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Glossary: Words E to L
EATING DISORDER: abnormal behaviors related to food and eating
that may include starving, binging, vomiting, laxative abuse, or excessive
exercise accompanied by bizarre ideas about food, unrealistic body image, and
psychologic and developmental abnormalities.
ECLAMPSIA: the late stage of pregnancy-induced hypertension characterized by
proteinuria and, often, grand mal seizures occurring near the time of labor.
ECZEMA: a noncontagious inflammation of the skin, marked mainly by redness,
itching, and the outbreak of lesions that discharge serous matter and become
encrusted and scaly.
EDEMA: the abnormal accumulation of fluid in the intercellular tissue spaces or
body cavities.
EICOSANOID: any of the biologically active substances derived from arachidonic
acid, eicosatetraenoic acid, and eicosapentaenoic acid, including the
prostaglandins, thromboxanes, and leukotrienes.
EICOSAPENTAENOIC ACID (EPA): an omega-3 fatty acid found in fish.
ELECTROLYTE: substances in solution with a positive electrical charge (sodium,
potassium, calcium, magnesium) or a negative charge (chloride, CO2,
phosphorus, sulfate, lactate).
ELECTRON TRANSPORT CHAIN (ETC): along with the process of oxidative
phosphorylation, enables the production of ATP, the energy “currency” of the
body.
ELIMINATION DIET: an eating plan in which individual foods suspected of causing
intolerance or allergic reactions are omitted for a period of time in order to
determine if there is an improvement in the individual’s condition.
EMBOLISM: when a thrombus breaks loose and causes sudden closure of a blood
vessel.
EMETIC; an agent that causes vomiting.
EMULSIFYING: converting two liquids into a suspension in which one liquid is
distributed in small globules throughout the body of a second liquid, usually
between an oil-based liquid and a water-based liquid.
ENDOCRINE GLAND: any of the ductless glands, such as the thyroid or adrenal, the
secretions of which pass directly into the bloodstream from the cells of the
gland.
ENDOGENOUS: produced from within.
ENDOGENOUS OPIATES: morphine-like compounds produced in the brain in response to
pain, stress, certain drugs, and exercise. They act as internal tranquilizers,
reducing arousal level.
ENRICHED FOOD: a food to which nutrients have been added, usually to replace
some of the nutrients lost in processing.
ENTEROGASTRONE: a hormone, secreted by the duodenal mucosa in response to the
presence of fat in the duodenum, that inhibits gastric secretion and motility,
thus slowing the delivery of further lipid into the duodenum.
ENTERAL NUTRITION: the delivery of nutrients directly into the stomach,
duodenum, or jejunum.
ENTEROHEPATIC CIRCULATION: the recurrent cycle in which bile salts and other
substances excreted by the liver pass through the intestinal mucosa and become
reabsorbed by the hepatic cells and re-excreted.
ENTEROPATHOGENIC ORGANISM: any organism, usually bacterial, that causes
intestinal disease or disturbance.
ENZYME: a protein, secreted by cells, that acts as a catalyst to induce chemical
changes in other substances, without being changed itself.
EPINEPHRINE: a hormone secreted by the adrenal medulla; a potent stimulant
resulting in increased heart rate and force of contraction, vasoconstriction or
vasodilation, relaxation of bronchiolar and intestinal smooth muscle,
glycogenolysis, lipolysis, and other metabolic effects.
EPITHELIUM: membranous tissue, usually in a single layer, composed of closely
arranged cells separated by very little intercellular substance, and forming the
covering of most internal surfaces and organs and the outer surface of the body.
ERGOCALCIFEROL: vitamin D2; plant derived.
ERGOGENIC AID: a substance or practice that increases energy or work output.
ERROR THEORY: a theory that relates aging to environmental damage to the DNA
template, leading to errors in the genetic program.
ERYTHROCYTE: mature red blood cell (RBC).
