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==What is Vitamin K (Menaquinone-7, MK-7)?==

==What is Vitamin K (Menaquinone-7, MK-7)?==

Vitamin K is category of '''essential fat-soluble vitamins''' that consist of napthaquinone rings with aliphatic side-chains. They are found naturally-occurring in the diet as one of two forms: '''plant-derived vitamin K₁ (phylloquinone) or animal-derived vitamin K₂ (menaquinone-7 or MK-7)''', the latter is derived from bacterial synthesis in the gastrointestinal tract. Vitamin K₃ (menadione) is a synthetic compound, often used as a dietary supplement in animal feeds<ref name="NRC">National Research Council (NRC). Vitamins. In Nutrient Requirements for Dogs and Cats. 2006 Washington, DC: National Academies Press p.210-212.</ref>. However this form of vitamin K (menadione) is not biologically active, until it is converted to vitamin K₂ (MK-7) by intestinal microbes prior to absorption. Vitamin K is incorporated into mixed micelles along with dietary [[Fat Overview - Nutrition|fat]] and absorbed by [[Diffusion - Physiology|diffusion]] across the mucosal surface of the [[Small Intestine Overview - Anatomy & Physiology|small intestine]]. Once in the enterocytes, absorbed vitamin K is incorporated into chylomicrons and released into the [[Lymphatic System Overview - Anatomy & Physiology|lymphatics]] for transport to the [[Liver - Anatomy & Physiology|liver]]. Vitamin K is primarily excreted through [[Bile acids|bile]] in faeces, though significant amounts are also lost through urine.

Vitamin K is category of '''[[Nutrition Glossary#Essential Nutrients|essential]] fat-soluble vitamins''' that consist of napthaquinone rings with aliphatic side-chains. They are found naturally-occurring in the diet as one of two forms: '''plant-derived vitamin K₁ (phylloquinone) or animal-derived vitamin K₂ (menaquinone-7 or MK-7)''', the latter is derived from bacterial synthesis in the gastrointestinal tract. Vitamin K₃ (menadione) is a synthetic compound, often used as a dietary supplement in animal feeds<ref name="NRC">National Research Council (NRC). Vitamins. In Nutrient Requirements for Dogs and Cats. 2006 Washington, DC: National Academies Press p.210-212.</ref>. However this form of vitamin K (menadione) is not biologically active, until it is converted to vitamin K₂ (MK-7) by intestinal microbes prior to absorption. Vitamin K is incorporated into mixed micelles along with dietary [[Fat Overview - Nutrition|fat]] and absorbed by [[Diffusion - Physiology|diffusion]] across the mucosal surface of the [[Small Intestine Overview - Anatomy & Physiology|small intestine]]. Once in the enterocytes, absorbed vitamin K is incorporated into chylomicrons and released into the [[Lymphatic System Overview - Anatomy & Physiology|lymphatics]] for transport to the [[Liver - Anatomy & Physiology|liver]]. Vitamin K is primarily excreted through [[Bile acids|bile]] in faeces, though significant amounts are also lost through urine.

==Why is it Important?==

==Why is it Important?==