Four kinds of B12
Vitamin B12 consists of group of four different cobalamins which, more or less, have the similar effect. They are called hydroxocobalamin, adenosylcobalamin, methylcobalamin, and cyanocobalamin. The most common form of B12 supplement is cyanocobalamine. The two active forms of B12 in the body, however, are adenocylcobalamin and methylcobalamin. When taking cyanocobalamin, the body needs to replace the cyanide molecule with either an adenosyl group or a methyl group. This usually does not present a problem, but the speed at which this replacement takes place is often reduced with age. This is also the explanation to why methylcobalamin e.g. is absorbed more easily than cyanocobalamin.
B12 deficiency
With vitamin B12 deficiency there is a build up of unhealthy homocysteine, or more specifically a substance called methylmalonate. The amount of these substances can be measured by a blood test.
Deficiency symptoms
Pernicious anaemia, macrocytic, megaloblastic aenemia (a different form caused by folic acid deficiency), neurological degeneration, degeneration of the optic nerve, brain damage, callousness, prickling and tingling in body tissue, unsteady walking, and loss of reflexes, mental symptoms (mood swings), debilitation and fatigue, impaired memory, failing concentration and learning difficulties, mental disorder and delusional paranoia, hearing voices, hallucinations (often diagnosed as senile psychosis), shiny smooth red tongue, problem skin, diarrhoea, loss of appetite, and failing sense of taste.
It has been claimed that an intake of large quantities of vitamin C can cause vitamin B12 deficiency. This is not the case. Two biochemical transport routes are involved in the absorption of vitamin B12: vitamin transport by means of a protein fraction called intrinsic factor (IF) and passive diffusion. Low concentrations are absorbed via the IF system, whereas high doses are absorbed via diffusion. An IF deficiency can cause pernicious anaemia, even with normal vitamin B12 intake. Even though IF is normal, problems can arise since the absorption of the vitamin is dependent on a sufficient amount of gastric acid.
Because elderly people often have a reduced gastric acid secretion, B12 deficiency can be expected in this group. Vitamin B12 in large quantities is mostly found in animal products, and many plant foods do not contain vitamin B12 at all except if contaminated by micro-organisms. Thus, vegans may need to look to other sources to get vitamin B12 in their diets.
Although some doctors oppose the administration of vitamin B12 except for diagnosed pernicious anaemia, experience shows that many debilitated and confused patients, particularly elderly people, thrive far better if treated regularly with B12 supplements although they do not suffer from pernicious anaemia.
Vitamin B12 tests on animals have shown a substantial reduction of cancer tumours. Cancer precursors in smokers have been reduced dosages of 500 mcg. daily combined with 10 mg. of folic acid. The test ran for 4 months.
Some neuropsychiatric conditions can be improved by vitamin B12, presumably because of the vitamin's function in the biosynthesis of nervous myelin sheaths.
Vitamin B12 has proved to be an effective analgesic and anti-inflammatory agent. Through its coenzyme function of activating the enzyme sulfite oxidase the vitamin neutralize the sulfites used extensively by the food industry although they are known for causing allergenic reactions such as asthma and headache.
Methylcobalanin for the nervous system
If the intention of B12 supplement use is to combat nervous system problems, methylcobalanin should be used. People with such problems have reported positive effects from this form of B12.
RDA
1 microgram.
Therapeutic dosages
- General supplement: 100 mcg. a day.
- For congenital enzyme failure: 15 mg. daily.
- For poor absorption from the intestinal tract: 1 mg. in the form of hydroxycobalamin administered as a subcutaneous injection once or twice a week.
- As lozenges: 1000 mcg. once or twice daily.
B12 poisoning has never been observed. Dosages up to 30 mg. daily have not given any negative reactions. The vitamin is therefore said to be without side effects in dosages which are above 30,000 times ADT!
Large single supplements are best utilized if taken together with vitamin B9 (folic acid) and ever better together with the rest of the B complex vitamins.
Richest natural sources
Organ meat, spirulina, poultry, fish, shrimp, oysters, eggs, cheese, dairy products, brewers' yeast, seaweed, and marine algae. Found in small amounts in leguminous plants and other vegetables.
