Webster's New World Medical Dictionary

vitamin D
An oil-soluble steroid vitamin that pro-
motes absorption and metabolism of calcium and
phosphorus and that is essential for tooth and bone
growth. Under normal conditions of sunlight expo-
sure, no dietary supplementation is necessary
because sunlight promotes adequate vitamin D syn-
thesis in the skin. Vitamin D is added to many com-
mon dairy products and breads, and it can also be
found in saltwater fish and egg yolks. Deficiency can
lead to osteomalcia (softening of bone) in adults and
bone deformity (rickets) in children. The daily adult
requirement is 10 micrograms.
vitamin D2
Calciferol, a synthetic form of vitamin
D that is created by treating ergosterol (provitamin
D2) with ultraviolet light waves. Vitamin D2 is impor-
tant in normal bone metabolism. Vitamin D2 is
largely supplied by the metabolism of vitamin D in the
body.
vitamin D3
Cholecalciferol, a D vitamin that is
needed for proper use of phosphorus, calcium, and
vitamin A. It plays a steroid-like role in regulating cel-
lular proliferation and differentiation. Vitamin D3 is
important in normal bone metabolism. Also known
as calcitrol. Vitamin D3 is largely supplied by the
metabolism of vitamin D in the body.
vitamin E
An oil-soluble vitamin that is vital for
muscle, skin, blood vessel, and organ development
and function. Dietary sources for vitamin E include
nuts, nut and corn oils, wheat germ, liver, sweet pota-
toes, and green leafy vegetables. Deficiency of vitamin
E can lead to anemia. The daily adult requirement is
10 milligrams.
vitamin H
Biotin, which is actually considered
part of the water-soluble, B vitamin family. It is a
coenzyme essential for many enzyme functions.
Normally produced by bacteria in the colon, biotin is
also found in yeast, organ meats, legumes, egg yolks,
whole grains, and nuts. The daily adult requirement
is 60 micrograms.
vitamin K
An oil-soluble vitamin essential to the
normal clotting of blood. Vitamin K is normally made
within the body by intestinal bacteria, but it is also
found in many foods, including leafy green vegetables,
yogurt, egg yolk, and fish-liver oils. Deficiency may
occur following the administration of drugs that
inhibit the growth of the vitamin-synthesizing bacteria
or as a result of disorders affecting the production or
flow of bile necessary for the intestinal absorption of
vitamin K. In newborn babies, the absence of intestinal
bacteria coupled with the absence of body stores of
vitamin K may result in hemorrhagic disease of the
newborn. This is a dangerous condition because there
can be bleeding into critical organs such as the brain.
This disorder can be prevented by the administration
of vitamin K to the baby shortly after birth or to the
mother during labor. Daily adult requirement is 65
micrograms.
vitamin P
Bioflavinoids, a group of substances
found with and essential to the use of vitamin C. They
are essential for building collagen and capillary walls,
among other functions.
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Document Outline

• Webster's New World Medical Dictionary, Third Edition
  • Acknowledgments
  • About the Authors
  • Introduction
  • Aa
  • Bb
  • Cc
  • Dd
  • Ee
  • Ff
  • Gg
  • Hh
  • Ii
  • Jj
  • Kk
  • Ll
  • Mm
  • Nn
  • Oo
  • Pp
  • Qq
  • Rr
  • Ss
  • Tt
  • Uu
  • Vv
  • Ww
  • Xx
  • Yy
  • Zz
  • Appendix A
  • Appendix B
  • Appendix C