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Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Like dietary lipids and other fat-soluble vitamins, ingested vitamin K is incorporated into mixed micelles via the action of bile and pancreatic enzymes, and it is absorbed by enterocytes of the small intestine (82). Vitamin K is rapidly metabolized and excreted. This rapid metabolism accounts for vitamin K’s relatively low blood levels and tissue stores compared to those of the other fat-soluble vitamins (82). Vitamin K deficiency is rare because vitamin K is present in dietary foods, mostly in leafy green foods, and the bacteria in human intestines can make vitamin K (3, 9, 33, 82–86). Sometimes taking antibiotics can kill the bacteria and lead to a temporary mild deficiency. Vitamin K deficiency can lead to bleeding and hemorrhage, such as oozing in the nose, gums, and intestines. Other diseases may lead to vitamin K deficiency such as celiac disease, Crohn’s disease, liver disease, bleeding disorders, gallbladder or biliary disease, cystic fibrosis, long-term hemodialysis, treatment by warfarin (an anticoagulant drug), and serious burns (33, 82–86). Because vitamin K is required for the carboxylation of osteocalcin in bone, vitamin K deficiency could also reduce bone mineralization and contribute to osteoporosis, and is associated with a higher risk of osteoarthritis (82–84). Allergic reaction to vitamin K supplementation is possible.
Nutraceuticals for Bone Health in Pregnancy
Published in Priyanka Bhatt, Maryam Sadat Miraghajani, Sarvadaman Pathak, Yashwant Pathak, Nutraceuticals for Prenatal, Maternal and Offspring’s Nutritional Health, 2019
In Western eating regimens the key type of dietary vitamin K is phylloquinone (vitamin K1). Vitamin K is a fundamental factor for the carboxylation of osteocalcin, a bone-unconventional protein blended by osteoblasts that is among the most lavish bone lattice proteins and furthermore assumes a role in bone mineralization. Inadequate vitamin K may prompt under carboxylation of osteocalcin and add to age-related bone loss and fractures.
The vitamins
Published in Geoffrey P. Webb, Nutrition, 2019
Similar carboxylated Gla proteins are found in other tissues. Three Gla proteins are found in bone: osteocalcin, matrix Gla protein and protein S. The presence of these proteins in bone suggests that vitamin K may play an important role in bone metabolism, and it has been suggested that vitamin K insufficiency may be a contributory cause of osteoporosis. Preliminary support for an association between vitamin K insufficiency and osteoporosis risk is summarised as follows. On a normal diet with normal blood clotting, the osteocalcin that circulates in the blood is not fully carboxylated and substantial supplements are needed to achieve full carboxylation. In very elderly women, there is reduced carboxylation of circulating osteocalcin. High levels of under-carboxylated osteocalcin in elderly women are associated with reduced bone density at the hip and increased risk of fracture. Low intakes of vitamin K have been associated with increased hip fracture risk. Women in the lowest quartile of vitamin K intakes have been reported to have lower bone density than those in the highest quartile.
Circulating uncarboxylated matrix Gla protein in patients with atrial fibrillation or heart failure with preserved ejection fraction
Published in Archives of Physiology and Biochemistry, 2022
Neshe Ferahova Nazifova-Tasinova, Atanas Angelov Atanasov, Milena Gincheva Pasheva, Yoto Trifonov Yotov, Daniela Ivanova Gerova, Deyana Georgieva Vankova, Miglena Nikolaeva Todorova, Diana Georgieva Ivanova, Yoana Dimitrova Kiselova-Kaneva, Bistra Tzaneva Galunska
Long ago had been suggested that uncarboxylated osteocalcin was a sensitive marker for the vitamin K status of extrahepatic tissues including the vessel wall (Schurgers et al. 2001). More representative marker for vitamin K status is the ratio between the two forms of osteocalcin (OCR) – uncarboxylated, inactive (ucOC) and carboxylated, active (cOC) (Dalmeijer et al. 2013). High OCR represents poor vitamin K status and deficient Gla protein carboxylation. Our data reveal relatively low vitamin K status, evaluated by OCR for the entire population and for the subgroups. We found a positive correlation between ucMGP and OCR for the entire CVD group, for controls and for the patients with atrial fibrillation. These findings indicate that poor vitamin K status is related to deficient carboxylation of ucMGP to cMGP and higher-circulating ucMGP levels.
Drugs in phase I and II clinical development for the prevention of stroke in patients with atrial fibrillation
Published in Expert Opinion on Investigational Drugs, 2021
Robert Bentley, Lewis J. Hardy, Laura J Scott, Parveen Sharma, Helen Philippou, Gregory Y. H. Lip
Warfarin is a VKA and, as described in Figure 1, its mode of action is to interfere with the hepatic synthesis of the pro-coagulant vitamin K-dependant clotting factors II, VII, IX and X, as well as the synthesis of the anticoagulant proteins C, S and Z [14]. These clotting factors undergo gamma-carboxylation of glutamic acid residues at the NH2-terminal molecular region [25] which requires the presence of the reduced and active form of vitamin K, which makes these coagulation factors fully functional (enabling them to be active following proteolytic cleavage). Under normal conditions, vitamin K epoxide reductase complex 1 (VKORC1) converts vitamin KO, the oxidized and inactive form of vitamin K, into the active vitamin KH2 form [25,26]. This provides a continuous supply of vitamin KH2 causing clotting factor synthesis. Warfarin specifically inhibits VKORC1 causing an accumulation of inactive vitamin KO, and effectively reduces the fully functional hepatic synthesis of vitamin K dependent clotting factors as well as proteins C, S and Z [25].
Dietary vitamin K is remodeled by gut microbiota and influences community composition
Published in Gut Microbes, 2021
Jessie L. Ellis, J. Philip Karl, Angela M. Oliverio, Xueyan Fu, Jason W. Soares, Benjamin E. Wolfe, Christopher J. Hernandez, Joel B. Mason, Sarah L. Booth
The results presented here nonetheless suggest MKn may be an important commensal factor in the gut, presenting a potentially novel role for vitamin K as a modulator of gut microbial composition. The relevance of gut bacterially produced menaquinones to human health (at least for known functions of vitamin K) has long been speculative.27 In the host, vitamin K functions as a cofactor for the carboxylation of vitamin K-dependent proteins involved in diverse functions such as blood clotting and regulation of calcification.28 Historically, gut bacteria were thought to contribute up to 50% of the vitamin K requirement of the host. However, there is no known mechanism of vitamin K absorption from the colon,29 and cofactor activity of vitamin K decreases with increasing sidechain length.30 Furthermore, vitamin K inadequacy in the host is created when vitamin K is removed from the diet,31 implying that the majority of the human vitamin K requirement comes from the diet. Gut bacterially produced MKn may instead contribute indirectly to human health through modulation of gut microbiota composition, and our results suggest that dietary vitamin K may be an influential factor in these dynamics. Vitamin B12 has similarly been demonstrated to be remodeled by gut bacteria and has been proposed to be a modulator of gut microbial ecology.32 Collectively, these data further the understanding of micronutrient-microbiota interactions.