Vitamin B₁₂ deficiency: Recognizing subtle symptoms in older adults

Vitamin B₁₂ deficiency is a common but under-recognized, yet easily treatable disorder in older adults. Although several causes exist, food-cobalamin malabsorption is now believed to be the most common etiology. Complications of vitamin B₁₂ deficiency are myriad, ranging from lethargy and weight loss to dementia. Causes of deficiency include failure to separate vitamin B₁₂ from food protein, inadequate ingestion, absorption, utilization, and storage as well as drug-food Interactions leading to malabsorption and metabolic inactivation. The roles of B₁₂ deficiency, elevated homocysteine and elevated methylmalonic acid in various disease states are still evolving. Timely screening and replacement of vitamin B₁₂ will help prevent many complications.