Mannose as a therapeutic supplement
Mannose is a six-carbon sugar that is naturally present in the human body and found in various fruits and vegetables such as peaches, apples, and tomatoes. It has gained attention as a potential therapeutic supplement, particularly for urinary tract infections (UTIs) and the management of carbohydrate-deficient glycoprotein syndrome type 1b, a rare genetic disorder. Some alternative medicine practitioners advocate for mannose to help prevent or treat UTIs, based on its interaction with the E. coli bacterium, which is often responsible for these infections. However, scientific support for this use is inconsistent, with limited studies showing mixed results.
While mannose supplementation may assist individuals with carbohydrate-deficient glycoprotein syndrome type 1b by alleviating related symptoms, further research is necessary to substantiate its effectiveness. Mannose is generally considered safe as it is a sugar commonly found in foods, but the maximum safe dosage for certain populations, including pregnant women and children, has not been established. As the understanding of mannose's therapeutic potential evolves, more rigorous scientific studies are essential to clarify its benefits and safety for various health conditions.
Mannose as a therapeutic supplement
DEFINITION: Natural substance of the human body used as a supplement to treat specific health conditions.
PRINCIPAL PROPOSED USE: Urinary tract infection, treatment of carbohydrate-deficient glycoprotein syndrome type 1b
Overview
Mannose is a six-carbon sugar, like the better-known and closely related substances glucose and fructose. Relying on highly inconsistent evidence, some alternative medicine practitioners have popularized mannose as a treatment for urinary tract infections. Supplementation with mannose is also believed to help manage the symptoms of carbohydrate-deficient glycoprotein syndrome type 1b, a rare genetic disorder.
Requirements and Sources
Mannose plays an important role in human physiology. However, there is no nutritional need for this substance, as the body can easily produce it from glucose. Nonetheless, significant quantities of it can be found in many fruits and vegetables, including peaches, apples, blueberries, green beans, cabbage, and tomatoes.
Therapeutic Dosages
A typical recommended dose of mannose for managing bladder infections is 1.5 grams (g) daily, often divided into three doses of 500 milligrams (mg) each.
Therapeutic Uses
The idea that mannose supplements can help prevent or treat bladder infections derives from a property of the Escherichia coli bacterium. E. coli is one of the common causes of bladder infections. Many strains of E. coli can attach to the mannose present in the bladder wall by means of threadlike structures called pili, which allows them to initiate the infection process.
Reasoning from this fact of basic science, medical researchers in the 1980s hypothesized that consumption of mannose as a supplement would increase levels of mannose in the urine to such an extent that this free mannose would saturate the E. coli’s mannose-binding pili and thereby make the bacteria unable to grapple onto the cells of the bladder wall.
This reasoning is restated by proponents of mannose for bladder infections. However, the argument has at least four problems. First, one of the main ways that the body’s white blood cells recognize and kill E. coli is via these mannose-sensitive pili. When these pili are saturated by mannose, white blood cells (specifically, macrophages) are less able to consume the E. coli bacteria. Second, many species of E. coli, including some of the most dangerous, do not have mannose-sensitive pili. Third, there are numerous other bacteria that cause bladder infections, and these are not known or suspected to have mannose-sensitive pili.
Perhaps the most important point is that the use of mannose for preventing or treating bladder infections needs more meaningful scientific study in human beings. There is a bit of evidence from animal studies performed in the 1980s, but it is a long way from animal studies to efficacy in humans. Proponents of mannose also cite numerous testimonials, but the placebo effect and related confounding factors are quite sufficient to produce numerous testimonials for any treatment. Only double-blind, placebo-controlled studies can actually prove a treatment effective, and only a limited number have been performed on mannose. One study published in 2023 failed to find benefit in mannose supplementation for urinary tract infections. Another study indicated a potential benefit for women with simple lower urinary tract infections, but further study is required to reach scientific certainty.
An additional proposed therapeutic use for mannose is to manage the symptoms associated with carbohydrate-deficient glycoprotein syndrome type 1b. This rare genetic disorder affects an individual’s ability to produce glycoprotein and can lead to digestive problems, low blood sugar, and issues with blood clotting. Supplementation with mannose has been shown to help with these conditions.
Further studies in mice with pancreatic, lung, or skin cancer found that mannose slowed tumor growth with few side effects. Though promising, further research and human trials must be conducted to better understand this potential application.
Safety Issues
As a sugar widely present in foods, mannose is assumed to be safe. However, the maximum safe dosage has not been established in healthy adults, pregnant or nursing women, or young children. Very weak evidence from test-tube studies hints that pregnant women consuming excessive amounts of mannose could conceivably increase the risk of congenital disabilities in their offspring.
Bibliography
Ala-Jaakkola, R., et al. "Role of D-mannose in Urinary Tract Infections – A Narrative Review." Nature Journal, vol. 21, no. 18, 2022, doi.org/10.1186/s12937-022-00769-x.
Hayward, Gail et al. "d-Mannose for Prevention of Recurrent Urinary Tract Infection Among Women: A Randomized Clinical Trial." JAMA Internal Medicine, vol. 184, no. 6, 2024, pp. 619-628, doi:10.1001/jamainternmed.2024.0264. Accessed 20 Sept. 2024.
Therrien, Alex. "Sugary Supplement Mannose Could Help Fight Cancer." BBC, 21 Nov. 2018, www.bbc.com/news/health-46291919. Accessed 20 Sept. 2024.
Wagenlehner, Florian, et al. "Why d-Mannose May Be as Efficient as Antibiotics in the Treatment of Acute Uncomplicated Lower Urinary Tract Infections-Preliminary Considerations and Conclusions from a Non-Interventional Study." Antibiotics, vol. 11, no. 3 Feb. 2022, p. 314, doi:10.3390/antibiotics11030314.