Vitamin B12
B12 was first isolated in 1947 and was the last vitamin to be discovered. Another name for B12 is cyanocobalamin, named after the cyanide ion in the molecule. It has also been known as the "red" vitamin, named for its characteristic color. B12 is not a single substance, but consists of several closely related compounds with similar activity. Cobalamins (hydroxocobalamin, nitrocobalamin, and thiocyanate cobalamin) all contain the trace mineral cobalt.
B12 is a complex, symmetrical molecule similar in many ways to hemoglobin, differing only in the center. An atom of iron is at the center of hemoglobin, whereas B12 has an atom of cobalt at the same position. It is the only nutrient known to contain cobalt.
B12 is not present IN foods so much as ON them within the dirt or bacteria. Because animals eat plantforms complete with the dirt, they are able to store B12 in their tissues. Meat eaters are then able to obtain this nutrient in their food, whereas vegans must obtain it in a supplemental form -- unless, of course, they adhere to the old saying "everyone must eat a peck of dirt in their lifetime." Still, it is advisable to take supplements in this case. When plant foods are cleaned, the bacteria and the B12 are removed. Modern farming techniques also deplete the soil of this nutrient unless "organic" methods are used. Brewer's yeast fortified with B12 is a good source of this nutrient. However, be aware that prolonged and excessive use of brewer's yeast can impair kidney function.
Many assume that vegetarians are deficient in B12 since it can be found only in animal tissues. Nutritionists now recognize that sufficient B12 can be obtained within a knowledgeable vegetarian diet. What needs to be addressed is the deficiency of this vitamin found in meat eaters. With protein digestion taking up to five days, which causes putrification, harmful bacteria begin to grow crowding out the "friendly" bacteria needed for the formation and absorption of nutrients. B12 and the necessary intrinsic factor are consumed in this type of environment and are never able to reach their intended destination. Therefore, even though the diet may be rich in the nutrient, it cannot be used in the body because of existing factors including this scenario.
Vitamin B12 is required only in minute amounts, but, when missing, results are not so minute -- producing irreversible brain damage and nervous disorders. The body requires only 3/1,000,000 of a gram per day (or 3 mcg.). One milligram of this vitamin will generally last for a period of two years, with a healthy individual usually carrying around a five year supply. The reabsorption of B12 is stored in the liver and is readily available when the need arises. These stores are sufficient to sustain physiologic needs for several years, even with a total absence of intrinsic factor. It is the only B vitamin that can be stored in the body for any length of time.
The digestive process of B12 begins in the stomach, where hydrochloric acid and pepsin (an enzyme) release B12 from dietary protein allowing it to bind to salivary R proteins. After passing into the small intestine, it is altered by pancreatic enzymes in the jejunum. (The small intestine is about 22 feet long, with the upper 2/5ths being the jejunum and the remaining 3/5ths the ileum). In the jejunum, B12 binds to intrinsic factor, which is secreted from the parietal cells in the gastric mucosa (membranes of the stomach). The resulting compound cannot be broken down any further by digestive enzymes and passes unchanged until it adheres to special receptors on cells lining the ileum. It is here that B12 can be absorbed and utilized by the system.
Pernicious anemia occurs when the intrinsic factor is absent, causing incomplete B12 absorption, even though there may be adequate amounts in the diet. Intrinsic factor is not only essential to the absorption of B12, but is also necessary for the formation of erythrocytes (red blood cells) which, if lacking, produce pernicious anemia. Pernicious anemia differs from megoblastic anemia, which is characterized by the presence of megoblasts in the bone marrow. Megoblastic anemia results from defective DNA synthesis (RNA synthesis continues) when the primitive RBC's (red blood cells) do not properly mature and become much larger than the mature normal erythrocytes. The megoblastic anemias of pregnancy and infancy respond readily to folic acid therapy and diet adjustment. Folate, taken with B12, can prevent such incidents. However, a B12 deficiency can be masked with the consumption of large doses of folacin.
B12 helps oxidize certain fatty acids and supports healthy nerves. It is known to promote growth, increase appetite, improve concentration, memory, and balance, and decreases irritability. B12 may also help in the treatment of chronic fatigue and age-related decline in energy levels and can improve diabetic retinopathy. Studies show that supplementation has reduced the amount of precancerous bronchial tissues in cigarette smokers and has been used to treat bronchial spasms (asthma), bursitis, and bone spur and neuralgia pain. Studies have shown that supplementation has improved recovery time from various illnesses and surgeries. Some have reported that taking B12 with garlic makes a good insect repellent.
