U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
March 1999

Section 4
Demand for Dietary Supplements

Consumers use DS products for a wide variety of reasons. Some products are taken because they are essential nutrients (e.g., vitamins and minerals at recommended dosages). Others are taken because they are expected to have some pharmacological effect (e.g., herbals and botanicals). In this section, we identify the uses of major DS products, describe the consumers of DS, and describe substitution possibilities.

4.1 DS Product Characteristics and Uses

DS products are desired by consumers based on, among other things, the actual, perceived, or suggested health benefits that they yield to consumers. Consumers learn of the beneficial effects of DS products from

• product labels,
• merchandise catalogs,
• media advertisements (radio, newspaper, magazines, television),
• the Internet,
• product literature,
• books and pamphlets, and
• physicians and other practitioners (e.g., chiropractors).

The claims made by DS manufacturers and retailers are regulated by DSHEA. They are allowed to make structure/function claims that describe the role of a nutrient or dietary ingredient in affecting part of the structure or a function of the human body or that describe the way a nutrient or dietary ingredient acts to maintain body function and structure. In order to make these claims, DS retailers must back their claims with sufficient data (substantiation) and must also place on the product a disclaimer stating that the "product is not intended to diagnose, cure, treat, or prevent a disease" (Raubucheck, 1997).

Some health claims that have been approved for use on conventional food products can be used on DS products as well. These include claims linking

• calcium and osteoporosis,
• folate and neural tube defects,
• soluble fiber from whole oats and coronary heart disease,
• soluble fiber from psyllium husks and coronary heart disease, and
• sugar alcohols and dental caries ¬cavities|.

(see Table 2 in Commission of Dietary Supplement Labels, 1997).

This section provides information on the perceived or actual health benefits of dietary supplements in the following categories: vitamins, minerals, herbal and botanicals, amino acids, proteins, and animal extracts. Within each category, commonly purchased products are detailed as to the perceived or actual health benefits consumers receive by ingesting them, some common claims that are made, and any scientific evidence backing the validity of these claims. Metabolites, constituents, and concentrates and other supplement products not elsewhere classified are discussed at the end of this section.

4.1.1 Vitamins

Vitamins are essential for normal health, metabolism, growth, and the proper functioning of cells. Vitamins are divided into two categories: fat-soluble, which can be stored in the body, and water-soluble, which are not stored in significant quantities in the body. Vitamins must be obtained from the diet because they are either not synthesized in the human body or are not synthesized in large enough amounts. Table 4-1 lists 13 vitamins and their health benefits and whether or not a particular vitamin is toxic or has a deficiency disease associated with it.

Vitamin supplements may be purchased as single vitamin products, multivitamin preparations, or combined with other DS products (e.g., some St. John's wort products contain B-complex vitamins). Dietary supplement product vitamin preparations come in many forms, including capsules, tablets, sprays, liquids, candies and lozenges, and chewable tablets (Hendler, 1990).

4.1.2 Minerals

Minerals are chemical elements required by our bodies for numerous biological and physiological processes that are necessary for the maintenance of health. Like vitamins, minerals are also divided into two categories. Those that are required in our diets in amounts greater than 100 milligrams per day are called "minerals" and those that are required in amounts less than 100 milligrams per day are "trace elements." Minerals include compounds of the elements calcium, magnesium, phosphorus, sodium, potassium, sulfur, and chlorine. Trace elements that are necessary for human health include iron, iodine, copper, manganese, zinc, molybdenum, selenium, and chromium (Hendler, 1990). Table 4-2 describes the role of minerals and trace elements in the body and lists claims made for particular minerals, any scientific evidence that exists to support these claims, and deficiency symptoms and toxicity. Some minerals that may have positive effects on human health are also included in the table. Sulfur, chlorine, and sodium, which are sometime included in DS products, are not included in the table because they are found in food via the soil it is grown in, in our water supply, and in the case of sodium, in numerous food products. Minerals are prepared in a variety of forms including, but not limited to, tablets, capsules, multivitamin-multimineral preparations, and liquids (Hendler, 1990).

Table 4-1. Health Benefits, Deficiency, and Toxicity of Vitamin Dietary Supplement Products

Vitamin	Health Benefit	Deficiency	Toxicity
Fat-Soluble Vitamins
Vitamin A (beta-carotene or retinol)	Maintenance of normal vision and night vision Essential for immune system Necessary for growth; induces differentiation of cells	Fairly common; results in night blindness and eye disease, dry pimply skin, increased infections, and kidney stones	Unlikely from diet alone, but supplements and excessive fish oil may produce toxic symptoms such as increased skull pressure, hair loss, and blurred vision
Vitamin D (calciferols)	Helps to maintain constant levels of calcium in the blood Important in insulin and prolactin secretion, muscle function, immune and stress response, melanin synthesis, and cellular differentiation Vital for kidney and parathyroid gland function Necessary for healthy bones	Disease is rickets, not a major problem in U.S.; symptoms include soft bones and teeth	Most people do not take in supplemental form since the body produces its own via exposure to the sun Toxic in doses larger than 1,000-1,500 I.U.s daily for a month or longer; produces nausea, weakness, and irritability May lead to brain or liver damage, jaundice, and the destruction of red blood cells
Vitamin E (tocopherols)	Protects vitamin A from oxidation during digestion Enhances immune response Inhibits carcinogens from reaching target sites Can stop neurological problems associated with cystic fibrosis, liver disease early in disease process Detoxifies free radicals, prevents damage to cell membranes Prevents LDL cholesterol from turning into damaging oxidized LDL, which initiates buildup of arterial plaque which can lead to heart disease	No disease; may produce vague symptoms and anemia	Unlikely, although high doses increase the action of anticoagulant medications High doses also interfere with the absorption of other fat-soluble vitamins, particularly vitamin K
Vitamin K (phylloquinone)	Helps blood coagulate In conjunction with vitamins A and D helps body build bone protein Given as injection to newborns to help blood clot, sometimes to women before labor or to patients before and after surgery	Rare	From food it is rare; can occur with medical treatment Not sold as a supplement
Vitamin	Health Benefit	Deficiency	Toxicity
Water-Soluble Vitamins
Vitamin B-1 (thiamin)	Vital for healthy nervous system and nerve transmission Essential in converting glucose to energy	Disease is beriberi Symptoms of a deficiency include depression, irritability, attention deficit Severe deficiency leads to edema, paralysis, and heart failure	No toxicity has been reported by those taking large doses over prolonged periods of time
Vitamin B-2 (riboflavin)	Essential for metabolizing carbohydrates, fats, and lipids and for the degradation of fatty acids and the synthesis of ATP Acts as an intermediary in the transfer of electrons in oxidation-reduction reactions Necessary for the function of vitamins B-6, folic acid, and niacin Involved in formation of red blood cells and maintenance of body tissues, particularly the skin and eyes	Symptoms are dry, scaly skin on face, oral swelling, and cracking at the corners of the mouth	No evidence that high doses have toxic effects
Vitamin B-6 (pyridoxine)	Necessary for immune system function, hormone modulation, gluconeogenesis Essential in making certain amino acids and turning others into hormones Involved in metabolizing polyunsaturated fats and proteins Used to build red blood cells and maintain nerve tissue Formation of niacin	Not common; symptoms include mouth sores, nausea, nervousness, anemia, convulsions	High doses over prolonged periods are very toxic and can cause temporary or permanent nerve damage
Vitamin B-12 (cobalamin)	Works with folic acid to produce red blood cells Helps build and maintain protective nerve sheaths Needed for RNA and DNA synthesis	Pernicious anemia, muscle and nerve paralysis	None reported
Vitamin	Health Benefit	Deficiency	Toxicity
Water-Soluble Vitamins (continued)
Vitamin C (ascorbic acid)	Activates liver-detoxifying systems Antioxidant to inactivate highly reactive oxygen species; protects against damage to lipids and other molecules Inhibits formation of carcinogenic compounds Protects cellular functions Enhances function of key white blood cells involved in the destruction of bacteria Protects vitamin E Integral to maintenance and building of collagen, a protein that holds the body's cells in place Vital to bones and teeth, blood vessels, healing of wounds, and iron absorption Helps metabolize several amino acids and hormones	Scurvy is the deficiency disease	Mostly nontoxic; diarrhea is a side-effect High doses not recommended for those with genetic conditions that cause iron overload
Biotin	Key role in metabolizing fats, carbohydrates, and proteins Part of a number of enzymes in which it functions as a carboxyl carrier Manufactured in lower digestive tract by bacteria	Not common; symptoms include baldness, a rash around the mouth and nose, and dry, flaky skin	No evidence of toxicity at high doses
Choline	Helps maintain central nervous system Precursor to acetylcholine, a neurotransmitter Involved in production and metabolism of fats and cholesterol Protects liver from fatty deposits	Increased fatty deposits in liver, memory loss, poor muscle coordination	Nontoxic, but excess consumption may result in tension headache
Folic acid (folate, B vitamin	Used by body to break down and synthesize amino acids Helps synthesize nucleic acids, which are needed to build new cells, particularly red blood cells Involved in a variety of reactions in amino acid and nucleotide metabolism Recommended for women of childbearing age; helps prevent neural tube birth defects	Leads to anemia similar to that caused by B-12 deficiency Can exist without anemia with broad signs including generalized weakness, easy fatigability, irritability, and cramps	Can mask B-12 deficiency (which causes neurologic problems) at high doses and interfere with some seizure and cancer drugs
Niacin (sometimes called vitamin B-3)	Enables body to use carbohydrates, fats, and proteins (to provide energy), and amino acids Influences metabolism of DNA, NAD, NADP Aids nervous system and digestive tract function and promotes healthy skin	Disease is pellagra, rare in U.S. Symptoms of deficiency: digestive upsets, insomnia, headaches, fatigue, sore and swollen tongue (disease is much worse)	Symptoms may include itching, skin flushing, and gastrointestinal distress Time-released capsules have caused impaired liver function, reported jaundice, and liver failure Toxic in high doses May produce skin discoloration and dryness, decrease glucose tolerance, produce high uric acid levels, aggravation of peptic ulcers, and symptoms that accompany hepatitis
Pantothenic Acid	Necessary for adrenal cortex function Part of chemistry of coenzyme A, which is vital to metabolism of carbohydrates, fats, and proteins and involved in making fatty acids, cholesterol, acetylcholine, steroid hormones, and nerve regulators	Can result in abdominal distress, vomiting, cramps, burning in heels, fatigue, and insomnia	No known toxicity, but research has been inadequate
a Health claims can be made regarding folic acid's reduction of a woman's risk of having a child with a brain or spinal cord defect. Source: Anderson, Jean, and Barbara Deskins. 1995. The Nutrition Bible. William Morrow & Company. Information for table from <http://www.phys.com/a_home/01home/home.htm>. As obtained on January 30, 1998. Brody, Jane E. October 26, 1997. "In Vitamin Mania, Millions Take a Gamble on Health." The New York Times. pp. 1, 20, 21. Hendler, Sheldon Saul. 1990. The Doctors' Vitamin and Mineral Encyclopedia. New York: Simon & Schuster. pp. 37-111. Smart Basics Inc. 1997. "Smart Basics Glossaries' Choline." <http://www.smartbasics.com/frameshome.html>.

