As you breathe, you take in oxygen from the air that is required by every cell in your body. The iron in hemoglobin delivers oxygen from the lungs to other body tissues. Unlike children and women of child bearing age who often need to supplement with iron, most men and women who are past menopause get enough iron from their diet and supplementing with a vitamin that contains iron could cause the body to have too much iron in the blood. It has been shown that too much iron buildup could contribute to heart disease. There are exceptions to this rule, of course and it can depend upon if you are eating enough iron rich foods such as spinach, broccoli and meat. Are you a man or post menopausal woman and not sure if you are getting enough iron in your diet? The best way is to have a simple blood test done and discuss the results with your doctor. If it shows adequate amounts of iron, then you should consider using a multi-vitamin that does not contain iron. If th