ERYTHROPOIESIS: the production of red blood cells (RBCs).
ERYTHROPOIETIN: a hormone that stimulates the bone marrow to produce RBCs.
ESADDI (Estimated Safe and Adequate Daily Dietary Intakes): recommended ranges
of appropriate intake of those nutrients for which not enough information is
available to establish an RDA.
ESSENTIAL AMINO ACIDS (EAA): see indispensable amino acids.
ESSENTIAL FAT: the body fat located in specific sites that is necessary for
survival; about 4% to 7% of body weight.
ESSENTIAL FATTY ACIDS (EFA): linoleic and alpha-linolenic acids, which cannot be
produced by the body and must be provided in the diet.
ESTERIFY: to combine an acid and an alcohol with elimination of a molecule of
water, forming an ester.
ESTIMATED AVERAGE REQUIREMENT (EAR): nutrient intake value that is estimated to
meet the requirement of half the healthy individuals in a group.
ESTIMATED SAFE AND ADEQUATE DAILY DIETARY INTAKES (ESADDIs): recommended ranges
of appropriate intake of those nutrients for which not enough information is
available to establish an RDA.
ESTROGEN REPLACEMENT THERAPY (ERT): administration of synthetic estrogen to
replace the natural hormone, which declines after menopause.
EXOGENOUS: derived or developed externally.
EXTERNAL CUE THEORY: the theory that some people eat in response to such
external factors as the presence of food, or the time of day, rather than to
such internal factors as hunger.
EXTRACELLULAR: occurring outside the cells.
EXTRACELLULAR WATER: the water in the plasma, lymph, spinal fluid, and
secretions.
FACILITATED DIFFUSION: movement of particles across a membrane via a carrier
protein.
FASTING HYPOGLYCEMIA: low blood glucose that occurs in the food-deprived state.
FAT: a mixture of triglycerides.
FAT CELL THEORY: the theory that during the growing years, fat cells respond to
overfeeding by increasing in number; that the number of fat cells becomes fixed
before adulthood, and that the number regulates hunger, so that an individual
overfed during infancy or childhood will always have the desire to overeat.
FATFOLD TEST: a clinical test of body fatness in which the thicknesses of folds
of skin in several areas of the body are measured with a caliper.
FAT-SOLUBLE VITAMINS: those vitamins that must be dissolved in dietary fats in
order to be absorbed (vitamins A, D, E, K).
FATTY ACID: a straight carbon chain (usually 4-22 carbons long) terminating in a
carboxyl group at one end, and a methyl group at the other; has the general
formula CnH2nO2 when fully saturated; originates from the hydrolysis of fats.
FATTY LIVER: an early stage of liver deterioration seen in several disease,
including kwashiorkor and alcoholic liver disease.
FATTY STREAK: a small, flat, yellow-gray area composed mainly of cholesterol
within an artery; probably an early stage of atherosclerosis.
FERMENTATION: enzymatic decomposition of carbohydrates that is anaerobic and
ends with the production of alcohol.
FERRITIN: an iron-apoferritin complex that is a major storage form of iron,
found in liver, spleen, bone marrow, and reticuloendothelia cells.
FERROUS IRON: divalent form of iron; form in which iron is absorbed.
FETAL ALCOHOL SYNDROME: a syndrome resulting from fetal exposure to the
teratogenic effects of alcohol.
FIBER (ROUGHAGE): compounds of plant origin that are not capable of hydrolysis
by enzymes in the human gut.
FIBROCYSTIC BREAST DISEASE: characterized by formation of small cysts containing
fluid.
FLAVONOIDS: a subclass of phenol phytochemicals that are pigments and that act
as free radical scavengers in plants.
FOOD ALLERGY: an adverse reaction to a food that is mediated by an immunologic
mechanism; occurs consistently after consumption of that food and causes
functional changes in target organs; food hypersensitivity.
