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NEWSLETTER 8 - Extension 2 : Saccharides in Our Biochemistry (Updated September 2005)

Diet
Biochemistry
Enzymes
Health and Research
Conclusion

Saccharides in Our Diet

Our modern diet provides mainly the polysaccharides saccharose, maltose and lactose. They contain the monosaccharides glucose, fructose, and galactose, only three of the eight monosaccharides our biochemistry uses (Table 1).

Common Name Polysaccharide Formed of and of
Sugar, Sucrose Saccharose Glucose Fructose
Starch Maltose Glucose Glucose
Milk Sugar Lactose Glucose Galactose

Table 1: Composition of the three main polysaccharides occurring in our diet.

Human diets have changed over time and not always for the better. Hunter-gatherer societies ate a variety of foods including roots, wild grains, berries, leaves and nuts. After the advent of agriculture, people settled down to regular consumption of a more limited variety of easy-to-grow foods, such as potatoes wheat and rice.

Archeologists tell us that the earliest hunter-gatherers people were actually taller, healthier, and had better teeth and bone structure than the agricultural people that came later.

More recently, modern refining methods further diminished the variety of nutritional components consumed in conventional diets. Whole wheat was replaced by refined flour, whole wild rice by polished rice and whole potatoes by mashed potato flakes.

Most of the source for the saccharides needed by our cells were lost by these changes. Science is only scarcely beginning to understand the consequent effect on our health.

(Bill McAnalley. The Potential Significance of Dietary Sugars in Management of Osteoarthritis and Rheumatoid Arthritis: A Review. Proceedings of the Fisher Institute for Medical Research. Vol.1, N°1, November 1997. 6-10)

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Saccharides in Plant and Human Biochemistry

Plant biochemistry synthesizes mono- and polysaccharides from carbonic acid and water.

Human biochemistry synthesizes glucose from lactate and from pyruvate. Human biochemistry is able (in perfect health condition) to convert the two or three saccharides occurring in modern diet into seven of the eight saccharides and saccharide derivatives it needs to assume all of its functions. Synthesis and conversion occurs with the assistance of vitamins from the B group and with minerals, as magnesium, manganese, selenium, iron, and zinc acting as enzyme activators.

The eight saccharides and saccharide derivatives the human biochemistry uses are : Glucose, Galactose, Mannose, Fucose, Neuraminic N-acetyl acid (NeuNAc), N-acetyl Glucosamine, N-acetyl Galactosamine, and Xylose.

Human biochemistry uses these eight saccharides in cell and organ structure, in cell communication, and in immunity.

Saccharides in Cell and in Organ Structure

Saccharides participate in cell and organ structure in association with proteins. Saccharides account for 5% of the mass of a cell membrane. The most frequent saccharide in cell and organ structure is N-acetyl glucosamine, followed by N-acetyl galactosamine.

N-acetyl glucosamine and N-acetyl galactosamine -- absent in our diet -- have to be synthesized from the saccharides provided in the diet. The synthesis of these two saccharides starting from glucosamine and galactosamine -- if these saccharides are available in the diet -- is much less expensive for our biochemistry than their synthesis from glucose.

Saccharides in Cell Communication

Cells communicate with "messages" they carry on the surface of their membrane. The "messages" are glycoforms, molecules formed essentially of saccharides. Glycoforms protrude from the external surface of the cell membrane. Glycoforms contain the monosaccharides mannose, N-acetyl galactosamine, and galactose.

Saccharides in Immunity

The immunity of a cell depends on the "messages" expressed by the glycoforms on the surface of its membrane. If in a message, words are missing or misspelled -- if some saccharide is missing in the glycoform-- the message is erroneous with all the consequences of it. An error in the message disguises the real identity of the cell bearing it. An error in the message can bring other cells "reading& it to act as if the bearer of the error was a foreign body.

Many diseases have in common the inability of certain cells to send correct messages -- to synthesize the correct glycoforms.

This inability may result from an error in the genetic code that governs the synthesis of the glycoforms.

The inability may also result from the absence of the needed saccharide in the diet or from a combination of the two conditions.

The Carbohydrate Deficient Glycoprotein Syndrome results from a mannose deficiency.

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The Role of Enzymes in Our Saccharide Biochemistry

The conversion from one molecule of saccharide into another is an enzymatic process involving multiple intermediary steps.

As an example, the conversion from glucose to mannose-6-phosphate involves three such intermediary steps (Table 2).

From Enzyme Direction To
Glucose Phosphate-6-kinase reversible Glucose-6-phosphate
Glucose-6-phosphate Isomerase reversible Fructose-6-phosphate
Fructose-6-phosphate Isomerase reversible Mannose-6-phosphate

Table 2: The conversion of glucose to mannose-6-phosphate involves three enzymatic steps. The process is theoretically reversible.

The conversion from glucose to galactose involves six intermediary enzymatic steps (Table 3). The process is reversible, galactose can be converted to glucose.

