Glossary (A-F) for Nutrition Research
The definitions that follow provide a brief explanation of the meaning of word as used on the NHRI site. Click on Read More, Dig Deeper, or See Article at the end of the definition for additional information. The structural formula for the nutrients marked with an (F) are located in the “Basic Science” section under Chemical Structural Formulas.
25-Hydroxyvitamin D – An intermediate in the body conversion from the substance produced by sunlight into a more usable Vitamin D form.
Abdomen – The body space between the chest and the pelvis. This is called the “belly”.
Accelerometry – A system of measuring body movement over time.
Acetaminophen – Tylenol, a pharmaceutical to relieve minor pains.
Acetyl Cysteine,n – Is able to break the disulfide bonds in mucous and useful in coughs and cystic fibrosis. Reduces symptoms of schizophrenia and bi-polar disorder. Is a precursor to glutathione.
Acidosis – Body overacidity resulting in nausea, headache, vomiting, and visual problems.
Actigraph – A device used to monitor physical activity during sleep or rest.
Acupuncture – Healing using needles under the skin to relieve pain or cure disease.
Adenoma – Benign tumor of a gland.
Adenosine Tri-Phosphate – See ATP.
Adiponectin – A protein involved in glucose regulation and fatty acid decomposition.
Adipose Tissue – Connective tissue in which fat is stored.
Adrenal Glands – Glands near the kidneys that produce adrenaline for emergencies.
Adverse Event – Any harmful and unintended response. Read more.
Aerobic – Living or taking place only in the presence of oxygen; literally, “requiring air”.
Alanine – A non-essential amino acid. High body levels have been linked to increased risk of high blood pressure and diabetes.
Aleurone – The layer just inside of the outer bran layer in many grains.
Alkali/Alkaline – A substance that counteracts acids.
Alopecia – The loss of hair.
Alpha-Carotene – The second most common of the carotenoids; reduced the risk of death in one study.
Alpha Linolenic Acid (F) – A polyunsaturated fatty acid in vegetable oil. Dig Deeper
Alpha Lipoic Acid (F) – An antioxidant soluble in both water and oils. Read more
Alpha Tocopherol – Compounds which have the same formula but have different shapes and are accepted as vitamin E by the FDA.
Alpha Wave – A rhythm in the brain that occurs in wakeful sleep.
Amalgam – A combination of mercury with other metals that is solid at room temperature.
Amines – Organic compounds with an NH2 group. Dig Deeper
Amino Acids - Contain an amino (-NH2) and carboxyl (-COOH) group. DigDeeper
Amylase – An enzyme which aids in the digestion of carbohydrates.
Amyloid Beta Protein – A protein forming abnormal deposits as in Alzheimer’s Disease.
Amyloid Plaque – A waxy protein material deposited under abnormal conditions such as Alzheimer’s Disease.
Analog – A member of a chemical family, such as methyl, ethyl, and propyl alcohol.
Angiogenesis -The formation of blood vessels, often to tumor cells.
Angina - Chest pains caused by insufficient oxygen to the heart.
Animal Study – A study using animals to test a theory or to evaluate toxicity. See Article.
Anthocyanidins – Polyphenols with three six member rings and strong antioxidants.
Antigen – Any substance that causes your immune system to produce antibodies against it.
Antihypertensive – A substance used for high blood pressure.
Antimicrobial – These kill or inhibit growth of micro-organisms (bacteria, fungi, molds).
Antihistamines – Compounds which oppose the action of histamine and useful in treating colds and allergies.
Antioxidant – A substance that can counteract the damage of free radicals and oxidation.
ApoB (Apo Lipoprotein) – High levels indicate greater heart risk.
Apoptosis – An automatic mechanism to reduce unwanted cells. Dig Deeper
Arachidonic Acid (F) – An unsaturated fatty acid found in most animal fats. Dig Deeper
Arginine (F) - An alkaline amino acid found in plant and animal proteins and plays an important role in cell division, wound healing, and the immune function.