FOOD DIARY: a means of assessing nutrient intake by asking an individual to
record the types and amounts of all foods and liquids consumed over a certain
number of days.
FOOD FREQUENCY QUESTIONNAIRE: a means of assessing nutrient intake in which
individuals are asked to indicate how frequently they consume particular foods;
may also include the amount of each food consumed.
FOOD GUIDE PYRAMID: translates the RDAs and the dietary guidelines into the
kinds and amounts of food to eat each day.
FOOD INTOLERANCE: an adverse reaction to a food caused by toxic, pharmacologic,
metabolic, or idiosyncratic reactions to the food or chemical substances in the
food.
FORTIFIED: refers to the addition of nutrients to a food, often not originally
present, and often added in amounts greater than might be found there naturally.
FREE RADICAL: an atom or molecule that has at least one unpaired electron;
highly reactive, they can damage structures in the body; neutralized by
antioxidants.
FREE-RADICAL THEORY: a theory that relates aging to cellular damage caused by
free radicals.
FRUCTOOLIGOSACCHARIDES (FOS): a nonabsorbed polymer of fructose that supports
the growth of colonic bacteria.
FRUCTOSE: a monosaccharide occurring in fruit, honey, and some vegetables; the
sweetest of the monosaccharides.
GALACTOSE: a monosaccharide produced by the hydrolysis of lactose by digestive
enzymes.
GALACTOSEMIA: an inborn error of metabolism resulting in the presence of lactose
in the blood; symptoms include jaundice, enlarged liver and spleen, anorexia,
weight loss, vomiting, diarrhea, cataract formation, and mental retardation.
GALLBLADDER: the organ that stores and concentrates bile.
GALLSTONE: a small stone formed by the accumulation of bile salts and can block
the bile duct.
GARLIC: a botanical that acts on the cardiovascular system and appears to lower
serum lipid levels.
GASTRIC GLANDS: glands in the stomach wall that secrete gastric juice into the
stomach.
GASTRIC INHIBITORY POLYPEPTIDE: a hormone released from the intestinal mucosa in
the presence of fat and glucose that inhibits gastric acid secretion and
stimulates insulin release.
GASTRIC JUICE: the secretion of the gastric glands in the stomach. Contains
mostly hydrochloric acid and pepsins.
GASTRIC MOTILITY: the spontaneous peristaltic movements in the stomach that mix
food and gastric secretions and move food through the stomach and into the
duodenum.
GASTRIC ULCER: an ulcer of the gastric mucosa that is not associated with
excessive gastric acid secretion, but rather with disruption of the gastric
mucosal barrier.
GASTRIN: a hormone elaborated by the pyloric mucosa that stimulates hydrochloric
acid secretion by the parietal cells.
GASTRITIS: inflammation of the stomach.
GASTROENTERITIS: inflammation of the stomach and the intestines.
GASTROINTESTINAL TRACT (GI tract): the system of the body responsible for the
intake, digestion, and absorption of nutrients; the main organs are the stomach
and intestines.
GENISTEIN: an isoflavone found in soy products.
GEOPHAGIA: a common pica of pregnancy involving the consumption of dirt or clay.
GESTATIONAL DIABETES: diabetes that exists only during pregnancy.
GINGER: a botanical that has adjunctive therapeutic use as an antiemetic,
reducing nausea, especially associated with motion sickness.
GINKGO BILOBA: a botanical from an ancient tree used as an adjunctive treatment
for cerebral insufficiency and dementia.
GLAND: an organ that excretes materials and manufactures substances not needed
for its own metabolic function.
GLOSSITIS: inflammation of the tongue.
GLUCAGON: a hormone produced by the alpha islets of the pancreas that stimulates
the conversion of glycogen to glucose, and gluconeogenesis in the liver to bring
about a rise in plasma glucose levels.