Table 4-2. Health Benefits, Claims, Deficiency, and Toxicity of Leading Mineral Dietary Supplement Products
These claims have not been evaluated by the Food and Drug Administration. DS products may not include statements that they diagnose, treat, cure, or prevent disease.

Mineral	Health Benefit	Claims	Support for Claims	Deficiency	Toxicity
Calciuma	Developing and maintaining healthy bones and teeth Assists in blood clotting, muscle contraction, nerve transmission Involved in production of energy and maintenance of immune function	Reduces the risk of osteoporosis Prevents cancer Useful in treating high blood pressure; lowers cholesterol; helps prevent cardiovascular disease Helps alleviate cramps in the legs Useful in treating and preventing arthritis Helps keep skin healthy	Effect against osteoporosis proven Studies suggest may help prevent cancer Studies say it helps reduce high blood pressure and CVD; mixed results for lowering cholesterol Anecdotal evidence it is used for leg cramps and as a tranquilizer No evidence for treating arthritis or healthy skin	If severe, may lead to abnormal heartbeat, dementia, muscle spasms, and convulsions Brittle, thinning bones (osteoporosis)	High doses may cause constipation and interfere with kidney function and iron absorption Causes tissue calcification May cause magnesium deficiency
Chromium	Aids in glucose metabolism and regulates blood sugar; essential trace element	Treatment and prevention of diabetes Protects against cardiovascular disease and high blood pressure Useful in treating hypoglycemia	No evidence that it prevents diabetes, although there is evidence that it may increase glucose tolerance Contradictory evidence for protecting against CVD and high blood pressure Aid re: hypoglycemia unclear	Possibly glucose intolerance, impaired growth, elevated blood cholesterol, and fatty deposits in the arteries	Hexavalent chromium is toxic and carcinogenic, but the dietary form (trivalent) has very low toxicity Trivalent form not associated with any type of cancer
Copper	Essential trace element; one of the factors in hemoglobin formulation; helps stimulate the absorption of iron; plays a role in respiration Helps maintain cell membranes; part of enzyme that protects against cellular damage; prevents peroxidation of polyunsaturated fatty acids Involved in production of collagen, elastin, melanin, and the neurotransmitter noradrenalin	Anticancer substance Protective against cardiovascular disease Anti-inflammatory and useful against some forms of arthritis Immune booster	No evidence for anticancer claims Studies done, need more re: protection against CVD Promising studies as an anti-inflammatory agent; need more work Role in human immune system needs clarification	Second most common trace metal deficiency occurring during intravenous feeding Symptoms include anemia that is unresponsive to iron, lowered white blood cell count, and loss of bone density (osteoporosis)	Relatively nontoxic
Iodine	Integral part of the thyroid hormones that have important metabolic roles; factor in the thyroid gland's regulation of energy production	Protects against toxic effects from radioactive materials Relieves pain and soreness from fibrocystic breasts Good for loosening up clogged mucus in the breathing tubes Good antiseptic	Does protect from toxic effects of radioactive materials More research needed for fibrocystic breast relief Iodine containing drugs (need prescription) are useful for loosening coughs Effective in purifying back-country water (not elemental)	Major cause of hypothyroidism in the world Symptoms include chronic fatigue, apathy, dry skin, intolerance to cold, weight gain, and enlargement of the thyroid	High doses may aggravate acne (rare from diet or typical supplement consumption) High doses may lead to a temporary block of hormone synthesis and temporary hyperthyroidism Over prolonged periods, high doses may result in hyperthyroidism High doses greater than 50 milligrams/day may lead to inflammation of the salivary glands, which is easily reversed
Iron	Necessary in red blood cell formation and function Protection from oxidant damage; maintenance of the immune system Backbone of energy-producing process Involved in the production of carnitine, collagen, elastin, several brain neurotransmitters	Prevents and cures iron-deficiency anemia Anticarcinogenic Boosts physical performance Prevents learning disorders in children	Prevents iron-deficiency anemia Anticancer evidence is meager; appears to play an important role in cellular immunity More research needed for muscular performance claim Evidence says may help prevent learning disorders in kids	Iron-deficiency anemia (significant decrease in number of red blood cells), which means decreased oxygenation of tissues and symptoms of fatigue and muscle weakness (Note: iron is the treatment for this deficiency) Associated with Plummer-Vision Syndrome, when there is difficulty in swallowing solid food because a web-like membrane grows across the esophagus (Note: supplementation has been found to eliminate this condition)	Toxic after prolonged usage; reports are rare Some concern that unbound iron can generate free radicals and be destructive to cells, but usually occurs just with certain genetic disorders Oversupplementation may cause abdominal pain, diarrhea, or constipation
Mineral	Health Benefit	Claims	Support for Claims	Deficiency	Toxicity
Magnesium	Activates nearly 100 enzymes; helps nerves and muscles function; necessary for every major biological process (e.g., glucose metabolism, production of cellular energy, and the synthesis of protein and nucleic acids) Regulator of calcium flow within cells; collaborates with calcium in the production of biologic energy	Protects against cardiovascular disease and helps in treatment of high blood pressure	Conflicting findings about role in CVD, but have found that magnesium plays an important role in the maintenance of the electrical and physical integrity of the heart muscle	Loss of appetite, nausea, vomiting, diarrhea, confusion, tremors, loss of coordination, and occasionally fatal convulsions Sometimes associated with calcium and potassium deficiencies at the same time Marginal deficiency is common	People with impaired kidney function can accumulate magnesium, which can be fatal Those with high-grade atrioventricular blocks or bifascicular blocks should not take (could slow heart rate) No evidence it is harmful other than in these two instances
		Helps in treating PMS	Insufficient research in helping PMS
		Helps prevent kidney and gallstones	No evidence that is helpful in treating gallstones, but evidence exists that it is helpful in preventing calcium oxalate kidney stones in people who have this recurrent problem
		Treats prostate problems	No evidence to support this
		Useful in treating polio, postpolio syndrome	No evidence to support this
		Helps fight depression	No evidence to support this
		Helps in treating neuromuscular and nervous disorders	Intravenous magnesium used to treat this
		Good for treating convulsions in pregnant women to prevent premature labor	No evidence of benefit for those with these symptoms unless symptoms are due to magnesium deficiency
		Helps with diarrhea, vomiting, and indigestion	Early symptoms of deficiency; products on market containing magnesium actually cause diarrhea, and it is used in laxatives
Manganese	Essential part of several enzyme systems, involved in protein and energy metabolism	Antioxidant Important for normal function of the brain, effective in treating schizophrenia and other nervous disorders Necessary for reproduction Needed for normal bone structure and helpful in treating osteoarthritis Necessary for normal glucose metabolism and beneficial in treating diabetes mellitus	Not clear; needs more research Appears to be involved in synthesis of neurotransmitters in brain, anecdotal reports that it works on schizophrenia, but no scientific reports Not demonstrated in humans Need more research No evidence in humans nor for treating diabetes	Not documented in humans; only one report of man who was on a manganese-deficient diet for 4 months	Dietary form has low toxicity, inhaled dust can cause serious neurologic disease
