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Dietary supplement

Dietary supplement is any product taken in addition to a normal balanced diet that is not a food or a drug. Dietary supplements include vitamins, minerals, amino acids, herbal preparations, and other substances derived from plants. Millions of people take dietary supplements to help ensure adequate nutrition, increase energy, reduce stress, or relieve some condition. They often regard the supplements as "natural" substitutes for drugs. Dietary supplements are sold as pills, capsules, liquids, extracts, teas, and powders. Many supplements are based on traditional folk or herbal remedies. Many kinds of supplements, such as vitamins, provide substances that are necessary to maintain good health. Most people, however, get enough of these substances in a balanced diet. Other dietary supplements contain naturally occurring compounds that can act like drugs. In the United States, drugs must be approved by the Food and Drug Administration (FDA) before they can be sold. The FDA ensures that drugs are safe and are effective to treat the conditions for which they are prescribed. Dietary supplements can be sold without FDA approval, and thus may not be safe or effective.

Most dietary supplements are safe when taken according to directions, but some can be dangerous. Ephedra, also called ma huang, an herb taken to help people increase energy, contains the natural chemical ephedrine. Ephedrine is a stimulant that is also an ingredient in several drugs. It may cause serious side effects, including irregular heartbeat, seizures, stroke, and even death. The FDA has banned all products containing the herb.

Dietary supplements can also cause harmful reactions by interacting chemically with prescription drugs. Responsible manufacturers have added labels to their products warning people not to take a supplement if they are taking certain medications. People should consult a physician before taking any dietary supplement.

Scientists are studying many kinds of dietary supplements to determine if they are effective in treating diseases. One supplement under study is made from the leaves of the ginkgo tree, which have been used as medicine for hundreds of years in China. Researchers have found that ginkgo extract may help improve short-term memory and concentration in people with Alzheimer's disease. The FDA, however, forbids manufacturers from claiming that any dietary supplement can treat, cure, or prevent disease.

Food additive
Food additive is any substance that a food manufacturer adds to a food. Some additives increase a food's nutritional value. Others improve the color, flavor, or texture of foods. Still others keep foods from spoiling.

Some food additives come from other foods. Scientists create other additives in the laboratory. Some people consider food additives dangerous to their health. But many of these substances occur naturally in foods that people have eaten for centuries.

Kinds of additives. There are thousands of food additives. They can be classified into six major groups: (1) nutrients; (2) flavoring agents; (3) coloring agents; (4) preservatives; (5) emulsifiers, stabilizers, and thickeners; and (6) acids and alkalis.

Nutrients, such as minerals and vitamins, make foods more nourishing. The addition of the B-complex vitamins folic acid and niacin to flour, pasta, and rice has helped reduce the incidence of a serious spinal defect called spina bifida and has virtually eliminated the nutrient deficiency disease pellagra. Addition of the mineral iodine to table salt has made incidence of goiter rare.

Flavoring agents include all spices and natural flavors, as well as such artificial flavors as vanillin, which is used in place of natural vanilla. Most flavors are added in tiny quantities. Some flavoring agents, such as monosodium glutamate (MSG), enhance a food's natural flavor. Sweeteners add sweetness. Natural sweeteners include sucrose, fructose, dextrose, and corn syrup. Artificial sweeteners include acesulfame-K, aspartame, saccharin, and sucralose.

Coloring agents help make foods look appealing. For example, canned cherry pie filling may have red color added to replace color lost during processing. Colas would be clear without the addition of caramel coloring.

Emulsifiers, stabilizers, and thickeners help the ingredients in a food to mix and hold together. Lecithin is an emulsifier, an additive that keeps one substance evenly dispersed in another. It helps prevent the fat in chocolate from separating and forming bloom, a white discoloration. The emulsifiers stearoyl-2-lactylate and polysorbate 60 keep bread soft. Carrageenin, a stabilizer, keeps the chocolate particles in chocolate milk from settling. Xanthan gum is used to thicken salad dressings.

Preservatives extend the shelf life of foods. Chemical compounds called antimicrobial agents destroy or inhibit the growth of microbes, allowing foods to be safely kept for a longer time. Nitrite added to cured meats prevents the growth of the bacteria that cause a kind of food poisoning called botulism (see BOTULISM). Calcium propionate retards the growth of mold in bread. Such antioxidants as BHA and BHT help maintain flavor by slowing down oxidation, a chemical reaction. EDTA and other sequestrants bind together metal ions in food to prevent them from promoting oxidation. See FOOD PRESERVATION.

Acids and alkalis are used to change the pH of some foods (see PH). Acids help prevent the growth of certain bacteria. They can also be used to add flavor. Citric acid added to drinks gives them a tart taste. Alkalis are added to cocoa to reduce its acidity. Alkalis can also be used to improve the appearance of foods. For example, manufacturers coat pretzels with alkali solutions so that baking produces a shiny, dark brown surface.

Government regulations. Government committees and regulatory bodies define the maximum amounts of additives permitted in food. In the United States, the Federal Food, Drug, and Cosmetic Act prohibits the use of any food additive shown, by appropriate tests, to cause cancer in people or animals. It also requires a manufacturer to prove a new food additive safe and effective before using it. The Food and Drug Administration (FDA) enforces the act.

Contributor:
Melanie Johns Cupp, Pharm.D., Drug Information Specialist, West Virginia Drug Information Center; Clinical Assistant Professor, West Virginia University School of Pharmacy.
Grady W. Chism, Ph.D., Professor of Food Science and Technology, Ohio State University. -
Source : World Book 2005

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