Arm – One of the groups in a test study.
Aromatic – Chemicals with rings of atoms that share electrons like benzene and toluene.
Arteriosclerosis – Hardening and thickening of the walls of the arteries. Dig Deeper
Ascorbic Acid (Vitamin C) (F) - A potent water soluble antioxidant. Read more.
Aspartic Acid (F) – An acidic, non-essential amino acid.
Association – A connection between a substance and a result. Read more.
Astaxanthin (F) - An antioxidant found in yeast, salmon, and crustaceans. Dig Deeper
Atherogenesis – Fatty deposits in the arteries or deterioration of the inner wall of the artery.
Atherosclerosis – Degeneration of the inner layer of the arteries by fatty deposits or other abnormalities.
Atomic Weight – The weight of an atom, based on about one for each neutron and proton. Read more.
Atoms – The combination of neutrons, protons, and electrons that make up elements like oxygen, sulfur, and iron.
Atopic Dermatitis – A genetic tendency to develop a skin irritation with intense itching and inflammation.
Atopy - A genetic tendency to develop an allergy.
ATP (Adenosine Tri Phosphate) (F) – Important in energy transfer. Has anti-inflammatory properties.
Atrial Fibrillation – An erratic rapid heartbeat due to an irregular impulse to the heart.
Atrophy – Decrease in size or wasting away of a body part.
Attenuate – To reduce in force, value or amount; weaken the effect of something.
Aura – A sensation of hearing voices or seeing colored lights before an epileptic or migraine attack.
Autoimmune – Relating to or caused by antibodies or T cells that attack body substances.
BAP (Benzoalphapyrenes or Benzo(a)pyene) –Carcinogens produced by high heat. Dig Deeper
Baseline – The normal or beginning level of a measurable factor in a research. Read more.
Berberine (F) – An anti-inflammatory material with benefits in diabetes, heart, and cancer.
Beta Amyloid Protein – See Amyloid Beta Protein.
Beta Carotene (F) – A source of vitamin A in yellow, dark green, or red plants. Dig Deeper
Beta Cells – Secretory cells of the pancreas or pituitary gland.
Beta Glucan – A class of soluble fibers found in cereal grains like oats.
Beta Sitosterol (F) – Compound in soy and corn oils used to reduce cholesterol levels.
Bias – An influence or action at any stage of a study that distorts the findings. Read more.
Bioavailable – The activity or amount of a substance available in a target issue. Read more.
Bioflavonoids – See Flavonoids.
Biomarkers – See Markers.
Biotin (F) – A B-Complex vitamin necessary for cell growth.
Blinded – A trial done so that one of the groups involved is unaware of the treatment. Read more.
Blood Brain Barrier – A blockade of cells separating the blood of the brain. Dig Deeper
Blood Lipid Profile – Fats in blood – cholesterol, LDL, HDL and triglycerides. This is often used to gauge the risk for coronary heart conditions.
Blood mononuclear Cells – Blood cells with a round nucleus that are infection fighters.
Blood Pressure – Pressure from circulating blood on the walls of blood vessels. Dig Deeper
Blood Urea Nitrogen (BUN) – The nitrogen level in the urea and a test for kidney health.
Body Adjustments – Changes done automatically by the body to meet its needs. Read more
Body Mass Index (BMI) – A measure of excess body weight. A value of 25 to 30 indicates overweight and over 30 indicates obesity.
Boswellic Acid – A family of complex five ring compounds used to kill cancer cells, reduce inflammation, and reduce asthma symptoms.
Bronchocontriction - A reduction in diameter of the main air passage to the lungs.
C3 Protein (Complimentary Component 3) – An important immunity protein.
C-Reactive Protein (CRP) – A blood protein which indicates a risk at high levels. Dig Deeper
Capillaries – Small, thin-walled blood vessels that connect the arteries to the veins. Dig Deeper
Caprylic Acid (F) – A short saturated fatty acid used as an antifungal remedy.
