Dietary intake and adequacy of vitamin K.
The current daily recommended dietary allowance for vitamin K is 1 microg/kg. Reliable measurements of vitamin K content in foods are now available, and data from 11 studies of vitamin K intake indicate that the mean intake of young adults is approximately 80 microg phylloquinone/d and that older adults consume approximately 150 microg/d. The vitamin K concentration in most foods is very low (<10 microg/100 g), and the majority of the vitamin is obtained from a few leafy green vegetables and four vegetable oils (soybean, cottonseed, canola and olive) that contain high amounts. Limited data indicate that absorption of phylloquinone from a food matrix is poor. Hydrogenated oils also contain appreciable amounts of 2', 3'-dihydrophylloquinone of unknown physiological importance. Menaquinones absorbed from the diet or the gut appear to provide only a minor portion of the human daily requirement. Measures of the extent to which plasma prothrombin or serum osteocalcin lack essential gamma-carboxyglutamic acid residues formed by vitamin K action, or the urinary excretion of this amino acid, provide more sensitive measures of vitamin K status than measures of plasma phylloquinone or insensitive clotting assays.
Booth
S L
SL
Vitamin K Laboratory, U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
Suttie
J W
JW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004032:Diet / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018673:Nutrition Policy; D014812:Vitamin K / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D014813:Vitamin K Deficiency / Q000097:blood / Q000378:metabolism / Q000503:physiopathology
D014812:Vitamin K