As stated, vegans do need B12 supplementation. Those relying on certain foods for this nutrient should be aware of some information. Tamari, tempeh, and miso were found to be lacking in B12, despite claims to the contrary. Also, tamari, sauerkraut, umeboshi plums, seaweeds, spirulina, and algae are not considered to be good sources of B12, with spirulina containing fewer usable vitamins than originally thought. The problem with seaweed seems to be that the amount of B12 varies, plus the fact that it contains B12 analogs. Analogs are compounds produced by overgrowth of gastric bacteria and are physically similar to B12, but contribute nothing as far as nutrition is concerned. In fact, these compounds compete with B12 for absorption causing a B12 deficiency.
Those who are at risk for Vitamin B12 deficiency are: the elderly, since the intrinsic factor declines with age; alcoholics; Crohn's sufferers; those experiencing severe food or chemical allergies/sensitivities; those who have had stomach surgery, a history of anemia, chronic yeast infections or parasitic infestations; and those who suffer from anxiety or depression. Irreversible nerve damage is possible with prolonged deficiency. A B12 deficiency can be masked by low levels of B1 and folic acid. This reinforces the fact that one B Vitamin should not be taken alone but must be accompanied with all the others in order to avoid a deficiency in any one or more of them.
Studies have shown that B12 blocks severe allergic reactions to sulfites in foods, with patients being given as much as 2000 mcg. of B12. The reactions included headaches, congestion, runny nose, and bronchial spasms. Mega doses of any nutrient should always be done under the supervision of a knowledgeable health care practishioner.
RDA -- 2 mcg. per day, while the optimal requirement is 100-400 mcg. per day (or 2-3 tbsp. of nutritional yeast (with B12) per day for adults. Nutritional surveys show that most American men consume about 6 mcg. of B12 daily, while women consume about 5 mcg., which are above the RDA, but well below what is considered to be an optimal level.
For those fond of technicalities, the following is a more critical breakdown of Vitamin B12:
Other names include: cobalamin, erthrotin, antipernicious factor, extrinsic factor of Castle,erythrocyte maturation factor, zoopherin, animal protein factor, factor X, Antipernicin, Bedoce, Bedodeka, Bedoz, Behepan, Berubi, Berubigen, Betalin-12, Bevatine-12, Bedidox, Bexii, Bexil, Biocobalamine, Biocres, Bitevan, B-Telve, B-Twelv, Byladoce, Claretin-12, Cobalin, Cobamin, Cobamine, Cobione, Covit, Crystamin, Cycobemin, Cycolamin, Cykobeminet, Cytacon, Cytamen, Cytobion, Distivit, Dobetin, Docemine, Docigram, Docivit, Dodecabee, Dodecavite, Dodex, Ducobee, Duodecibin, Embiol, Emocicline, Eritrone, Erycytol, Erythrotin, Euhaemon, Fresmin, Hemo-B-Doze, Hemomin, Hepagon, Hepavis, Hepcovite, Hydoxamin, Hydroxobase, Macrabin, Megabion, Megalovel, Milbedoce, Millevit, Nagravon, Normocytin, Peraemon, Pernaevit, Pernipur, Plecyamin, Poyamin, Redamina, Redisol, Rhodacryst, Rubesol, Rubivitan, Rubramin, Rubripca, Rubrocitol, Sytobex, Vibalt, Vibisone, Virubra, Vitarubin, Vita-Rubra, Vitral.
Forms include: cyanocobalamin, Vitamin B12a/hydroxycobalamin/Vitamin OHB12, Vitamin B12b/aquocobalamin, Vitamin B12c/nitritocobalamin, Vitamin B12f, Vitamin B12m, Vitamin B12p/etiocobalamin/factor B, Vitamin B12r/cob(II)alamin, Vitamin B12s/cob(I)alamin/hydridocobalamin, Vitamin B12III, psi-vitamin B12, psi-vitamin B12d.
Inhibitors include: acid, alkali, water, sunlight, alcohol, estrogen, sleeping pills, neomycin, methotrexate, cholestyramine, colchicine, sodium aminosalicylate, slow-releasing potassium chloride, metaformin, phenoformin, sodium, nitroprusside, chloramphenicol, codeine, oral anti-diabetic agents, aspirin, aspirin substitutes, hydralazine, antibiotics, antidepressants (tricyclics and chloromazine), and the ulcer drug Prilosec (omeprazole) which can cause a deficiency of B12 because of its effectiveness in reducing stomach acid secretion vital to the absorption of B12. A poorly functioning thyroid gland will also contribute to a deficiency. Some feel that Vitamin C of more than 500 mg. taken within an hour of B12 destroys it. However, it is now thought that Vitamin C actually helps promote its absorption. Although not a huge worry for most, the anaesthetic nitrous oxide (laughing gas), can destroy B12.
