Vitamins are organic compounds that the human body cannot produce and therefore must acquire through the diet. To help maintain good health, humans need 13 different vitamins. These include: vitamin A, the various B and D vitamins, vitamin C, vitamin E, and vitamin K. Deficiencies of these essential vitamins can cause the body to enter a diseased state. Deficiencies of different vitamins manifest themselves with differing diseased states. For example, night-blindness is linked to vitamin A deficiency, while Rickets is linked to vitamin D deficiency.

The relationship between foods and maintaining health has been recognized for centuries. For example, in 1747, Dr. James Lind discovered that citrus fruits prevented scurvy. Some stores of vitamins within the body can last well over a year, as is the case with vitamin B12. Others can deplete more rapidlylasting only a couple of weeks. A vitamin can be either fat or water soluble. Water-soluble vitamins are not stored in the body. Often they need to be replenished more frequently. Fat-soluble vitamins, however, are stored in the body. Excessive intake of fat-soluble vitamins can cause toxicity in the body. Fat-soluble vitamins include A, E, D and K.

Today there is debate among experts over the benefits of vitamin supplements. Some believe supplements must be taken in conjunction with the daily diet. This is because many foods are processed and artificially enrichedwhich can reduce the nutrient level naturally found in these foods. Moreover, even fresh fruits and vegetables are picked prematurely and shipped long distances before arriving on grocery shelves. For this reason, some physicians recommend taking vitamins.

The US RDA is a standard set forth by the Food and Nutrition Board of the National Academy of Sciences National Research Council to help Americans determine a proper level of daily vitamin intake. It is important to note, however, that these levels are sometimes quite modest intended to meet the nutrient needs of already healthy individuals. For some, these amounts may be lower than optimal. For example additional amounts of vitamins may be needed during illness. Consequently, the Board has also set two other values: the tolerable upper intake levels (UL) and the adequate intakes (AI). The UL values are designed to help people avoid over consumption. AL values are established when there is not enough scientific evidence to set an RDA.

It is important to note that different developmental stages and physiologies may require varying vitamin intakes. Children, adolescents, women, and men all have differing needs. Consulting a specialist is the best way to determine personal vitamin needs. Moreover, some supplements may negatively interact with prescription drugs. Therefore, all supplemental intakes should be discussed with a physician.

A proper balance of vitamin intake can enhance personal health and increase energy levels. These essential nutrients aid in the regulation of many bodily functions and can prevent illnesses. Their value must not be underestimated.