Does D-mannose prevent and treat UTI?

Discomfort. Restlessness. Helplessness.

3 words that best describe 3 letters - UTI.

If you’ve ever experienced Urinary Tract Infection, you’d know what I’m talking about. It could get really uncomfortable that many people try different means to prevent it.

The most popular remedy perhaps is - wait for it - the good old cranberry juice. Word on the street is that it’s great for preventing it. As to why?

It contains an ingredient that is found beyond the trusty berry. And it can mean the world for those who suffer from UTI.


What is D-mannose?

A simple sugar pretty much like glucose, D-mannose acts as an antibacterial agent. [1] It works well in preventing and treating UTI because of its components and the way the body absorbs it.

According to Livestrong:

“D-mannose does not readily enter the blood stream. Some preliminary research has shown that 90% of mannose taken orally is excreted in the urine unchanged within 30-60 minutes. Therefore, D-mannose is not metabolized like other sugars in the body, it does not alter blood sugar levels and the plant components are filtered directly into the bladder. As D-mannose is excreted it essentially passes through the kidneys, fills the bladder and flushes the entire urinary tract when you urinate.” [2]


How does D-mannose treat UTI?

UTI is usually caused by bacteria such as the Escherichia coli, or E coli. In fact, E coli is responsible for at least 85% of UTI cases, according to an Emerging Infectious Diseases report in 2012. [3]

During cases of UTI, E coliis said to bind to mannosylated proteins such as the Tamm-Horsfall, the most abundant protein found in urine, in the urinary tract. [4] In the urinary tract, D-mannose keeps the E colifrom sticking by binding to lectins on the bacterial wall, hence preventing it from binding to cells found in the urinary tract. So instead of the bacteria sticking - and worse reproducing - in the urinary tract, it binds with D-mannose instead. E-coli then gets eliminated when you pee. [5]

According to Livestrong: [2]

“The sugars in D-mannose coat the lining of the urinary tract and bladder as they pass through the body. These sugars not only cover mucus membranes but they surround bacterial cells making it impossible for them to stick to the walls of the bladder or urinary tract. The bacteria remain free floating and are passed out of the body in the urine.”

D-mannose can significantly lower the number of bacteria in the urinary tract and urine within a day. [6] So if you’re suffering from this pesky infection, go ahead and find yourself D-mannose right away!


Sources for D-mannose: where is it found?

D-mannose is commonly found in fruits and vegetables such as berries - cranberries and blueberries - peaches, pineapple, apples, oranges, and broccoli.

It’s also found in lesser amounts among monosaccharides, glucose and fructose, and naturally in the cells lining the epithelial track.

D-mannose supplements are also great sources for this simple sugar, and may be found in retail and online stores.



Side effects

While D-mannose is generally considered safe because it’s naturally found in the body and most fruits anyway, it’s best not to go overboard with the intake. Some say that because it’s excreted from the body through urine, it may impair the kidneys. “May” is the operative word here - jury's still out on this one and there’s no evidence supporting this claim yet.

Other side effects are bloating, diarrhea and loose stools. [7]

And because D-mannose is a simple sugar, it can affect blood sugar levels. So those suffering from diabetes should take extra precaution and consult their doctor prior to taking any D-mannose supplements.



What studies say about D-mannose

A number of studies and clinical trials have been performed to gauge the effectivity of D-mannose in preventing and treating UTI. Some of them have looked into D-mannose as a separate ingredient, while others have studied it in combination with other natural ones.

  • 2013 study indicates that D-mannose is as effective as the antibiotic nitrofurantoin in UTI prevention. [8]
  • 2014 study shows that D-mannose is even more effective than the antibiotic trimethoprim/sulfamethoxazole in getting rid of UTI symptoms in women with an active infection. [9]
  • A 2016 study showed that D-mannose led to improved UTI symptoms for most of the 43 women with an active UTI. [10]
  • Several studies have looked into products that have D-mannose and other natural ingredients like cranberry, probiotics such as the Lactobacillus species, and N-acetylcysteine. They all demonstrated the beneficial effects for reducing UTI symptoms or reducing the rate of recurrent UTIs. [11, 12, 13, 14]



D-mannose is an effective ingredient for preventing and treating Urinary Tract Infection or UTI. It prevents bacteria such as E coli from latching onto the urinary tract. Ingesting D-mannose helps get rid of these bacteria and keep them from building up in the bladder upon urination. Several studies have proven its effectivity - even against some of the antibiotics - so it’s a great go-to as a UTI remedy!

The good news is that it’s readily available in fruits and vegetables, as well as in dietary supplements such as the VALI D-Mannose UTI Support.



If you're keen to know more about UTI, here's a video from Mayo Clinic:

And if you need more information on treating UTI, check out this article on how to treat a Urinary Tract Infection.