Nutrition
A science that studies the interactions between living organisms and food.
Nutrients
Substances in foods that provide energy and structure and help regulate body processes.
Food Environment
The physical, economic, and social factors that affect eating habits and patterns.
Food Processing
The practices used by the food industry to transform raw plant and animal materials, such as grains, produce, meat, and milk, into products for consumers. Nearly all our food has been processed in some way.
Essential Nutrient
A nutrient that must be provided in the diet because the body either cannot make it or cannot make it in sufficient quantities to satisfy its needs.
Fortified Food
Food to which one or more nutrients have been added.
Enriched Grains
Grain products to which specific amounts of thiamin, riboflavin, niacin, and iron have been added. Since 1998 folic acid has also been added to enriched grains.
Dietary Supplements
A product intended for ingestion in the diet that contains one or more of the following: vitamins, minerals, plant-derived substances, amino acids, and concentrates or extracts.
Phytochemical
A substance found in plant foods (phyto- means plant) that is not an essential nutrient but may have health-promoting properties.
Energy-yielding nutrient
A nutrient that can be metabolized to provide energy in the body.
Macronutrient
A nutrient needed by the body in large amounts. These include water and the energy-yielding nutreints: carbohydrates, lipids, and proteins.
Micronutrient
A nutrient needed by the body in small amounts. These include vitamins and minerals.
Organic Molecule
A molecule that contains no carbon-hydrogen bonds.
Kilocalorie (kcal, kcalorie)
The unit of head used to express the amount of energy provided by foods. It is the amount of heat required to raise the temperature of 1 kg of water 1 degree Celsius (1 kcal = 4.18 kJ).
Kilojoule (kJ, kjoule)
A unit of work that can be used to express energy intake and energy output. It is the amount of work required to move an object weighing 1 kg a distance of 1 meter under the force of gravity (1 kJ = 0.24 kcal).
Legumes
Plants in the pea or bean family that produce an elongated pod containing large starchy seeds. Green peas, kidney beans, and peanuts are legumes.
Homeostasis
A physiological state in which a stable internal body environment is maintained.
Metabolism
The sum of all chemical reactions that take place in a living organism.
Malnutrition
Any condition resulting from an energy or nutrient intake either above or below that which is optimal.
Undernutrition
Any condition resulting from an energy or nutrient intake below that which meets nutritional needs.
Overnutrition
Poor nutritional status resulting from an energy or nutrient intake in excess of that which is optimal for health.
Genes
Units of a larger molecule called DNA that are responsible for inherited traits.
Nutritional Genomics
The study of how our genes affect the impact of nutrients or other food components on health (nutrigenetics) and how nutrients affect the activity of our genes (nutrigenomics).
Nutrient Density
An evaluation of the nutrient content of a food in comparison to the calories it provides.
Scientific Method
The general approach of science that is used to explain observations about the world around us.
Hypothesis
An educated guess made to explain an observation or to answer a question.
Theory
An explanation based on scientific study and reasoning.
Epidemiology
The study of the interrelationships between health and disease and other factors in the environment or lifestyle of different populations.
Correlation
Two or more factors occurring together.
Case-control Study
A type of observational study that compares individuals with a particular condition under study with individuals of the same age, gender, and background who do not have the condition.
Human Intervention Study or Clinical Trial
A study of a population in which there is an experimental manipulation of some members of the population; observations and measurements are made to determine the effects of this manipulation.
Experimental Group
In a scientific experiment, the group of participants who undergo the treatment being tested.
Control Group
In a scientific experiment, the group of participants used as a basis of comparison. They are similar to the participants in the experimental group but do not receive the treatment being tested.
Depletion-repletion study
A study that feeds a diet devoid of a nutrient until signs of deficiency appear and then adds the nutrient back to the diet to a level at which symptoms disappear.
Balance Study
A study that compares the total amount of a nutrient that enters the body with the total amount that leaves the body.
Variable
A factor or condition that is changed in an experimental sitting.
Placebo
A take medicine or supplement that is indistinguishable in appearance from the real thing. It is used to disguise the control and experimental groups in an experiment.
Single-blind study
An experiment in which either the study participants or the researchers are unaware of which participants are in a control or an experimental gorup.
Double-blind study
An experiment in which neither the study participants nor the researchers know which participants are in a control or an experimental group.