Helpers include: Vitamins B6, B13, B17, Bc, BH, Bp, Bw, C, potassium, sodium, calcium, and sorbitol.
Deficiencies produce: pernicious anemia, yellow-blue color blindness, large or abnormal blood cells, decreased blood clotting, menstrual deterioration, heart palpitations, deterioration of growth and of carbohydrate metabolism, muscle weakness, weak pulse, numbness or tingling extremeties, stiffness, fatigue, depression or stuperous depression, emotional agitation and deterioration, decreased memory/concentration, deterioration of the nervous system and brain, hallucinations, manic behavior, senility, difficulty in walking, decreased reflexes, nervousness, paleness, sore tongue, red tongue, difficulty in swallowing, diarrhea, body odor, dandruff, deteioration of folacin utilization, hangover, blood iron levels deceptively increased, sterility, decreased immunity and in color perception, with side effects of dreaming in color, (rebound deficiency can occur if large doses are halted abruptly). Mental deterioration, senility, and neuropsychiatric disorders (dementia, depression, and loss of balance) have
responded well to B12 supplementation. Although toxicity is virtually unknown when taken orally, injections can produce elevated blood levels.
Vitamin B12a is a specific form of Vitamin B12. Other names include: hydroxycobalamin, Vitamin OHB12, Alpha Cobione, Alpha-Ruvite, Axion, Axlon, Ciplamin H, Cobalex, Codroxomin, Depogamma, Docelan, Docevita, Droxomin, Ducobee-Hy, Duradoce, Duralta-12, Hydrogrisevit, Hydrovit, Hyxobamine, Idrogriseovit, Lyovit-H, Neo-Betalin 12, Neo-Cytamen, Neo-Macrabin, Neo-Rojamin, OH-Duphar, Oxobemin, Primabalt RP, Oxolamine, alpha-Redisol, Redisol-H, Sytobex-H, Vitadurin.
Vitamin B12b is a specific form of Vitamin B12 produced from Streptomyces aureofaciens cultures. Other names include: aquocobalamin, aquocobamide, hydroxocobalamin.
Vitamin B12c is a specific form of Vitamin B12 produced from Streptomyces griseus cultures. Other names include: nitrosocobalamin, nitrocobalamin, nitritocobalamin.
Vitamin B12f is a specific form of Vitamin B12.
Vitamin B12m is a specific form of Vitamin B12.
Vitamin B12p is a specific form of Vitamin B12. Other names include: etiocobalamin, factor B, cobinamide dicyanide. The term "etiocobalamin" is sometimes used to denote any Vitamin B12 form lacking the nucleotide group.
Vitamin B12r is a specific form of Vitamin B12 also known as cob(II)alamin.
Vitamin B12s is a specific form of Vitamin B12 also known as cob(I)alamin or hydridocobalamin.
Vitamin B12-zinc tannate complex is a specific form of Vitamin B12 and is also known as cyanocobalamin zinc tannate complex or zinc-vitamin B12-tannate. It is used in long-acting injectable Vitamin B12 preparations.
Vitamin B12III is a specific form of Vitamin B12.
Psi-V-vitamin B12 is a specific form of Vitamin B12.
Psi-Vitamin B12d is a specific form of Vitamin B12.
Vitamin B12 Coenzyme is the actual form best used in the body. Other names include: Vitamin OHB12, Cobamamide, cobamamidum, coenzyme B12, DBC, Actimide, Ademide, Anabasi, Betarin, Calomide, Cobalion, Cobaltamin S, Cobanzyme, Cobazymase, Dolonevran, Enzicoba, Heraclene, Hi-Fresmin, Hycobal, Indusil, Ripresil, Sabalamin, Xobaline.
There are radioactive forms of B12 known as B12-60Co and B12-57Co. Other names include: radioactive Vitamin B12, radioactive cyanocobalamin, Racobalamin, Rubratope. Radioactive forms are used as diagnostic aides with tracking radioactive isotopes. The half-life for B12-60Co is 5.2 years and for B12-57Co, 270 days. Therefore, B12-57Co is preferred over B12-60Co for this reason.
