Many people are at risk for vitamin B12 deficiency and they do not even realize it. Women in their menstrual years, vegetarians, vegans, alcoholics, anemic and those with immunosuppressive disorders tend to be deficient in vitamin B-12. Deficiency may also be caused by poor absorption of B-12 in the digestive track. This is particularly a problem for the elderly and people with eating disorders. Find out more about vitamin B12 deficiency risk through the above link.