D Mannose supplement benefits and side effects, for urinary tract infections
August 22 2018 by
Ray Sahelian, M.D.

D Mannose is a simple sugar molecule. It can be used safely and has few side effects if ingested in small amounts. Perhaps we will find that it works even better for urinary tract infections if combined with cranberry extract.

Urinary tract infection prevention
D Mannose has been found to be helpful in preventing bladder infections.

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D-Mannose supplement 500 mg, 30 count

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D-Mannose side effects, risk, how safe is it?
Thus far no major clinical side effects have been published in medical journals. Flatulence (farting) is a common minor side effect.

Q. I read that it can be useful for bladder infections so I purchased some and dissolved 1/2 teaspoon in a glass of water and drank it. I did not have a bladder infection and wanted to evaluate its results for use next time I do because I do not like to rely on antibiotics when it happens. Shortly thereafter I started to have severe irritation in my bladder and urethra. I don't know whether it was due to the d-mannose but feel that is a good possibility because it was alleviated by taking pyridium. The pain is constant and does not become worse with urination so I doubt it is cystitis. Today is the third day I have had this problem although I did not take any more D-mannose. I have looked up the MSDS for mannose and it does mention skin irritation. Also eye irritation which I had yesterday but not today. It is the NOW Foods brand. Apparently it has no other ingredients. The info on the package says "Technically known as D-Mannose, this is a simple six-carbon sugar. Mannose is a stereoisomer that is a mirror image of glucose and naturally occurs as a monosaccharide (simple sugar) in fruit like blueberries and cranberries, as well as in other plants and fungi. NOW Foods pure Mannose is derived from corn, white and sweet potatoes, beech or birch woods and has a caloric value (similar to other sugars) of four calories per gram. Mannose exists in two forms - alpha and beta. The alpha form is mild and sweet, while the beta form is bitter. The natural manufacturing methods for Mannose results in a mixture of these two forms; yielding a product that is mildly sweet with a slight bitter aftertaste."
   A. This is the first report we have had of possible d mannose side effects regarding irritation. Perhaps it is an infection that is causing the adverse reactions.

Q. I started taking D-Mannose supplement about a month ago along with cranberry 300mg supplemental three times a day to cure frequent UTI (5-6 times a year). Also Iím taking metoprolol 25 mg twice daily to treat my blood pressure and arrhythmia for about one year. Within about last month I had experienced extensive heart arrhythmia and went to my cardiologist for treatment. I will stop taking my UTI supplementals to see if these events are related. Do you know any potential these medications interactions on this matter?
   A. Thus far I am not aware of these natural supplements causing heart rhythm problems.

Multiple sclerosis patients
Neurourol Urodyn. 2016. Open label feasibility study evaluating D-mannose combined with home-based monitoring of suspected urinary tract infections in patients with multiple sclerosis. To assess the feasibility of using D-mannose, a natural food supplement, in patients with multiple sclerosis (MS) reporting recurrent urinary tract infections (UTIs) as a preventative. A single-center, open-label, feasibility study enrolled patients with MS, using and not using urinary catheters, experiencing recurrent UTIs. Participants were given D-mannose powder 1.5 grams twice daily for 16-weeks and were instructed to monitor suspected UTIs at home using urine dipsticks. The number of monthly proven UTIs decreased both in catheter users and non-users. No adverse effects were reported. Using D-mannose in patients with MS experiencing recurrent UTIs and self-monitoring for infections is feasible and safe.

Mannose -binding plant lectins information
Mannose-binding lectin, a serum protein characterized by both collagenous regions and lectin domains, plays an important role in innate immune defense. It binds to the repeating sugar arrays on many microbial surfaces through multiple lectin domains and, following binding, is able to activate the complement system via an associated serum protease, MASP-2.

Research study
Mannose binding plant lectins: different structural scaffolds for a common sugar-recognition process.
Biochimie. 2001.
Mannose-specific lectins are widely distributed in higher plants and are believed to play a role in recognition of high-mannose type glycans of foreign micro-organisms or plant predators. Structural studies have demonstrated that the mannose-binding specificity of lectins is mediated by distinct structural scaffolds. The mannose/glucose-specific legume (e.g., Con A, pea lectin) exhibit the canonical twelve-stranded beta-sandwich structure. In contrast to legume lectins that interact with both mannose and glucose, the monocot mannose-binding lectins (e.g., the Galanthus nivalis agglutinin or GNA from bulbs) react exclusively with mannose and mannose-containing N-glycans. These lectins possess a beta-prism structure. More recently, an increasing number of mannose-specific lectins structurally related to jacalin (the lectins from the Jerusalem artichoke, banana or rice), which also exhibit a beta-prism organization, were characterized. Jacalin itself was re-defined as a polyspecific lectin which, in addition to galactose, also interacts with mannose and mannose-containing glycans. This structural diversity associated with the specific recognition of high-mannose type glycans highlights the importance of mannose-specific lectins as recognition molecules in higher plants.

