Glossary (N-S) for Nutrition Research
The definitions that follow provide a brief explanation of the meaning of word as used on the NHRI site. It may have other meanings elsewhere. 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.
[ N ]
N-Acetyl Cysteine – 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.
Nanogram – One billionth of a gram.
Nasopharyngeal – The cavity including the nose and throat.
Natural History – A collection of facts about the development of a natural process or condition, without a change in the conditions until an endpoint is reached- often applied to disease prevention.
Natural Molecules – Molecules found as components of living systems. Read more.
Naturopathy (ND) – Treatment that avoids drugs and surgery and uses natural agents.
Necrosis – Death of a body part, such as a tumor.
Nested Case Controlled Studies – Matches specific groups and conditions. Read more
Neural – Related to or affecting the nervous system.
Neural Tube Defects – Genetic defects of the neural tube like Down’s Syndrome. These risks can be reduced by use of folic acid during pregnancy.
Neurobiology – A branch of biology that deals with the nervous system.
Neuropathy – Abnormal degenerative state of the nervous system.
Neuropsychological – Involved with the brain and nervous system and behaviour.
Neutrons – Particles without an electrical charge found in nucleus of various elements.
Niacin (Nicontinic Acid) (F) - Originally its deficiency caused pellegra. Dig Deeper
Nitric Oxide (F) – A gas regulating body processes like the transmission of nerve impulses.
Non-Steroidal – Not containing steroids Steroids are hormones made from cholesterol and include testosterone and estrogen.
Norepinephrine (F) – An adrenal hormone involved in the transmission of nerve impulses.
NSAID – Non-steroid, anti-inflammatory drugs to treat inflammation.
Nuclear Cataract – A cloudiness in the center of the lens of the eye.
Nucleus – The center of an element made up of neutrons and protons.
Nutraceutical – A food supplement with health benefits in addition to its nutritive value.
Nutrient – A substance providing nutrition and benefiting body processes.
Omega 3 Fatty Acids – Polyunsaturated oils in fish and a few vegetables oils. There is evidence their use reduces heart risk.
Omega 6 Fats - Vegetable oils in which the first double bond occurs between the 6th and 7th carbons opposite from the acid end.
Open-Label Trial – A clinical trial in which both the researchers and participants know the treatment administered.
ORAC – A method of measuring antioxidant capacities. Dig Deeper
Orbital – Relating to the bony cavity in the front of the skull around the eyes.
Organelle – A component of a cell with a specific function.
Ornithine (F) – Reduces fatigue from heavy exercise.
Orthopedics – Relates to treatment of the spine and related structures.
Osteoarthritis - This disease normally begins at middle age or later with changes in cartilage or bones near joints that causes repositioning of the joint and causes pain, swelling, and stiffness.
Osteopenia – Bone size that is below normal.
Osteoporosis – Low bone density which causes an increased risk of bone farctures.
Oxidative Damage – The damage caused by free radicals and oxidizing agents.
Oxidative Stress – Increased oxidants in animal cells causing free radicals and damage.
Oxidized – Reacted with an unstable oxygen containing compound.
Oxidizing Agent – A compound that readily oxidizes other materials. Dig Deeper
p-coumaric Acid (F) - A ring compound with antioxidant properties. Dig Deeper
P Value – See Statistical Significance.
Palm Kernel Oil – An unsaturated oil from the kernel of the palm tree normally partially hydrogenated to make it more solid. This creates trans fatty acids which are harmful.
Pancreatic – Relating to the pancreas, a gland behind the stomach that secretes digestive enzymes.
Pantothenic Acid (F) - A B-Vitamin sometimes called B-5. Dig Deeper
Para Aminobenzoic Acid (F) – A B-Complex vitamin used to reduce free radicals.
Parathyroid – A gland near the thyroid gland producing a hormone to regulate calcium and phosphorus metabolism.
Parenchyma- Abnormal growth.
Paresthesea – A sense of picking, tingling, or creeping of the skin without cause, except for possible nerve injury.
Partially Hydrogenated – Treatment of an unsaturated fat with hydrogen to make it more solid.
PCBs (Polychlorinated Biphenyls) – Compounds from chlorination of biphenyl. Dig Deeper
PDD-NOS (Pervasive Development Disorder- not otherwise specified) – Severe impairment of social or communication skills for unknown reasons.
Peer Review – Evaluation of a research study by professional colleagues. Read more.
Peer-Reviewed Publications – Professional journals that only publish articles subjected to a rigorous process which may require proof of findings in addition to peer review.
Peptides – Combinations of amino acids from the partial digestion of protein.
Perimenopause – The time period at the start of the menopause symptoms.
Periodontal – Relating to tissues and structures surrounding and supporting the teeth.
Peripheral Arterial Disease – A disease with arteries outside the heart providing inadequate blood flow.
Peroxide – An unstable compound with two oxygen atoms linked together.
pg/ml – Picograms (one millionth of a gram) per mililiter.
Pharmaceutical Model – The pharmaceutical philosophy. Read more
Pharmacognosy – Study of natural substances (plants, animals, microorganisms) used for drugs.
