Vitamin B12 deficiency is present in 5% to 20% of the elderly population and may begin in middle age. One common cause, malabsorption, is affected by many factors often seen in the primary care setting, including prolonged use of proton pump inhibitors or metformin, or as a result of gastric bypass surgery.
The traditional sign of B12 deficiency, macrocytic anemia, can be masked by the folic acid supplementation in all enriched cereals/grains mandated by the US Food and Drug Administration since 1998. Vitamin B12 deficiency often causes neurologic deficits such as numbness and tingling in the arms, dizziness, loss of memory, burning mouth and fatigue etc.
B12 is vital for optimal function of the immune system. B12 is stored in the liver, but it can take 5 to 10 years for a person to become B12 deficient due to malabsorption; however, demand for B12 markedly increases during times of physical stress, which depletes stores as well. B12 deficiency is common with celiac's disease and crohn's disease. Homecysteine levels are often high with Vitamin B12 deficiency. B12 levels should be checked if any of the above symptoms are present.
