Healthy Eating: Valuable Vitamins
In This Article:
What Are Vitamins?
Vitamins are natural substances that are necessary for almost every process in the body. Micronutrients help trigger thousands of chemical reactions essential to maintaining good health. Most of these reactions are linked because one triggers another. A missing vitamin or a deficiency of a certain vitamin anywhere in the linked chain can cause a collapse, with health problems being the result.
Vitamins are organic compounds (or compounds that contain carbon), which are required in small amounts and are necessary to promote growth, health, and life. Vitamins are produced by living material such as plants and animals. Most vitamins are not made by the body in sufficient amounts to maintain health, so they must be obtained through a person's diet. Vitamins are classified into two groups: fat-soluble and water-soluble.
Vitamins are labeled as "micro" nutrients because they are needed in only small amounts to do their jobs properly. Don't let the word "micro" fool you, though; good things come in small packages! The micronutrients are just as essential as the macronutrients in helping to keep your body functioning properly.
What are antioxidants? When cells burn oxygen, they form free radicals. Free radicals can damage body cells, tissue, and DNA, which could lead to the onset of chronic health problems. Certain environmental factors can also cause free radicals. Antioxidants are vitamins that counteract the effects of these harmful free radicals.
Unlike macronutrients, vitamins do not provide calories or supply direct energy, but they do assist the calories in carbohydrates, proteins, and fats to produce energy. Consuming the macronutrients (carbohydrates, proteins, and fat) supplies the thirteen vitamins that the body requires. Vitamins are found in a wide variety of foods, with some foods being better sources than others. For this reason, eating a wide variety of foods ensures a better intake of vitamins.
Dietary Reference Intakes (DRIs)
Before learning why each vitamin is important and how much you need, it is crucial to understand how these values are generated. In the United States, the Food and Nutrition Board of the National Academy of Sciences/National Research Council is responsible for establishing and updating nutrition guidelines. The Recommended Dietary Allowances, or RDAs, have always been the benchmark for adequate nutritional intake in the United States. The RDAs are based on scientific evidence. They reflect the amount of a nutrient that is sufficient to meet the requirement of 97 to 98 percent of healthy individuals in a particular life stage and gender group. Because scientific knowledge of the relationship between nutrition and health has broadened so much, the Food and Nutrition Board partnered with Health Canada in the late 1990s. Together, the agencies developed a new approach called Dietary Reference Intakes (DRIs).
The DRIs represent an approach that serves to optimize health instead of just preventing nutritional deficiencies, as the RDAs have. The DRIs include RDAs as goals for intake by individuals, but also incorporate three new types of reference values. Where adequate information is available, each nutrient will have a set of DRIs. Each group of nutrients is presently being studied individually. Eventually, DRIs will replace RDAs in the United States and RNIs (Recommended Nutrient Intakes) in Canada.
The DRIs incorporate an average of three types of reference values:
- Estimated Average Requirement (EAR)
- Recommended Dietary Allowance (RDA) or Adequate Intake (AI)
- Tolerable Upper Intake Level (UL)
More on: Nutritional Resources for Families
Copyright © 2002 by Kimberly A. Tessmer. Excerpted from The Everything Nutrition Book: Boost Energy, Prevent Illness, and Live Longer with permission of its publisher, Adams Media Corporation.
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