GLUCOCORTICOID: the group of corticosteroids predominantly affecting
carbohydrate metabolism through promotion of gluconeogenesis and liver glycogen
deposition and elevation of blood glucose levels.
GLUCONEOGENESIS: the formation of glucose from noncarbohydrate molecules, such
as glycerol and the carbon skeletons of amino acids.
GLUCOSE: the simple sugar formed by the breakdown of complex carbohydrates;
blood, corn, grape, or starch sugar.
GLUCOSE TOLERANCE FACTOR (GTF): a potentiator of insulin action, thought to be
comprised of niacin, glutathione, and trivalent chromium.
GLUCOSURIA: the presence of sugar in the urine.
GLUTATHIONE: a tripeptide composed of glutamic acid, cysteine, and glycine; it
performs three functions: 1) the destruction of peroxides and free radicals; 2)
a cofactor for several enzymes; and 3) the detoxification of harmful compounds.
GLUTATHIONE PEROXIDASE: a selenium-containing enzyme that is the major active
form of selenium in tissues; participates in antioxidant reactions and protects
tissues against damage from free radicals, especially hydrogen peroxide formed
within the cell.
GLUTEN-FREE DIET: a restrictive eating pattern in which foods containing the
protein gluten are eliminated; these foods include wheat, rye, barley, and oats.
GLUTEN-SENSITIVE ENTEROPATHY (Celiac Disease): a malabsorption syndrome
precipitated by the ingestion of gliadin-containing foods (wheat, rye, oats,
barley), and characterized by a flattening of the villi of the small intestine.
GLYCEMIC INDEX: a ranking of the effect on blood glucose of the consumption of a
single food relative to a reference carbohydrate.
GLYCEROL: a three-carbon alcohol; a sweet oily fluid obtained by the
saponification (conversion into soap) of fats and oils.
GLYCOGEN: storage form of carbohydrate in animals. Broken down to yield glucose.
GLYCOGENESIS: the synthesis of glycogen.
GLYCOGENOLYSIS: the splitting up of glycogen in the body tissues, yielding
glucose.
GLYCOLIPID: a compound containing an alcohol, fatty acids, and a carbohydrate.
GLYCOLYSIS: the breaking down of glucose to pyruvate (aerobic; with oxygen) or
to lactate (anaerobic; without oxygen).
GLYCOPROTEIN: a special class of proteins that have a carbohydrate group
attached.
GLYCOSURIA: an abnormally high level of glucose in the urine occurring in
diabetes mellitus.
GLYCOSYLATED (or GLYCATED) HEMOGLOBIN: a laboratory test estimating glucose
association with hemoglobin; used to examine how well a diabetic is controlling
his blood glucose level.
GOITER: a chronic enlargement of the thyroid gland, visible as a swelling at the
front of the neck, which is usually associated with iodine deficiency.
GOITROGENIC EFFECT: an effect of substances in some foods (cabbage, turnips,
rapeseeds, peanuts, cassava, soybeans) capable of producing goiter.
GOUT: a group of disorders of purine and pyrimidine metabolism characterized by
hyperuricemia and deposition of urate crystals in joints.
GRAS (Generally Recognized As Safe): a list, established by the FDA in 1958, of
food additives that had long been in use and were believed safe.
GYNOID FAT DISTRIBUTION: deposition of fat in the thighs and buttocks;
“pear-shape” fat distribution.
HARD WATER: water containing high concentrations of calcium and/or magnesium.
HAWTHORN: a botanical that has a concentration of flavonoids, particularly
oligomeric procyanidins, which affect the cardiovascular system.
HEARTBURN: a burning pain in the esophagus caused by the back-flow of gastric
contents and acid.
HEAVY METAL: any of a number of mineral ions, such as mercury and lead, so
called because they are of relatively high atomic weight. Many heavy metals are
poisonous.
HELICOBACTER PYLORI: the pathogenic microorganism associated with the
development of atrophic gastritis.
