About Vitamin B 12
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Vitamin B12 (cyanocobalamin) is a member of the vitamin B complex group. Due to the fact that no foods of vegetable origin have been found to contain B12, it is of concern to vegans, who eat no animal products. The presence of B12, claimed to be found in some foods, such as mushrooms, is thought to be due to "contaminants", such as animal manures or microorganisms living on the vegetable or fruit surface.
Other concerns are that the small amount of the vitamin present may not be sufficient for needs, and that the "intrinsic factor" needed for absorption, may not be able to absorb these quantities. Some believe that, if humans are meant to be frugivorous, then the vitamin will be synthesized in the healthy small intestine or large intestine and absorbed into the circulation. Other frugivorous animals do not need supplements. It is possible that, if we grow organic vegetables and fruits and wash them only in water, the "contaminants", the microorganisms, would be present in the diet, and provide the environment in the intestines for the production and absorption of B12.
If you have no B12 deficiency symptoms, particularly the early symptoms, you may choose not to take a supplement. It may be found that some vegans will produce and absorb B12 in the small intestine or large intestine, if the digestive system is healthy and is functioning properly.
Until these factors are confirmed or clarified, if any of the early symptoms of B12 deficiency occur, it is advisable to visit a practitioner who is suitably qualified in Nutrition, who can assist in the diagnosis and treatment of Vitamin B12 deficiency. Early symptoms are vague and may be similar to some of the symptoms for fatigue, stress, iron deficiency or other lifestyle factors that cause typical symptoms of anaemia.
Mechanism in stomach, called Intrinsic Factor, with calcium present. Maximum of 8 mcg absorbed by this mechanism. Only one per cent of the oral dose is absorbed by simple diffusion (in the stomach).
Needed for synthesis of DNA the basis of all body cells; maintains a healthy myelin sheath on the nerve fibres; detoxifies cyanide in food and tobacco smoke. Deficiency finally results in Pernicious Anaemia.
Burning tongue (glossitis); smooth, sore tongue; tiredness (can be a variety of causes on its own), tingling in extremities (fingers and toes); failing memory, depression.
Nerve degeneration causing tremors; psychosis; mental deterioration; menstrual disorders; hand pigmentation (coloured people only); typical symptoms of anaemia (tiredness, fatigue, moodiness, poor memory, paranoia, mental confusion, poor appetite); loss of sensation in lower extremities; loss of appetite; constipation alternating with diarrhoea; vague abdominal pains; weight loss, chronic depression.
At least 3mcg (a resin-imbedded form remains unaffected in the stomach and ensures optimum absorption in the small intestine). A 100mcg tablet will assure maximum absorption. The liver stores an average of five years supply of B12, so deficiency symptoms may not occur for several years. However, this is no reason to be complacent, as many factors can cause this reserve to be depleted more rapidly.
Non-absorption due to lack of Intrinsic Factor (protein); Sprue; Intestinal Parasites; Veganism; Pregnancy; Old Age; Alcohol Abuse; Heavy Smoking.
Reference: "Thorsons Complete Guide To Vitamins & Minerals".
Estimated requirements per day - 3mcg (microgram)- 1 microgram = 1/1000 th of 1 mg.
I don't recommend that vegans take synthetic vitamins, except Vitamin B12, when indicated. Let's get our nutrition from natural vegan food, whenever possible!
