title: Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women.
abstract: BACKGROUND
  Vitamin K₂ contributes to bone and cardiovascular health. Therefore, two vitamin K₂ homologues, menaquinone-4 (MK-4) and menaquinone-7 (MK-7), have been used as nutrients by the food industry and as nutritional supplements to support bone and cardiovascular health. However, little is known about the bioavailability of nutritional MK-4. To investigate MK-4 and MK-7 bioavailability, nutritional doses were administered to healthy Japanese women.
  
  
  RESULTS
  Single dose administration of MK-4 (420 μg; 945 nmol) or MK-7 (420 μg; 647 nmol) was given in the morning together with standardized breakfast. MK-7 was well absorbed and reached maximal serum level at 6 h after intake and was detected up to 48 h after intake. MK-4 was not detectable in the serum of all subjects at any time point. Consecutive administration of MK-4 (60 μg; 135 nmol) or MK-7 (60 μg; 92 nmol) for 7 days demonstrated that MK-4 supplementation did not increase serum MK-4 levels. However, consecutive administration of MK-7 increased serum MK-7 levels significantly in all subjects.
  
  
  CONCLUSIONS
  We conclude that MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels. MK-7, however significantly increases serum MK-7 levels and therefore may be of particular importance for extrahepatic tissues.
authors.affiliation: Fine Chemical Laboratory, J-OIL MILLS, INC, 1746 Nakashinden, Fukuroi-city, Shizuoka, 437-1111, Japan. toshiro.sato@j-oil.com
authors.forename: Toshiro
authors.initials: T
authors.lastname: Sato
authors.forename: Leon J
authors.initials: LJ
authors.lastname: Schurgers
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Uenishi
mesh_terms: D000328:Adult; D050071:Bone Density Conservation Agents / Q000097:blood / Q000378:metabolism; D062408:Breakfast; D002317:Cardiovascular Agents / Q000097:blood / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007408:Intestinal Absorption; D007700:Kinetics; D057230:Limit of Detection; D009753:Nutritive Value; D013050:Spectrometry, Fluorescence; D024482:Vitamin K 2 / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D055815:Young Adult
chemical_list: D050071:Bone Density Conservation Agents; D002317:Cardiovascular Agents; D024482:Vitamin K 2; C030814:menatetrenone; C062629:menaquinone 7