Korn
May 12th, 2004, 10:12 AM
From http://tuberose.com/Vitamins.html
"Vitamin B12
Vitamin B12 has the most complex structure of all vitamins and is also unique in that it is the only vitamin containing a metal ion. Cobalamin is the generic name of the vitamin because of the presence of the metal ion cobalt in its structure. Vitamin B12 was isolated in 1948. Merck and Company is the holder of various patents of procedures for producing synthetic B12 and owns the product claim. B12 functions primarily as an essential coenzyme for the normal metabolism of all cells, including those of the gastrointestinal tract, bone marrow, and nervous tissue. It is also a coenzyme in the synthesis of red blood cells and in the maintenance of nerve cells, and is involved with protein, lipid and nucleic acid synthesis. It is considered necessary for growth. The coenzyme of vitamin B12 is a carrier of methyl groups and hydrogen and is necessary for protein, fat, and carbohydrate metabolism. Coenzyme B12, methylcobalamin, functions as a methyl-group donor to form methionine from homocysteine. Vitamin B12 coenzyme deoxyadenosylcobalamin functions in the conversion of methylmalonic acid to succinic acid. Methionine and B12 coordinate in the regulation of folate metabolism. A deficiency of either vitamin results in defective synthesis of DNA in any cell that attempts chromosomal replication and division.
Chronic mercury inhalation from mercury amalgam dental fillings, with its great affinity to bind to methionine and cysteine has the potential to decrease the availability of these amino acids and affect the metabolism of both vitamin B12 and folate in man. Methionine is needed in choline synthesis, which means that vitamin B12 plays a secondary role in this lipid pathway. A choline deficiency that causes fatty liver can be prevented by vitamin B12 or the other methyl donors--betaine, methionine, and folic acid. Impaired fatty acid synthesis, observed in vitamin B12 deficiency conditions, can result in impairment of brain and nerve tissue. The insulation around nerve cells, the myelin sheath, is misformed in vitamin B12 deficiency, contributing to faulty nerve transmission.
Neurological disturbances result from prolonged vitamin B12 deficiency. Inorganic mercury inhibits outgrowth of nerve fibers and the development of glial cells, and also depresses the outgrowth of fibroblasts. Methyl-B12 is able to inhibit the neurotoxic effects of organic mercury but not those caused by inorganic mercury. Mercury vapor released from dental amalgam fillings is inorganic mercury. Very low concentrations of mercury and arsenic are able to inhibit nerve outgrowth, and lead directly interferes with the process of myelination. Proper DNA replication is dependent on the function of coenzyme vitamin B12 as a methyl-group carrier. Methyl-B12 may play an important role in immune regulation. Methyl-B12 is able to enhance the activity of helper T-cells for immunoglobulin synthesis of B cells. The presence of methyl-B12 significantly potentiates the induction of suppressor cells. Polymorphonuclear leukocytes (PMNs) are white blood cells that function in a phagocytic capacity (capable of destroying foreign substances). Low levels of mercury inhibit the metabolic reaction called respiratory burst in human PMNs. Mercury acts as an interference to normal biological functions involving the formation and/or function of sulfur containing proteins in cells, enzymes, and hormones. Biological damage will occur long before the appearance of any clinically observable signs and symptoms of mercurialism. Known causes of B12 malabsorption are a lack of intrinsic factor and hydrochloric acid in the stomach, the removal or disease of the second portion of the ileum, and competition for B12 by microorganisms or parasites.