Molybdenum	Necessary for several enzymes	May be an antioxidant, protect against cancer May be a detoxifier of potentially hazardous substances (sulfiting agents for preserving drugs and food) Protects teeth Prevents sexual impotence Prevents anemia and mobilizes iron	No evidence supplementation protects against cancer No evidence supplementation protects against cancer No clinical support No evidence Role not thought to be significant	Only one report of deficiency, from a patient fed intravenously	Noted in animals due to antagonism of copper
Phosphorous	Works with calcium to develop and maintain strong bones and teeth; enhances use of other nutrients Component of cell membranes Important in vital biologic processes (storage and processing of biological information, cellular communication, energy production, and integrity of tissue)	Increases endurance in athletes Fights fatigue, overall good tonic	If adequate phosphate intake, supplementation will not boost energy only if suffering from depletion (if alcoholic, antacid user, various medical conditions) Homeopathic remedies claim this, no adequate research on its effectiveness	Rare, although severe deficiency could lead to seizures, coma, and death Depletion has been reported in those taking antacids between 2 and 12 years because antacids contain magnesium and aluminum, both of which prevent the absorption of phosphate into the body	Toxic; treatment of deficiency should be administered by physician
Mineral	Health Benefit	Claims	Support for Claims	Deficiency	Toxicity
Potassium	Major component of our cells; regulates heartbeat; maintains fluid balance; helps muscles contract; role in nerve conduction Involved in production of energy, synthesis of nucleic acids and proteins	Useful in preventing and treating high blood pressure	Diets rich in potassium appear to protect against hypertension (epidemiologic studies indicate); as for supplementation lowering hypertension, differs across individuals: more work needs to be done	Produces broad physical problems from fatigue, weakness, muscle pains, to death if untreated	Unlikely to have adverse effects unless person has kidney failure, in which case it may accumulate to high levels and be fatal
		Protective against stroke-related death	One 12-year study did find a link between increased potassium intake and lower risk of stroke-related death, but findings need confirmation
		Helpful in prevention and treatment of cancer	No evidence
		Enhances athletic performance	Not known to improve performance of someone who is not deficient in potassium
Selenium	Role in immune system, enhances cellular immunity; essential component of a key antioxidant enzyme Necessary for normal growth and development	Anticarcinogenic Enhances immune system Protective against heart and circulatory diseases Increases male potency and sex drive Useful against arthritis, autoimmune diseases (anti-inflammatory) Capable of detoxifying heavy metals, various drugs, alcohol, cigarette smoke, peroxidized fats	Not well understood; studies have shown it does have anticancer properties Has been observed in animal studies Some evidence that it may inhibit free-radicals linked to tissue damage related to restricted blood flow or oxygen supply Anecdotal Injectable and oral forms used in animals; no scientific work done on humans Detoxifies mercury and cadmium; results are mixed on drugs and alcohol and more work needs to be done on protection against damage from smoking	Linked to heart disease Supplementation: Useless with concurrent intake of vitamin C -may convert selenium to nonabsorbable form	Highly toxic even in tiny doses, although we may be able to tolerate in higher doses than previously believed May cause changes in hair and nails, slower mental function, and gastrointestinal distress Capable of producing harmful mutations in cells (in form of sodium selenite, but at doses much higher than normally consumed) Carcinogenic; early studies claimed this, but National Research Council said the studies were faulty
		Beneficial to skin	Shown to reduce skin tumors in mice (oral); not reliably investigated (oral and topical)
Mineral	Health Benefit	Claims	Support for Claims	Deficiency	Toxicity
Zinc	Essential part of more than 200 enzymes involved in digestion, metabolism, reproduction (sperm formation), and wound healing Involved in sense of taste Role in function and structure of cell membranes Major part of the immune system Component of insulin	Treats common cold Boosts immunity Prevents cancer Prevents blindness as people age Accelerates wound healing Increases male potency and sex drive Useful in treatment and prevention of infertility	Based on preliminary findings, dissolve in throat; if swallowed, it is ineffective Some findings, need more research Contradictory findings Promising findings in double-blind clinical study Conflicting studies, needs more work Useful in combating male impotence only when he has moderate to severe zinc deficiency Needs more research	Common among patients fed intravenously, so it is added to the IV solution Moderate deficiency symptoms include growth retardation, poor appetite, mental lethargy, delayed wound healing, abnormalities of taste, smell and vision, skin changes Mild deficiency leads to low sperm count Moderate to severe deficiency in males leads to decreases sexual interest, mental lethargy, emotional problems	High doses may cause copper deficiency, gastrointestinal distress, and impaired immune function Large doses for long periods of time depress "good" HDL cholesterol
		Prevents prostate problems	No evidence that it prevents and treats enlarged prostate
		Useful in treating acne	More research needed on oral supplementation; topical use may treat acne effectively
		Prevents hair loss	No evidence
		Helpful in diabetics	More research is needed
		Useful in treating rheumatoid arthritis	Little recent work, needs more research
		Restores taste, smell	No evidence age-related disturbances can be improved with supplementation
Boron	Essentiality in humans has yet to be proven	Prevents osteoporosis in postmenopausal women Beneficial in treating arthritis Builds muscle	Needs more study re: osteoporosis No evidence for arthritis treatment No evidence for building muscle	Essentiality in humans has yet to be proven	None reported
Fluorine	Yet to be established as nutritionally essential	Protects against dental cavities Protects against osteoporosis and useful in its treatment	Evidence that it does protect against cavities Need more information about role in osteoporosis (if any)	Yet to be established if nutritionally essential	Supplements must be prescribed by a dentist or doctor Is toxic in high doses, can be fatal High doses may cause abnormal hardening of bones, leading to arthritic pain, joint stiffness, occasional nerve damage and paralysis
Germanium	No evidence has any nutritional, biological or biochemical role in humans	Useful in treatment of ARC and AIDS Stimulates the immune system	Effects on AIDS patients being studied, don't know if has beneficial effects Further research is needed on effects on immune system	No known role in humans	Appears to be low Small percentage reported skin eruptions and stool softening Some reports of kidney failure
		Useful in treating cancer	Human studies for cancer prevention are needed
		Useful in treating chronic Epstein-Barr virus syndrome	Clinical anecdotes on its effects on Epstein-Barr virus
a Health claims regarding osteoporosis disease prevention can be made on calcium products. Sources: Council for Responsible Nutrition. February 3, 1997. "Baby Boomers Fuel Trends in Vitamins." Chain Drug Review 19(3):20-22. Hendler, Sheldon Saul. 1990. The Doctors' Vitamin and Mineral Encyclopedia. New York, NY: Simon & Schuster, pp. 112-207. Day, Kathleen. January 11, 1997. "Cold Sufferers Find Zinc as Good as Gold." The Washington Post. pg. D1. Brody, Jane E. October 26, 1997. "In Vitamin Mania, Millions Take a Gamble on Health." The New York Times. pp. 1, 20, 21.