Carbon Tetrachloride (CCl4) – A solvent formerly used in dry cleaning. Dig Deeper
Carcinogen – A cancer causing agent.
Cardiac – Pertaining to the heart.
Cardiometabolic -Related to obesity, diabetes, and heart issues.
Cardiovascular Disease (CVD) – A disease of the heart and blood vessels.
Carnitine (F) – An amino acid involved in energy production. Dig Deeper
Carotenoid – A class of about 600 natural occuring pigments in plants, algae, and some other micro-organisms. Some convert into Vit. A or serve as an antioxidant.
Case Controlled Studies – Studies done with a group of subjects with a specific condition. Read more
Case Studies – Formal report of individual cases normally done by a doctor. Read more
Catalyst – A substance, usually in small amounts, that modifies and increases the rate of a reaction without being consumed in the process.
Catechin (F) – One of a family of strong aromatic antioxidants with multiple OH groups.
Celiac Disease - A disease due to the inability of the body to digest gliadin, a protein found in wheat and similar grains.
Cell Study (In-Vitro) - Is done in cells kept alive outside of a living organism. Read more.
Chelating Agent – Substance which combines with a metal to change its activity. Dig Deeper
Chemistry Panel – Tests providing an overall picture of the body’s metabolism. Dig Deeper
Chi Gong (Quigong) – A health practice involving alignment of breathing, movement, and awareness.
Chlorella - A green algae used to reduce cholesterol, abnormal blood fats, and blood pressure.
Chlorination – Reacting with chlorine. Used to remove harmful microorganisms in water.
Chloroform (CCl3H) – A solvent widely used as an anesthetic to replace ether. However it was found to cause cardiac arrhythmia, liver problems, and a possible carcinogen.
Cholesterol (F) - A fatty substance involved in moving material in and out of cells. Dig Deeper
Choline (F) - An essential B-vitamin lacking in the average diet. Dig Deeper
Chromium (F) – Chromium has a RDI of 35 micrograms per day for males and 25 micrograms for females. Dig Deeper
Chronic Obstructive Pulmonary Disease (COPD) – Lung disease with impaired air flow.
Chondroitin - A compound formed of chains of sugar units and found in the cartilage of joints.
Cirrhosis – Disruption of the liver function. Can be caused by alcohol abuse.
Citrulline (F) – An amino acid used to enhance athletic performance.
CLA (Conjugated Linoleic Acid) - A fatty acid family mainly in meat and dairy products with two double bonds in parallel separated by carbons with a single bond.
Clarification – Removing solids from a solution.
Clinical Investigator (Principal Investigator) – Lead scientist or engineer for a clinical trial.
Clinical Trial – Studies to determine safety and efficacy of materials. Dig Deeper
Coenzyme – A loosely bound factor that assists enzyme activity.
Coenzyme Q10 (F) – Aids in the production of body energy.
Cognition – Knowing, including awareness, perception, reasoning, and judgment.
Cohort – A collection of individuals with a common characteristic, like the same age or sex.
Collagen – The supportive protein of cartilage, connective tissue, tendon, skin, and bone.
Colon – Large intestine.
Colonic Mucosal Cells – The innermost cellular layer of cells in the colon. Dig Deeper
Colorectal – Pertaining to the colon, rectum, and anus.
Colorectal Adenoma - Relating to the large intestine (colon and rectum).
Compassionate Use – Providing experimental treatments before FDA approval and used with very sick patients who have no other options. Often, case-by-case approval is needed.
Competition – Interaction between nutrients for absorption or elimination. Read more.
Complementary and Alternative Therapy – A range of healing philosophies, and therapies that conventional medicine does not commonly use, such as acupuncture and herbs.
Compliance – Adherence to a recommended treatment. Read more.
Comprehensive Medical Panel – (See Chemistry Panel).
Confidence Interval – Used to indicate the reliability of an estimate or measurement.
