Glossary
having a pH of less than 7.
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).
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.
basic; having a ph of more than 7.
organic (carbon-containing) molecules that serve as the building blocks of proteins.
a chemical compound that is structurally similar to another but differs slightly in composition (e.g., the replacement of one functional group by another).
a class of medication used to prevent seizures, commonly used in individuals with seizure disorders or epilepsy.
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.
a respiratory condition characterized by difficulty breathing and reversible narrowing of the airways, known as bronchospasm.
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.
adenosine triphosphate. An important compound for the storage of energy in cells, as well as the synthesis (formation) of nucleic acids.
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.
a nutritional balance study involves the measurement of the intake of a specific nutrient as well as the elimination of that nutrient in urine, feces, sweat, etc. If intake is greater than loss of a particular nutrient the individual is said to be in "positive balance." If intake is less than loss, an individual is said to be in "negative balance" for the nutrient of interest.
the portion of a nutrient (or other chemical) that can be absorbed, transported, and utilized physiologically.
a term used in quantifying the mineralization of bone. The mineral component of bone consists largely of calcium and phosphorus. BMD is possitively associated with bone strength and resistance to fracture. BMD can be determined through a low radiation X-ray technique known as DEXA.
referring to the heart and blood vessels.
literally, diseases affecting the heart and blood vessels. The term has come to encompass a number of conditions that result from atherosclerosis, including myocardial infarction (heart attack), congestive heart failure, and stroke.
a study in which the risk factors of people who have been diagnosed with a disease are compared with those without the disease. Because the risk factor (e.g., nutrient intake) is generally measured at the time of diagnosis, it is difficult to determine whether the risk factor was present prior to the development of the disease. Another potential draw back is the difficulty in obtaining well-matched control subjects.
also called the plasma membrane. The external limiting membrane of a cell. It is composed of lipids (fat molecules) that have a hydrophobic (insoluble in water) end and a hydrophilic (water-soluble) end. Cell membranes are made of lipid bilayers in which the lipids line up in two layers with the hydrophobic ends facing each other and the hydrophilic ends facing the outside and the inside of the cell.
communication among individual cells so as to coordinate their behavior to benefit the organism as a whole. Cell-signaling systems elucidated in animal cells include cell-surface and intracellular receptor proteins, protein kinases and protein phosphatases (enzymes that phosphorylate and dephosphorylate proteins), and GTP-binding proteins.
the combination of a metal with an organic molecule to form a ring-like structure known as a chelate. Chelation of a metal may inhibit or enhance its bioavailability.
a structures composed of a long DNA molecule and associated proteins that carries part of the hereditary information of an organism.
a research study, generally used to evaluate the effectiveness of a new treatment in human participants. Clinical trials are designed to answer specific scientific questions and to determine the efficacy of new treatments for specific diseases or health conditions.
the process of involved in forming a blood clot
The organic (nonmineral) structural element of bone. Collagen is a fibrous protein that provides the organic matrix upon which bone mineralize crystallizes.
sometimes called the large bowel or intestine, the colon is a long, coiled, tubelike organ that removes water from digested food after it has passed through the small intestine. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus.
a tumor of the colon or rectum that arises in glandular tissue. Although not cancer, colorectal adenomas may develop into colorectal cancer over time.
Congestive heart failure (CHF)
a disorder of the heart, resulting in the loss of the ability to pump blood efficiently enough to meet the demands of the body. Symptoms may include swelling, shortness of breath, weakness, and exercise intolerance.
one of the vessels that supply oxygenated blood to the heart muscle itself. They are called coronary arteries because they encircle the heart in the form of a crown.
also known as coronary artery disease and coronary disease, coronary heart disease is the result of atherosclerosis of the coronary arteries. Atherosclerosis may result in narrowing or blockage of the coronary arteries and is the underlying cause of myocardial infarction (heart attack).
any of the steroid hormones made by the cortex (outer layer) of the adrenal gland. Cortisol is a corticosteroid. A number of medications are analogs of natural corticosteroid hormones.
an inflammatory disease of the gastrointestinal tract, often affecting the small intestine and colon.
a study of a group of people at one point in time to determine whether a risk factor or a level of a risk factor is associated with the occurrence of a disease. Because the disease outcome and the risk factor (e.g., nutrient intake) are measured at the same time, a cross-sectional study provides a "snapshot" view of their relationship. Cross-sectional studies cannot provide information about causality.
dual energy X-ray absorptiometry. A precise instrument that uses the energy from very small doses of X-rays to determine bone mineral density (BMD) and to diagnose and follow the treatment of osteoporosis.