4.1.3 Herbals and Botanicals

Herbal products are those made from the leaves and stems of plants, and botanical products are those made from any part of the plant. They are both becoming increasingly valued by some consumers for their perceived medicinal properties; however, FDA regulations prevent statements that these products are intended to diagnose, treat, cure, or prevent disease. In addition to the more familiar herbs, Chinese traditional herbs and Ayurvedic (traditional Indian) medicinal herbs are becoming available in the United States. An estimated 2,500 herbs have been used for medicinal purposes at one time or another throughout history (Griffith, 1988). Table 4-3 lists some of the common conditions and symptoms and the herbal products that are used to treat them. The active ingredients within herbal products vary depending on the plants' growing conditions and degree of maturity when harvested as well as the drying process used and the type and duration of storage. Herbals and botanicals are available in many forms including teas, powders, tinctures, extracts, and liquids (Hendler, 1990).

4.1.4 Amino Acids

Amino acids are compounds that include an amino group (NH2) and an acidic function. Twenty amino acids are the chief components of proteins and are the building blocks of all living structures. They are divided into two categories: essential and nonessential. Table 4-4 lists the essential amino acids, which are not synthesized in the body, and the nonessential amino acids, which are. Children require the eight essential amino acids plus histidine and arginine for physical well-being. Essential amino acids must be obtained from the diet while the nonessential amino acids can be made by the body from other substances. There are other amino acids which are found in the human body but are not involved in the synthesis of proteins. Table 4-4 includes two of these, ornithine and taurine. Amino acids come in a variety of forms such as tablets, capsules, powders for oral solution, and as a constituent of multivitamin/mineral preparations. Injectable forms are also available but must be administered by a doctor (Griffith, 1988; Hendler, 1990; HealthWorld Online, 1998a).

4.1.5 Proteins

In the human body, proteins are antibodies as part of the immune system; an energy source; important in fetal formation, during pregnancy and in children's growth; essential in the replacement of all the body's cells; involved in maintaining the proper sodium, water and potassium balance inside cells which enables the heart, lungs, and nervous system to function properly; and important in regulating blood pH. There are specific dietary requirements for proteins although the exact amounts are not known. The Recommended Daily Allowance is 0.8 grams per kilogram of ideal body weight for the adult. Protein deficiency is not common in the Western world, but it does occur in Third World countries.

Table 4-3. Herbs Used to Alleviate Conditions and Symptoms
These claims have not been evaluated by the Food and Drug Administration. DS products may not include statements that they diagnose, treat, cure, or prevent disease.

Condition/Symptom	Herbs Used
Angina	Hawthorn (Crataegus laevigata, C. monogyna)
Anxiety and Sleep Disorders	Valerian (Valeriana officinalis) Passion flower (Passiflora incarnata) Hops (Humulus lupulus) Catnip (Nepeta cataria) L-Tryptophan (natural amino acid, occurs in concentrations of 1%-2% in plant and animal proteins)
Appetite Loss
Significant bitter herbs	Gentian (Gentiana lutea) Centaury (Centaurium erythraea)
Minor bitter herbs	Bitterstick (Swertia chirata) Blessed Thistle (Cnicus benedictus) Bogbean (Menyanthes trifoliata) Wormwood (Artemisia absinthium)
Arteriosclerosis	Garlic (Allium sativum)
Arthritis	Willow bark (Salix alba, S. purpurea, S. fragilis)
Bronchial Asthma	Ephedra or ma huang (Ephedra species, particularly E. sinica, E. equisetina, E. gerardiana)
Burns, Wounds, and Infections	Calendula (Calendula officinalis): tea for putative and antispasmodic effects Comfrey (Symphytum officinale)
Cancer	Apricot pits (Prunus armeniaca) Pau d'arco (Tabebuia) also called lapacho, or taheebo Mistletoe (Viscum album)
Colds and Flu
Demulcent antitussives	Cough suppressants Coltsfoot (Tussilago farfara),however, it contains toxic pyrrolizidine alkaloids Iceland moss (Cetraria islandica) Marshmallow root (Althaea officinalis, Malva sylvestris) Mullein flowers (Verbascum thapsus, V. densiflorum, V. phlomoides) Plantain leaves (Plantago lanceolata) Slippery elm (Ulmus rubra)
Expectorants	Treat irritative, nonproductive coughs associated with a small amount of secretion
Nauseant-expectorants (caution given about safe consumption)	Lobelia (Lobelia inflata) Ipecac (Cephaelis ipecacuanha, C. acuminata)
Local irritants	Anise (Pimpinella anisum) Fennel (Foeniculum vulgare) Thyme (Thymus vulgaris, T. zygis) Eucalyptus leaves (Eucalyptus globulus)
Surface tension modifiers	Increase gland secretion of mucous Licorice, also known as glycyrrhiza (Glycyrrhiza glabra) Seneca snakeroot (Polygala senega)
Communicable Diseases and Infections	Echinacea (Echinacea angustifolia, E. pallida, E. purpurea)
Congestive Heart Failure	Adonis (Adonis vernalis) Oleander (Nerium oleander) Apocynum or black Indian hemp (Apocynum cannabinum, A. androsaemifolium) Black hellebore (Helleborus niger) Cactus grandiflorus (Selenicereus grandiflorus) Convallaria or lily of the valley (Convallaria majalis) Squill (Urginea maritima) Strophanthus (Strophanthus kombe, S. hispidus)
Control Hypertension	Garlic
Depression	St. John's wort (Hypericum perforatum)
Diarrhea	Blackberry leaves (Rubus fruticosus) Blueberry leaves (Vaccinium corymbosum or V. Myrtillus) Raspberry leaves (Rubus idaeus)
Digestion	Ginger (Zingiber officinale)
Gastric and Duodenal (Peptic) Ulcers	Licorice, also known as glycyrrhiza (Glycyrrhiza glabra) Ginger (Zingiber officinale)
Gynecological Disorders
Menopausal symptoms, PMS, dysmenorrhea, female sex hormone imbalances or deficiencies	Black cohosh (Cimicifuga racemosa) Chaste tree berry (Vitex agnus-castus) Evening primrose oil (Oenothera biennis) Black currant oil (Ribes nigrum) Raspberry leaves (Rubus idaeus, R. strigosus) Borage seed oil (Borago officinalis)
PMS	Evening primrose oil (Oenothera biennis)
Hyperthyroidism	Bugle weed (Lycopus virginicus, L. europaeus)
Indigestion Dyspepsia
Carminatives	Carminative effects (to eruct air from stomach, increase stomach secretions, relax intestine to enable gas passage, limit development of undesirable microorganisms, promote bile flow to facilitate nutrient absorption)
Significant carminative herbs	Peppermint (Menthax piperita) Chamomile (Matricaria recutita, M. chamomilla, Chamomilla recutita, Chamaemelum nobile)
Minor carminative herbs	Anise (Pimpinella anisum) Caraway (Carum carvi) Coriander (Coriandrum sativum, C. vulgare, C. microcarpum) Fennel (Foeniculum vulgare) Calamus (Acorus calamus) Rosemary (Rosmarinus officinalis)
Cholagogues	Act to empty the gall bladder or to stimulate the production of bile or both Turmeric (Curcuma domestica, C. longa, C. zanthorrhiza, C. zedoaria) Boldo (Peumus boldus) Dandelion (Taraxacum officinale)
Infections and Kidney Stones
Significant aquaretic-antiseptic herbs	Enhance fluid and electrolyte excretion, increase blood flow in the kidneys. Useful for: local infection of renal tissue (pyelonephritis); inflammation of urethra (urethritis); inflammation of urinary bladder (cystitis); preventing kidney stones Goldenrod (Solidago virgaurea, S. serotina, S. canadensis) Parsley (Petroselinum crispum) Juniper (Juniperus communis)
Minor aquaretic herbs	Used in diuretic teas Birch leaves (Betula verrucosa, B. pubescens) Lovage root (Levisticum officinale)
Antiseptic herbs	Bearberry (Arctostaphylos uva-ursi, two varieties: coactylis, adenotricha),antibacterial herb for urinary tract infections
Anti-infective herbs	Cranberry (Vaccinium macrocarpon), most useful for preventing and treating urinary tract infections
Prostate enlargement	Saw palmetto (sabal) (Serenoa repens) Nettle root (Urtica dioica, U. urens)
Laxative
Bulk-producing laxative	Plantago, also known as psyllium seed (Plantago psyllium, Plantago indica, Plantago ovata)
Significant stimulant laxatives	Cascara sagrada (Rhamnus purshiana) Buckthorn (frangula) bark (Rhamnus frangula),br> Senna (Cassia acutifolia,known in commerce as Alexandria senna, or Cassia angustifolia known in commerce as Tinnevelly senna, or these two grouped into Senna alexandrina)
Other stimulant laxatives	Aloe (Aloe barbadensis, A. vera, A. ferox, A. africana, A. spicata) Rhubarb (Rheum officinale, R. palmatum, R. emodi, R. webbianum)
Minor laxatives
Drastic purgatives	Jalap Podophyllum Colocynth
Mild and uncertain inaction	Dandelion root Manna
Liver Damage	Milk thistle (Silybum marianum) Schizandra (Schisandra chinensis)
Lower Cholesterol	Garlic Plantago, also known as psyllium seed (Plantago psyllium, or Plantago indica, Plantago ovata)
Migraine or Vascular Headache	Feverfew (Tanacetum parthenium)
Nausea and Vomiting	Ginger (Zingiber officinale)
Pain (General)	Willow bark (Salix alba)
Performance and Endurance Enhancers	The ginsengs (Panax ginseng, P. quinquefolius, P. pseudo-ginseng) Eleuthero (Eleutherococcus senticosus) Sarsaparilla (Smilax aristolochiaefolia, S. febrifuga) Ashwagandha (Withania somnifera) Sassafras (Sassafras officinalis)
Peripheral Vascular Disease
Cerebrovascular disease	Ginkgo (Ginkgo biloba)
Other peripheral arterial circulatory disorders	Rosemary (Rosmarinus officinalis): questionable effectiveness
Varicose vein syndrome	Horse chestnut seed (Aesculus hippocastanum, A. glabra) Butcher's broom (Ruscus aculeatus)
Sexual Impotence	Yohimbe (Pausinystalia yohimbe): not recommended for self-treatment, not for OTC sale in US Ginkgo (Ginkgo biloba)
Source: Tyler, Varro E. 1994. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Binghamton, NY: Pharmaceutical Products Press. 209 pp.