HEMATOCRIT: the volume percentage of RBCs in the blood.
HEMATOPOIESIS: the formation of blood cells in the bone marrow.
HEME: the nonprotein, insoluble iron protoporphyrin constituent of hemoglobin.
HEME IRON: the form in which iron occurs in meat, fish, and poultry.
HEMICELLULOSES (Noncellulose Polysaccharides): a group of high molecular
polysaccharides that resemble cellulose but are more soluble and more easily
decomposed.
HEMODIALYSIS: removal of certain elements from the blood by virtue of
differences in rates of their diffusion across a semipermeable membrane while
the blood is being circulated outside the body.
HEMOGLOBIN: the iron-containing pigment in RBCs which carries oxygen to the
cells.
HEMOLYSIS: disruption of the integrity of the red blood cell membrane causing
release of hemoglobin.
HEMOLYTIC ANEMIA: anemia caused by shortened survival of mature RBCs, sometimes
caused by a vitamin E deficiency.
HEMOPROTEIN: protein linked to a metal-porphyrin compound.
HIGH-DENSITY LIPOPROTEIN (HDL): a plasma lipid/protein complex rich in
phospholipid and cholesterol; considered to be of benefit in reducing the risk
of cardiovascular disease.
HISTAMINE: a chemical in the body tissues that constricts the smooth bronchial
tube muscles, dilates small blood vessels, allows fluid leakage to form itchy
skin and hives, and increases secretion of stomach acid. It is implicated as the
mediator if immediate hypersensitivity.
HOMEOSTASIS: a tendency to stability in the internal environment of the
organism; achieved by a system of control mechanisms activated by negative
feedback.
HOMOCYSTEINE: an amino acid that functions as an intermediate in the production
of methionine and the methyl group donor, S-adenosylmethionine; deficiencies of
vitamin B12 and folate are associated with hyperhomocysteinemia, an independent
risk factor for coronary artery disease.
HONEYMOON PHASE: the period after initial diagnosis of diabetes when there may
be some recovery of beta-cell function and a temporary decrease in exogenous
insulin requirement.
HORMONE: a chemical substance secreted into the blood stream by one organ which
affects the function of another organ.
HORMONE-SENSITIVE LIPASE: an enzyme within the adipose cell that catalyzes the
release of free fatty acids from the cell.
HUNGER: craving for food more pronounced than appetite.
HYDROCHLORIC ACID: an acid secreted by the parietal cells in the lining of the
stomach that helps in protein digestion.
HYDROGENATION: the process of adding hydrogen to the double bonds and thus
increasing the saturation of fatty acids; can convert oils into semi-solids.
HYDROLYSIS: a chemical process whereby a compound is cleaved into two or more
simpler compounds. Hydrolysis is effected by the action of acids, alkalies, or
enzymes. See digestion.
HYDROPHOBIC: water hating. A substance that does not dissolve in water. Also
called lipophilic (fat loving).
HYDROXYAPATITE: a crystalline structure in bone, consisting of calcium phosphate
and calcium carbonate in an organic collagen matrix that gives strength and
rigidity to bones and teeth.
HYPERCALCEMIA: excess calcium in the blood.
HYPERCALCIURIA: excessive urinary losses of calcium that may occur in
individuals who have excessive intestinal absorption of calcium, or who have
high-protein intakes, especially from animal protein.
HYPERCAROTENODERMIA: accumulation of carotenoids in the skin with consequent
yellowing.
HYPERCHOLESTEROLEMIA: when blood cholesterol is above normal limits.
HYPERGLYCEMIA: increased glucose concentration in the blood above normal limits
(≥180 mg/dL).
HYPERKALEMIA: abnormally high level of potassium in the blood.
HYPERLIPIDEMIA: excess lipids in the blood.
HYPERLIPOPROTEINEMIA: excess lipoproteins in the blood.
HYPERNATREMIA: high level of sodium in the blood.
