VITAMINS Flashcards
are essential organic substances needed daily in very small amounts to perform a specific
function in the body. Although they are grouped under one term because they all contain
carbon, the essentiality of vitamins for one species may not apply to another.
Vitamin
To be classified as a vitamin, a compound has to meet several criteria:
- It must be an organic dietary substance that is not energy producing, as are carbohydrate, fat,
and protein. - It is needed in very small quantities to perform a particular metabolic function and prevent an
identified deficiency disease. - It cannot be synthesized by the body, so it must be supplied in food.
Most vitamins have multiple roles or actions in the body,
sometimes working independently and sometimes working cooperatively with other nutrients. For
example, while we associate vitamin A with its major role of helping us see in dim light, this vitamin
also maintains the mucous membranes that protect against infection.
Individual vitamins are multifunctional:
All vitamins must be available in sufficient
amounts for the body to function normally and for tissues to remain healthy. For example, an
abundant supply of vitamin C cannot take the place of folate in preventing a neural tube defect
(NTD).
One vitamin cannot substitute for another vitamin:
The formation and maturation of red blood
cells require the actions of folate, pyridoxine, vitamin B12, and ascorbic acid, along with several
important minerals.
Vitamins work together in carrying out body functions:
High-potency vitamin
A supplements interfere with the action of vitamin D, decreasing calcium
These functional truths underscore the importance of eating a variety of foods
Vitamins function best when all are present in the appropriate proportions:
are A, D, E, and K.
They are closely associated with body
lipids and are easily stored. Their functions
are usually related to structural activities
with proteins.
Fat-Soluble Vitamins
vitamins are vitamin C
and the B-complex family. These vitamins
are more easily absorbed and trans-
ported, but unlike the fat-soluble vitamins,
they cannot be stored except in the
general sense of tissue saturation.
Water-Soluble Vitamins
The B
vitamins function mainly as _____
factors in cell metabolism. Vitamin C works
with enzymes that support tissue building
and maintenance.
coenzyme
a yellow pigment in plants that can be con- verted to vitamin A in the intestinal wall.
Carotene:
a condition in which lesions appear on the lips and the angles of the mouth (cracks).
Cheilosis:
a substance such as a vitamin that can attach to the inactive form of an enzyme to
make it an active compound or complete enzyme.
Coenzyme:
a gelatin-like protein substance found in connective tissue and bones; a cementing
material be- tween body cells.
Collagen:
inflammation of the skin.
Dermatitis:
a compound that speeds up the rate of a chemical reaction without itself being
changed in the process.
Enzyme:
