Vitamin K deficiency from dietary vitamin K restriction in humans.
Vitamin K is required for the maintenance of normal hemostatic function. Ten college-aged male subjects chose diets restricted in vitamin K content for 40 d. Median phylloquinone intakes based on analysis of food composites dropped from 82 micrograms/d during the prestudy period to 40 and 32 micrograms/d at d 9 and 27 of dietary restriction, respectively. Serum phylloquinone concentrations fell from a mean of 0.87 to 0.46 ng/mL during a 21-d period of vitamin K restriction. Supplementation with 50 micrograms phylloquinone/d for 12 d increased serum phylloquinone to 0.56 ng/mL, and supplementation with 500 micrograms phylloquinone/d increased serum phylloquinone to 1.66 ng/mL. Vitamin K restriction resulted in alterations in a functional clotting assay that detects undercarboxylated prothrombin species in plasma and in a decrease in urinary gamma-carboxyglutamic acid. Supplementation with either 50 or 500 micrograms of phylloquinone restored both these indices to near normal values. These data are consistent with a human dietary vitamin K requirement of approximately 1 microgram/kg body wt/d.
Suttie
J W
JW
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706.
Mummah-Schendel
L L
LL
Shah
D V
DV
Lyle
B J
BJ
Greger
J L
JL
D000328:Adult; D001777:Blood Coagulation; D006801:Humans; D008297:Male; D013997:Time Factors; D014812:Vitamin K / Q000008:administration & dosage*; D010837:Vitamin K 1 / Q000008:administration & dosage; D014813:Vitamin K Deficiency / Q000097:blood / Q000209:etiology*
D014812:Vitamin K; D010837:Vitamin K 1