Quite simply, vitamins are organic substances necessary for life. Vitamins are essential to the normal functioning of our bodies and, save for a few exceptions, cannot be manufactured or synthesized internally. Necessary for growth, vitality, and general well-being, they are found in minute quantities in all natural food. We must obtain vitamins from these foods or from dietary supplements. It is impossible to sustain life without all the essential vitamins.
Many people think vitamins can replace food.
In fact, vitamins cannot be assimilated without ingesting food. There are a lot of erroneous beliefs about vitamins, and this information should clear up most of them. Vitamins are not energy pills, and have no caloric or energy value of their own. Vitamins themselves are not the components of our body structures. You cannot take vitamins, stop eating, and expect to be healthy.