HYPERPLASIA: increase in tissue size by an increase in the number of cells.
HYPERTENSION: persistently high arterial blood pressure.
HYPERTROPHY: increase in tissue size by an increase in cell size.
HYPERVITAMINOSIS A: condition resulting from excessive intakes of preformed
vitamin A over an extended period; leads to liver damage.
HYPOALLERGENIC: a substance that has a low capacity for inducing
hypersensitivity (allergic reaction).
HYPOCALCEMIA: below normal levels of calcium in the blood.
HYPOCHLORHYDRIA: deficiency of hydrochloric acid in the gastric juice.
HYPOCHROMIC: having less than normal color; used to describe a RBC with a
below-normal hemoglobin content.
HYPOGLYCEMIA: abnormally low level of sugar in the blood which results in
symptoms caused by compensatory sympathetic nervous system activity (≤70 mg/dL).
HYPOGLYCEMIA OF NONDIABETIC ORIGIN: low levels of blood glucose that lead to
neuroglycopenia symptoms which are ameliorated by the ingestion of
carbohydrates.
HYPOKALEMIA: abnormally low level of potassium in the blood.
HYPONATREMIA: low blood sodium level.
HYPOTHALAMUS: a brain center that integrates signals about the blood’s
temperature, glucose content, and other conditions.
IATROGENIC: disorder caused by a drug, treatment procedure, or diagnostic
procedure.
IDIOPATHIC: self-originated; of unknown causation.
ILEUM: the portion of the small intestine extending from the jejunum to the
cecum.
IMMUNE SYSTEM: a combination of cells and proteins that assists in the host’s
ability to fight foreign substances, such as viruses and harmful bacteria;
includes the liver, spleen, thymus, bone marrow, and lymphatic system.
IMMUNOGLOBIN: antibodies; specialized proteins with a capacity to combine
chemically with the specific antigens stimulation their production.
INDISPENSABLE AMINO ACIDS (Essential Amino Acids): amino acids for which
synthesis is inadequate to meet metabolic needs and that must be supplied in the
diet. Include: leucine, isoleucine, valine, tryptophan, phenylalanine,
methionine, threonine, lysine, histidine.
INFLAMMATORY BOWEL DISEASE (IBD): a general term for inflammatory diseases of
the bowel of unknown etiology, including Crohn’s disease and ulcerative colitis.
INITIATING EVENT: an event caused by radiation or chemical reaction that can
give rise to cancer.
INSENSIBLE WATER LOSS: water lost with air expired from the lungs or sweat
evaporated from the skin.
INSOLUBLE FIBER: cellulose and some hemicelluloses that do not dissolve in
water.
INSTITUTE OF MEDICINE: A division of the National Academy of Sciences. The
mission of the IOM is to advance and disseminate scientific knowledge to improve
human health. The Institute provides objective, timely, authoritative
information and advice concerning health and science policy to government, the
corporate sector, the professions, and the public.
INSULIN: a pancreatic hormone that promotes glucose utilization, protein
synthesis, and the formation and storage of neutral lipids.
INSULIN-DEPENDENT DIABETES MELLITUS (Type 1): diabetes usually occurring in
childhood and characterized by abrupt onset of symptoms: insulinopenia,
dependence on exogenous insulin to sustain life, and a tendency to develop
ketoacidosis; usually occurs before 30 years of age.
INSULIN RESISTANCE: an impaired biologic response to either exogenous or
endogenous insulin; insulin resistance and insulin deficiencies are usual causes
of Type 2 diabetes.
INTERCELLULAR: between the cells.
INTERCELLULAR (INTERSTITIAL) WATER: the water between and around the cells.
INTERMITTENT CLAUDICATION: a complex of symptoms characterized by absence of
pain or discomfort in a limb when at rest, and severely increasing pain during
walking.
INTESTINAL FLORA: the bacteria normally present in the intestines.
