What are vitamins?

Vitamins are organic substances that are not produced by the human body, but they are required to sustain life. Because the body cannot supply these essential substances, vitamins must be obtained through food.

Knowledge of the body's need for vitamins has been gained through scientific studies that has related certain diseases such as pellagra, rickets, and scurvy with a lack of a particular vitamin in the diet. Further studies have found that vitamins serve many functions in the body and they are required by nearly every organ in the human body.

Vitamins play an important role in aiding metabolism, reducing fatigue, increasing mental alertness, and increasing the body's resistance to bacterial infection. Without the essential vitamins, the body cannot function properly and life cannot be sustained.

How much of a vitamin does the body need?

Because every person is unique, each will have his or her own vitamin requirements. Some factors influencing the nutritional needs of each individual are genetics and lifestyle. Some people are better at absorbing nutrients than others due to genetics. Others require more nutrients due to their particular lifestyle.

Exactly how much of a certain nutrient the body needs cannot be universally determined. However, recommended dietary allowances (RDAs) have been established by the Food and Nutrition Board in the United States. These allowances apply to the level of dietary intake of a particular nutrient that satisfies the nutritional requirements of a particular group of people.

RDA's have not been established for all vitamins due to a lack of information. However, adequate intake (AI) levels have been established. Tolerable Upper Intake Levels (UL) have also been determined to reduce the risk of adverse effects arising from too much nutrient intake.

For most people, taking nutritional supplements that satisfy the RDA have no adverse effects. However, too much vitamin intake can have serious consequences to the body's health. An overdose of certain vitamins such as vitamins A and D can have toxic effects. Although controversial studies on the benefits of taking mega doses of vitamins have been reported, excessive nutrient intake is generally not recommended.

Are Nutritional Supplements Necessary?

Whether a person needs to supplement his or her diet with nutritional supplements is a controversial topic. The only universally accepted opinion about supplements is that they are no replacement for a healthy diet. Nor can the body absorb the nutrients contained within supplements without food.

In general, a person can prevent nutrient deficiencies with a balanced diet. However, this fact does not imply that a person can achieve optimum health from just an adequate diet. In many cases, people are unable to satisfy their nutrient needs with their daily diet. Simply, people don't eat well.

Nutritional supplements provide a means of maintaining a healthy balance of nutrients in the body. It must be emphasized, however that they are not a replacement for a healthy, balanced diet; they are as their name implies, a complement to one's diet so that an individual may maintain a healthy nutritional balance.