This FAQ covers all the basic concepts you need to know as you read our health articles.
What are herbs?
According to Webster’s dictionary, an herb is “a plant valued for its medicinal, savory or aromatic qualities.” In fact, a number of today’s synthetic pharmaceutical preparations are derived from herbal extracts that were originally discovered and prescribed many years ago. The drug digitalis, for example, which is used to treat various types of heart ailments, is made from the leaves of the foxglove plant.
What are standardized extracts?
One problem with selecting herbal supplements is that you can’t always be certain of the potency of a particular formulation. Potency depends on a number of factors — what part of the plant was used, where it was grown, when it was harvested, how it has been processed and packaged — and it can either be very strong or virtually inert.
Because of these variables, it’s best to look for herbal supplements that list a “standardized” level of potency. The active compounds found in herbal extracts are usually expressed as a percentage of the total. For example, if a typical standardization level for an ingredient is expressed as 6 percent, that means 100 mg of the standardized herb supplies 6 mg of the active ingredient.
What are vitamins and carotenoids?
Although vitamins do not share a common chemistry, they share certain characteristics. They are all organic nutrients that are necessary in small amounts for normal metabolism and good health. Most vitamins must be provided by the diet or by supplements, but three vitamins (D, K and the B-vitamin biotin) can be manufactured in the body from non-dietary sources. Vitamins are not sources of energy as are carbohydrates, fats and proteins. Instead, vitamins serve as chemical partners for the enzymes involved in the body’s metabolism, cell production, tissue repair and other vital processes. Vitamins are either fat-soluble or water-soluble.
The fat-soluble vitamins, which include A, D, E and K, are absorbed by the body using processes that closely parallel the absorption of fat. They are stored in the liver and used up by the body very slowly. The water-soluble vitamins include vitamin C and the B vitamins. The body uses these vitamins very quickly. Excess amounts are eliminated in urine.
The recommended daily allowance (RDA) for vitamins, which is set by the Food and Nutrition Board of the National Academy of Sciences-National Research Council, has been enhanced with a standard called the Dietary Reference Intake (DRI). The DRI is a general term for four different rating sets that apply to vitamins, minerals and proteins taken by men or women in specific age groups. These ratings are:
* Estimated Average Requirement (EAR)
EAR is the daily intake of vitamins that meets the requirements of 50 percent of the population group.
* Adequate Intake (AI)
If the EAR is unknown, AI is used. This is an estimate of an average intake that seems to be healthy and not dangerous.
* Recommended Daily Allowance (RDA)
RDA is the amount of a supplement that is sufficient to meet nearly all the needs of men or women in certain age groups.
* Tolerable Upper Intake Level (UL)
UL is the maximum dose likely to be safe in nearly all individuals.
Another standard being developed is Daily Reference Values (DRV), which covers nutrients and other food components, such as phytoestrogens, fiber and nutritional factors that do not yet have any standards. Because vitamins and other dietary supplements are regulated as food (not drugs) by the government, no standards exist for effectiveness. Various manufacturers’ brands of vitamins differ in quality and in their ability to be absorbed by the body. The wise consumer shops for the lowest priced vitamins, as there appears to be no significant difference in quality between vitamins in various price ranges.
The FDA requires that vitamins and other dietary supplements include labels similar to those found on commercial foods. The label must include nutrient information and a list of all ingredients, as well as identification of the parts of plants from which ingredients are taken. Nonetheless, evaluation of the quality of a particular supplement is not required. There is no control over what goes into a dietary supplement, and little is known about long-term effects and risks. Studies on ginseng, for example, found that some supplements did not contain any active ingredients while others varied widely in the amount they contained. The US Pharmacopoeia, an independent organization that sets standards for drugs, has implemented standards for vitamins. Consumers should look for the USP label on supplements to ensure the products adhere to these standards.
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