Pharmacology – The science of drugs, including their composition, uses, and effects.
Pharynx – The opening between the mouth and the esophagus (tube to the stomach).
Phase Study (Phase I, II, III, or IV) – See clinical trials.
Phenolic Compounds – Benzene family antioxidants with OH functional groups.
Phenylalanine (F) - An essential amino acid with a benzene ring. Dig Deeper
Phosphatidylserine –A fatty compound combined with phosphorus found in the walls of cells and used to reduce dementia.
Phospholipase – Enzymes which metabolize phospholipids such as lecithin.
Phospholipid – A class of compounds in which phosphorus is part of a fatty substance.
Phosphoric Acid (F) - A strong acid which is not harmful when diluted.
Phosphorylated – Reacting to bond to a phosphate group.
Phylloquinone, Vitamin K (F) – A co-factor that helps blood coagulate.
Phytic Acid (F) - A substance in whole grains with antioxidant properties.
Phytochemicals – Active chemicals in a plant that account for its medicinal properties.
Phytoestrogen – A plant material with estrogen (female hormone) activity.
Phytomedicines – Medicines derived from plants.
Phytonutrients – See Phytochemicals.
Phytosterols – Plant compounds that form the membranes of cells and help reduce blood cholesterol levels. Phytosterols are abundant in plant oils and other plant foods.
Phytotherapy – Treatment of ailments with plant material.
Picogram(pg) – One millionth of a gram.
Picomoles/Liter – One trillionth of the molecular weight of a substance in grams per liter.
Pilot Study – See Preliminary Study.
Pineal Gland – A small gland with the main function of producing melatonin.
Pituitary – Relates to the pituitary gland which develops hormones which control other endocrine type glands.
Placebo – An inactive substance given to a control group. Read more.
Placebo-Controlled Study – A trial in which controls receive a sham treatment with no real effect.
Placebo Effect – An effect from the patient’s expectations rather than the treatment itself.
Plaque – A small disk-shaped formation or growth; a patch. Dig Deeper
Plasma – The fluid part of a liquid (normally blood).
Platelet – An irregularly shaped cell-like particle that is an important part of blood clotting.
Platelet Aggregation – Clumping together of the platelets, possibly restricting blood flow.
Polynicotinate – A combined form of niacin.
Polyphenols – Antioxidants found in most plants. Dig Deeper
Polyps – Swollen projecting masses of tissue-often tumorous.
Polyubiquitinated – Bonding together to the same target protein to destroy it.
Polyunsaturated Fatty Acids – Fatty acids with more than one double bond. Dig Deeper
POMS Index – A measurement of mood state based on numerous adjectives.
Postmenopausal – Occurring after menopause (change of life).
Post Nasal Drip – Flow of mucous from the back of the nasal passage, normally due to an infection or allergy.
Post Prandial – After a meal.
Preclinincal Study – See Preliminary Study.
Pre-eclampsia – Hypertension during pregnancy.
Pre-Hypertension – Slightly elevated blood pressure: a systolic pressure from 120 to 139 millimeters of mercury (mm Hg) or a diastolic pressure from 80 to 89 mm Hg.
Preliminary Study – Tests done with few subjects-often animal or cell studies. Read more.
Preprandial – Before a meal.
Preventive Medicine – Science to prevent disease rather than cure it or treat its smptoms.
Probiotic – A substance which increases the amount of beneficial microorganisms.
Proline (F) - A non-essential amino acid used to treat arthritis and tissue strain.
Prophylactic – Protecting against an ailment or its spreading.
Prospective Study – Research that follows a particular group over time. Read more.
Prostate – A male gland surrounding the bladder neck and urethra; it contributes to the semen.
Protein carbonyl – The detection of protein=O groups which indicates oxidation damage to protein.
Proteinuria – Excess protein in the urine.
Protocol – The plan for a course of medical treatment or for a scientific experiment.
Protons – A component of atoms with a positive charge equal to that of an electron.
Prototype – The original form typical of later individuals, species, ailments, or treatments.
Psoriasis – A chronic, non-contagious disease with inflamed lesions with silvery-white scabs of dead skin.
Psyllium – Members of the genus Plantago used for its dietary fiber properties as a laxative.
Pulsatility Index – Related to the amount of blood flow in a blood vessel.
Pycnogenol – A pine bark extract with strong antioxidant properties. Dig Deeper
Pyridoxine (F) - One of the compounds called vitamin B-6. Dig Deeper
Qigong – A health and exercise practice using alignment of breathing, movement, and awareness.
Quartile – Twenty five percent or one fourth of the test group.
Quercetin (F) - An antioxidant flavonoid pigment in tea and other foods. Dig Deeper
Quintile – A subgroup that is 20%” or one fifth of the test group.
Randomization – Assigning subjects or objects to a group on a random basis. Read more.
Randomized Controlled Trial – An experimental design in which individuals are assigned randomly to a treatment group or a control group and the outcomes are compared.
