Vitamin B12 (cyanocobalamin, methylcobalamin, and adenosylcobalamin) deficiency is one of the most common deficiencies. Because the deficiency isn't recognized until it has progressed to anemia, it is important to incorporate it into your diet via food or supplement before it becomes a problem. A vitamin B12 deficiency can be caused by malabsorption, which is most common in older adults and in people with digestive disorders. A low serum vitamin B12 levels can lead to significant impairment of our immune system.
Vitamin B12 is linked to the production of acetylcholine, a neurotransmitter that assists memory and learning. Vitamin B12 deficiency results in impaired nerve function, which can cause numbness, "pins and needles" sensations, or a burning feeling in the feet, as well as impaired mental function, which in the elderly can mimic Alzheimer's disease. In addition to depression or mental confusion, vitamin B12 deficiency can present as anemia; a smooth, beefy red tongue; and diarrhea. One study has also found that women over 64 with low levels of vitamin B12 were far more susceptible to osteoporotic bone loss. A deficiency of vitamin B12, or folic acid, results in significantly reduced white blood cell production and abnormal white blood cell responses.
Many older people become deficient in vitamin B12 because they do not produce adequate amounts of stomach acid for proper digestion. This creates a perfect environment for the overgrowth of certain bacteria that steal whatever vitamin B12 is extracted from protein in the digestive tract. Other people do not produce enough of a substance called intrinsic factor, without which vitamin B12 cannot travel from the stomach to the rest of the body, even if nothing else is standing in its way. This vitamin deficiency often appears very gradually. Patients may describe complaints such as mental fuzziness, a sensation of burning on the tongue, or poor coordination for months or even years before a proper diagnosis is made. Vitamin B12 is made by microorganisms found in the soil and by microorganisms in the intestines of animals, including our own. The amount made in our intestines is not adequately absorbed, so it is recommended that we consume B12 in food. Research has convincingly shown that plants grown in healthy soil that has a a good concentration of vitamin B12 will readily absorb this nutrient.