INTESTINAL MOTILITY: the rhythmic contractions of the intestinal muscle layer
that move the intestinal contents along the passageway.
INTRACELLULAR: within the cell.
INTRINSIC FACTOR: a glycoprotein secreted by the gastric glands necessary for
the absorption of vitamin B12; its secretion is impaired in pernicious anemia.
IODOPSIN: the light-sensitive pigment of the cones in the retina.
ION: an atom or molecule that has acquired a net electric charge by gaining or
losing electrons.
IRRITABLE BOWEL SYNDROME (IBS): an abnormal stooling pattern associated with
symptoms of intestinal dysfunction that persists for longer than 3 months.
ISCHEMIA: deficiency of blood in a tissue, due to functional constriction or
actual obstruction of a blood vessel.
ISCHEMIC HEART DISEASE: damage to the heart from a decreased blood supply and
insufficient oxygen.
ISOFLAVONES: a subclass of phenol phytochemicals, found in beans and other
legumes (esp. soy), that may have cancer-preventing properties, especially
against hormone-driven cancers.
JAUNDICE (Icterus): yellowish discoloration of skin, mucous membranes, and
certain body fluids caused by an accumulation of bile pigments in the blood,
either from reduced excretion resulting from failure of the liver, or from
increased production of bile pigments from hemoglobin.
JEJUNUM: the section of the small intestine between the duodenum and the ileum.
KERATIN: a water-insoluble protein found in hair and nails.
KETOACIDOSIS: a pathologic condition resulting from the accumulation of acid
accompanied by the presence of ketone bodies.
KETONES: compounds derived from the oxidation of a secondary alcohol; produced
when the body is relying almost entirely on stored fat for energy, such as in
uncontrolled diabetes mellitus, or prolonged fasting or starvation.
KETOSIS: clinical condition is which ketone bodies accumulate in the blood and
appear in the urine; acetone odor is apparent in the breath.
KILOCALORIE (KCAL OR CAL): 1,000 calories (small “c” calories); sometimes
written as Calorie (big “C” calorie). Usually in nutrition, whether the “C” in
calorie is capitalized or not, it means kilocalorie. The term kilocalorie is
less confusing.
KREBS CYCLE: also called tricarboxylic acid cycle (TCA) or citric acid cycle;
the main source of energy in the mammalian body, and the end toward which
carbohydrate, fat, and protein metabolism are directed.
KWASHIORKOR: a form of protein-energy malnutrition associated with extreme
dietary protein deficiency and characterized by hypoalbuminemia, edema enlarged
fatty liver.
LABILE: Likely to undergo chemical change; unstable; labile nutrients are
affected by light, oxygen, heat, etc.
LACTALBUMIN: protein found in the whey component of milk.
LACTASE: the intestinal enzyme that hydrolyzes lactose to glucose and galactose;
necessary for digestion of milk and milk products.
LACTIC ACID: a product from glucose metabolism in anaerobic metabolism.
LACTOBACILLUS ACIDOPHILUS: a bacterium that can reside in the colon and inhibit
the growth of bacteria that might be harmful. In milk or yogurt, reduces the
lactose level.
LACTOOVOVEGETARIAN: a vegetarian who consumes dairy foods and eggs in addition
to plant foods.
LACTOVEGETARIAN: a vegetarian who consumes dairy foods in addition to plant
foods.
LACTASE: the intestinal enzyme that hydrolyzes lactose to glucose and galactose.
LACTOBACILLUS: a beneficial intestinal organism that produces organic acids
which retard the growth of pathogenic bacteria.
LACTOSE: a disaccharide composed of glucose and galactose; the principal sugar
found in mammalian milk.
LACTOSE INTOLERANCE: an inability to digest lactose to galactose and glucose
because of a deficiency of lactase.
LEAN BODY MASS (LBM): the total of all body components except storage lipid.
