Glossary of Terms & Definitions
Listed Alphabetically - "A"

Absorption: The taking up of liquids by solids or of gases by solids; intake of fluid or other substances by cells of the skin or mucous membranes;  the passage of digested foods from the gastrointestinal tract into blood or lymph.

Acetylation: the addition of an acetyl group (-COCH3) group to a molecule.

Acetylcholine: A neurotransmitter liberated by peripheral nervous system neurons and some central nervous system neurons. It is excitatory at neuromuscular junctions but inhibitory at some other synapses.

Acidic: having a pH of less than 7.

Acute: having a rapid onset, short and relatively severe course; not chronic.

Adjunct: assisting in the prevention, amelioration, or cure of a disease.

Adrenal glands: a pair of small glands, located above the kidneys, consisting of an outer cortex and inner medulla. The adrenal cortex secretes cortisone-related hormones and the adrenal medulla secretes epinephrine (adrenaline) and norepinephrine (noradrenaline).

AI: adequate intake. A recommended intake value based on observed or experimentally determined approximations or estimates of nutrient intake by a group of healthy people that are assumed to be adequate, The AI is used when the RDA cannot be determined.

AIDS: acquired immune deficiency syndrome. AIDS is caused by the HIV (Human Immunodeficiency Virus) virus, which attacks the immune system, leaving the infected individual vulnerable to opportunistic infection.

Alkaline: basic; having a pH of more than 7.

Allele: One of a set of alternative forms of a gene. Diploid cells possess two homologous chromosomes (one derived from each parent) and therefore two copies of each gene. In a diploid cell, a gene will have two alleles, each occupying the same position on homologous chromosomes.

Alpha Lipoic Acid: Alpha-lipoic acid is an antioxidant and an enhancer of other antioxidants. Normal metabolism and other processes produce oxidative or free radical byproducts that damage all living tissues in the body. The antioxidant properties of alpha-lipoic acid help to protect these tissues from damage caused by aging, sugar metabolism and certain pollutants in our environment and the foods we eat. In, particular, alpha-lipoic acid can reduce damage oxidative damage to blood vessels, brain, peripheral nerves, liver, skin and bone. Other beneficial effects have been demonstrated that are not yet well understood. Alpha-lipoic acid is effectively used to treat neuropathy, muscle fatigue, diabetic insulin resistance, vitamin E deficiency, vascular dysfunction, radiation injury, mushroom poisoning, and alcoholic hepatitis. It inhibits cataract formation and also frequently used as an anti-aging supplement. Click here for more info.

Alzheimer's disease: a neurological condition characterized by the degeneration of brain cells. Symptoms include memory loss, confusion, and physical decline.  Alzheimer's disease usually occurs later in life and worsens over time.

Amino acids: organic (carbon-containing) molecules that serve as the building blocks of proteins.

Anaerobic: refers to the absence of oxygen or the absence of a need for oxygen.

Analog: a chemical compound that is structurally similar to another but differs slightly in composition (e.g., the replacement of one functional group by another).

Anaphylaxis: a rapidly developing and severe systemic allergic reaction. Symptoms may include swelling of the tongue, throat, and trachea, which can result in difficulty breathing, shock, and loss of consciousness. If not treated rapidly, anaphylaxis can be fatal.

Anemia: the condition of having less than the normal number of red blood cells or hemoglobin in the blood, resulting in diminished oxygen transport. Anemia has many cause, including: iron, vitamin B-12, or folate deficiency, bleeding, abnormal hemoglobin formation (e.g., sickle cell anemia), rupture of red blood cells (hemolytic anemia), and bone marrow diseases.

Anencephaly: a birth defect, known as a neural tube defect, resulting from failure of the upper end of the neural tube to close during embryonic development. Anencephaly is a devastating and sometimes fatal birth defect resulting in the absence of most or all of the cerebral hemispheres of the brain.

Angina pectoris: pain generally experienced in the chest, but sometimes radiating to the arms or jaw, due to a lack of oxygen supply to the heart muscle.

Angiography (coronary): a diagnostic test used to identify the exact location and severity of coronary artery disease.  During angiography a small tube or catheter is inserted into an artery and guided with the assistance of a fluoroscope (x-ray) to the opening of the coronary arteries which supply blood to the heart.  A dye, visible on x-rays, is then injected into each coronary artery to reveal the extent and severity of blockages.  Images produced by angiography are known as angiograms.

Anion: a negatively charged ion.

Antagonist: a substance that counteracts the cellular effects of a natural compound, for example, a nutrient or a hormone.

Antibodies: also known as immunoglobulins (Ig), antibodies are specialized proteins produced by white blood cells that circulate in the blood recognizing and binding to foreign proteins, microorganisms or toxins in order to neutralize them. They are a critical part of the immune response.

Anticoagulant: a class of compounds that inhibit the formation of blood clots.

Anticonvulsant: a class of medication used to prevent seizures, commonly used in individuals with seizure disorders or epilepsy.

Antigen: a substance that is capable of causing an immune response.

Antihistamine: a chemical that blocks the affect of histamine in a susceptible tissues.  Histamine is released by immune cells during an allergic reaction and also during infection with viruses which cause the common cold.  The interaction of histamine with the mucus membranes of the eyes and nose results in "watery eyes" and the "runny nose" often accompanying allergies and colds.  Antihistamines can alleviate such symptoms.

Antioxidant: any substance that prevents or reduces damage caused by reactive oxygen species (ROS) or reactive nitrogen species (RNS). ROS and RNS are highly reactive chemicals that attack other molecules and modify their chemical structure. Antioxidants are commonly added to foods to prevent or delay their deterioration due to exposure to air.

Antiresorptive agents: medications or hormones that inhibit bone resorption.

Apoptosis: gene-directed cell death or programmed cell death that occurs when age, condition, or state of cell health dictates. Cells that die by apoptosis do not usually elicit the inflammatory responses that are associated with necrosis. Cancer cells are not able to undergo apoptosis.

Arginine: L-Arginine is crystalline, free-form amino acid. It is a important factor in muscle metabolism and works to transport, store and excrete nitrogen and is involved in DNA synthesis. It is also a precursor of guanidophosphate, phosphoarginine, and creatine, three high-energy compounds found in muscles.

Arrhythmia: an abnormal heart rhythm. The heart rhythm may be too fast (tachycardia), too slow (bradycardia) or irregular. Some arrhythmias, such as ventricular fibrillation, may lead to cardiac arrest if not treated promptly.

Asthma: a respiratory condition characterized by difficulty breathing and reversible narrowing of the airways, known as bronchospasm.

Ataxia: a lack of coordination or unsteadiness usually related to a disturbance in the cerebellum, a part of the brain that regulates coordination and equilibrium.

Atherosclerosis: also known as arteriosclerosis, atherosclerosis results from the accumulation of cholesterol-laden plaque in artery walls.  Plaque accumulation causes a narrowing and a loss of elasticity of the arteries, sometimes referred to as hardening of the arteries.

ATP: adenosine triphosphate. An important compound for the storage of energy in cells, as well as the synthesis (formation) of nucleic acids.

Atrophic gastritis: a chronic inflammation of the lining of the stomach, which ultimately results in the loss of glands in the stomach (atrophy) and decreased stomach acid production.

Atrophy: decrease in size or wasting away of a body part or tissue.

Autoimmune disease: Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to destroy pathogens, particularly viruses and bacteria that cause infections. Individuals with autoimmune diseases have antibodies in their blood which target their own body tissues.