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The Integrative Coronary Heart Disease (CHD) Prevention Program
Published in Mark C Houston, The Truth About Heart Disease, 2023
There are two forms of vitamin K—called K1 and K2—and there are subtypes of each of these. Vitamin K is a fat-soluble vitamin. Vitamin K1 (phylloquinone) is found in plant foods, like leafy greens. Vitamin K2 (menaquinone) is found in animal and fermented foods. However, supplementing with K2 MK 7 is recommended to obtain an adequate blood level in order to prevent CHD, coronary artery calcification, and heart disease. While vitamin K1 is absorbed and used primarily by the liver, vitamin K2 MK 7 is available, and measurable, in the blood. As such, unlike vitamin K1, vitamin K2 does not get sequestered in the liver for only the liver's function. Rather, because it is available in serum blood, it can travel and go to work in other areas of the body.
An Overview of Molecular Nutrition
Published in Nicole M. Farmer, Andres Victor Ardisson Korat, Cooking for Health and Disease Prevention, 2022
Vincent W. Li, Catherine Ward, Delaney K. Schurr
Vitamin K1, or phytomenadione, is the most common form of vitamin K in the diet and is found mainly in green leafy vegetables. It’s most commonly known for its role in blood clotting. There is another less recognized form of vitamin K known as vitamin K2 (menaquinone) that is particularly notable for its antiangiogenic properties. In 2009, a research group in Japan found that vitamin K2 was capable of suppressing blood vessel growth and through this mechanism also suppressing colon cancer cells (Kayashima et al., 2009). Another study demonstrated this antiangiogenic effect in prostate cancer cells (Samykutty et al., 2013). Vitamin K2 is found in specific age-ripened hard cheeses like Gouda, Edam, and Müenster cheese but not in other cheeses such as feta, mozzarella, Pecorino, or Parmesan (Vermeer et al., 2018).
Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
People are generally encouraged to get their daily requirement of vitamin K through dietary foods because deficiency in vitamin K is rare. In addition, fat-soluble vitamins A, D, E, and K, are stored long-term in the body’s fat tissues, and can cause hypervitaminosis, which is toxic for the body. Vitamin K1 (phylloquinone) is present primarily in green leafy vegetables because it is synthesized in plants through photosynthesis. Vitamin K1 is the main dietary form of vitamin K. Vitamin K2 (menaquinones) have several related chemical subtypes with different unsaturated isoprenyl side chains and are designated as MK-4 through MK-13, based on the length of their side chain. MK-4, MK-7, and MK-9 are the most well studied menaquinones (3, 9, 33, 82–88). Menaquinones, which are predominantly of bacterial origin, are present in modest amounts in various animal-based and fermented foods. Almost all menaquinones, in particular the long-chain menaquinones, are also produced by bacteria in the human gut (82).
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.
Helicobacter pylori antibiotic eradication coupled with a chemically defined diet in INS-GAS mice triggers dysbiosis and vitamin K deficiency resulting in gastric hemorrhage
Published in Gut Microbes, 2020
Lisa Quinn, Alexander Sheh, Jessie L Ellis, Donald E Smith, Sarah L Booth, Xueyan Fu, Sureshkumar Muthupalani, Zhongming Ge, Dylan A Puglisi, Timothy C Wang, Tamas A Gonda, Hilda Holcombe, James G Fox
As AAD diets have a reduced fiber content, and low-fiber diets have been implicated in vitamin K deficiency in rats,28 we compared feces from uninfected mice on the low-fiber AAD diet (2/8CTL) with feces from uninfected, age- and sex-matched INS-GAS mice on standard rodent diet (Chow) (Figure 4(e–f)). 2/8CTL mice had increased relative abundance of MK7, MK8, MK9, and MK10 but decreased abundance of MK11, MK12 and MK13 compared to Chow mice (P< .05). Interestingly, both Chow and antibiotic-treated mice experienced a large increase in the relative abundance of MK11 compared to uninfected and antibiotic-free, H. pylori-infected mice on the AAD diet. However, as Chow mice did not develop severe gastric hemorrhage, we concluded MK11 increases in antibiotic-treated mice were not responsible for the phenotype observed. Furthermore, as the blood in the GI of anemic mice was unclotted, we speculated that antibiotic-treated mice experienced a loss of clotting function due to the loss of MKn, specifically MK5 and MK6, which were in lower abundance following antibiotic treatment. Differences in MKn abundances caused by antibiotics were largely lost in POST-PK mice (Figure S4). Interestingly, differences in multiple menaquinones were observed in mice fed diets with either 2 or 8 mg folate/kg of diet but did not lead to anemia or gastric hemorrhage (Figure S4).
Role of vitamin K2 in bone metabolism: a point of view and a short reappraisal of the literature
Published in Gynecological Endocrinology, 2020
A. Capozzi, G. Scambia, S. Migliaccio, S. Lello
Vitamin K2 (vit K2) includes different types of menaquinones (from menaquinone-4 – MK-4 – to menaquinone-13 – MK13), a group of chemicals characterized by a naphthoquinone ring and a side variable length chain. The chemical formulation of vit K2 is MK_n (MK-2 to MK-14) where ‘n’ stays for the number of chains of isoprenoid, which are mainly unsaturated; in contrast, forms of menaquinones, except for MK-4, which are produced by anaerobic bacteria present in the colon, have saturated prenyl units [1]. All types of vitamin K differ in their biological actions, due to discrepancies in enzyme affinity and tissue distribution. Vitamin K1 is mainly stored in the liver; thus, it plays a pivotal role in synthesis of coagulation proteins, while vit K2 is extensively distributed in the human body [1]. In particular, vit K2 properties were largely investigated since this fat-soluble compound seems to be involved in different physiological processes [1]. Specifically, the role of vit K2 in maintenance of bone integrity assumed growing interest in bone biology and treatment of osteopenia/osteoporosis.