Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women
1 Fine Chemical Laboratory, J-OIL MILLS, INC, 1746 Nakashinden, Fukuroi-city, Shizuoka, 437-1111, Japan
2 Department of Biochemistry, Cardiovascular Research Institute, University Maastricht, Maastricht, The Netherlands
3 Laboratory of Physiological Nutrition, Kagawa Nutrition University, 3-9-2, Chiyoda, Sakado, Saitama, 350-0288, Japan
Nutrition Journal 2012, 11:93 doi:10.1186/1475-2891-11-93Published: 12 November 2012
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.
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.
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.