There is far more unknown than known about B12 and its metabolism in the body. There are several vegetarian food sources of B12. While these sources may not be constant, it appears that they occur with sufficient frequency to supply the minute quantities of B12 that are needed by those who are not abusing their health. These include: wheat, soybeans, various common greens, olives, fruits, and many other foods that occasionally have B12 either in or on the food. Vitamin B12 has been found in roots and stems of tomatoes, cabbage, celery, kale, broccoli and leeks. It has been found in the leaves of kohlrabi. Seaweed and alfalfa contain B12 also. It is difficult to avoid vitamin B12. A further source of B12 is bacterial growth in the mouth (around the teeth and gums), in the nasopharynx, around the tonsils and tonsillar crypts, in the folds at the base of the tongue, and in the upper bronchial tree. Up to 0.5 micorograms daily can be obtained from this source. It's likely that this source alone will supply sufficient quantities of B12 for the small requirement that a pure vegetarian has, especially considering his low protein intake, which further reduces the need for B12. It has also been shown that some bacteria, which may colonize the small intestine of man, can synthesize considerable amounts of biologically active forms of the vitamin. The terminal ileum is principally involved in absorbing B12. Since bacteria can form B12 above the terminal ileum, and since intrinsic factor, which is needed for most rapid absorption, is found in the ileum, there can be adequate absorption of vitamin B12 produced from these bacteria in the ileum in healthy people.
Individuals taking conventional diets need only about 0.1 micrograms of B12 per day even though conventional diets contain excess fat, animal protein and refined foods all of which increase the need for B12. True vegetarians require only 0.05 micrograms of B12 daily. An ounce of the roots of leeks, beets and other vegetables will provide 0.1 to 0.3 mcg. of B1, more than a day's supply. The routine use of vitamin B12 is not advised. Cases of increased cancer production in animals receiving high levels of B12 have been published. A group of French investigators reported a series of cases suggesting that B12 may stimulate multiplication of cancer cells and aggravate the disease. Patients with rheumatoid arthritis present serum B12 levels significantly higher than normal subjects. It is also known to be higher in patients with ulcerative colitis, leukemia and other serious illnesses. Breast-fed infants get only a tiny fraction of a microgram of B12 per day, even if their mothers are on a high intake. Yet, they can build neurological tissue, convert their hemoglobin from F to A type, and do other complex functions dependent on B12. Iron deficiency interferes with absorption of B12. Large doses of vitamin B1 can also destroy vitamin B12, as can the use of oral contraceptives. Lactose intolerance may increase B12 needs."
"Vitamin B12
Vitamin B12 has the most complex structure of all vitamins and is also unique in that it is the only vitamin containing a metal ion. Cobalamin is the generic name of the vitamin because of the presence of the metal ion cobalt in its structure. Vitamin B12 was isolated in 1948. Merck and Company is the holder of various patents of procedures for producing synthetic B12 and owns the product claim. B12 functions primarily as an essential coenzyme for the normal metabolism of all cells, including those of the gastrointestinal tract, bone marrow, and nervous tissue. It is also a coenzyme in the synthesis of red blood cells and in the maintenance of nerve cells, and is involved with protein, lipid and nucleic acid synthesis. It is considered necessary for growth. The coenzyme of vitamin B12 is a carrier of methyl groups and hydrogen and is necessary for protein, fat, and carbohydrate metabolism. Coenzyme B12, methylcobalamin, functions as a methyl-group donor to form methionine from homocysteine. Vitamin B12 coenzyme deoxyadenosylcobalamin functions in the conversion of methylmalonic acid to succinic acid. Methionine and B12 coordinate in the regulation of folate metabolism. A deficiency of either vitamin results in defective synthesis of DNA in any cell that attempts chromosomal replication and division.
Chronic mercury inhalation from mercury amalgam dental fillings, with its great affinity to bind to methionine and cysteine has the potential to decrease the availability of these amino acids and affect the metabolism of both vitamin B12 and folate in man. Methionine is needed in choline synthesis, which means that vitamin B12 plays a secondary role in this lipid pathway. A choline deficiency that causes fatty liver can be prevented by vitamin B12 or the other methyl donors--betaine, methionine, and folic acid. Impaired fatty acid synthesis, observed in vitamin B12 deficiency conditions, can result in impairment of brain and nerve tissue. The insulation around nerve cells, the myelin sheath, is misformed in vitamin B12 deficiency, contributing to faulty nerve transmission.
