Nutrition Glossary

An organic molecule containing an amino group and a carboxyl group that serves as the building block of proteins. There are 20 standard amino acids, nine of which are essential and must be obtained from the diet.

A substance that inhibits oxidation by neutralizing free radicals, thereby protecting cells from damage. Dietary antioxidants include vitamins C and E, beta-carotene, and selenium.

The proportion of a consumed nutrient that is absorbed, enters the systemic circulation, and is available for use or storage in the body.

A measure calculated by dividing body weight in kilograms by the square of height in meters (kg/m2), used as a screening tool for categorizing weight status in populations.

A unit of energy. In nutrition, the term 'calorie' typically refers to a kilocalorie (kcal), the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius.

An organic macronutrient composed of carbon, hydrogen, and oxygen that serves as the body's primary and preferred energy source, providing approximately 4 kilocalories per gram.

A waxy, fat-like substance produced by the liver and obtained from animal-based foods, essential for cell membrane structure, hormone synthesis, and bile acid production.

A set of reference values including RDA, Adequate Intake, and Tolerable Upper Intake Level used for planning and assessing nutrient intake of healthy people.

A mineral that carries an electrical charge when dissolved in body fluids, essential for nerve signaling, muscle contraction, and fluid balance. Key electrolytes include sodium, potassium, and chloride.

A polyunsaturated fatty acid that the body cannot synthesize and must obtain from the diet, specifically linoleic acid (omega-6) and alpha-linolenic acid (omega-3).

The process of adding essential nutrients to food products during manufacturing to prevent or correct widespread nutrient deficiencies in a population.

A numerical scale (0-100) that ranks carbohydrate-containing foods by how rapidly they raise blood glucose levels relative to pure glucose.

A highly branched polysaccharide of glucose that serves as the primary storage form of carbohydrate energy in the liver and skeletal muscles.

A metabolic state in which the liver produces ketone bodies from fatty acid oxidation as an alternative energy source when carbohydrate availability is very low.

A nutrient required in large amounts that provides energy to the body: carbohydrates, proteins, and fats. Water is sometimes included as a fourth macronutrient.

The totality of chemical reactions in the body that convert food into energy and structural components, encompassing both catabolic (breakdown) and anabolic (synthesis) pathways.

A vitamin or mineral required in small amounts (milligrams or micrograms) that is essential for normal growth, development, and physiological function.

An inorganic element required by the body for structural support, enzyme function, fluid balance, and various metabolic processes, obtained from food and water.

A measure of the amount of essential nutrients a food provides relative to its caloric content. Nutrient-dense foods supply vitamins, minerals, and other beneficial substances with relatively few calories.

A family of polyunsaturated fatty acids characterized by a double bond at the third carbon from the methyl end, important for cardiovascular health, brain function, and anti-inflammatory processes.

A biologically active chemical compound found in plants that may provide health benefits beyond basic nutrition, including antioxidant and anti-inflammatory effects. Examples include flavonoids, carotenoids, and polyphenols.

A macronutrient composed of chains of amino acids, essential for building and repairing tissues, producing enzymes and hormones, and supporting immune function. It provides approximately 4 kilocalories per gram.

A type of fat in which all carbon atoms in the fatty acid chain are bonded to hydrogen atoms with no double bonds, found primarily in animal products and some tropical oils. High intake is associated with elevated LDL cholesterol.

The highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in a given life stage and sex group.

An organic compound required in small amounts for essential metabolic functions that the body generally cannot synthesize in sufficient quantities, necessitating dietary intake.