Table 4-4. Health Benefits and Claims of Amino Acids and Amino Acid Supplement Claims
These claims have not been evaluated by the Food and Drug Administration. DS products may not include statements that they diagnose, treat, cure, or prevent disease.

Amino Acid	Health Benefits	Claims	Notes
Nonessential (synthesized in the body)
Alanine	Inhibitory neurotransmitter in the brain; component of cell walls; glucose can be made from alanine in the liver or from muscles when energy is needed; part of some intestinal bacteria	Increases excitation (i.e., in epilepsy); maintains blood sugar level; helpful in treating hypoglycemia; helps those with suppressed immune systems	No scientific evidence supporting these claims
Serine	Component of nerve coverings and brain proteins; involved in metabolism of purines and pyrimidines (part of RNA and DNA); important information of cell membranes and creatine synthesis
Proline	Major amino acid in collagen; involved in formation of bone, skin, and cartilage	Aids in tissue repair after injury, wound healing, and maintaining joints and tendons
Asparagine	Formed from aspartic acid; helps in the metabolic function of brain and nervous system cells
L-arginine	Effects on several major endocrine hormones; plays a large role in muscle growth and healing; helps regulate and support key components of the immune system; important in male fertility (is essential in children)	Boosts immunity; fights cancer; builds muscle and burns fat; promotes healing of burns and wounds; protects liver and detoxifies harmful substances; enhances male fertility	Effects on several major endocrine hormones; plays large role in muscle growth and healing; helps regulate and support key components of the immune system; important in male fertility (is essential in children)
L-ornithine	Shares arginine's properties; is also capable of stimulating growth hormone release	Can increase the weight and activity of the thymus gland, possibly enhancing the immune system response; shown to have liver-regenerating effects in animals
L-aspartic Acid	Involved in formation of ammonia and urea for disposal; excitatory function in the brain	Treatment of chronic fatigue, "aerobic enhancers" to boost energy; may be helpful in overcoming opiate withdrawal	Suggestions that it works in this way are preliminary; used clinically to treat fatigue and depression
L-cysteine	Precursor of glutathione, a major antioxidant in the body	Said to inactivate free radicals and therefore protect and preserve cells; extends lifespan via DNA repair; burns fat; builds muscle; protects against various toxic substances; combats arthritis	More work needs to be done re: extending lifespan; need more research on protection from toxins and pollutants; preliminary study on arthritis claim but needs more study
L-glutamine and L-glutamic Acid	Glutamine is a derivative of glutamic acid; important in brain function; precursor of important neurotransmitters in nervous system	Glutamine may help curb alcohol craving, speed healing of peptic ulcers, energize the mind, inhibit senility, counter depression; glutamic acid is claimed to boost IQs of mentally retarded people	Studies have consistently contradicted one another; recent animal work on alcohol claim and its possible favorable effects, more work is needed; used in alcoholism clinics as it decreases the craving for alcohol, may do so for sugar as well, not proven yet though
Glycine	Helps save glucose for energy by facilitating glycogen storage; involved in brain metabolism; necessary for synthesis of hemoglobin and collagen	May help dampen overactive brain processes that produce certain forms of spastic movement; helps heal wounds; reduces gastric acidity	More work is needed
L-histidine	Essential in children for growth; involved in production of blood cells and histamine	May be helpful in treating arthritis, rheumatoid arthritis	More work is needed
L-tyrosine	Synthesized from phenylalanine; involved with important brain neurotransmitters; can cause large short-term increase in levels of dopamine, epinephrine and norepinephrine in the blood	Psychic energizer and stress reliever; antidepressant; effective in treating PMS; addictive drug detoxifier; diminishes pain; improves memory; increases sexual interest; appetite suppressor; treats Parkinson's disease	Studies suggest that it may be an energizer and antidepressant; anecdotal evidence and accumulating clinical data for PMS relief; favorable reports on detoxifying addictive drugs
Amino Acid	Health Benefits	Claims	Notes
Essential (not synthesized in the body)
Threonine	Important constituent in many proteins; essential in formation of elastin, collagen, and tooth enamel protein; minor role in controlling fat buildup in the liver	Helps some cases of depression	No evidence that it treats depression
L-leucine, L-isoleucine, L-valine		Promoted as potent anabolics (muscle builders) and energizers; help restore muscle mass in those who have liver disease or who have had trauma; useful in treating liver damage; helpful in some neurologic disorders and Lou Gehrig's disease	Little scientific evidence to support claims of muscle building and energy enhancing; appears useful for effects of chronic liver disease
L-lysine	Promotes tissue repair and growth; involved in production of hormones, enzymes and antibodies	Inhibits herpes; builds muscle	Studies have reported positive and negative findings; only anecdotal evidence on building muscle
L-methionine and Taurine	Taurine and cysteine, important amino acids, depend on methionine for biosynthesis in the body; helps regulate nervous system and muscle system	Help eliminate fatty substances that might otherwise clog the arteries; may be essential for growth of adolescents, children and infants	Shown to have a depressant effect on the central nervous system and may impair short-term memory; otherwise, little research has been done
L-phenylalanine, D-phenylalanine, DL-phenylalanine	Involved in a number of biochemical processes related to brain synthesis of various neurotransmitters	Claimed to increase mental alertness; help control addictive substance abuse; promote sexual arousal and releases hormones to control appetite; alleviate chronic pain; treats Parkinson's disease	DL- no scientific support for pain relief, analgesic, and anti-inflammatory effects shown; some anecdotal, experimental evidence that L-increases alertness; no evidence on appetite suppression or sex stimulation; preliminary evidence re: addictive behavior
L-tryptophan	Important in the biosynthesis of serotonin, a brain neurotransmitter thought to be an inducer and regulator of certain stages of sleep	Natural sleeping aid; mood regulator; may reduce sensitivity to pain and have tranquilizing effects; appetite suppressor and reduces cravings for alcohol and some other drugs; helps prevent panic attacks	Appears to work well for sleeping and jet lag; in preliminary studies, acts as a mood regulator and prevents panic attacks; some studies say does relieve pain; results in humans re: appetite suppression mixed; alcohol craving suppression not directly investigated
Sources: Hendler, Sheldon Saul. 1990. The Doctors' Vitamin and Mineral Encyclopedia. New York, NY: Simon & Schuster. pp. 208-234. HealthWorld Online. 1998b. <http://www.healthy.net/hwlibrarybooks/haas/amino/his.htm> and <http://www.healthy.net/hwlibrarybooks/haas/amino/thr.htm>. As obtained on March 19, 1998.

