Vitamin B12 will stimulate growth in many malnourished children. In older people, it has helped with energy levels as well as psychological symptoms, including senile psychosis. B12 has also been used to help treat osteoarthritis and osteoporosis and for neuralgias, such as Bell's palsy, trigeminal neuralgia, or diabetic neuropathy. It has likewise been used in the treatment of hepatitis, shingles, asthma, other allergies, allergic dermatitis, urticaria, eczema, and bursitis. Cobalamin has been used for many other symptoms besides fatigue, including nervousness and irritability, insomnia, memory problems, depression, and poor balance. Vitamin B12 is something to keep in mind when we are not "feeling our oats."
Deficiency and toxicity: There have been no known toxic effects from megadoses of
vitamin B12. Thousands of times more than the RDA have been injected both intravenously and intramuscularly without any ill consequences. On the contrary, there is often some benefit.
Vitamin B12 deficiency usually results from a combination of factors. Restricted diets, as seen in vegetarians or poor nations, can be very limited in B12. Since the absorption into the body is so finely tuned, depletion and deficiency occur even more commonly from poor digestion and assimilation, or from deficient production of intrinsic factor. That is why it is so important to be aware of B12 and use some sort of supplementation once a deficiency has been diagnosed. Vitamin B12 blood levels, along with folic acid levels, are the most common vitamin tests performed by doctors. As we age, it is more likely that we may become B12 deficient. Also, alcoholics and people with malabsorption or dementia may have low B12 levels. Since the body stores vitamin B12, it may take several years to become deficient with dietary restriction or a decrease in intrinsic factor.
The strict vegetarian has more concern than the average meat- and dairy-eating person. B12 is not found in the vegetable kingdom other than in foods fermented by certain bacteria; thus most fermented foods have some vitamin B12. However, in vegetarians, there is usually a high folic acid intake, and since folic acid and B12 work similarly in the body, a B12 deficiency may be masked for a period of time, and then more pronounced symptoms may occur. If B12 is deficient in an animal eater, then we pretty much know there is a problem in absorption of the vitamin.
Most problems of B12 deficiency affect the blood, energy level, state of mind, and nervous system. Often, subtle symptoms may start with the nervous system. Vitamin B12 nourishes the myelin sheathes over the nerves, which help maintain the normal electrical conductivity through the nerves. Soreness or weakness of the arms or legs, decreased sensory perceptions, difficulty in walking or speaking, neuritis, a diminished reflex response, or limb jerking may result from B12 deficiency. Psychological symptoms may include mood changes with mental slowness may be one of the first symptoms.
With B12 deficiency, the body forms large, immature red blood cells, resulting in a "megaloblastic" anemia. Pernicious anemia refers to the deficiency in blood cells as well as the myriad of psychological and nerve symptoms. The anemia usually generates more fatigue and weakness. Menstrual problems, even amenorrhea (lack of menstrual flow), may also occur in B12-deficient women.
The problems related to the nervous system caused by vitamin B12 deficiency can lead to permanent damage, not correctable by B12 supplementation. This irreversible nerve damage may occur when the B12 deficiency effect on the red blood cells is masked by adequate levels of folic acid, as I mentioned. More severe pernicious anemia can cause a red, sensitive tongue, referred to as "strawberry tongue," which may even ulcerate, and nerve or brain and spinal cord degeneration, which can cause weakness, numbness, tingling, shooting pains, and sensory hallucinations. Paranoid symptoms may even occur. In the early part of this century, pernicious anemia was often a fatal disease.