LECITHIN (Phosphatidylcholine): a choline-containing phospholipid that is found
in all plant and animal tissues, and frequently functions as an emulsifier.
LEGUMES: the fruit or pod of beans, peas, lentils, etc.
LESION: a wound or injury; a pathological alteration of tissue.
LEUKOCYTE: white blood cell; classified as granular or nongranular.
LEUKOPENIA: a reduction in the number of white blood cells in the blood.
LEUKOTRIENE: an eicosanoid whose function is the communication among the various
types of cells involved in immunosurveillance, inflammation, protection against
infection, and immune responses.
LIGAND: an organic molecule that donates the necessary electrons to form
coordinate covalent bonds with metallic ions; for example, as oxygen is bound to
the central iron atom of hemoglobin.
LIGNANS: phytoestrogens, found in flaxseeds, wheat bran, and other whole grains,
that affect sex hormone metabolism and may reduce the risk of hormone-linked
cancer.
LIGNIN: a noncarbohydrate material sometimes included in fiber determination
that is a major component of the woody portion of plants.
LIMITING AMINO ACID: the essential amino acid found in the shortest supply
relative to the amounts needed for protein synthesis in the body.
LIMONOIDS: a subclass of terpenes found in citrus fruits; identified as
chemopreventive agents that induce enzymes in the liver’s phase I and II enzyme
detoxification system.
LINOLEIC ACID: an essential fatty acid; a polyunsaturated fatty acid with 2
double bonds and 18 carbon atoms, found in linseed (flax seed), safflower,
cottonseed, soybean, corn, and fish oils and in animal tissues.
LINOLENIC ACID: polyunsaturated fatty acid with growth-promoting effect;
contains three double bonds and 18 carbon atoms, and can be synthesized in the
body from linoleic acid.
LIPASE: an enzyme in pancreatic juice that digests fats.
LIPID: any of numerous fats (and oils) and fat-like materials that are generally
insoluble in water, but soluble in common organic solvents; by definition, fats
are solid at room temperature and oils are liquid at room temperature.
LIPOGENESIS: the transformation of nonfat food materials into body fat.
LIPOIC ACID (lipoate; lipoamide): classified as a sulfur-containing fatty acid;
a component of the enzyme that converts pyruvate to acetyl CoA. Is also both a
water- and fat-soluble antioxidant.
LIPOLYSIS: the breaking down of fat.
LIPOPHILIC: fat loving. A substance that dissolves in fat. Also called
hydrophobic (water hating).
LIPOPROTEIN: a combination of a lipid and protein, possessing the solubility of
proteins; lipoproteins act as agents of lipid transport in the lymph and blood;
chylomicrons, HDL, VLDL, LDL.
LIPOPROTEIN LIPASE: an enzyme that catalyzes the hydrolysis of fats present in
chylomicrons and lipoproteins; found in various tissues and important in
mobilization of fatty acids from depot fats.
LIPOTROPIC: pertaining to substances preventing or correcting the fatty liver of
choline deficiency.
LISTERIOSIS: infection by listeria bacteria; produces diarrhea, vomiting,
meningitis, and endocarditis.
LONG-CHAIN FATTY ACID: a fatty acid containing 13 to 27 carbons; 16 to 18 are
most common.
LOW-DENSITY LIPOPROTEIN (LDL): a lipid/protein complex circulating in the
plasma, transporting most of the blood cholesterol. This lipoprotein fraction is
implicated in the risk of cardiovascular disease.
LUMEN: the inner open space of a tubular organ, as of a blood vessel or an
intestine.
LYCOPENE: one of the carotenoid phytochemicals found in tomatoes that acts as a
free radical scavenger.
LYMPH: a clear fluid that flows through lymph vessels and is collected from the
tissues throughout the body; its function is to nourish tissue cells and return
waste matter to the blood stream.
LYMPH GLANDS: located along the lymph vessels, they trap foreign material and
produce lymphocytes.
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