Cranberries, by Henk van der Steege of Unsplash.
D-mannose benefits people in several ways, in fighting and preventing disease, and possibly even in weight loss.
A headline in the scholarly journal Cell spells out some d-mannose benefits:
That article, which studied the effects of d-mannose in young mice, is available for free as a PDF . Mice are helpful in studying the supplement because their biology closely parallels human biology.
Livescience says :
Another reason rodents are used as models in medical testing is that their genetic, biological and behavior characteristics closely resemble those of humans, and many symptoms of human conditions can be replicated in mice and rats.
So don't reject the results just because the test subjects in the Cell study were mice.
HFD is a high-fat diet. (Unsplash photoby Sandy Millar)
The Cell article says to get the full benefits of d-mannose, youngsters should start taking a supplement early in life. But adults can also benefit, especially women with urinary tract infections.
About 8 million U.S. patients visit doctors annually for urinary tract infections. D-mannose quickly quells UTIs, and patients usually get back to feeling normal in a couple of days, as we reported in the VALI blog .
D-mannose: a prebiotic
Researchers are starting to study d-mannose as a prebiotic substance that helps foster the growth of good bacteria in the gut for overall digestive health, says WebMd . Says the site:
In some lab studies and studies in mice, D-mannose components were shown to increase the growth of "good" bacteria. This suggests D-mannose may have some use for people with dysbiosis, an imbalance in good and bad bacteria.
The simple sugar d-mannose, found in fruits and vegetables, is related to glucose. It gets absorbed more slowly in the digestive system than some other sugars.
D-mannose is also a probiotic. Probiotic means it works to stimulate the growth of microorganisms that benefit the health. D-mannose works as a probiotic particularly well in the case of UTIs while the infection is underway.
It also works well as a prebiotic for UTIs -- that is, it works to prevent urinary tract infections and possibly other diseases of the GI tract as well as curing them after you have been infected.
Another thing the supplement may help do is to reduce the taking of energy by germs in the gut. That's right, germs in your stomach right now are stealing some of the food you eat to sustain your life. D-mannose prevents some of that food-harvesting by gut microbes in young mice on high-fat diets.
D-mannose also prevents UTI
The substance does not just cure urinary tract infections--it also prevents them, scientists are discovering.
ClinicalAdvisor.com  says:
D-mannose has also been found to slow recurrence of UTI. A group of researchers studied 60 women with recurrent UTI (defined as ≥3 occurrences within the previous 12 months). Participants were randomly assigned to either trimethoprim/sulfamethoxazole or daily d-mannose for 24 weeks. In the antibiotic group, the mean time to recurrence of UTI was approximately 53 days. For the group treated with d-mannose, time to recurrence of UTI was 200 days.
If you buy VALI's supplement , you get cranberry, which is high in both d-mannose and concentrated cranberries. Cranberries are high in proanthocyanidins, another substance thought to be helpful in combating UTIs.
A study in the Journal of Functional Foods  says that proanthocyanidins derived from cranberries reduce the invasiveness of the E. coli bacteria that cause UTI.
It's important to note that about 10% of UTIs are caused by germs other than E. coli, and d-mannose and proanthocyanidins will not help cure those types of infections.
If you get a UTI (see the Mayo clinic article we link to below for symptoms), we strongly advise you to see a doctor.
Take VALI D-Mannose, observe good hygiene
The upshot of this is to take the VALI D-Mannose supplements with concentrated cranberries or to consume large amounts of foods that contain d-mannose. It is in peaches, apples, oranges, blueberries, and most notably, cranberries.
The Mayo Clinic website has an article  that advises ways to avoid UTIs in the first place:
- Drink sufficient liquids, water especially. Water dilutes urine and helps you urinate more. Plentiful urination flushes the urinary tract before an infection can take hold.
- Wipe from front to back when you urinate or defecate. Wiping this way prevents spreading the harmful bacteria to your urethra and vagina.
- Urinate and drink a full glass of water right after having sexual intercourse to help flush the infectious germs.
- Avoid feminine products that irritate the genital region. Deodorant sprays, douches, and powders can cause irritation to the urethra.
- Avoid diaphragms, unlubricated condoms, and spermicide-treated condoms, which can contribute to bacterial growth.
That Mayo Clinic article also provides symptoms, complications, risk factors, and causes of UTI.
Other benefits of d-mannose
Doctors also use d-mannose to treat the rare disease carbohydrate-deficient glycoprotein syndrome type 1b. WebMd says:
This disease is passed down through families. It makes you lose protein through the intestines. Some reports say D-mannose slows down this protein loss and makes your liver work better. It may also reduce bleeding disorders and low blood sugar in people with this disease.
Are there risks with d-mannose?
Scientists have found that people tolerate d-mannose well, but women who are pregnant or breastfeeding should be cautious about using it because there haven't been enough studies on women in these situations.
All that said, possible side effects of d-mannose are bloating and loose bowel movements. Experts advise against taking too much d-mannose. Healthline gives some guidance on dosage :
- To prevent frequent UTIs: 2 grams once a day, or 1 gram twice a day
- To treat an active UTI: 1.5 grams twice a day for 3 days, and then once a day for 10 days; or 1 gram three times a day for 2 weeks
Also, people with diabetes mellitus should not take it, says Clinical Advisor. https://www.cell.com/cell-reports/pdf/S2211-1247(18)31368-8.pdf