Range Study – A clinical trial in which two or more doses of a substance are used to determine which one is most effective and least harmful. Read more.
Reactive Hypertrophy – Excessive enlargement of a body part due to stress.
Reactive Oxygen Species (ROS) – Extremely reactive oxygen products. Dig Deeper
Recent Research – The NHRI normally uses research done in the last three years. Read more.
Receptor – A molecule that recognizes and binds with specific molecules. Dig Deeper
Recruitment – Identifying and enrolling participants for a study. See Recruitment Status.
Recruitment Status – The status of a trial, planned, ongoing, or completed. Dig Deeper
Rectal – Relates to the rectum; the place where feces are eliminated from the body.
Referee – A participant in the peer review of an article; normally experienced in the same field.
Regulate – The act of controlling or directing the rate, time, levels, in a body process.
REM Sleep – A normal sleep stage with rapid and random eye movement.
Renal – Pertaining to the kidneys.
Resistin – A cysteine-rich protein that increases with increasing obesity.
Resveratrol (F) - An antioxidant found in grape skins. Dig Deeper
Retina – A delicate, multi-layered, light-sensitive membrane lining the inner eyeball and connected by the optic nerve to the brain.
Retinol (F) - An animal form of vitamin A converts to other vitamin A forms. Dig Deeper.
Reviews – Summaries of research in a particular area. Read more.
Rheumatoid Arthritis – Pain, swelling, stiffness, inflammation, and sometimes destruction of joints.
Rheumatoid – Medical problems in the joints and connective tissue.
Rhinitis – Inflammation of the mucous membrane of the nose.
Riboflavin (Vitamin B 2) (F) - An essential B vitamin. Dig Deeper.
Risk-Benefit Ratio – The risk to individual participants compared to the potential benefits.
Royal Jelly – A nutritious secretion from worker bees to nourish the larvae and queen bees.
Rutin (F) - A substance in plants that strengthens the blood capillaries. Dig Deeper
Saccharomyces Boulardii – A form of yeast from lychee and mangosteen fruit.
Saccharomyces Cerevisiae – A strain of yeast found on the skin of many fruits and used in winemaking, brewing, and baking.
Salacin (F) - An aspirin like anti-inflammatory substance from white willow bark.
Salivary – Related to the saliva or fluid in the mouth.
Saturated Fats – Solid fats with no double bonds. High intakes are considered heart risks.
Saw Palmetto – A plant from Florida and Mexico with berries used for prostate problems.
Sebum – A fatty lubricant secreted by skin glands that coats and softens the skin and hair.
Selenium – A sulfur family member essential in nutrition and found in whole grains and meats.
Seratonin (F) - A substance produced from melatonin that helps treat depression.
Serine (F) - A non-essential amino acid which helps control depression and anxiety.
Serum – The watery part of an animal fluid, normally the blood.
Side Effects – Results occurring in addition to the intended one.
Signal – Sending information by active material or electrical impulse between body parts.
Single-Blind Study – A study in which one party, whether the investigator or participant, is unaware of what treatment is applied to the participant (also called single-masked study).
Spatial Configuration – The shape of molecules. Read more
SOD (Superoxide Dismutase) – An enzyme composed of metal-containing proteins that converts superoxide radicals into less toxic agents.
Soleus – A broad flat muscle in the calf of the leg.
Spectroscopy – The analysis of light type emissions to determine properties of their source.
Spirulina – An edible microorganism which has been used for nutrition in humans, poultry, and in aquaculture. Preliminary research has shown benefits for arthritis, hypertension, and improving exercise tolerance.
Squalene (F) - A natural compound in shark liver oil, and some vegetable oils. Dig Deeper
Standard Treatment – A treatment currently in wide use and approved by the FDA.
Stanol – A fully saturated steroid alcohol such as cholesterol.
Statistical Significance – Indicates if a result was probably not by chance. Read more.
Steam Deodorization – Using boiling water to remove small odor causing molecules.
Stearic Acid (F) - A saturated fatty acid common in animal and vegetable fat.
Steroids - Hormones that are made from cholesterol and include testosterone and estrogen.
Steatohepatitis (Fatty Liver Disease) – Includes fatty deposits and inflammation in the liver.
Stroke – Blockage or rupture of an artery to the brain. Dig Deeper
Study Endpoint – Outcome used to judge the effectiveness of a treatment, like a cure or lack of cure.
Subclinical – Conditions that are not detectable by standard clinical tests.
Sucrose (Table Sugar) (F) - A combination of dextrose and fructose. Dig Deeper
Sulfation – Combining with a sulfate group.
Symbiotic – The relationship between plants or animals where dissimilar species live together with each assisting the other.
Synergy – The interaction of two or more agents or forces so that their combined effect is greater than the sum of their individual effects. Read more
Systemic Lupus Erythematosis – An inflammatory disease with fever, skin rash, arthritis, and sometimes anemia.
Systolic Pressure- The peak pressure in the arteries. This occurs near the end of the cardiac cycle, when the ventricles are contracting. It is the higher number of the two blood pressure readings.