a chronic condition associated with abnormally high levels of glucose (sugar) in the blood. The two types of diabetes are referred to as insulin-dependent (type 1) and non-insulin dependent (type 2). Type 1 diabetes results from a lack of adequate insulin secretion by the pancreas. Type 2 diabetes (also known as adult-onset diabetes) is characterized by an insensitivity of the tissues of the body to insulin secreted by the pancreas (insulin resistance).
the lowest arterial blood pressure during the heart beat cycle. The diastolic blood pressure is measured while the heart muscle is filling with blood.
an agent that increases the formation of urine by the kidneys, resulting in water loss from the individual using the diuretic.
deoxyribonucleic acid. A long thread-like molecule made up of large numbers of nucleotides. Nucleotides in DNA are composed of a nitrogen containing base, a 5-carbon sugar (deoxyribose), and phosphate groups. The sequence of bases in DNA serves as the carrier of genetic (hereditary) information.
refers to a study in which neither the investigators administering the treatment nor the participants know which participants are receiving the experimental treatment and which are receiving the placebo.
a biological catalyst. That is, a substance that increases the speed of a chemical reaction without being changed in the overall process. Enzymes are vitally important to the regulation of the chemistry of cells and organisms.
a study examining disease occurrence in a human population.
Familial adenomatous polyposis
a hereditary syndrome characterized by the formation of many polyps in the colon and rectum, some of which ultimately develop into colorectal cancer.
a break in a bone or cartilage, often but not always the result of trauma.
referring to or affecting the stomach and intestines (small and large bowel).
a region of DNA that controls a specific hereditary characteristic, usually corresponding to a single protein.
a large polymer (repeating units) of glucose molecules, used to store energy in cells, especially muscle and liver cells.
guanosine triposphate. A high energy molecule, required for a number of biochemical reactions, including nucleic acid and protein synthesis (formation).
a chemical, released by a gland or a tissue, which affects or regulates the activity of specific cells or organs. Complex bodily functions, such as growth and sexual development, are regulated by hormones.
a calcium phosphate salt. Hydroxyapatite is the main mineral component of bone of bone and teeth, and is what gives them their rigidity.
high blood pressure, defined as a systolic blood pressure greater than 140 mm hg and/or diastolic blood pressure greater than 90 mm Hg.
an excess of thyroid hormone which may result from an overactive thyroid gland or nodule, or from taking too much thyroid hormone.
a peptide hormone secreted by the b-cells of the pancreas required for normal glucose metabolism.diminished responsiveness to insulin.
an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons.
also known as renal calculi, kidney stones are the result of crystallization of certain substances found in urine, including calcium, phosphate, oxalic acid, and uric acid. Stones may form in the urine collecting area (pelvis) of the kidney, as well as the ureters (narrow tubes connecting the kidney to the urinary bladder).
different types of fat molecules. For example, phospholipids, cholesterol, triglycerides.
a disease or condition that results in poor absorption of nutrients from food.
a mathematical or statistical analysis, used to pool the results of all studies investigating a particular effect (e.g., the effect of folic acid supplementation on homocysteine levels) and provide an overall estimate of that effect.
millimeters of mercury. The unit of measure for blood pressure.
commonly known as a "heart attack", a myocardial infarction refers to changes that occur in the heart muscle due to an interruption in its blood supply. An MI is often the result of a clot that lodges in a coronary artery, resulting in deprivation of oxygen to a portion of the heart muscle (ischemia), and ultimately the death (necrosis) of a portion of the heart muscle, if the oxygen supply is not restored within a few minutes.
The National Institutes of Health are U.S. health agencies, devoted to medical research. Administered under the Department of Health and Human Services (HHS), the NIH consists of more than 20 separate Institutes and Centers.
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Long thread-like molecules made up of large numbers of nucleotides. Nucleotides are composed of a nitrogen containing base, a 5-carbon sugar, and one or more phosphate groups. The sequence of bases in DNA or RNA represents the genetic (hereditary) information of a living cell.
a study in which no experimental intervention or treatment is applied. Participants are simply observed over time.
cells associated with bone that are responsible for the new formation of bone in the bone remodeling process.
cells associated with bone that are responsible for the breakdown or resorption of bone. Bone remodeling is a continuous process of resorption and formation.
a condition of increased bone fragility and susceptibility to bone fracture due to a loss of bone mineral density (BMD)
a small organ located behind the stomach. The head of the pancreas is connected to the duodenum (the first section of the small intestine). The pancreas makes enzymes that help digest food in the small intestine and hormones, including insulin, that control the amount of glucose in the blood.
glands located behind the thyroid gland in the neck. The parathyroid glands secrete a hormone called parathormone (PTH) that is critical to calcium and phosphorus metabolism.
