Researchers subsequently identified gut bacteria as a major driver of vitamin K2 conversion (from K1). These were first identified in the 1950s. Vitamin K2 comprises a group of 10 molecules with side chains of 4–13 isoprenoid units, mostly unsaturated, and are called menaquinones. The two forms of vitamin K are vitamin K1, discovered by Dam and Doisy (also known as phylloquinone), and the more recently recognised vitamin K2.
Vitamin K, specifically the vitamin K2 form, plays a significant role in the maintenance of healthy bones, and we are only beginning to appreciate the full extent of its impact on human health. For their pioneering work, Dam and Doisy shared a 1943 Nobel Prize.ĭecades later, the understanding of vitamin K has evolved with the recognition of two primary forms of vitamin K, each with very different contributions to human health. 1 A few years later, American biochemist Edward Adelbert Doisy determined the chemical structure of vitamin K and succeeded in synthesising it. He named it vitamin K after the German word for coagulation (koagulation). In 1935, Danish scientist Henrik Dam described a fat-soluble factor that reduced bleeding in chicks fed an extremely low fat diet. This article focuses on the use of MK-7 as a dietary supplement to promote bone health, as well as some of the other potential advantages of MK-7 supplementation. Recently, the health benefits of MK-7, a form of vitamin K2, have received considerable attention. Recent studies suggest that dietary intakes of vitamin K2 among the general population are inadequate and that vitamin K2 supplementation may improve bone health and reduce the healthcare costs associated with osteoporosis. Incorporating calcium into the bone matrix means that less calcium is available for harmful deposits in soft body tissues. Thus, the additional intake of MK-4 might be beneficial in the maintenance of bone health in postmenopausal Japanese women.Vitamin K2 is necessary for the activation of osteocalcin, a protein that transports and integrates calcium into bone to ensure a healthy skeleton. The concentrations of serum lipids and other indices were not different between the groups at either intervention period. These results suggest that supplementation with 1.5 mg/d MK-4 accelerated the degree of OC gamma-carboxylation.
The serum ucOC and GlaOC concentrations in the MK-4 group were significantly different from those in the placebo group at 2 wk. Serum undercarboxylated OC (ucOC) concentration decreased, and the gamma-carboxylated OC (GlaOC) and GlaOC/GlaOC+ucOC ratio that indicates the degree of OC gamma-carboxylation increased significantly at 2 and 4 wk compared with that at baseline in the MK-4 group. The most marked effects of MK-4 intake were observed on serum osteocalcin (OC) concentrations.
The participants aged 53-65 y were randomly assigned to 2 groups and supplemented with 1.5 mg/d of MK-4 or a placebo for 4 wk (n=20 for each group). The study was performed as a randomized double blind placebo-controlled trial. The aim of this study is to examine the effects of the supplementation of 1.5 mg/d MK-4 for 4 wk on bone and lipid metabolism in healthy postmenopausal Japanese women. However, it is not known whether supplementation with low dose MK-4 has beneficial effects on bone metabolism in healthy women. It has been reported that treatment with a pharmacological dose (45 mg/d) of menaquinone-4 (MK-4) prevents bone loss in postmenopausal women.