vitamin K

noun

1
: either of two naturally occurring fat-soluble vitamins essential for the clotting of blood because of their role in the production of clotting factors in the liver:
a
or vitamin K1 : the vitamin C31H46O2 that is produced by plants and obtained especially from green leafy vegetables (such as collards and kale)
b
or vitamin K2 : the vitamin C41H56O2 that is produced by bacteria (as in the intestines of animals) and obtained especially from meat and fermented foods
2
: any of several synthetic compounds closely related chemically to vitamins K1 and K2 and having similar biological activity

Example Sentences

Recent Examples on the Web This results in an increase in an inactive form of vitamin K, which plays a critical role in blood clotting. Beth Mole, Ars Technica, 7 Oct. 2022 Growth factors, peptides, extracts, centella asiatica, and vitamin K are the stars of the Youth Eye Complex. Kiana Murden, Vogue, 27 Oct. 2022 Your body uses vitamin K to build substances such as prothrombin that help your blood to clot when needed. Bruce Y. Lee, Forbes, 8 Oct. 2022 But this enzyme is essential in maintaining appropriate levels of vitamin K in your blood. Bruce Y. Lee, Forbes, 8 Oct. 2022 Prunes have vitamins and minerals that likely work together to protect the bone, including fiber, vitamin K, magnesium, potassium, boron, copper, and polyphenols. Chris Mohr, Phd, Better Homes & Gardens, 30 Sep. 2022 Along with fiber, green beans are a source of folate (important for pregnant women) and vitamin K, which supports bone health and the blood's ability to clot. Cate Geiger Kalus, Country Living, 8 Aug. 2022 In 1951, a person attempting suicide with warfarin recovered fully after treatment with vitamin K, and doctors realized that this drug used in low doses might be effective for people with a tendency to clot too much. Dr. Keith Roach, oregonlive, 6 July 2022 Adams also caution those on blood-thinning medications should be careful with vitamin K supplements, as studies show those can cause blood clots when combined together. Allure, 25 Apr. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'vitamin K.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

Etymology

from the initial letter of Danish & Swedish koagulation coagulation, Norwegian koagulasjon & German Koagulation

First Known Use

1935, in the meaning defined at sense 1

Time Traveler
The first known use of vitamin K was in 1935

Dictionary Entries Near vitamin K

Cite this Entry

“Vitamin K.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vitamin%20K. Accessed 9 Dec. 2022.

Kids Definition

vitamin K

noun
: any of several vitamins that are needed in order for blood to clot properly

Medical Definition

vitamin K

noun
1
: either of two naturally occurring fat-soluble vitamins that are essential for the clotting of blood because of their role in the production of prothrombin in the liver and that are used in preventing and treating hypoprothrombinemia and hemorrhage:
a
: a yellow oily naphthoquinone C31H46O2 that is obtained especially from alfalfa or made synthetically and that has a fast, potent, and prolonged biological effect, is effective orally, and is useful especially in treating hypoprothrombinemia induced by anticoagulant drugs

called also phylloquinone, phytonadione, vitamin K1

see mephyton
b
: a pale yellow crystalline naphthoquinone C41H56O2 that is obtained especially from putrefied fish meal and is synthesized by various bacteria (as in the intestines of humans and higher animals) and that is much more unsaturated than vitamin K1 and slightly less active biologically

called also menaquinone, vitamin K2

2
: any of several synthetic compounds that are closely related chemically to vitamins K1 and K2 but are simpler in structure and that have similar biological activity
especially : menadione
Last Updated: - Updated example sentences
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