hormones that are proteins, as opposed to steroid hormones, which are made from cholesterol. Insulin is an example of a peptide hormone.a disease characterized by ulcers or breaks in the inner lining (mucosa) of the stomach or duodenum (region of the small intestine closest to the stomach). The three major causes of peptic ulcer disease are non-steroidal anti-inflammatory drugs (NSAIDS), chronic Heliobacter pylori infection, and states of acid hypersecretion, like Zollinger-Ellison syndrome.
a measure of acidity or alkalinity.
the dose or intake level of a nutrient many times the level associated with the prevention of deficiency or the maintenance of health. A pharmacologic dose is generally associated with the treatment of a disease state and considered to be a dose at least 10 times greater than that needed to prevent deficiency.
the creation of a phosphate derivative of an organic molecule. This is usually achieved by transferring a phosphate group (-PO4) from ATP to another molecule.
a sugar pill or false treatment that is given to a control group while the experimental group is given the experimental treatment. Placebo-controlled studies are conducted to make sure that significant outcomes of a trial are due to the experimental treatment rather than another factor associated with participating in the study.
a temporary organ joining the mother and unborn child (fetus). The placenta transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste products from the fetus.
the liquid part of blood (as opposed to blood cells) that makes up about half its volume. Plasma differs from serum in that the blood sample has not clotted. A centrifuge is used to separate plasma from cells in the laboratory.
a benign (non-cancerous) mass of tissue that forms on the inside of a hollow organ, such as the colon.
an observational study in which a group of people—known as a cohort—are interviewed or tested for risk factors (e.g., nutrient intake), and then followed up at subsequent times to determine their status with respect to a disease or condition of interest.
a complex organic molecule composed of amino acids in a specific order. The order is determined by the sequence of nucleic acids in a gene coding for the protein. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs, and each protein has unique functions.
one fourth of a sample or population.
Randomized controlled trial (RCT)
A clinical trial that involves at least one test treatment and one control treatment, in which the treatments administered are selected by a random process (e.g., coin flips or a random-numbers table).
an experiment in which participants are chosen for the experimental and control groups at random, in order to reduce bias caused by self-selection into experimental and control groups. This type of study design can provide evidence of causality.
recommended dietary allowance. Set by the Food and Nutrition Board of the Institute of Medicine, the RDA is the average daily dietary intake level sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in a specific life stage and gender group (e.g., women from 19-50 years of age). It is intended as a goal for daily intake of specific nutrients by individuals.
the last section of the large intestine (colon). It connects the sigmoid colon (above) to the anus (below).
ribonuceic acid. a chain of nucleotides, which are composed of a nitrogen containing base, a 5-carbon sugar (ribose), and phosphate groups. RNA functions in the translation of the genetic information in DNA to protein synthesis.
uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms.
the liquid part of blood (as opposed to blood cells) that makes up about half its volume. Serum differs from plasma in that the blood sample has clotted. A centrifuge is used in the laboratory to separate serum from cells after blood has clotted.
the part of the digestive tract that extends from the stomach to the large intestine. The small intestine includes the duodenum (closest to the stomach), the jejunum, and the ileum (closest to the large intestine).
the state of nutrition of an individual with respect to a specific nutrient. Diminished or low status indicates inadequate supply or stores of a specific nutrient for optimal physiological functioning.
a protein within a cell which binds to a specific steroid hormone. Binding of the steroid hormone changes the shape of the receptor protein and activates it, allowing it to activate gene transcription. In this way, a steroid hormone can activate the synthesis of specific proteins.
the highest arterial pressure measured during the heart beat cycle. It occurs when the heart muscle is contracting (pumping).
a condition of prolonged and painful spasms of the voluntary muscles, especially the fingers and toes (carpopedal spasm) as well as the facial musculature.
(DNA transcription); the process by which one strand of DNA is copied into a complementary sequence of RNA.
(RNA translation) process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into a protein.
tolerable upper intake level. Set by the Food and Nutrition Board of the Institute of Medicine, the UL is the highest level of daily intake of a specific nutrient likely to pose no risk of adverse health effects in almost all individuals in the specified life stage and gender group.
narrowing of a blood vessel.
relaxation or opening of a blood vessel.
literally a small bag or pouch. Inside a cell, a vesicle is a small organelle surrounded by its own membrane.
a rare disorder caused by a tumor called a gastrinoma, most often occurring in the pancreas. The tumor secretes the hormone gastrin, which causes increased production of gastric acid leading to severe recurrent ulcers of the esophagus, stomach, and the upper portions of the small intestine.