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Vitamins Basic

The word" vitamin" is a relatively new term. The word first appeared in dictionaries in 1912 and was coined to describe the organic substances in food essential for most chemical processes in the body. Before vitamins were discovered, doctors recommended food itself: carrots (rich in vitamin A) to maintain vision, citrus fruit (high in vitamin C) to prevent scurvy, and whole grains and legumes (abundant in vitamin B1) to ward off beriberi.

Scientists have identified 13 vitamins that are considered essential for health-essential because the body does not manufacture these nutrients itself. In other words, these vitamins must come either from food or from supplements. Essential vitamins are grouped into two categories: fat-soluble and water soluble.

Essential fat-soluble vitamins include vitamins A, D, E, and K. These are stored in the body's fat to be used as needed. Because the body stockpiles fat-soluble vitamins, it is possible to take too much of one or more of these vitamins, although this rarely occurs. Vitamin overdose can lead to various symptoms, including headaches and irritability.
The essential water-soluble vitamins are C, B, B1, B2, B3, B5, B6, B12, folic acid, and biotin. These are not stored in the body: The body uses just what it needs at any given time and excretes the unused amount in the urine.

Two important points about vitamins. Many people believe that if they take nutritional supplements, they won't have to worry about a balanced diet. But vitamins are just that, supplements. It is important to remember that the human body absorbs vitamins from food more readily than from pills. In addition, science is rapidly discovering dozens of health-supportive phytonutrients in food that work with vitamins to promote health-and these phytonutrients are unavailable in pill form.

Another important point to remember when it comes to vitamins is that you can have too much of a good thing. While large amounts of some vitamins are helpful in specific situations, too much may cause side effects that range from the merely annoying (such as dry skin or sleep disturbances) to the truly dangerous (such as liver damage).

How to take Vitamin supplements

• Take vitamin supplements with food to increase absorption. Fat-soluble vitamins should be eaten with food containing some fat.
• If you experience nausea within a half-hour after taking a vitamin, you may not have had enough food in your stomach.
• High doses of vitamins should not be taken at one time. For most efficient absorption, space dosages throughout the day.

Over-the-counter vitamin supplements come in various forms, combinations, and amounts. They are available in tablet, capsule, gel-capsule, powder, sublingual, lozenge, and liquid forms. They can also be administered by injection. In most cases, it is a matter of personal preference as to how you take them; however, due to slight variations in how rapidly the supplements are absorbed and assimilated into the body, we will sometimes recommend one form over another.

RDA VERSUS RDI VERSUS ODI

Recommended Dietary Allowances (RDA's) were instituted over forty years ago by the National Academy of Sciences' U.S. Food and Nutrition Board as a standard for the daily amounts of vitamins needed by a healthy person. These RDA's were the basis for the U.S. Recommended Daily Allowances (U.S. RDA's) adopted by the Food and Drug Administration (FDA). The provisions of the Nutrition Labeling and Education Act and the Dietary Supplement Act of 1992 required a change in food product labeling to use a new reference term, Daily Value (DV), which began to appear on FDA-regulated product labels in 1994.

DV's are made up of two sets of references: Daily Reference Values (DRV's) and Reference Daily Intakes (RDI's). DRV's are a set of dietary references that apply to fat, saturated fat, cholesterol, carbohydrate, protein, fiber, sodium, and potassium. RDI's are a set of dietary references based on the Recommended Dietary Allowances for essential vitamins and minerals and, in selected groups, protein. The term RDI replaces U.S. RDA.

Scientific studies have shown that taking dosages of vitamins above the RDI's helps our bodies work better. The RDI's therefore are not very useful for determining what our intake of different vitamins should be. We prefer to speak in terms of optimum daily intakes (ODI's)-the amounts of nutrients needed for vibrant good health.