Office of Dietary Supplements, National Institutes of
Health. 6100 Executive Blvd., Room 3B01, MSC 7517,
Bethesda, MD 20892-7517 Telephone: (301) 435-2920.
Fax: (301)480-1845. Website: http://dietary-supplements.
info.nih.gov/
OTHER
Agricultural Research Service, USDA. ‘‘Vitamin K:
Another Reason to Eat Your Greens.’’ United States
Department of Agriculture, February 23, 2007.
<http://www.ars.usda.gov/is/AR/archive/jan00/
green0100.htm>.
American Cancer Society. ‘‘Vitamin K.’’ American Cancer
Society, March 23, 2006.<http://www.cancer.org/
docroot/eto/content/
ETO_5_3X_Vitamin_K.asp?sitearea=ETO>.
Higdon, Jane. ‘‘Vitamin K.’’Linus Pauling Institute-Oregon
State University, May 25, 2004.<http://lpi.oregonstate.
edu/infocenter/vitamins/VitaminK>.
Harvard School of Public Health. ‘‘Vitamins.’’ Harvard
University, November 10, 2006.<http://www.hsph.
harvard.edu/nutritionsource/vitamins.html>.
Medline Plus. ‘‘Vitamin K.’’ U. S. National Library of Med-
icine, August 1, 2006.<http://www.nlm.nih/gov/medli-
neplus/ druginfo/natural/patient-vitamink.html>.
Warren Grant Magnuson Clinical Center Drug-Nutrient
Interaction Task Force. ‘‘Important Information to
Know When You Are Taking Coumadin and Vitamin
K.’’ National Institutes of Health, December 2003.
<http://dietary-supplements.info.nih.gov/factsheets/
cc/coumadin1.pdf>.Tish Davidson, A.M.Vitamins
Definition
Vitamins are organic compounds found in plants
and animals that are necessary in small quantities for
life and health. Thirteen different vitamins have been
identified as necessary for humans. The body can
make small quantities of two of these vitamins, vita-
mins D and K. All other vitamins must be obtained
either from food or fromdietary supplements.Purpose
Each of the 13 vitamins has specific functions, and
taken together vitamins play a role in almost every
function in the body. They help convert food to
energy, and are involved processes as diverse as
blood clotting, vision, reproduction, and transmission
of nerve impulses.DescriptionFor centuries before vitamins were formally dis-
covered, people knew that eating certain foods pre-
vented certain diseases. For example, the ancient
Egyptians knew that eating liver (later shown to be
high invitamin A) prevented night blindness. Sailors
on long voyages often developed a serious disease
called scurvy. James Lind, a Scottish surgeon who
sailed with the British navy conducted the first con-
trolled experiment on vitamins in 1753. He supple-
mented the regular diet of four groups of sailors with
four different foods. The group that received oranges
and lemons as supplements did not develop scurvy,
while the other three groups did. Although Lind didVitamins