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    The digestibility of a dietary supplement into the bloodstream (similar to bioavailability).

Adequate intake (AI)

    A dosage recommendation that may be used on a product label where RDA information is lacking and that is labeled as DV's.

Adverse event report (AER)

    A report of an incident where it is believed that a substance may have caused a health problem or detrimental event.


    The analysis of a substance or mixture to determine its constituents and the relative proportion of each.




    The rate and extent to which a drug or dietary supplement is absorbed into general circulation, thereby permitting access to the site of action. Measured by the concentration in body fluids, usually blood, or by the magnitude of the pharmacological response. Expressed as a fraction of an administered dose.

Biological assay

    Estimation of strength of a drug or substance by comparing its effects in test animals to a reference standard.

Biological marker compound

    A compound for which a product is tested to determine if a particular plant material is present. Used for quality control.


    Products made from plants, including herbs.



Certificate of authenticity

    Documentation that accompanies raw materials used to manufacture dietary supplements that attests to their authenticity.

Clinical trial

    Research studies that use human beings (rather than animals). Clinical trials are conducted in health care settings with voluntary patient-participants.

Control group

    The group of patients in a clinical trial who receive either the current standard care or a placebo. Results of the control group are compared to results of the treatment group. No patient is placed in a control group without treatment if any beneficial treatment is known. (See also randomized, controlled research)



Dietary reference intakes (DRIs)

    An umbrella term for groups of values (including RDAs, AIs, EARs, and UIs) that specify recommended dosages. Proposed by the Food and Nutrition Board of the Institute of Medicine of the National Academy of Sciences in partnership with Health Canada.

Dietary supplement

    The term "dietary supplement" has a specific legal meaning in the U.S. established by DSHEA. It refers to a product that supplements the diet and whose label clearly states that it is a dietary supplement. It is distinct from a drug which is represented as a substance that is intended to diagnose, cure, mitigate, treat, or prevent diseases and which must undergo extensive testing and be preapproved by the FDA before being sold. There are specific cases where dietary supplements may also be labeled as impacting disease.

    Dietary supplements may contain the following kinds of ingredients: vitamins, minerals, herbs, botanicals, other plant-derived substances, amino acids (the individual building blocks of protein) and concentrates, metabolites, constituents, and extracts of these substances. They are intended for ingestion in pill, capsule, tablet, or liquid form and are not represented for use as a conventional food or as the sole item of a meal or diet.


    The term disease commonly refers to any deviation from the normal structure or function of the human body that is manifested by a characteristic set of one or more signs or symptoms. The FDA is no longer proposing to broaden the definition of disease to include such conditions as pregnancy, menopause, and aging.

Disease claim

    See health claim.


    The drop in potency of a dietary supplement while in storage as a function of time and storage conditions (light, heat, moisture, and air). Stable supplements have a low rate of disintegration allowing for a later expiration date, while others lose potency comparatively quickly.


    The portion of an ingredient, usually expressed as a percentage, that dissolves in the human digestive tract -- thereby making it available for absorption in the body. The combined effect of dissolution and absorption determines how much of a consumed ingredient ends up in the bloodstream.

Double blind research

    A clinical trial in which neither the researchers nor the patients know who is receiving the treatment being tested and who is in the control group. Blinding a study prevents personal reactions and bias from influencing the study results. If necessary, treatment received by any specific individual can be quickly identified by a special code. (See also single blind research.)


    In the United States, medicinal products used for the treatment of diseases.


    The Dietary Supplement Health and Education Act passed in the United States in 1994. DSHEA served to deregulate the labeling of dietary supplements by giving manufacturers freedom to market more products as dietary supplements and to provide specified kinds of information about their products' benefits.


    "Daily value" -- New dietary supplement regulations went into effect in March of 1999 that require labeling of dietary reference intakes (DRI) and which appear as "DV" on product labels.




    A synomym for effectiveness.

Effectiveness (in the context of dietary supplements)

    The likelihood of benefit from use of a product when taken according to published or labeled guidelines.

Estimated average requirement (EAR)

    The intake value that is estimated to be optimal for about half of the individuals in a specified group. In other words, the EAR meets a specified requirement in 50 percent of an age- and gender-specific group. At this level of intake, the remaining 50 percent of the specified group would not have its needs met. EAR is one of the guidelines encompassed in DRI (dietary reference intakes) established by the National Academy of Sciences.


    An inert substance used as a medium in pills and capsules that forms a vehicle for delivery of a drug or dietary supplement.


