Mannose
Mannose appears to be the foundation of all the essential sugars. It is involved
in so many fundamental cell actions that any deficiency of this one saccharide
can lead to a host of physical problems. Called D-Mannose, this form is now sold
as a remedy for UTIs (urinary tract infections), but it is capable of so much
more. Like Xylose and Xylitol, Mannose also has its sugar alcohol in the form
known as Mannitol.
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.
Evidentally, 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 glyconutrients.
Other sources include
Black or Red Currants, Gooseberries, Green Beans, Capsicum (cayenne pepper),
Cabbage, Eggplant, Tomatoes, Turnips, Shiitake Mushrooms, and Kelp
References
1.Mondoa, Emil I. MD and Mindy Kitei. Sugars that Heal. Ballantine Publishing,
2001.
2.Elkins, Rita MH. Miracle Sugars. Woodland Publishing, 2003.
3.Glycoscience website (This site prohibits direct linkage.)
4.http://www.cdgs.com/freeze5.htm (an essay on Carbohydrate Deficient Glycoprotein
Syndrome)
5.http://www.healingtherapies.info/D-Mannose.htm (a urologist's report on using
Mannose for UTIs)
6.http://www.lis.net.au/~dbird/glyconutrients.htm (A glyconutrient site by Dr
David Bird MbChB, Dip Clinical Nutrition, FACNEM [Fellow of the Australian College
of Nutritional and Environmental Medicine])
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