Vitamin K (phytomenadione) is a fat-soluble vitamin. Known as the clotting vitamin, it is essential to ensure proper blood clotting and bone health. In addition, numerous studies have shown that it contributes to longer life. Low levels of vitamin K increase the risk of bleeding, calcification of blood vessels, and bone fracture. This vitamin is obtained from the diet, but a portion is obtained from our own bodies, since the intestinal microbiota is able to synthesise it. The destruction of the microbiota from excess medication, such as antibiotics, or alcoholism, for example, can reduce the amount of vitamin K in the body.
Genetic variations, as with the VKORC1 gene, have been described that are associated with abnormally low levels of vitamin K.
Table of Contents
What Is Vitamin K and Why Is It Important?
Vitamin K is a fat-soluble vitamin that exists in two main forms: K1 (phylloquinone), found in green leafy vegetables, and K2 (menaquinone), produced by intestinal bacteria and present in fermented foods and animal products. Its most well-known role is in activating proteins involved in blood clotting, preventing excessive bleeding. Additionally, vitamin K is essential for bone metabolism regulation by activating osteocalcin, a protein that helps incorporate calcium into bones, thus strengthening the skeleton and reducing the risk of fractures.
Sources of Vitamin K
Dietary Sources
The most common dietary sources of vitamin K1 include green leafy vegetables like spinach, kale, and broccoli. On the other hand, vitamin K2 is found in fermented foods like natto (a traditional Japanese food made from fermented soybeans) and animal products such as liver and cheese.
Synthesis by the Gut Microbiota
The gut microbiota also plays a crucial role in the production of vitamin K, specifically K2. This vitamin’s synthesis by intestinal bacteria is a process dependent on the balance and diversity of the gut flora. Dysbiosis, or alteration of the microbiota, which can be caused by prolonged antibiotic use, alcoholism, or an inadequate diet, can reduce endogenous vitamin K production, increasing the risk of deficiency.
Factors Affecting Vitamin K Levels
Influence of Diet and Gut Health
Vitamin K levels in the body are directly related to dietary intake and gut health. A diet rich in green leafy vegetables and fermented foods, combined with a healthy gut microbiota, ensures adequate levels of this vitamin. However, certain habits, such as excessive alcohol consumption or chronic antibiotic use, can damage the microbiota and decrease vitamin K production, increasing the risk of deficiency.
Genetic Factors
In addition to diet and gut health, genetic factors also play a significant role in regulating vitamin K levels. Variations in the VKORC1 gene, for example, have been associated with abnormally low levels of this vitamin. The VKORC1 gene encodes for vitamin K epoxide reductase, a key enzyme in the vitamin K regeneration cycle. Mutations in this gene can lead to reduced enzyme activity, resulting in lower availability of active vitamin K in the body.
Consequences of Low Vitamin K Levels
Insufficient vitamin K levels can have several negative health consequences. Among the most severe are an increased risk of bleeding due to inadequate clotting, as well as a higher risk of bone fractures due to poor bone mineralization. Additionally, vitamin K deficiency has been linked to arterial calcification, which could contribute to the development of cardiovascular diseases.
Conclusion
Maintaining adequate vitamin K levels is crucial for bone health, blood clotting, and potentially longevity. A balanced diet rich in vitamin K sources, along with a healthy gut microbiota, is essential to ensure sufficient intake and synthesis of this vitamin. Additionally, it is important to consider the influence of genetic factors, such as variations in the VKORC1 gene, which may predispose individuals to deficiencies. A comprehensive understanding of these factors can help design personalized strategies to maintain optimal vitamin K levels and prevent complications associated with its deficiency.
References
- Shearer, M. J., & Newman, P. (2014). Metabolism and cell biology of vitamin K. Thrombosis and Haemostasis, 110(5), 755-771.
- Schwalfenberg, G. K. (2017). Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health. Journal of Nutrition and Metabolism, 2017, 6254836.
- Vermeer, C., & Schurgers, L. J. (2000). A comprehensive review of vitamin K and vitamin K antagonists. Hemostasis and Thrombosis, 5th Edition. Arnold Publishers.
- Tie, J. K., & Stafford, D. W. (2016). Structural and functional insights into enzymes of the vitamin K cycle. Journal of Thrombosis and Haemostasis, 14(2), 236-247.
