Amino Acid - The basic building block of proteins. Each protein consists of a different set of amino acids, put together according to instructions in the corresponding gene. There are 22 amino acids, each encoded by a three-letter "word" of the genetic code.
Antioxidant - Any compound that prevents or neutralizes the damaging effects of free radicals-reactive oxygen molecules in cells. Some natural antioxidants are produced in the body while others, such as certain vitamins, are found in a variety of foods.
Body Mass Index (BMI) - A measurement using height and weight to express the relative percentages of fat and muscle mass in the human body, the results are used as an index of overweight and obesity.
Carbohydrates - Organic compounds that contain carbon, hydrogen, and oxygen. They include simple sugars such as fructose and glucose, as well as the more complex saccharides such as lactose, starch, and cellulose. Carbohydrates are an excellent source of energy and of many vitamins and minerals.
Cell - The basic structural subunit of any living organism. It is a tiny, watery compartment filled with chemicals containing a complete copy of the organism's genome. Some organisms are made up of only one or two cells, whereas the human body consists of billions. Each cell is enclosed by a membrane and in most cases has a nucleus containing genetic material (DNA) organized in the form of chromosomes.
Chromosome - A tightly coiled microscopic structure made up mainly of DNA. Chromosomes are found in most cells of the human body, inside the nucleus.
Cloning - The process of making an identical copy of something. The term is used when making copies of a piece of DNA, usually a gene (molecular cloning), culturing cells (cell cloning) or making copies of a living organism (for example, animal cloning).
Detoxification - The process by which the body rids itself of unwanted and potentially harmful substances, or toxins. These toxins can come from food, water, air, or from the by-products of normal metabolism. Detoxification generally happens in the liver or kidneys, where toxins are either broken down or attached to a water-soluble, natural chemical to be easily excreted in the urine or sweat.
DNA - The genetic material of living organisms, an abbreviation for deoxyribonucleic acid. The DNA is known as a "double helix" because its molecules have the shape of a twisted rope ladder consisting of two intertwined coils.
DNA forms the genetic blueprint; it contains the genes that carry all the information about our appearance, how our bodies function and, sometimes, the diseases we will get. The building blocks of DNA contain four different chemicals-adenine, thymine, cytosine, and guanine, or A, T, C, and G for short-referred to as the "letters" of the genetic code.
Double helix - refers to DNA; the physical structure of DNA resembles the shape of a twisted rope ladder or a spiral staircase.
Enzyme - A protein that carries out the biochemical reactions essential for the body to metabolize food and produce energy for growth, repair, and movement. Organisms could not function if they had no enzymes.
Fats - Organic compounds composed of glycerol and fatty acids, which serve as the most concentrated source of energy in foods. Depending on the predominant type of fatty acids they contain, they are divided into saturated and unsaturated molecules.
Free radical - An extremely active portion of an oxygen or other molecule formed in the body as part of normal metabolism. If produced in excess, or not neutralized efficiently, it releases an electric charge that can damage cell structures and proteins.
Gene - A segment of the DNA molecule that contains instructions for making a protein. The sequences of genetic "letters" (e.g., ATT CGG) in our genes determine how, when, and where our bodies make each of the many thousands of proteins required for life.
Genotype - The genetic makeup of an individual.
Gene Variation - A naturally occurring variation in the DNA that is present in at least one percent of the population. The variation means an alteration in one or more letters of the genetic alphabet. For example, where most people have the genetic letter A, the person with the variation may have a T. Scientists call such variations "polymorphisms." Most gene variations are harmless and are part of normal human genetic diversity.
Gene Variant - See Gene Variation above
Genetic Code - The instructions in a gene that tell the cell how to make a specific protein. A, T, C, and G are the "letters" of the genetic code; they stand for the chemicals adenine, thymine, cytosine, and guanine, which make up DNA. Each gene's code combines the four chemicals in various ways, spelling out three-letter "words" that specify which amino acid is needed at every step in making a protein.
Genetic Engineering - The use of various experimental techniques to produce DNA that contains new or modified genes or combinations of genes.
Genome - The total genetic code of a particular organism. The normal human genome consists of about three billion genetic "letters."
Genomics - A specialized branch of science that studies the genome.
Metabolism - The natural process by which all living organisms, including humans, transform food into energy and dispose of their waste products. Metabolism is essential for life.
Minerals - inorganic molecules that are essential for normal metabolism, growth and development, and for the regulation of cell function. Minerals are not made by the body and must be obtained through the diet. Insufficient levels of minerals in the diet lead to deficiency.
Molecule - The smallest part of any compound or substance that is chemically stable. It consists of two or more atoms joined together by chemical bonding. Nucleus - The central cell structure; it contains the chromosomes.
Nucleotide - the buildling blocks of nucleic acids, such as DNA
Nutrigenomics - the science that studies the relationship between genes and diet, how gene variants affect nutrient requirements and how diet and other lifestyle factors influence gene expression.
Oxidative Stress - A situation in which the environment within cells becomes highly "oxidized"-that is, comes to contain reactive, unstable molecules, particularly those of oxygen. These reactive molecules can attach themselves to proteins and DNA inside the cell and cause damage. Cells in this highly activated state lose control of their regulatory systems. Oxidative stress has been linked to the development of disease.
Pedigree - a picture diagram of a family's medical history, usually including multiple generations of a family and the health conditions of each member.
Pharmacogenomics - the study of drug-metabolizing genes and the influence of their variants on an individual's ability to use a drug safely and effectively.
Phenotype - the observable characteristics of an individual.
Phytonutrients - bioactive components from plants that have health benefits.
Polymorphism - Scientific term for "gene variation."
Proteins - Complex, organic compounds that contain carbon, hydrogen, oxygen, and nitrogen. It is the presence of nitrogen that differentiates proteins from carbohydrates and fats. The basic building blocks of proteins are amino acids. Humans need 22 amino acids for the synthesis of their proteins. The human body can make only 13, known as nonessential amino acids because we don't need to get them from the food we eat. There are nine essential amino acids that are not made by the body and can be obtained only from food.
SNP - Single nucleotide polymorphism, pronounced "snip." A gene variation that consists of alteration in a single genetic "letter," or base: for example, GGT instead of GCT. Such common, though minute, variations occur in human DNA at a frequency of one in every 1,000 bases.
Toxin - A harmful substance, specifically one produced by an animal, plant, or bacterium. Toxins can enter the body from one of these sources or be generated as by-products of metabolism. Constant exposure to toxins can overwhelm the body's detoxification mechanisms and lead to disease.
Vitamins - Organic molecules that are essential for normal metabolism, growth and development, and for the regulation of cell function. Some vitamins activate specific enzymes in the body. Insufficient vitamins in the diet lead to deficiency.