Mannose

Note: See also Economical Alternatives.

Mannose appears to be the foundation of all the essential sugars. Mannose is formed from glucose in the body and used in the formation of short chain sugars naturally attached to certain proteins. It is involved in so many fundamental cell actions that any deficiency of this one saccharide is said to lead to a host of physical problems. Like xylose and xylitol, mannose has its own sugar alcohol form known as mannitol.

Called D-mannose, this form is now sold as a remedy for UTIs (urinary tract infections), but it is capable of so much more. Studies suggest that D-mannose is ten times more effective than cranberries in dislodging E. coli bacteria from the bladder wall, improving more than 90% of UTIs in 24-48 hours. However, unlike antibiotics, D-mannose does not kill any bacteria but simply displaces them, thereby, discouraging them from attaching to the wall of the bladder. In addition, because the body metabolizes only small amounts of D-mannose and excretes the rest in the urine, it does not interfere with blood-sugar regulation, even in diabetics.

Absorption
Mannose is absorbed 8 times more slowly than glucose; and, when ingested, it is not converted to glycogen or stored in the liver, but rather Mannose goes directly to the blood stream from the upper gastrointestinal tract. Furthermore, Mannose easily crosses the placenta allowing it to assist in fetal formation. Amniotic fluid has been shown to contain Mannose in amounts comparable to concentrations in the blood. Within an hour after ingestion, Mannose is widely distributed throughout body tissues and fluids. Highest levels are generally found in the liver and intestines.

Excretion
Based on animal studies, it appears that Mannose is actively reabsorbed by the kidneys with very little being eliminated in the urine. There appears to be two different transport sites on the surface of the kidney tubules; one for Glucose and Galactose and the other for Mannose. Although Glucose and Galactose are excreted in the urine, very little Mannose is eliminated.

Functions

• Mannose is gaining a reputation as a remedy for urinary tract infections (UTIs). Often, these infections come as a result of E. coli contamination, affecting the bladder as well as other urinary structures. The bladder lining is comprised of polysaccharide molecules. Finger-like projections on the cell surface of E. coli bacteria adhere to these molecules, initiating an infection. When Mannose molecules are present, E. coli prefers to attach to them to form a complex which is then expelled with the next voiding. Mannose works about 90% of the time without causing any additional harm to the body. This is not the case when antibiotics are used to correct the problem. Studies have also shown that about 80% of painful bladder syndromes become symptom-free when a Mannose supplement is added to the diet.
• Mannose prompts anti-inflammatory activity and tissue regeneration. It appears to have an active role in the activation of macrophages, whose function it is to clean up debris which can cause inflammation. In fact, macrophages have at least four different receptors that bind Mannose implying that the sugar is vital for the proper function of these garbage collectors. Further evidence for its anti-inflammatory abilities is based on studies involved in wound healing. Mannose stimulates fibroblasts to make more collagen and proteoglycans, which means that healing is speeded up, pain is lessened, and skin integrity returns to normal faster. Mannose also works to correct over-active neutrophils (T cells) that cause misguided inflammation. Researchers in Australia have confirmed this action. Evidently, Mannose displaces certain enzymes required for T cells to flow into various areas such as the joints, liver tissue, kidneys, and even central nervous system areas, thereby acting as a natural anti-inflammatory agent.
• Mannose, Galactose, Fucose, and N-acetylneuraminic acid are all involved in reversing Failure to Thrive (FFT) syndromes. Failure to thrive and cachexia (general ill health and malnutrition) are also seen in adults with AIDS and cancer. It appears that a direct cause of FTT symptoms in children is the failure of glycoproteins to transport sugar, something that can actually start in the placenta. This malfunction of glucose transporters (glycoproteins) can also occur in the blood-brain barrier and muscle cells of the developing infant, inevitably producing a host of undesirable symptoms. Research has shown that supplementation with glyconutrients resulted in significantly improved conditions. Apparently, it takes the combination of essential sugars to correct the problem and not just a supplementation of one sugar or of one nutrient.
• Mannose is found in all cell membranes, thereby affecting every organ and system of the body. It is also another essential sugar that can be found in the photoreceptor layer of the retina, thus playing an important role in vision. It also has been shown that supplementation of Mannose can be used in conjunction with other therapies for the management of diabetic cataracts. Based on studies to date, Mannose has the ability to preserve membrane metabolites which have a protective effect in the lens.
• Since Mannose is found in distribution sites of the brain and nerve structures, it is assumed that it plays an important role in nerve physiology.
• Mannose is capable of activating insulin-like growth factor receptors, implying it can be beneficial for diabetics. Mannose, like another essential sugar (Glucosamine), is also crucial for joint protection, especially in cases of rheumatoid arthritis. When lab animals received mannans (polymers of Mannose), inflammation flare-ups were prevented. It is well known that genetic mutations in, or the lack of, mannose-binding proteins can predispose a person to the disease; but, by adding glyconutrients to the diet, such miscommunication between immune cells is corrected.
• Mannose has also proven to reduce tumor growth and increase survival rates of cancerous animals. It appears that the sugar stimulates macrophages which secret interferons. These, in turn, activate natural killer cells involved in the elimination of cancer cells. Mannose has also been used to depress the rate of growth of other tumor cells in cultures. When scientists added Mannose and Glucosamine into the drinking water of mice with tumor cells, their survival rate increased while the tumors decreased. Some studies concluded that Mannose and Fucose appeared to be the most effective sugars when it came to slowing the growth of cancer cells.
• Mannose acts as an antibacterial agent. Bacteria have lectins on their surfaces that bind to host cells, resulting in infection. However, Mannose competes with the bacterial lectins, occupying sites that would normally bind to host cell Mannose receptors, thus preventing attachment and thwarting possible infection. Mannose has proven to be particularly effective against Salmonella and E. coli.
• Mannose also has antiviral, antiparasitic, and antifungal properties.

Safety
There have not been any adverse reactions to high doses of Mannose either orally or from injection. Based on animal studies, the highest dose for humans could be around 23 grams for a healthy 150-pound adult. However, that much is hardly necessary. In humans, no adverse effects have been noted when oral doses of approximately 15 grams were administerd. Even at oral doses as extreme as 53 grams per day given over an 11-month period showed no adverse side effects. However, when excessively large amounts (35 grams per hour) of Mannose was injected intravenously continuously for 10 hours, human subjects did experience fatigue, anorexia, malaise, and massive uric acid crystalluria. No matter how small or large the dosage, it should be divided in at least two portions so as to maintain a functional level in the blood.

Dietary Sources
It is not difficult to obtain plenty of Mannose in the diet. It is one of the few essential sugars that is easy to obtain. One of the main sources is Aloe vera gel, which contains “acemannan”, a Mannose polysaccharide. Another good source is ground Fenugreek as it contains a high amount of galactomannan (as does Carob gum and Guar gum), a polysaccharide of Mannose and Galactose. Bread Molds also contain small amounts of Mannose, a minor nutritional source of glyconutrients in the days when bread went moldy routinely and people were often too poor and hungry to worry about mold in food. Today, there are better and tastier ways to obtain sugar-nutrients.

Other Sources
These include Black or Red Currants, Gooseberries, Green Beans, Capsicum (cayenne pepper), Cabbage, Eggplant, Tomatoes, Turnips, Shiitake Mushrooms, and Kelp.

References