are organic compounds necessary for
growth, health, normal metabolism
and physical well-being. Some vitamins
are essential parts of enzymes --
the chemical molecules that catalyze
or facilitate the completion of chemical
reactions. Other vitamins form essential
parts of hormones -- the chemical
substances that promote and protect
body health and reproduction.
are classified as either fat-soluble
or water-soluble. The fat-soluble
vitamins (which include Vitamins A,
D, E, and K) require protein carriers
for absorption. These vitamins can
be stored in the body for use at a
later time. These nutrients are usually
found in the liver and fatty tissue.
Vitamin C and the B vitamins are water-soluble.
These vitamins are more easily lost
through excretion and are more sensitive
to the effects of storage and cooking.
can be obtained in "adequate" amounts
from food sources, provided one eats
a well-balanced diet made up of foods
grown in nutrient-rich soil. However,
there are many conditions and circumstances
that make eating a well-balanced diet
difficult, resulting in an inadequate
vitamin intake. During such times,
a vitamin supplement may be required.
Some people, such as pregnant women,
have special nutritional needs. Others,
such as those with a restricted caloric
intake, may be at risk for a vitamin
deficiency. In these cases, supplements
may be necessary to obtain optimal
vitamin intake. Vitamin supplements
are not meant to take the place of
a good diet, but to enhance the benefits
of a healthy lifestyle.