Plasma lipoproteins as carriers of phylloquinone (vitamin K1) in humans.
The purpose of this study was to characterize the absorption and transport of phylloquinone (vitamin K1) by plasma lipoproteins. Twenty-six healthy subjects (11 men and 15 women) aged 20-78 y received phylloquinone in the amount of either 1.43 or 50 microg/kg body wt orally with a fat-rich meal containing 1.0 g/kg body wt of fat, carbohydrate, and protein and 7.0 mg cholesterol/kg body wt. Blood was obtained at baseline (0 h) and 3, 6, 9, and 12 h after the meal for the measurement of plasma lipid and phylloquinone concentrations in plasma and lipoprotein subfractions. In both groups of subjects, triacylglycerol concentrations peaked after 3 h in plasma and in the triacylglycerol-rich lipoprotein fraction, composed of chylomicrons and VLDLs. Plasma phylloquinone concentrations peaked at 6 h. At baseline and during the postprandial phase, > 53% of plasma phylloquinone was carried by the triacylglycerol-rich lipoprotein fraction. In 9 of the 11 subjects supplemented with 50 microg phylloquinone/kg, plasma lipoproteins were isolated by sequential ultracentrifugation. In these subjects the fraction of plasma phylloquinone carried by LDLs and by HDLs increased progressively from 3% and 4% at 3 h to 14% and 11% at 12 h, respectively. Our data indicate that whereas triacylglycerol-rich lipoproteins are the major carriers of phylloquinone, LDL and HDL may carry small fractions of this vitamin.
Lamon-Fava
S
S
Vitamin K Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston 02111, USA.
Sadowski
J A
JA
Davidson
K W
KW
O'Brien
M E
ME
McNamara
J R
JR
Schaefer
E J
EJ
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000933:Antifibrinolytic Agents / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D001692:Biological Transport; D002784:Cholesterol / Q000097:blood; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008074:Lipoproteins / Q000008:administration & dosage / Q000097:blood* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood; D010837:Vitamin K 1 / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D000933:Antifibrinolytic Agents; D004041:Dietary Fats; D008074:Lipoproteins; D014280:Triglycerides; D010837:Vitamin K 1; D002784:Cholesterol