, compounded with the speed that E. coli acquires resistance, prudent use of antimicrobial agents remains crucial.”
2. May Suppress Type 1 Diabetes
Researchers were surprised to find that D-mannose may be able to prevent and suppress type 1 diabetes, a condition in which the body doesn’t produce insulin — a hormone that’s needed to get glucose from the bloodstream into the body’s cells. When D-mannose was administered orally in drinking water to non-obese diabetic mice, researchers found that the simple sugar was able to block the progress of this autoimmune diabetes.
Because of these findings, the study published in Cell & Bioscience concludes by suggesting that D-mannose be considered a “healthy or good” monosaccharide that could serve as a safe dietary supplement for promoting immune tolerance and preventing diseases associated with autoimmunity.
3. Works as a Prebiotic
Mannose is known to act as a prebiotic that stimulates the growth of good bacteria in your gut. Prebiotics help feed the probiotics in your gut and amplify their health-promoting properties.
Research shows that mannose expresses both pro- and anti-inflammatory cytokines and has immunostimulating properties. When D-mannose was taken with probiotic preparations, combined they were able to restore the composition and numbers of indigenous microflora in mice.
4. Treats Carbohydrate-Deficient Glycoprotein Syndrome Type 1B
Evidence suggests that D-mannose is effective for treating a rare inherited disorder called carbohydrate-deficient glycoprotein syndrome (CDGS) type 1b. This disease makes you lose protein through your intestines.
It’s believed that supplementing with the simple sugar may improve symptoms of the disorder, including poor liver function, protein loss, low blood pressure and issues with proper blood clotting.