Chapter 5: Vitamins Flashcards
Micronutrients
nutrients that are needed in very small amounts
Vitamins
organic compounds made of carbon, hydrogen, oxygen, and sometimes, nitrogen or other elements
Oxidation
a chemical reaction in which a substance combines with oxygen; the loss of electrons in an atom
Provitamins
precursors of vitamins
Enzymes
proteins produced by cells that catalyze chemical reactions within the body without undergoing change themselves
Coenzymes
organic molecules that activate an enzyme
Free Radicals
highly unstable, highly reactive molecular fragments with one or more unpaired electrons
Antioxidants
substances that donate electrons to free radicals to prevent oxidation
Food Additives
substances added intentionally or unintentionally to food that affect its character
Enrich
to add nutrients back that were lost during processing; for example, white flour is enriched with B vitamins lost when the bran and germ layers are removed
Fortified
to add nutrients to a food that were either not originally present or were present in insignificant amounts
Megadoses
amounts at least 10 times greater than the Recommended Dietary Allowance (RDA)
Preformed Vitamin A
the active form of vitamin A
Carotenoids
a group name of retinol precursors found in plants
Essential Nutrient
a nutrient that must be supplied by the
diet because it is not synthesized in the body. Essentiality does not refer to importance, merely to the need for a dietary source
IU: International Units
the former unit of measure of vitamin D that has been replaced by micrograms of cholecalciferol, the active form of vitamin D. To convert micrograms of vitamin D to IU, mul- tiply micrograms by 40
Rickets
vitamin D deficiency disease in children, most prominently characterized by bowed legs
Osteomalacia
adult rickets characterized by inadequate bone mineralization due to the lack of vitamin D
Homocysteine
an amino acid correlated with increased risk of heart disease
Methionine
an essential amino acid
Niacin Equivalents (NEs)
the amount of niacin available to the body including that made from tryptophan
Dietary Folate Equivalents (DFEs)
DFE = microgram of food folate + (1.7 x micrograms synthetic folic acid)
Phytochemicals
bioactive, nonnutrient plant compounds associated with a reduced risk of chronic diseases