Nutrition, Metabolism, and Energy Balance

Vocabulary flashcards covering key terms and definitions related to human nutrition, macronutrients, micronutrients, vitamins, minerals, and energy balance.

Leptin

A hormone that signals the hypothalamus to suppress appetite after eating.

Ghrelin

A hormone secreted by the stomach that stimulates appetite; continuous secretion causes persistent hunger, and inhibiting its action can assist with weight loss.

Macronutrients

The nutrient category consisting of carbohydrates, proteins, and fats, which are required by the body in large amounts.

Lacto-vegetarian diet

A dietary regimen that includes fruits, vegetables, and dairy products, but excludes meat and eggs.

Essential amino acids

Amino acids that the body cannot synthesize and must obtain through the diet; adults require $8$ essential amino acids, whereas growing children require additional ones such as arginine and histidine.

Adiponectin

A hormone secreted by fat cells that affects the response of target cells to insulin.

Sucrose

A disaccharide composed of glucose and fructose; it is not classified as a monosaccharide.

Lipogenesis

The metabolic pathway by which excess carbohydrates, once broken down into glucose, are converted into fats and stored in adipose tissue.

Carbohydrates

Organic macromolecules that serve as the primary source of cellular energy in the body.

Nervous system

The body system whose cells demand an uninterrupted, continuous supply of glucose.

Glycogen

A storage polysaccharide produced and stored in the liver that replenishes cellular glucose supplies once free glucose is depleted.

Ribose and deoxyribose

The five-carbon monosaccharides (pentoses) that form the structural backbone of RNA and DNA, respectively.

Triglyceride

A lipid molecule composed of one glycerol molecule covalently bonded to three fatty acids.

Olive oil

A plant-derived dietary oil that is particularly rich in monounsaturated fats.

Complete proteins

Dietary proteins, such as those found in eggs, that supply all the essential amino acids in adequate proportions.

Negative nitrogen balance

A physiological state that results from a net loss of amino acids or proteins, occurring when protein degradation exceeds protein incorporation.

Deamination

The enzymatic removal of an amino group from an amino acid during protein catabolism for energy production.

Basal metabolic rate (BMR)

The rate of energy expenditure under basal conditions; it is influenced by body size, body temperature, and endocrine activity, but not by diet composition.

Negative energy balance

A condition in which energy expenditure exceeds caloric intake, leading to weight loss.

Body Mass Index (BMI)

A metric that assesses body weight in proportion to height to evaluate health status and categorize weight levels.

Kilocalorie (large Calorie)

The amount of thermal energy needed to raise the temperature of $1\,\text{kg}$ of water by $1^\circ\text{C}$, equal to $1{,}000$ small calories.

Vitamin A

A fat-soluble vitamin stored in the liver that is essential for the synthesis of visual photopigments; deficiency causes night blindness.

Vitamin D

A fat-soluble vitamin that facilitates intestinal absorption of calcium and phosphorus; deficiency causes osteomalacia, while severe excess can cause irreversible renal damage.

Vitamin K

A fat-soluble vitamin necessary for blood clotting; deficiency can develop following treatment with antibiotic drugs that eliminate gut flora.

Vitamin E

A fat-soluble antioxidant vitamin; excessive intake can result in headache, nausea, fatigue, easy bruising, and abnormal bleeding.

B-complex vitamins

A group of water-soluble vitamins that all function as coenzymes involved in the oxidation and cellular breakdown of carbohydrates, lipids, and proteins.

Intrinsic factor

A glycoprotein required for the intestinal absorption of cyanocobalamin (vitamin $\text{B}_{12}$); its absence results in pernicious anemia.

Pantothenic acid

A B-complex vitamin that serves as a functional component of coenzyme A.

Niacin

A B-complex vitamin whose excessive consumption can produce acute symptoms including flushing, vomiting, and diarrhea.

Vitamin C

A water-soluble vitamin required for the biosynthesis of collagen.

Iron

An essential trace element necessary for the synthesis of hemoglobin.

Magnesium

An essential mineral cofactor required for the synthesis and cellular utilization of ATP.

Potassium

A major intracellular cation whose deficiency can lead to cardiac arrhythmias.

Kwashiorkor

A form of severe malnutrition occurring in children that is specifically driven by a dietary deficiency of proteins.

Colloid osmotic pressure

Osmotic pressure produced by plasma proteins in blood vessels; a drop in this pressure due to protein malnutrition leads to tissue edema.

Malnutrition

The medical condition resulting from inadequate nutrition, insufficient essential nutrient intake, or an inability to properly metabolize nutrients.

Amino acids

The basic building block subunits that polymerize to form proteins.