Neurological disturbances result from prolonged vitamin B12 deficiency. Inorganic mercury inhibits outgrowth of nerve fibers and the development of glial cells, and also depresses the outgrowth of fibroblasts. Methyl-B12 is able to inhibit the neurotoxic effects of organic mercury but not those caused by inorganic mercury. Mercury vapor released from dental amalgam fillings is inorganic mercury. Very low concentrations of mercury and arsenic are able to inhibit nerve outgrowth, and lead directly interferes with the process of myelination. Proper DNA replication is dependent on the function of coenzyme vitamin B12 as a methyl-group carrier. Methyl-B12 may play an important role in immune regulation. Methyl-B12 is able to enhance the activity of helper T-cells for immunoglobulin synthesis of B cells. The presence of methyl-B12 significantly potentiates the induction of suppressor cells. Polymorphonuclear leukocytes (PMNs) are white blood cells that function in a phagocytic capacity (capable of destroying foreign substances). Low levels of mercury inhibit the metabolic reaction called respiratory burst in human PMNs. Mercury acts as an interference to normal biological functions involving the formation and/or function of sulfur containing proteins in cells, enzymes, and hormones. Biological damage will occur long before the appearance of any clinically observable signs and symptoms of mercurialism. Known causes of B12 malabsorption are a lack of intrinsic factor and hydrochloric acid in the stomach, the removal or disease of the second portion of the ileum, and competition for B12 by microorganisms or parasites.
There is far more unknown than known about B12 and its metabolism in the body. There are several vegetarian food sources of B12. While these sources may not be constant, it appears that they occur with sufficient frequency to supply the minute quantities of B12 that are needed by those who are not abusing their health. These include: wheat, soybeans, various common greens, olives, fruits, and many other foods that occasionally have B12 either in or on the food. Vitamin B12 has been found in roots and stems of tomatoes, cabbage, celery, kale, broccoli and leeks. It has been found in the leaves of kohlrabi. Seaweed and alfalfa contain B12 also. It is difficult to avoid vitamin B12. A further source of B12 is bacterial growth in the mouth (around the teeth and gums), in the nasopharynx, around the tonsils and tonsillar crypts, in the folds at the base of the tongue, and in the upper bronchial tree. Up to 0.5 micorograms daily can be obtained from this source. It's likely that this source alone will supply sufficient quantities of B12 for the small requirement that a pure vegetarian has, especially considering his low protein intake, which further reduces the need for B12. It has also been shown that some bacteria, which may colonize the small intestine of man, can synthesize considerable amounts of biologically active forms of the vitamin. The terminal ileum is principally involved in absorbing B12. Since bacteria can form B12 above the terminal ileum, and since intrinsic factor, which is needed for most rapid absorption, is found in the ileum, there can be adequate absorption of vitamin B12 produced from these bacteria in the ileum in healthy people.
Individuals taking conventional diets need only about 0.1 micrograms of B12 per day even though conventional diets contain excess fat, animal protein and refined foods all of which increase the need for B12. True vegetarians require only 0.05 micrograms of B12 daily. An ounce of the roots of leeks, beets and other vegetables will provide 0.1 to 0.3 mcg. of B1, more than a day's supply. The routine use of vitamin B12 is not advised. Cases of increased cancer production in animals receiving high levels of B12 have been published. A group of French investigators reported a series of cases suggesting that B12 may stimulate multiplication of cancer cells and aggravate the disease. Patients with rheumatoid arthritis present serum B12 levels significantly higher than normal subjects. It is also known to be higher in patients with ulcerative colitis, leukemia and other serious illnesses. Breast-fed infants get only a tiny fraction of a microgram of B12 per day, even if their mothers are on a high intake. Yet, they can build neurological tissue, convert their hemoglobin from F to A type, and do other complex functions dependent on B12. Iron deficiency interferes with absorption of B12. Large doses of vitamin B1 can also destroy vitamin B12, as can the use of oral contraceptives. Lactose intolerance may increase B12 needs."