VITAMIN K

Vitamin K refers to a group of similar, fat-soluble, compounds. Vitamin K cannot be manufactured by humans and is thus a true vitamin, obtained exclusively from the diet.

Vitamin K is an enzyme cofactor for proteins that are needed for blood coagulation, in particular, factors II, VII, IX, and X, as well as proteins C and S. Vitamin K also assists in controlling the binding of calcium in bones and other tissues.

Vitamin K deficiency can develop in certain conditions, especially in severe gastrointestinal disease. In vitamin K deficiency, blood coagulation is impaired, and uncontrolled bleeding occurs. Additionally, deficiency can lead to osteoporosis (weakened bones), and may promote calcification of arteries and other soft tissues.

Vitamin K is often supplemented in newborns, in individuals with liver or intestinal disease, and to reverse the blood thinning effects of the drug warfarin.

The term “vitamin K” refers to two naturally-occurring compounds, vitamin K1 (phylloquinone) and vitamin K2 (several forms of menaquinone, especially types 4 (K2-4) and 7 (K2-7). Of note, The U.S. Institute of Medicine (IOM) does not distinguish between K1 and K2, and both are counted as vitamin K. Vitamin K supplementation generally involves K1 (phylloquinone), which is the form present in EnergyNeeds®. Humans can convert K1 to K2-4. Gut bacteria can convert K1 into K2-4 and other forms, including K2-7. Vitamin K2-7 is found in some fermented and animal-based products, especially natto and egg yolks. Vitamin K2-7 can be supplemented, but is uncommon due to price.

Despite being fat soluble, vitamin K is broken down very quickly, and rarely reaches toxic levels even with high intakes. Side effects are rare at usual doses used in supplementation.

Laboratory testing can reveal the presence of a deficiency of this nutrient, but is generally not likely to have clinically utility.