    A solution obtained by soaking a plant in solvent, then allowing it to evaporate.

Extramural research

    Studies conducted by outside organizations.



Food additive

    Substance added to food to increase its flavor, storage characteristics, color, aroma, nutritional content, or other qualities.

Functional foods

    Generally refers to a broad category of food that is formulated for (and promoted as having) special health benefits.



Genetically modified organisms (GMOs)

    Foods that have been created or modified by the use of genetic engineering techniques in which DNA has been introduced, deleted, or inhibited.

Good Manufacturing Practices (GMPs)

    Procedures for manufacturing dietary supplements that are used to ensure a consistent level of quality. GMPs embody procedures that ensure purity, cleanliness, freshness, and proper labeling.


    "Generally Recognized As Safe" -- a category of food additives designated by the U.S. Food and Drug Administration.



Hazard analysis critical control points (HACCP)

    Protocol adopted by Codex for controlling outbreaks of contaminated foods. The USDA and FDA are working to integrate Codex guidelines into U.S. regulations. This could affect dietary supplements for specific cases where food bacteria or other extreme conditions infiltrate a supply.

Health Claim

A claim that a dietary supplement or drug can be used to prevent or treat abnormalities or disease.


    A supplement derived from a seed-producing plant that does not develop persistent woody tissue but dies down at the end of a growing season.

Homeopathy, homeopathic remedies

    The term homeopathy comes from the Greek homoios (meaning "similar") and pathos (meaning "suffering"). Homeopathic remedies are usually dilutions of natural substances from plants, minerals, and animals. These remedies act to stimulate the body's natural healing responses to specific symptoms. Homeopathy was founded by Dr. Samuel Hahnemann in the late 18th century.



In-vitro research

    Studies that use biological substances.


    Side effect resulting from concurrent use of multiple drugs or dietary supplements. The result may be antagonism (counteracting) or synergism (amplifying) and consequently may be adverse in some cases.

Intramural research

    Studies being conducted within the limits of an organization or institution.

I.U. (International Unit)

    An international unit (I.U.) is a standard unit of measurement of biological activity that is used for fat soluble vitamins A,D, &,E (as well as for some hormones, enzymes, and vaccines). It is an internationally-recognized standard established by the International Conference for Unification of Formulae. One I.U. represents a different amount for different substances. The weight equivalents for fat soluble vitamins are as follows:

    Beta Carotene (Vitamin A) 1mg. = 833 IU
    Vitamin D 2.5 mcg = 100 IU
    Vitamin E 1mg = 1 IU



LOAEL (lowest observed adverse effect levels)

    The lowest intake at which some adverse effects have occurred under certain circumstances; the lowest dosage of a particular dietary supplement at which an adverse effect was ever reported. (Developed by CRN.)



Metabolism (assimilation)

    Physical and chemical changes that take place within an organism; all energy and material transformations that occur within living cells. Includes growth as well as energy changes: all transformations of chemical energy of foodstuffs to mechanical energy or heat. Includes anabolism (the conversion of ingested substances into the constituents of protoplasm), and catabolism (the breakdown of substances into simpler substances, the end products usually being excreted).


    A substance essential to the metabolism of a particular metabolic process.


    A published research report about a dietary supplement or class of dietary supplement that includes information regarding category, pharmacology, precautions, side effects, patient consultation, and general dosing information.



Natural foods

    Usually identified as foods that are either unprocessed or organically grown, or that contain products that are unprocessed or have been organically grown.

Naturopathy, naturopath, naturopathic physician

    Naturopathic medicine focuses on the body's innate ability to heal. Naturopathic physicians provide complete diagnostic and therapeutic services and are licensed or accredited, depending on where they received their degree and what state they practice in. They consider a patient's diet, lifestyle, work, and personal history when designing treatment -- which may include nutrition, herbs, homeopathy, acupuncture, hydrotherapy, massage, and counseling as well as more conventional therapies.

NOAEL (no observed adverse effect levels)

    Intake level of a dietary supplement at which there are no credibly-substantiated adverse reactions observed in humans. From CRN.


    A legal definition that, according to the Dietary Supplement Health and Education Act (DSHEA), is any non-toxic food extract supplement that has scientifically proven health benefits for disease treatment or prevention. DSHEA requires that this food component be standardized in the nutraceutical product and manufactured under good manufacturing practices (GMPs). Nutraceuticals are not whole foods, yet are partially or completely derived from them. There are four types of nutraceuticals:

      1. vitamins, minerals, and other dietary supplements in the form of pills or capsules

      2. products based on extracts from foods or beverages in normal use (such as garlic, broccoli, red wine)

      3. food extracts claiming a medical benefit (such as oat bran lowering cholesterol, aloe vera juice healing ulcers)

      4. natural substances that people might not usually eat but that may prevent or treat illness (such as colloidal silver, hypericin, ginsenosides)


    Food or substance that supplies the body with elements necessary for metabolism.