Proteins are taken as DS products because they are believed to aid in the maintenance of a positive nitrogen balance in muscles, post-exercise recovery, building of muscles, and to increase energy. Proteins do not have specific medical or biological names; therefore they are marketed simply as "protein" supplements and the name attached to the label is the company's choice. They come in a variety of forms from powdered drink mixes and energizing shakes to capsules and tablets (HealthWorld Online, 1998c).

4.1.6 Animal Extracts

Animal extracts are the tissue extracts from animals of specific tissues or glands. The term glandulars refers to the concentrated extracts of various animal glands. These products can be found as tablets, powders, capsules, as constituents of multivitamin/mineral preparations and oils. The following are commonly found animal extract and glandular supplement products (110% Products, 1998; Sequential Healing Health Services, 1998):

Companies are marketing glandular products with claims that they revive and rejuvenate glands that are not functioning as well as they once were due to the aging process. In other words, glandular products are claimed to restore health and function to the tissue that is targeted (e.g., consumers' adrenal glands will work better if they take adrenal extracts). Glandulars are claimed to be effective in treating cancer and hypoglycemia, in lowering cholesterol, boosting sex drive and building muscle, and preventing and reversing aging. There is no legitimate scientific evidence that any of these claims are valid, and glandulars can be dangerous due to the fact that some of the organ concentrates may contain chemicals that livestock come in contact with, such as antibiotics, growth hormones, pesticides, herbicides, and fertilizers.

4.1.7 Metabolites, Constituents, and Concentrates

As mentioned in Section 2, these are alternative forms of products classified in the other categories. Thus they are not specifically addressed here.

4.1.8 Other Supplement Products Not Elsewhere Classified

A variety of other products are marketed as DS products and claim to have numerous beneficial impacts on human health and physical well-being. They may be available as capsules, liquids, tablets, powders, and as constituents of multivitamin/mineral preparations. A few of the more widely available products are described below (HealthWorld Online, 1998d).

• Acidophilus: bacterium found in yogurt and other products. It helps maintain bacteria balance in the lower intestines.

• Algae: green or blue-green freshwater, one-celled organisms. The three main algae products are chlorella, spirulina, and blue-green manna. All these products are high in protein and contain large amounts of vitamins and minerals. Blue-green algae products contain all the amino acids and are marketed as body rejuvenators, which improve energy levels, decrease appetite, and increase mental energy. These products are commonly used for weight loss and fasting and are sold in powdered or tablet form.

• Bee pollen: microscopic male seed of flowering plants. No beneficial effects have been proven.

• Bioflavinoids: chemical constituent of pulp and rind of citrus fruits, green pepper, apricots, cherries, grapes, papaya, tomatoes, and broccoli. Intake of these treats a rare bioflavinoid deficiency and prevents vitamin C and adrenalin from being oxidized.

• Brewer's yeast: supplies B vitamins, proteins, and minerals and is a good source of enzyme-producing vitamins. It helps regulate sugar metabolism via the chromium it contains and provides bulk to prevent constipation.

• Coenzyme Q: part of mitochondria of cells. It is found in beef, sardines, spinach, and peanuts and helps control the flow of oxygen within individual cells.

• Dietary fiber: makes up cell walls of plants. Because it passes through the digestive tract without being absorbed, it lessens the chances of constipation, helps to control blood-sugar levels in diabetics, and helps reduce cholesterol and triglycerides in the blood.

• Gamma-linolenic acid: an oil found in evening primrose plant (see Herbals and Botanicals).

• Inositol: (also called myo-inositol) made synthetically and found in beans, nuts, oats, pork, rice, veal, wheat germ, whole-grain products, cantaloupe, calves' liver, citrus fruits, chickpeas, lentils, and lecithin. It helps move fats out of the liver.

• Lecithin: made synthetically and also found in all animal and plant products and in cabbage, eggs, green beans, lentils, rice, and split peas, among other natural sources. It protects cells from damage by oxidation, is a major source of choline, and is found in chemicals that aid the passage of nutrients into cells from the bloodstream.

• Nucleic acids: large molecules that are encoded with genetic instructions and are part of each living cell. Nucleic acids taken orally are not effective and have no impact, as they are changed or destroyed in the intestinal tract before they can be absorbed. There is no deficiency for nucleic acids, and the oral tablet and capsule forms are nontoxic (Griffith, 1988; HealthWorld Online, 1998d).

• Royal jelly: substance secreted by salivary glands of worker bees. It has no known effects in the human body.

• Spirulina: (Spirulina geitler, S. maxima, S. platenis) algae. It has no known or proven effects.

• Superoxide dismutase: enzyme associated with copper, zinc, and manganese. The oral forms have no effect, as they are destroyed in the intestines before being absorbed.

To construct a demand curve for a DS product, one would include characteristics of the population that consumes the product. These demographic characteristics (e.g., income, gender, age) are the factors that shift the demand curve for a particular product. However, information on the demographic characteristics of DS users is scarce. Most of the large-scale studies on DS use were conducted several years ago and did not contain information on nontraditional DS products (i.e., products other than vitamins and minerals). However, a new survey of 43,000 households that was conducted by Hartman and New Hope includes information on the use of nontraditional DS products (Wingate, 1998).

In general, studies indicate that gender, age, race, income, educational level, and body weight are related strongly to DS use. Most studies found that whites, women, individuals over 30, and individuals living in the western United States are more likely to consume DS products. One study also found that other health habits and occupation are also strongly related to DS use. In comparison, studies that considered smoking and tobacco use, alcohol use, exercise level, and marital status found no correlation with DS use.

In this section, we summarize the large-scale studies and briefly describe some of the small-scale studies that have been conducted on DS use.

4.2.1 Major Studies of DS Use

Stewart et al. (1985): This survey assessed vitamin and mineral supplement usage via a national telephone interview survey of an age-stratified random sample of 2,991 people age 16 and over. This survey revealed that, excluding pregnant or lactating women, 39.9 percent of the population consumed one or more supplements daily. Of these, 52.4 percent consumed only one supplement and 10.9 percent consumed five or more supplements daily. The most any person consumed was 14 products daily. However, the percentage of people taking at least one supplement in the past year declined from 51.1 percent in 1987 to 46.2 percent in 1992. Use of supplements by women was greater than used by men for each age group (16 to 24, 25 to 64, 65+). Women ages 25 to 64 had the highest supplement usage (46.8 percent), and men ages 25 to 64 had the lowest usage (33.3 percent). The most widely used supplements were single vitamin/miscellaneous supplements, with vitamin/mineral combinations as the second most common and multivitamin/minerals as the third most common supplement product consumed. Use was more common in the West census region than in the rest of the country. Those with higher incomes and those who had at least finished high school were more likely to use supplements than those who had lower incomes and those who had not finished high school.

Block et al. (1988): The data used for this assessment came from the first National Health and Nutrition Examination Survey, 1971-1974, in which 21,000 people were sampled. Because the information is outdated, we give just a brief overview of the data. This paper presented detailed information on the use of nine specific vitamins and minerals for a broad range of behavioral and demographic characteristics. More women were found to consume supplements than men, at 26.1 percent vs. 19.4 percent. Consumption of supplements was much more common for whites, with 24.1 percent using supplements, than for blacks, with 11.7 percent using supplements. Overall, those older than 65 consumed the most supplements. Consumption was found to be highest in the West and lowest in the South. Educational level was found to correlate with supplement consumption, although no significant correlation could be found between income and usage. Body weight, however, was found to have a significant negative relation to use of vitamin and mineral supplements.