Questions from readers
Thank you for sharing your knowledge. Your website is very informative. What is the effect of D-Mannose on yeast overgrowth in the gut?
    I have not seen such research, so I don't know.

After years of suffering through the bladder infection / antibiotics / yeast infection cycle, I tried D-mannose. It gets rid of the infection very quickly, and without stirring up any yeast issues. I think many people would be helped tremendously if they ditched the Cipro and tried the mannose.

I received promotional material from a manufacturer. They claim D-Mannose can benefit those with diabetes, obesity, constipation and high cholesterol,  and has anti-inflammatory and inhibition of tumor growth potential. Itís mainly used for additives of food and beverage.
   A. I need to see more studies to determine whether these claims are true.

For the past 5-6 years I have suffered with many many bouts of cystitis and have been on several anti biotics. At one point a GP prescribed me with a bottle of 30 trimethoprim and told me to just take them when I had problems I had visited him so often with bladder infections. I was also on the drug amytriptiline to kill pain or numb the nerves in my bladder as most of the time when i went along to the GP's my symptoms would either be down to e coli or no ecoli and my GP put this down to interstitial cystitis. Lately these drugs stopped working for me and I would say that I have almost continually ber fighting bladder infections for the past year. Eventually my legs and lower half of the body began to take on water. My GP again prescribed trimethoprim two months ago and this just did not completely hit the infection. So consequently a few weeks later I had another raging bladder infection and I started to hit the forums on the net in complete desperation for a cure that was natural as cranberries were just not cutting it. Eventually I stumbled across D mannose articles. I learned that D mannose was just a simple sugar but I came across so many articles that gave positive review from women on the net that I started to look for Health companies within New Zealand that supplied D mannose and I found that this was available in the Clinicians range at www.clinicians dot co.nz which is a reputable supplement range. They supplied it in 50 gram jars so I went to the local pharmacy in town and purchased one jar. On the side it recommended to take 1.25 ml only every few hours but as I had researched and read to take 1 tsp I did so. To go on as I have been taking anti biotics so often over the past few years my immune system is wrecked beyond belief. I started with bowel problems some years ago. Despite trying to take pre and pro biotics, I never seemed to be able to get on top of this and had tremendous bloating and cholic pain after eating in the past few months which my Doctor had labelled "IBS" and begun to treat. I had also suffered from anaemia (low iron) and despite treatment with iron and vitamin c the tests would always come back as me being anaemic. I do not feel my bowels were absorbing nutrients from my food and I became very run down. When I took the first tsp of d mannose powder in water, within 20 minutes I had an awful lot of grunbling in my stomach, slight stomach upset and diahearea. However, knowing it was just a simple sugar I continued taking this. It cleared my bladder infection symptoms in one day and best still, for some reason my stopped having stomach bloat within days! As d mannose is only active in the upper gi tract and then it is taken into the blood stream and then pushed out through the kidneys, I decided that possibly I had had some e coli in the upper gi tract and that it had flushed that out adn killed two birds with one stone. However, me being me i had to know WHY I felt so much better on it so at this point i started to research glyconutrients themselves and I came across many articles that have all made complete sense to me as someone who used this product and had great effects from it. This is just ONE glyconutrient that I have used here. Not the other 7 that articles tout as being magnificent out there. I came across several articles that mentioned d mannose and galactose being particularly useful for people who have been on anti biotics therapy a great deal. They work in tandem with each other. Galactose is also a glyconutrient, so I went out and purchased a large bottle of dufolac and started to mix galactose in with the d mannose as i had read the d mannose flushes unfriendly bacteria out and the galactose assists the body to build friendly bacteria up in the gut. I can say that I have been doing this for one week now and I feel so much better. I also started to take Flora Restore from the Clinicians range in NZ and this has improved my stomach problems as well as my UTI problems in a week. All with NO anti biotics and their awful side effects. Better still if you research d mannose you will note that e coli cannot build resistance to this stuff, and upon researching further, d mannose is now being used alongside amamannan in order to build the immune system. It made complete sense to me because within 20 minutes of taking d mannose I felt an instant lift. Some articles now suggest that this glyconutrient actually feeds cells in the blood, and that cells are then able to communicate far better and detect rogue cells and destroy them. All I can say is, this I felt was felt within almost 20 minutes of taking d mannose. I just felt relaxed and less tense. I feel it didn't just kill E. coli, it boosted my immune system in the above way. It's a little like taking Glutamine when you've done a workout. thought the body can make it's own glutamine from other amino acids we eat, there is nothing quite like getting a boost immediately before and after a workout as it leaves your body with more energy to repair intead of going through all the rigmarole of trying to convert various amino acids into glutamine which burns energy. Not only this but we lack in some amino acids in a lot of cases in some diets. So taking glutamine works two fold.

Other products online
buy D-Mannose supplement by Source Naturals
Now Foods, D-Mannose Pure Powder, 3 oz (85 g)