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Cachexia:
a state of ill health, malnutrition and wasting.
Calcification:
the
process of deposition of calcium salts, primarily hydroxyapatite. In the formation of bone this is a
normal condition. In other organs, this could be an abnormal condition.
Calcification of the aortic valve causes narrowing of the passage (aortic stenosis).
Also called mineralization.
Calorie: a unit of
heat. A calorie (cal) is the standard unit and the amount of heat
necessary to raise 1 gram of water from 14 to 15 degrees C. The
kilocalorie (kcal), used in metabolic and nutrition studies, is equal to
1000 calories.
Cancer:
also
known as malignancy, cancer refers to abnormal cells, which have a tendency
to grow uncontrollably and metastasize or spread to other areas of the body.
Cancer can involve any tissue of the body and can have many different forms
in one tissue. Cancer is a group of more than one hundred different
diseases.
Carbohydrate:
considered a macronutrient because carbohydrates provide a significant
source of calories (energy) in the diet. Chemically, carbohydrates are
neutral compounds composed of carbon, hydrogen and oxygen. Carbohydrates
come in simple forms known as sugars and such as starches and fiber.
Carboxylation:
the
introduction of a carboxyl group (-COOH) or carbon dioxide into a compound.
Carcinogen:
a
cancer-causing agent; adjective: carcinogenic.
Carcinogenesis:
the
formation of cancer cells from normal cells.
Carcinoid
syndrome:
the
pattern of symptoms exhibited by individuals with carcinoid tumors.
Carcinoid tumors secrete excessive amounts of the neurotransmitter,
serotonin. Seratonin causes blood vessels to dilate (widen). Symptoms
include flushing, diarrhea, and sometimes wheezing.
Cardiomyopathy:
literally, disease of the heart muscle that often leads to abnormal
function.
Cardiovascular:
referring
to the heart and blood vessels.
Cardiovascular diseases:
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.
Carnitine:
a
compound that is required to transport long chain fatty acids across the
inner membrane of the mitochondria, in the form of acyl-carnitine, where
they can be metabolized for energy.
Cartilage:
a soft,
elastic tissue that composes most of the skeleton of vertebrate embryos and
except for a small number of structures is replaced by bone during
ossification in the higher vertebrates. Cartilage cushions joints, connects
muscles with bones, and makes up other parts of the body such as the larynx
(voice box) and the outside portion of the ears.
Case-control study:
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.
Case
reports:
individual observations based on small numbers of subjects. This type of
research cannot indicate causality but may indicate areas for further
research.
Catalyze:
increase
the speed of a chemical reaction without being changed in the overall
reaction process. See enzyme.
Catecholamines:
substances with a specific chemical structure (a benzene ring with two
adjacent hydroxyl groups and a side chain of ethylamine) that function as
hormones or neurotransmitters. Examples include epinephrine, norepinephrine,
and dopamine.
Cataract:
clouding
of the lens of the eye. As cataracts progress they can impair vision and may
result in blindness.
Cation:
a
positively charged ion.
Celiac
disease:
also
known as celiac sprue, celiac disease is an inherited disease in which the
intestinal lining is inflamed in response to the ingestion of a protein
known as gluten. Treatment of celiac disease involves the avoidance of
gluten, which is present in many grains, including rye, oats, and barley.
Inflammation and atrophy of the lining of the small intestine leads to
impaired nutrient absorption.
Cell
membrane:
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.
Cell
signaling:
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.
Central
nervous system (CNS):
the
brain, spinal cord, and spinal nerves.
Cerebrospinal fluid:
the fluid
that bathes the brain and spinal chord.
Cerebrovascular disease:
disease
involving the blood vessels supplying the brain, including cerebrovascular
accident (CVA), also known as a stroke.
Chelate:
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.
Chemotherapy:
literally, treatment with drugs. Commonly used to describe the systemic use
of drugs to kill cancer cells, as a form of cancer treatment.
Cholesterol:
a lipid
used in the construction of cell membranes and as a precursor in the
synthesis of steroid hormones. Dietary cholesterol is obtained from animal
sources, but cholesterol is also synthesized by the liver. Cholesterol is
carried in the blood by lipoproteins (e.g., LDL and HDL). In
atherosclerosis, cholesterol accumulates in plaques on the walls of some
arteries.
Cholestatic liver disease:
liver
disease resulting in the cessation of bile excretion. Cholestasis may occur
in the liver, gall bladder or bile duct (duct connecting the gall bladder to
the small intestine).
Cholinergic:
resembling acetylcholine in action, a cholinergic drug for example.