Moss et al. (1989): This study provides estimates from the National Center for Health Statistics' 1986 survey of adults and young children who use nonprescription vitamin and mineral products. A vitamin and mineral user was defined as anyone who had taken a nonprescription vitamin, mineral, or fluoride product in the 2-week period before the interview was conducted. This report estimated that 36 percent of all adults took vitamin and mineral supplements in 1986 and that women were more likely than men to consume supplements (41 percent to 31 percent). An estimated 40 percent of whites used supplements versus 20 percent of blacks. This racial difference was found in both sexes and among all age groups. This study estimated that 29 percent of Hispanic adults take supplements. Both family income and educational level were found to be directly related to supplement usage. Those in the West were found to be more likely to consume supplements, as were those who live in a metropolitan statistical area. Most people take just one supplement, and it is a multivitamin, according to this report. For those over 45, the percentage of adults using two products or more (45 percent) was higher than for those under 45 (36 percent). More women than men used more than one vitamin and mineral product. Differences in the types of products taken were also reported, with only 16 percent of adults who took any vitamin product taking a single vitamin product, and 86 percent of adults who purportedly took three products or more taking a single vitamin product. The paper also indicates that supplement use is frequent, with 70 percent of all adults and children who use supplements taking them every day.

Slesinski, Subar, and Kahle (1995): This study detailed the trends in the use of vitamin and mineral supplements in the United States. Information is based on the 1987 and 1992 National Health Interview Surveys, making this paper relatively current. This study found that multivitamin use increased from 17.4 percent to 19.3 percent from 1987 to 1992. In general, more women than men took supplements, and far more whites than either blacks or Hispanics consumed supplements, although the percentage of blacks taking supplements increased 2 percent while white and Hispanic use increased by only 0.3 percent and 0.1 percent, respectively. Also, those with higher incomes and educational levels were more likely to consume supplements in both 1987 and 1992. Those age 55 and older had the highest percentage of supplement consumption in both 1987 and 1992. Overall, supplement usage did not change much between 1987 and 1992.

Subar and Block (1990): This study used data from the 1987 National Health Interview Survey which was collected from 22,080 adults age 18 to 99. Only 23.2 percent of the adults interviewed used DS products daily, although 51.1 percent said they had used a supplement within the year before the interview. Whites, women, and older people were found to be much more likely to consume supplements on a regular basis than blacks, men, and younger adults. Multivitamins were the most common supplements consumed, followed by vitamin C, calcium, and vitamins E and A. Daily usage was highest among both men and women in the 55 to 64 age range (32.2 percent) and declined slightly with age. White women age 55 to 64 had the highest percentage consuming supplements (39.9 percent); this number declined slightly with age. Within other sex-race categories, use increased with age. Whites consumed the most supplements within age-sex categories, followed by Hispanics and then blacks.

This study also looked at other demographic and behavioral characteristics. Those completing high school and college were significantly more likely to consume supplements than those who did not finish high school. Supplement use was also shown to increase with income. As in other studies, consumption was highest in the West and lowest in the South. Individuals with the highest body mass index were the least likely to take supplements. Former smokers were the heaviest supplement users, followed closely by those who never smoked. People in the highest alcohol consumption category used supplements the least, although use of supplements was relatively similar for all other drinking categories. Those who believe that diet affects disease prevention were found to be significantly more likely to consume supplements than those who did not believe there was a link between diet and disease prevention. This study included a variable not found in the other major studies' occupation category. The category with the highest daily supplement use (27.5 percent) was "not in the labor force," which includes women working in the home and retired persons. Close behind are white-collar workers, 24.6 percent of whom use supplements regularly. The highest rates among white-collar workers were for senior executives and those with a professional specialty. Less than 20 percent of blue-collar workers and those in the military regularly use supplements.

Wingate (1998): This study, conducted in December 1997, is the most recent large-scale survey undertaken. A sample of 43,000 households with a member who had used vitamins, minerals, or herbal supplements in the past 6 months was asked about usage of 97 different vitamin, mineral, herbal, and other supplement products. This survey was unique in that it addressed the use of supplement products not typically asked about in other surveys, like herbs and amino acids.

Overall, 68 percent of the 43,000 households responding to the survey reported that they had used vitamins, minerals, or herbal supplements in the past 6 months. The study found that women age 21 to 40 are the most educated consumers, while those over 50 tend to use more products and use them more frequently than younger consumers. Almost half the people using saw palmetto and glucosamine sulfate are over age 60. Pygeum, chondroitin sulfate, and bilberry are also popular among those over age 60. The largest percentage of households with a member who used a vitamin, mineral, or herbal product (30 percent) was in the 60+ age group. The 40-49 age group followed, with 22 percent, and the 30-39 group, 21 percent.

Geographic region and specific product purchases were also addressed. The highest concentration of garlic and ginseng users/buyers was in the southern Atlantic states, followed by the Pacific states. Eighteen percent of households had a member who had used a supplement in the past 6 months in the southern Atlantic states, followed by 16 percent in the central Northeast and 15 percent each in the Pacific and mid-Atlantic regions, the survey found. Garlic was used by 19 percent of those surveyed, followed by ginseng (10 percent), ginkgo (9 percent), echinacea (7 percent), and antioxidants (7 percent). The survey found that 32 percent buy their supplements at a pharmacy or drug store, 23 percent purchase them at a supermarket, 17 percent buy them from network marketing and 11 percent buy them at health food stores.

4.2.2 Smaller Studies

Thomsen, Terry, and Amos (1987): A study of 163 adolescent students in a rural Iowa town found that 16 percent took a supplement daily and that 64 percent had taken one during the past month. The teens' use of supplements was correlated with their parents' use of supplements.

Zive et al. (1996): Young adults were the focus of another survey that used 24-hour diet recalls from 1988 to 1991 on a sample of 504 19- to 28-year-olds in Bogalusa, Louisiana. Nine and one-half percent of the participants reported taking a DS product in the prior 24-hour period. About 11 percent said they took supplements daily, 17 percent said they took them "once in a while," and 72 percent said they had never taken a DS product.

Medeiros et al. (1991): People in seven western states were surveyed in the spring of 1986, and by telephone in the winter of 1986/1987 and again, in the fall of 1987. Forty percent used supplements at the baseline and in both telephone surveys. Those who used supplements long-term (in all three surveys) did not differ from nonusers by income or educational level, but they did have a slightly higher mean age. Women represented 55 percent of long-term users, and 60 percent of the nonusers were men.

Eliason et al. (1997): This survey of 136 patrons of two health food stores had findings contrary to the major studies and to some of the smaller studies as well. Respondents took an average of 5.9 supplements a day. Patrons took a total of 805 supplements, 50 of which had reported toxicities. Herbal products were the most commonly used supplements, followed by multivitamins. The most popular herbal products were garlic, ginseng, ginkgo biloba, evening primrose oil, alfalfa, and echinacea. Like the other studies, the typical supplement user was a white, middle-aged woman with an education beyond high school.

Eliason et al. (1996): Two hundred consecutive patients over age 18 attending a family medical practice were surveyed. Of these, 53 percent reported taking supplements. This study reported higher usage of more than one supplement product than other studies had (18 percent took 2 to 5 supplements). Their average estimated expenditure was $6.60 per month, and 84 percent of the products they purchased were vitamins and minerals, 8 percent herbals, and 3 percent amino acid and protein supplements. No tissue or organ extracts were taken. Only educational level was found to correlate significantly with supplement use.

Oakland and Thomsen (1990): The use of supplements by the elderly was investigated in this 1990 study of 24 males and 78 females in seven Iowa counties. Forty-nine percent had used vitamin and mineral supplements within the last 6 months. According to this study, 25 percent of men and 27 percent of women regularly used supplements.

Merkel, Crockett, and Mullis (1990): In another study, 340 surveys were collected from randomly selected women age 26 to 51 with school-age children. Fifty-two percent of the women reported using DS products. Only 11 percent said they had never used a DS product. Over two-thirds of the supplement users took only one or two products, and only 7 percent regularly used more than six supplements. Multivitamins (78 percent), followed by calcium and vitamin C, were the most commonly consumed supplements.

Applied Biometrics (1996): According to information provided by Applied Biometrics in a 1996 presentation to the Food and Drug Law Institute, 67 percent of supplement users do not have any children under age 18 living with them and 7 out of 10 have had some college education. Fifty-one percent of supplement users have incomes between $20,000 and $50,000, according to Applied Biometrics, and 19 percent have incomes greater than $50,000. The majority exercise at least three times a week and 23 percent exercise daily. Eighty percent do not smoke and 60 percent drink only occasionally. Applied Biometrics also notes that 30 percent of all women and 23 percent of the total take only one supplement, most likely a multivitamin. Only about 11 percent of women and 12 percent of men take two supplements.