Confounding Factor - A complication that confuses the results. Read more
Congestive Heart Failure – Failure of the heart to maintain adequate circulation.
Contraindication– A factor that renders the use of a substance or procedure inadvisable.
Control – A standard to which trial measurements are compared. Also a member of a control group. Read more.
Control Group– An untreated group of subjects to which the trial group is compared.
Controlled Study – A study that all variables except the trial ones are controlled. Read more.
Coordination Compound or Complex – See Chelating Agent.
CoQ10 (F) – A nutrient that supports heart health and has other benefits.
Coronary Heart Disease – A condition that reduces blood flow.
Corticosteroids – Produced in the adrenals involved in stress response, immunity, and inflammation.
Cortisol (F) – A steroid hormone released during stress which suppresses the immune system and aids in fat, protein, and carbohydrate metabolism.
Creatine (F) - A substance found in muscles. Dig Deeper
Curcumin (F) – Main component of the Indian spice, tumeric ( an East Indian spice involved in test treatments for Alzheimer’s Disease, cancer, and arthritis).
Cyanide - A family of deadly compounds with a CN group which inactivates respiratory enzymes.
Cyanocobalamin (F) - The most common source of vitamin B12.
Cysteine (F) – A sulfur containing amino acid.
Cystic Fibrosis – A disease often resulting in frequent lung infections. Dig Deeper
Cytochrome C – A soluble blood protein that transports electrons in the body.
Cytokines – Protein molecules that convey information from the nervous system glial glands.
Data Safety and Monitoring Board – An independent committee of community representatives and clinical research experts, that reviews data during a clinical trial.
Dementia – Dementia is a loss of brain function that occurs with certain diseases. It affects memory, thinking, language, judgment, and behavior. Alzheimer’s disease is one cause of dementia.
Detoxification – To remove a toxic substance or its effects from the blood or tissues.
Devil’s Claw – A plant in the sesame family used to treat pain, fever, and arthritis. Read more.
Dextro (d) – A form of a molecule that has another shape as seen in a mirror. Dig Deeper
Dextrose (glucose) – A sugar harmful to diabetics. Dig Deeper
DHA (Docosahexaenoic Acid) (F) – An omega 3 fatty acid in fish oils. Dig Deeper
DHEA (Dehydroepiandrosterone) (F) – Used in body production of testosterone.
Diabetes Mellitus – Faulty carbohydrate metabolism with sugar in the urine. Dig Deeper
Dialysis – Separation of substances by semi-permeable membranes.
Diastolic Pressure – The minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle. It is the lower number of the two blood pressure readings.
Dilation – Stretching or enlarging an opening or hollow structure.
dL (deciliter) – 0.1 liters.
DNA (Deoxyribonucleic Acid) – The primary carrier of genetic information found in almost all organisms.
Dopamine (F) – A neurotransmitter involved in the production of epinephrine.
Dose-Ranging Study – See Range Study.
Double-Blind Placebo Controlled Crossover Study – A study in which the control group and the test group are reversed after equilibrium is reached. Read more.
Double-Blind Placebo Controlled Study – A double-blind study in which one group receives an inactive substance. Read more.
Double-Blind Study or Double Masked Study – A clinical trial in which neither the participants, nor the researchers know which participants are receiving the test materials or conditions.
Double Bond – Unsaturated carbon to carbon bonds which can react with other substances.
Downregulation – The process by which a cell decreases the amount of a cell component, such as RNA or protein, in response to external variables.
DPA (Docosapentanoic Acid) – An omega 3 fatty acid found in seal oil.
Dyslipidemia – Abnormally high concentrations of fats or lipoprotein in the blood.
Eczema -A skin condition with severe redness and itching.
Edema – Abnormal accumulation of fluid in connective tissue. Also called dropsy.
Efficacy – Power or capacity to produce a desired effect.
EGCG (Epigallocatechin-Gallate) (F) – A polyphenol (a compound with multiple benzene rings and OH groups) which is a strong antioxidant found in tea.