Cholinergic nerve fibers liberate or are activated by the neurotransmitter,
acetylcholine.
Chorionic
villus sampling (CVS):
a
procedure for obtaining a small sample of tissue from the placenta (chorionic
villi) for the purpose of prenatal diagnosis of genetic disorders. CVS can
be performed between 9 to 12 weeks of pregnancy.
Chromosome:
a
structures composed of a long DNA molecule and associated proteins that
carries part of the hereditary information of an organism.
Chronic
disease:
an
illness lasting a long time. By definition of the U.S. Center for Health
Statistics, a chronic disease is a disease lasting 3 months or more.
Cirrhosis:
a
condition characterized by irreversible scarring of the liver, leading to
abnormal liver function. Cirrhosis has a number of different causes,
including chronic alcohol use and viral hepatitis B and C.
Citric acid
cycle: A series of biological reactions that occurs in the matrix of
mitochondria in which electrons are transferred to coenzymes and carbon
dioxide is formed. The electrons carried by the coenzymes then enter
the electron transport chain, which generates a large quantity of ATP.
Also called the Krebs cycle.
Clinical
trial:
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.
Clone:
an exact
copy of a DNA segment; produced by recombinant DNA technology.
Coagulation:
the
process of involved in forming a blood clot
Coenzyme:
a
molecule that binds to an enzyme and is essential for its activity, but is
not permanently altered by the reaction. Many coenzymes are derived from
vitamins.
Cofactor:
a
compound that is essential for the activity of an enzyme.
Cognitive:
an
adjective referring to the processes of thinking, learning, perception,
awareness, and judgment.
Cohort
study:
a study
that follows a large group of people over a long period of time, often 10
years or more. In cohort studies, dietary information is gathered before
disease occurs, rather than relying on recall after disease develops.
Collagen:
a fibrous
protein that is the basis for the structure of skin, tendon, bone, cartilage
and all other connective tissue.
Collagenous matrix (of bone):
The
organic (nonmineral) structural element of bone. Collagen is a fibrous
protein that provides the organic matrix upon which bone mineralize
crystallizes.
Colon:
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.
Colorectal adenoma:
a tumor
of the colon or rectum that arises in glandular tissue. Although not
cancer, colorectal adenomas may develop into colorectal cancer over time.
Colorectal cancer:
cancer of
the colon (large intestine) or rectum.
Congenital hypothyroidism: also known as cretinism, congenital
hypothyroidism occurs in two forms, although there is considerable overlap.
The neurologic form is characterized by mental and physical retardation and
deafness. It is the result of maternal iodine deficiency that affects the
fetus before its own thyroid is functional. The myxedematous or hypothyroid
form is characterized by short stature and mental retardation. In addition
to iodine deficiency, the hypothyroid form has been associated with selenium
deficiency and the presence of goitrogens in the diet that interfere with
thyroid hormone production.
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.
Cornea:
the
transparent covering of the front of the eye that transmits and focuses
light into the eye.
Coronary
artery:
the
vessels that supply oxygenated blood to the heart muscle itself, so named
because they encircle the heart in the form of a crown.
Coronary
artery bypass graft (CABG):
a
surgical procedure used in individuals with significant narrowings and
blockages of coronary arteries to create new routes around narrowed and
blocked arteries, permitting increased blood flow to the heart muscle. The
bypass graft for a CABG can be a vein from the leg or an inner chest wall
artery.
Coronary
heart disease (CHD):
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).
Corticosteroid:
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.
Creatine
phosphate:
a
high-energy compound found in muscle cells which is used to convert ADP into
ATP by donating phosphate molecules to the ADP. ATP is the molecule which is
converted into ADP with a release of energy that the body then uses.
Crohn's
disease:
an
inflammatory disease of the gastrointestinal tract, often affecting the
small intestine and colon.
Cross-sectional study:
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.
Cystic
fibrosis (CF):
a genetic
(inherited) disease characterized by the production of abnormal secretions,
leading to the accumulation of mucus in the lungs, pancreas, and intestine.
This build-up of mucus causes difficulty breathing and recurrent lung
infections, as well as problems with nutrient absorption due to problems in
the pancreas and intestines. Without treatment, CF results in death for 95
percent of affected children before age five; however, the longest-lived CF
patient survived into his late 30s.
Cytochrome P-450:
an enzyme
that plays an important role in the metabolism of drugs and toxins in the
liver. It also plays a role in the synthesis (formation) of steroid hormones
in the adrenal cortex.
Cytokine:
a protein
made by cells that affects the behavior of other cells. Cytokines act on
specific cytokine receptors in the cells they affect. |
