What is the most common cause of anemia and/or vitamin b12 deficiency in older adults?

In women of reproductive age, blood loss through menstruations is a common cause of iron deficiency anemia. B12 deficiency is usually due to poor absorption resulting from lesions in the stomach and/or ileum. Alcohol abuse can cause deficiency of both iron and B12. In adult men iron deficiency anemia warrants an investigation of GI bleeding. For healthy diet: http://www.choosemyplate.gov/