Eicosanoids – Compounds from polyunsaturated fatty acids involved in cellular activity.
Elastin – A protein-like collagen and main component of the fiber in connective tissue.
Electroencephalogram – Measure of brain waves.
Electrons – Negatively charged particles that circulate around the center of various atoms.
Electroretinogram – The electrical activity of the retina in graph form.
Element – A fundamental substance composed of one type of atom, like iron or copper.
Eligibility Criteria – Criteria for participant selection. Read more.
Empirical – Based on observational or experimental data, not on a theory.
Emulsify – To suspend small droplets of a liquid in a second that does not mix with it.
Enantiomorph – See Isomer.
Endocrine – Pertaining to the glands that secrete substances via the blood stream.
Endometrial – Pertaining to the membrane lining the uterus.
Endoscopy – Use of a tube to transmit light and see the interior of a body part, like the colon.
Endothelial – Relating to the thin, flattened cell layer, lining internal body cavities, such as lymph and blood vessels.
Enteral – Given by mouth to pass thru the stomach.
Enzymatic – Relates to using enzymes to produce a biochemical reaction.
Eosinophilic – Abnormal increase in some white blood cells, normally from allergy or infection.
EPA (Eicosapentaenoic Acid) (F) - An omega-3 fatty acid in fish oils. Dig Deeper
Epidemiological Study – A statistical study on human populations that links human health effects (e.g. cancer) to a cause, such as exposure to a specific chemical. Read more.
Epigenetics – The study of how nutrients and pollutants can have positive and negative effects on the activation of various genes.
Epithelial Cells – Cells lining an outer or inner surface such as skin or mucous membranes.
Equilibrium - A condition in which competing influences are balanced. Read more.
Erectile - Capable of being raised to an erect position. Often refers to the penis.
Ergogonic – Increasing capacity for bodily or mental labor, especially by reducing fatigue.
Erythrocyte - Red blood cell.
Esophagus – A tube that conveys food from the mouth to the stomach.
Essential Amino Acid – An amino acid not produced enough in the body to meet body needs.
Estrogen Replacement Therapy – Administering estrogen, normally after menopause.
Estrogens – Female hormones.
Ethical Review Board – See Institutional Review Board.
Etiology – Science to determine the origin or causes of a disease.
Exclusion Criteria – See Eligibility Criteria.
Exocrine – Glands that supply a secretion via a duct.
Fasting Insulin Level – Body level of insulin after an overnight fast.
Fasting Level – The body levels of a test substance after a fasting period, often overnight.
Fasting Plasma Glucose – The glucose level in the blood 12 hours after the last meal. A range of 4-7 mmol/l is normal.
Fatty Acids – Carbon chain acids with one carboxyl group usually combined with glycerol.
Femoral – Related to the femur, a bone that goes from the hip to the knee.
Fetal - Related to the period between conception and birth.
Fibrogen – A plasma protein that increases with increasing obesity.
Fibromyalgia – A disease with pain and stiffness of muscles usually associated with weakness, sleeplessness, and headache.
Fibroid – A benign tumor of the uterine wall, alternatively fibrous or woody tissue.
Fibrosis – The formation of excess fibrous connective in an organ or tissue.
Flavonoids (bioflavonoids) – Plant pigments with antioxidant benefits. Dig Deeper
Flavonols – A subgroup of flavonoids (bioflavonoids).
Flow Mediated Dilation – Measuring the size change of arteries when blood flow is stopped.
Folate – A combined form of folic acid, a B-complex vitamin.
Folic Acid (F) - A B-vitamin that can reduce the risk of Down’s Syndrome. Dig Deeper
Fractionation – Separation into components. This can be done in vegetable oils by reducing the temperature until solids appear and then separating these out.
Free Radicals – Unstable compounds which cause damage to tissues. Dig Deeper
Fructose – A sweetener that is sweeter than table sugar and does not raise blood sugar more than other carbohydrates.