If you’ve ever had a urinary tract infection (UTI), you know how painful it can be. Adding to the sharp pain is the bother of having to drag yourself to the doctor’s office for an exam and, likely, a costly prescription.
Fortunately, there’s an all-natural remedy that can be found in certain foods, as well as in supplement form, that has shown promise in preliminary studies for providing an alternative for UTIs: D-Mannose. And that’s not the only health issue that this natural sugar may help cure. Here’s what you need to know about D-Mannose.
What Is D-Mannose?
“Our body makes D-Mannose to help modify specific molecules so that they work efficiently through a process called glycosylation,” says Dr. Oreoluwa Ogunyemi, a urologist and health coach based in the San Francisco Bay area.
Although D-Mannose is structurally similar to glucose, the most common sugar, it’s absorbed more slowly in the gastrointestinal tract, which accounts for its lower glycemic index. Another difference: After D-Mannose is absorbed in the gut, it isn’t stored in the liver like glucose. Instead, it’s filtered out of the body directly by the kidneys.
In addition to occurring naturally in some cells within the human body, D-Mannose is available via several sources, including the larch rod tree and birch trees. Here are some other fruits and vegetables in which it’s found:
- Some berries, such as blueberries and cranberries
- Black and red currants
- Green beans
D-Mannose is also available as a nutritional supplement. It is sold in pill, powder, and liquid forms.
D-Mannose for UTIs and More
D-Mannose is of interest to the research community for its potential to prevent or cure various conditions. But to date, the most promising finding is that D-Mannose may prevent bacteria from adhering to cells lining the urinary tract. Fewer bacteria in the bladder lowers your risk of UTIs, which is why a number of smaller studies have found it effective for both treatment and prevention of recurrent simple UTIs (primarily in healthy women who do not have major health conditions), says Dr. Ogunyemi.
One such study, published in the World Journal of Urology, examined the use of D-Mannose to prevent recurrent UTIs (1). After one week of initial treatment with antibiotics for an acute UTI, 308 women with a history of recurrent UTIs took either D-Mannose powder, an antibiotic, or nothing for six months. The rate of recurrent UTIs was significantly higher in women who took nothing compared to those who took D-Mannose or the antibiotic. However, those given D-Mannose reported fewer side effects. (The main one, diarrhea, occurred in just 8 percent of the women taking D-Mannose.)
Some animal studies also show that D-Mannose may be useful for preventing dysbiosis, or overgrowth of harmful bacteria in the gut. This is because it is a prebiotic that stimulates the growth of “good” bacteria in your digestive system.
In addition, D-Mannose is used to treat a rare disease called carbohydrate-deficient glycoprotein syndrome type 1b (TK). This disease, passed down through families, makes you lose protein through the intestines. D-Mannose is said to slow down this protein loss so that your liver works better. It may also reduce bleeding disorders and low blood sugar in people with this disease.
How to Choose a D-Mannose Supplement
D-Mannose is primarily available as powders and capsules. Dr. Ogunyemi tends to steer her patients toward supplements in powder form. “Powder tends to be less expensive and does not contain any additives that are often found in capsules,” she explains.
The treatment dose for a UTI (in adults) is generally one teaspoon of powder dissolved in water (or 1.5-2 grams if you use capsules) every few hours. For prevention against UTIs, the dose is 1-2 grams of powder dissolved in water daily. “The powder dissolves easily, and the water will have a sweet taste,” Dr. Ogunyemi observes.
She cautions her patients with corn allergies to check the ingredients panel carefully (or call the manufacturer) because D-Mannose products often contain corn. “If you have an allergy to corn, look for a source that is corn-free,” she advises.
Quality can differ widely between different brands and even batches, so look for a reputable brand and, if you choose to take capsules over powder, make sure that there are no added additives (magnesium stearate, silica, etc.). Look to see the source of your D-Mannose. (Some people feel more comfortable with products made in the USA, Dr. Ogunyemi observes.)
D-Mannose Side Effects
If you think you have a UTI, consult your doctor before taking D-Mannose. As promising as the early findings have been, the natural sugar only treats one type of bacteria (E.coli, the most common UTI culprit), so it may not work for everyone. Also, if you develop a fever or chills when taking D-Mannose, or your symptoms are not improving, you should see your doctor.
In terms of side effects, D-Mannose can cause diarrhea and bloating if taken too often or in too large a dose. In addition, high doses are thought by some researchers to cause kidney damage.
If you are pr
egnant, talk to your doctor before taking D-Mannose because, as Dr. Ogunyemi points out, there are no studies at this time showing it is safe during pregnancy or while breastfeeding. There is also a concern that, as a sugar, D-Mannose can negatively affect people with diabetes. However, “little of the sugar is absorbed, so it should have little impact on blood sugar,” says Dr. Ogunyemi.
Bottom line: It’s always best to talk with your doctor before starting D-Mannose.