4.3 Substitution Possibilities for DS products

In addition to the demographic characteristics described in Section 4.2, the price of substitute products shifts the demand curve for DS products as well. If products can substitute for one another, then an increase in the price of one product will increase the demand for its substitutes. However, DS products are so heterogeneous that either (1) no substitutes will exist or (2) if substitutes do exist, consumers will have strong preferences for one product over another. For example, zinc, echinacea, and vitamin C are all consumed because individuals believe they will prevent colds, but they are dissimilar enough that even large price changes in one will probably have little effect on the demand for the others. In other words, the cross-price elasticity of demand is small.

For traditional vitamin and mineral products, an obvious source of substitution is food products that contain the vitamin or mineral. Consumers could obtain adequate amounts through the diet. However, nontraditional DS products are taken for reasons other than nutritional supplementation. For these products, the substitute product may be conventional medical care. In the section below, we review some of the information that is available on both forms of substitution for DS products.

4.3.1 DS Products as Substitutes for Nutrients in Conventional and Fortified Foods

Dietary supplements are imperfect substitutes for both conventional foods and fortified foods. While consumers can get all the nutrients they require from foods, the opposite is not true, they cannot get all the nutrients they require from supplements. At most, dietary supplements can replace a small portion of the diet. Substitution possibilities for both conventional and fortified foods are described briefly below.

Conventional Foods

Some consumers of DS products, particularly vitamins and minerals, may be using them as substitutes for the nutrients available in foods. For example, consumers who wish to increase their intake of calcium may prefer to take a calcium pill rather than eat more dairy products. Or, an individual may prefer taking an iron supplement to eating red meat. If the price of the supplement were to increase, it is possible that some consumers would respond by taking less of the supplement and eating more of the foods that are rich in that nutrient. Conversely, an increase in the price of the nutrient rich-food could cause some consumers to rely more heavily on supplements. Price may be a very small factor in determining the consumer's choice, however. Many consumers have compelling reasons for avoiding certain foods. Individuals with lactose intolerance would not eat more dairy products as a source of calcium, nor would vegetarians eat red meat as a source of iron. Consumers' strong preferences regarding food limit the extent to which supplements and food can act as substitutes for each other.

Fortified Foods

In some cases, fortified foods and DS products may act as substitutes for each other. For example, an individual may choose a breakfast cereal that contains 100 percent of the RDAs for vitamins instead of taking a daily vitamin supplement. The same manufacturers who produce vitamins for the dietary supplement industry also supply the food industry. Major manufacturers including Hoffmann LaRoche, BASF, Rhone-Poulenc, and ADM produce vitamins for the food industry as well as the DS and animal feed industries. In terms of value, the food industry accounts for about 20 percent of vitamins consumed, compared to 30 percent used in supplements and 50 percent used in animal feeds worldwide (Ullman's Encyclopedia of Industrial Chemistry, 1996). If consumers switch from a fortified food to a supplement, or vice versa, they may still be consuming vitamins from the same manufacturer that have been prepared and packaged in a different form. Although the demand for vitamins from the manufacturer might remain unchanged, such a shift would affect businesses involved in the later stages of processing, packaging, or marketing either fortified foods or DS products.

4.3.2 DS Products as Substitutes for Conventional Medical Care

Alternative medicine has become mainstream in its popularity as Americans increasingly turn to self-medication for treatment and prevention of disease. In 1996, $94 million was spent in the United States for books on herbs and related topics (Cuthbert, 1998). Unconventional medicine is sometimes more accessible than traditional medicine to health care consumers, and a large segment of the population is disgruntled with traditional medicine. Thus, some consumers are taking a more proactive role in their health care and are looking to prevent illness to avoid the need to see a doctor. Studies also show that consumers substitute herbal remedies and supplements for traditional medical intervention. However, only a very small percentage of consumers rely completely on unconventional therapies. Most people who use alternative medicine do so in conjunction with traditional medicine and generally use alternative therapies for long-term, chronic conditions; for secondary health problems; or for general well-being and disease prevention. Most of those faced with serious conditions requiring medical treatment still consult a medical physician rather than pursuing unconventional therapies (Taylor, 1997).

In a survey of 1,539 adults nationwide, one-third of respondents reported using at least 1 of 16 possible unconventional therapies, defined as medical interventions not taught widely in U.S. medical schools nor generally available in U.S. hospitals and including herbal medicine and megavitamin therapy. Rates of use of unconventional therapies ranged from 23 to 53 percent, and use was more common among those 25- to 49-years-old, white, with some college education, and who lived in the West and had an annual income above $35,000 (Eisenberg et al., 1993). Comprehensive Therapy also reports that one in three Americans uses an unconventional therapy at some time (Taylor, 1997).

The majority of those using nontraditional therapies to treat their principal medical problem use them to treat chronic medical conditions. In particular, patients with cancer, arthritis, chronic back pain, AIDS, chronic renal failure, eating disorders, and gastrointestinal problems frequently use unconventional therapies. Of these conditions, megavitamin therapy is most commonly used because individuals believe it will treat digestive difficulties. Those using megavitamin therapy to treat their ailments reported out-of-pocket expenditures averaging $203 per person per year (Eisenberg et al., 1993).

Women are also using alternative medicine as a substitute for hormone replacement therapy after menopause. Supplements containing calcium, magnesium, boron, DHEA (a hormonal supplement), and phytoestrogens, or naturally occurring plant sterols that may exhibit effects similar to estrogen are taken to mimic the effects of estrogen therapy in mitigating the symptoms of menopause as well as to provide benefits beyond the treatment of menopausal symptoms (stronger bones, lower cardiovascular disease and cancer risk). Botanicals commonly used in menopause treatment are angelica, black cohosh, chamomile, damiana, evening primrose, ginseng, saw palmetto, and licorice. Women are choosing such natural alternatives because they believe they will avoid the possible side effects of synthetic estrogen replacement therapy, such as breast cancer, weight gain, and breakthrough bleeding.

Supplementation and herbal healing are also being considered by some insurance companies and health maintenance organizations (HMOs) as possible avenues by which to offset some of the skyrocketing costs of medical care by substituting some traditional care with less costly unconventional therapies. Oxford Health Plans Inc. became the first network provider for alternative medicine, according to Nutrition Business Journal (Nutrition Business International, October 1996a). Oxford plans to establish a network of 1,000 holistic providers, include alternative medicine coverage, and establish a mail order service for purchasing vitamins, remedies and alternative medicine products (Nutrition Business International, October 1996a). Indeed, Eisenberg's study does touch on the growing interest in insurance providers in this area; 83 percent of those using the services of herbal therapists were reimbursed by third parties, as were 30 percent of those using megavitamin therapies. Also, 70 percent of respondents in a survey of HMOs reported an increase in the number of members asking for the provision of alternative care therapies (Nutrition Business International, October 1996a).

However, Eisenberg's study found that serious, life-threatening medical conditions are still generally treated by conventional doctors. Among people who did use an alternative therapy to treat a serious medical problem, 83 percent also sought treatment from a medical doctor for that condition. Of the 1,279 respondents reporting at least one principal medical condition, only 3 percent saw an unconventional provider and not a medical doctor. Seven percent saw both a medical doctor and a provider, and 58 percent saw just a traditional medical doctor. These numbers illustrate the rarity of visits to unconventional providers in the absence of a consultation with a medical doctor (Eisenberg et al., 1993).

A study conducted by the Medical College of Wisconsin of customers of two health food stores supports the Eisenberg study regarding use of unconventional therapies for overall wellness and disease prevention and not as the preferred method of medical care. Of the 805 different supplements taken by the 136 persons surveyed, 84.3 percent were taken to prevent disease and health problems, and only 15.7 percent of those surveyed took supplements to treat health problems. Both studies found the use of unconventional therapy was not supervised by a physician the majority of the time these therapies were used. As in the Eisenberg study, most users of these unconventional therapies did have health insurance and had a regular physician (Eliason et al., 1997).

The use of unconventional therapies is also reflected in developments in alternative health law. In 1996 alone, Utah, Maine, and Vermont licensed all their naturopaths; Washington State's King County established a natural health clinic; University of California at San Francisco created an Integrative Medicine Program and more than 30 other medical schools planned courses in alternative medicine; and medical freedom bills were active in 12 states (Nutrition Business International, January/February 1997).