From Enzyme Direction To
Glucose Phosphate-6-kinase reversible Glucose-6-phosphate
Glucose-6-phosphate Mutase reversible Glucose-1-phosphate
Glucose-1-phosphate Pyrophosphorylase reversible UDP-Glucose
UDP-Glucose 4 -Epimerase reversible UDP-Galactose
UDP-Galactose Uridyl-Transferase reversible Galactose-1-phosphate
Galactose-1-phosphate Phosphate-6-kinase reversible Galactose

Table 3: The conversion of galactose to glucose involves six enzymatic steps. (UDP stands for: Uridine DiPhosphate). The process is reversible, galactose can be converted to glucose.

The conversion from glucose to Glucosamine-Acetyl-1-Phosphate involves eight intermediary enzymatic steps (Table 4).

From Enzyme Direction To
Glucose Phosphate-6-kinase reversible Glucose-6-phosphate
Glucose-6-phosphate Isomerase reversible Fructose-6-phosphate
Fructose-6-phosphate Amidotransferase reversible Glucosamine-1-Phosphate
Glucosamine-1-Phosphate Acetyl-CoA-transferase reversible Glucosamine-Acetyl-6-Phosphate
Glucosamine-Acetyl-6-Phosphate Mutase reversible Glucosamine-Acetyl-1-Phosphate
Glucosamine-Acetyl-1-Phosphate Pyrophosphorylase reversible UDP-Glucosamine-Acetyl
UDP-Glucosamine-Acetyl Pyrophosphorylase reversible Glucosamine-Acetyl-1-Phosphate

Table 4: The conversion of glucose to Glucosamine-Acetyl-1- Phosphate involves eight enzymatic steps. (UDP stands for: Uridine DiPhosphate).

The same Glucosamine-Acetyl-1-Phosphate is obtainable from glucosamine in a much more economical way involving only two enzymatic steps (Table 5).

Glucosamine Acetyl-CoA-transferase reversible Glucosamine-Acetyl
Glucosamine-Acetyl Phosphokinase reversible Glucosamine-Acetyl-1-Phosphate

Table 5: The conversion of glucosamine to Glucosamine-Acetyl-1-Phosphate involves two enzymatic steps.

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Saccharides in Health


Any defect in the enzymatic processes involved results in altered health conditions. The list of health conditions related to saccharide deficiency comprises but is not restricted to : Collagen diseases - Endocarditis - Hashimoto disease - Juvenile chronic arthritis - Mixed connective tissue disease - Myocarditis - Myositis - Nephritis - Peritonitis - Pericarditis - Pleuritis - Polymyositis-dermatomyositis - Progressive systemic sclerosis - Rheumatoid arthritis - Sjšrgen's syndrome - Skin rashes - Synovitis - Systemic lupus erythematosus - Vasculitis

In health conditions related to saccharide deficiency, laboratory tests indicate : Alteration of serum complement - Antinuclear antibodies - Cryoglobulins - Elevated muscle enzymes - False serologic positive test for syphilis - Hemolitic anemia - Immunoglobuline excess or deficiency - Leukopenia - Rheumatoid factor - Thrombocytopenia

Saccharides in Research

There is much work to do on saccharides. Research is only beginning to decifer the numerous implications of the saccharide metabolism and the significance of a particular saccharide deficiency.

The biochemistry of mannose has recently received more attention.

Mannose is an essential part of cell glycoforms. Until now it was assumed that all the mannose cell may need is converted from glucose occurring in the diet.

Recent research indicates that mannose -- when available in the diet -- contribute to 75% of the mannose utilization for glycoform synthesis (G.Alton 1997).

The direct utilization of mannose from the diet avoids the three enzymatic steps needed to convert glucose into mannose-6-phosphate.

The glucose to mannose-6-phosphate conversion , involves the intermediary step of the conversion of fructose-6-phosphate to mannose -6-phosphate by the enzyme phosphomannose isomerase (PMI)

The direct conversion of mannose to mannose-6-phosphate is activated by the enzyme phosphokinase (PK).
The enzyme PMI needs zinc, the enzyme PK iron and magnesium.

It is worth mentioning that zinc deficiency occurs much more frequently than iron or magnesium deficiency, particularly in older people.

For people with a low glucose to mannose conversion, supplementing the diet with mannose significantly contribute to maintaining their health.




The Consequence of a Mannose Deficiency : The Carbohydrate Deficient Glycoprotein Syndrome

The Carbohydrate Deficient Glycoprotein Syndrome (CDGS) is an inherited metabolic disorder with multi-systemic abnormalities resulting from a failure to add entire N-linked oligosaccharide chains to many glycoforms.

Children with the Carbohydrate Deficient Glycoprotein Syndrome--a congenital recessive condition--do not synthezise sufficient mannose from other sugars. Are you concerned about it? See the information provided by Hudson Freeze, Ph.D, a Senior Staff Scientist at the Burnham Institute in La Jolla CA, USA.

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Conclusion

Saccharides play an important role in cell and organ structure, in cell communication, and in immunity.

Our refined diet does not provide the eight saccharides our biochemistry needs. The conversion of the two or the three saccharides occurring in the diet into the missing saccharides - although theoretically possible -- is often not effective.

Many health-compromised situations result from this inability. It has become obvious that supplementing our diet with the missing saccharides is helpful in maintaining and restoring health.

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