incomplete protein : A protein low in one or more amino acids.

inorganic nutrients : Nutrients that don’t contain carbon, hydrogen, and oxygen atoms.

inositol : A lipotropic vitamin-like substance that is found in soy lecithin along with choline.

insoluble fiber: Fiber that includes cellulose, some hemicelluloses, and lignin found in whole grains and other plants. This kind of dietary fiber is a natural laxative. It absorbs water, helps you feel full after eating, and stimulates your intestinal walls to contract and relax. These natural contractions, called peristalsis, move solid materials through your digestive tract.

insulin: A hormone that enables you to move blood sugar (glucose) out of the blood and into cells where it’s needed for various chores.

International Units; IU: A measurement for vitamin needs.

iodine : A required nutrient for humans with limited natural dietary sources in some areas. Before the introduction of iodized salt, iodine was the most common mineral deficiency in the United States.

iron: An essential trace element found in hemoglobin and myoglobin, two proteins that store and transport oxygen.

ischemic stroke: A stroke caused by a blood clot in a cranial artery

isoleucine: An essential amino acid that helps give you energy.