Vitamin B12 plays many crucial roles in the body. It is involved in neurologic function, red blood cell production, DNA synthesis, and a number of important chemical reactions. Vitamin B12 deficiency, while not common, can cause megaloblastic anemia (a disorder of the red blood cells that can cause symptoms such as fatigue, pale skin, and lightheadedness) and neurological and cognitive disorders.
Consumption of animal products (like fish, meat, chicken, and dairy) and fortified foods (like breakfast cereals) generally provides plenty of B12 to meet our needs. Because plant foods like fruits, vegetables, and grains do not contain this vitamin, strict vegans should be conscious of their B12 intake. People who have had bariatric surgery or who have had part of their intestines removed, as well as those with absorptive disorders like inflammatory bowel disease, are also at increased risk for B12 deficiency. Additionally, the ability to digest and absorb B12 may decline with age. Now, long-term use of several common medications has been added to the list of reasons to monitor B12 status.