Billions of dollars are spent every year by millions of people around the world on vitamin supplements. In 2004 alone, it is estimated, nearly $20B dollars went to supplements. A lot of the people spending their hard-earned money on vitamin supplements believe they are warding off cancer, heart disease, or other conditions just by taking vitamins. Most people don't know, however, that it is not possible to stock up the nutritional value of many vitamins. Water soluble vitamins and minerals like vitamins B and C are actually eliminated each day (don't ask me to go into details about how that happens!).

Other vitamins are "fat-soluble" meaning they dissolve in fat. Those include vitamins A, K, D, and E. The fat-soluble vitamins can be more dangerous than water-soluble. What is not used by the body actually ends up in the liver, where it can build up and could potentially be toxic.

You should check with your doctor or healthcare practitioner about whether or not you can absorb the vitamins you want to be taking. That's the first place to look when deciding what supplement may be right for you. If you are not absorbing a vitamin or mineral as it naturally occurs, you will want to supplement it. Don't supplement vitamins you are already supplying your body in adequate quantities.

The next thing to consider is if your nutritional needs have changed due to medical conditions like pregnancy or more time spent bodybuilding. These and other conditions have special requirements and you may not be naturally getting enough of certain vitamins and minerals.

Check with your doctor on potential interactions between your supplement, and any medication you are on. It is also prudent to talk to him about whether or not you even need a particular supplement vitamin.

Doctors can find out a lot about your nutritional needs by taking a simple blood sample. She can then see what you may be deficient in, and need to supplement. You don't want to be taking something you don't need.

Perhaps moreso in the vitamin supplement world than in other areas of your life, "buyer beware" is an important thing to remember. Vitamin supplements are largely unregulated by the government (in the USA, and even less elsewhere). You will be bombarded with messages about how this or that supplement will keep you safe from cancer or other diseases, with little research to back up such claims.

Be careful, and don't rely on the supplement manufacturer's claims alone. The internet is a great place to research different supplement companies and supplements, and of course your doctor is a trained professional. The US Government (FDA) and other agencies also provide free information on supplements they have tested.