Vitamin K has important functions within the body, some of which are still being discovered. Research has shown that vitamin K is an anticalcification, anticancer, bone-forming and insulin-sensitising molecule. Recent data indicate that subclinical vitamin K deficiency is not uncommon. Additionally, vitamin K antagonists such as warfarin may cause detrimental side effects, which may partly be b...

In Japan, γ-carboxylation of blood coagulation factors is the basis for determining adequate intake (AI) for vitamin K in Dietary Reference Intakes (DRIs) issued in 2010. Recently, vitamin K is also known to be essential for preventing fracture. In this study, relative susceptibility of liver and bone to vitamin K deficiency was studied. Thirty-seven elderly institutionalized subjects were eval...

Summarg 1. The dose-response relationship between the oral anticoagulant, warfarin, and its effect on the metabolism of phylloquinone (vitamin K,) has been examined in normal male volunteer subjects. 2. In each study the subject received a single, oral dose of warfarin and, 2 h later, an intravenous injection of [l ',2'-3H2 Jphylloquinone. Changes in the metabolism of phylloquinone were assesse...

It has been known since the isolation of the vitamins K that derivatives of 2-methyl-1,4-naphthoquinone (MN&) are unstable to light (l-5). However, the exact nature of the chemical change is still under discussion (6, 7). An interesting observation by MacCorquodale and coworkers (3) that the vitamin is quite stable as it exists in crude extracts, only becoming labile after a fair degree of puri...

Vitamin K occurs widely in foods and has been shown to have a beneficial effect on the cardiovascular system, as well as anticancer, anti-inflammatory, and antiosteoporosis properties. A previous study indicates that long-chain menaquinone-7 may be more bioavailable than vitamin K and short-chain menaquinones. In the present study, acute, subacute toxicity and genotoxicity assays were carried o...

There are inconsistent findings on the effects of vitamin K on bone mineral density (BMD) and undercarboxylated osteocalcin (UcOC). The present intervention study evaluated the effect in subjects over 60-yr-old. The vitamin K group (vitamin K + vitamin D + calcium supplement; 15 mg of vitamin K2 [menatetrenone] three times daily, 400 IU of vitamin D once a day, and 315 mg of calcium twice daily...

Serum undercarboxylated osteocalcin (ucOC) is an index of vitamin K nutritional status in treatment-naive postmenopausal osteoporotic women. The purpose of the present study was to reveal the association between vitamin K nutritional status and serum ucOC concentrations in postmenopausal osteoporotic women taking bisphosphonates. Eighty-six postmenopausal women with osteoporosis (age range: 47-...