    All the processes involved in the taking in and utilization of food substances by which growth, repair, and maintenance of activities in the body as a whole or in any of its parts are accomplished. Includes ingestion, digestion, absorption, and metabolism.



Off-the-shelf testing

    See random off-the-shelf testing.

Organic foods

    A labeling term for products produced under the authority of the Organic Foods Production Act, which regulates allowable soil conditions and restricts the use of irradiation, genetically-engineered organisms, pesticides, fertilizers, and additives in the production of foods. From OTA.

Over-the-counter drugs

    In the United States, drugs that do not require a prescription.


    Excess potency that is manufactured into a dietary supplement to allow for disintegration so that the product maintains the potency level of its labeled unit amounts through the expiration date.



Peer review

    Analysis of research by a group of professionals of comparable knowledge and expertise in a specific scientific or medical field.


    See drugs.


    The study of drugs and dietary supplements and their origin, nature, properties, and effects upon living organisms.


    Authorized treatise on drugs or dietary supplement and their preparation, especially a book containing formulas and information that provides a standard for preparation and dispensation.


    Relating to the chemistry of plants, plant products, and plant processes.


    Medicines derived from plants.


    An inactive substance with no medicinal effects that sometimes is used in research control groups.


    A treatment plan or outline. In clinical trials, a protocol is the plan for using an experimental procedure or treatment.



Random off-the-shelf testing

    Testing of one or more products performed by an independent laboratory to measure quality. Products are picked randomly from a retail store shelf in accordance with a procedure that ensures random and unbiased selection.

Randomized controlled trial

    A research study that uses two or more groups of research subjects. The treatment group receives the experimental treatment while the control group receives either a placebo or current standard treatment. (If the research is also a clinical trial, these research subjects are people.)


    Refers to both Recommended Dietary Allowance (RDA) and U.S. Recommended Daily Allowance (US RDA).


    Reference Daily Intake. See DRI.

Recommended Dietary Allowance (RDA)

    Dietary intake goals for healthy people in 16 different age and gender groups based on a consensus of the Food and Nutrition Board of the Institute of Medicine of the National Academy of Sciences. RDAs serve as the basis for the U.S. Recommended Daily Allowances, the Food and Drug Administration's standards for required nutrition labeling of foods.

Recommended Daily Allowance (US RDA)

    Dietary intake goals established by the U.S. Food and Drug Administration and based on the highest RDA values in a gender/age group. US RDAs are more widely used than RDAs.


    Many varieties and categories of research are relevant to dietary supplements. See clinical trial, control group, double-blind study, in-vitro research, peer review, placebo, randomized controlled trial, single-blind study, treatment group.




    A safe dietary supplement is one that does no harm when used under defined conditions and as intended. An unsafe substance may result from toxicity, drug interactions, contraindications, allergies, or contamination.


    The period of time during which a dietary supplement remains sufficiently potent to be effective. The expiration date on a product label should indicate the end of this time period.

Single blind research

    Clinical trials in which the patients do not know which treatment they are receiving -- but the researcher does. (See also double blind research.)

Standard operating procedures

    Internal procedures for manufacturing and quality control of dietary supplements.

Structure / function claims

    Claims that a dietary supplement benefits by maintaining healthy or normal structures or functions of the human body -- as opposed to preventing or treating abnormalities (health claims).


    A person or animal in a research study whose reactions or responses are studied.



Tolerable upper intake level (UI)

    The maximum level of daily nutrient intake that is unlikely to pose risks of adverse health effects to almost all of the individuals in the group for whom it is designed. UI is one of the guidelines encompassed in DRI (dietary reference intakes) established by the National Academy of Sciences.


    The extent, quality, or degree to which a substance is poisonous; in other words, the degree to which it interferes with normal physiological functions. Because almost any substance can be poisonous if consumed in sufficient quantity, toxicity generally refers to intake of excessive dosages.

Treatment group

    The group of patients who receive the new treatment in a clinical trial. Results of the treatment group are compared to results of the control group. Researchers can then judge whether the new treatment is as good as or better than current standard care.



Upper intake level (UI)

See tolerable upper intake level.


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