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Vitamin K Requirements and Dietary Sources

Vitamin Guide

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Updated March 02, 2014

Spinach and vitamin K

Spinach is a great source of vitamin K.

Florin Bleiceanu

A member of the fat-soluble family of vitamins that also includes vitamin D, vitamin E and vitamin A. Vitamin K is important for normal blood clotting and may help to keep your bones strong as you age.

Vitamin K deficiency is rare but may occur after long-term use of antibiotics. It's important to note that people who take blood thinners should consult with their doctors or pharmacists about vitamin K supplementation because taking extra vitamin K can reduce the effectiveness of blood thinners.

Daily Requirements

Males

1 to 3 years: 30 micrograms per day
4 to 8 years: 55 micrograms per day
9 to 13 years: 60 micrograms per day
14 to 18 years: 75 micrograms per day
19+ years: 120 micrograms per day

Females

1 to 3 years: 30 micrograms per day
4 to 8 years: 55 micrograms per day
9 to 13 years: 60 micrograms per day
14 to 18 years: 75 micrograms per day
19+ years: 90 micrograms per day

Vitamin K is found in dark green leafy vegetables, cabbage, cauliflower, broccoli, and soybeans, and it's also synthesized in your digestive tract by friendly bacteria.

Sources:

Vitamin K. http://www.nlm.nih.gov/medlineplus/ency/article/002407.htm.

Otten JJ, Hellwig JP, Meyers LD. "Dietary Reference Intakes: The Essential Guide to Nutrient Requirements." IOM, 2006.

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