Essential for blood clotting; required for bone formation and cell growth.
Useful in the prevention of osteoporosis.
Deficiency is rare in adults and causes impaired blood clotting; it is more common in newborns and can cause severe bleeding. Injections of vitamin K1 are typically given to newborns.
Symptoms of deficiency include easy bruising and bleeding (nosebleeds, bleeding gums, blood in the urine or stool, or heavy menstrual bleeding).
Drugs that deplete: antibiotics, aspirin, phenytoin, phenobarb, cholestyramine, colestipol, orlistat, and mineral oil.
High intake of vitamin K from foods or supplements can reduce the effi cacy of blood-thinning drugs (warfarin).
Most people get adequate vitamin K from the diet and/or a multivitamin.
Food Sources : Green leafy vegetables, cabbage, Brussels sprouts, vegetable oils (canola, soybean, cottonseed, and olive)
Adequate Intake : (mcg/day)* Men = 120 Women = 90 Pregnancy = 90 Lactation = 90
Upper Limit : Not determined
Side Effects : No adverse effects known from foods or supplements; those taking anticoagulant drugs should monitor their intake of vitamin K