Recommended Amount Of Vitamin K

Vitamin K is a fat-soluble vitamin. The body stores vitamin K rather than excretes it in the urine; however, unlike most fat-soluble vitamins, vitamin K is not stored in a large amount at any one time. Therefore, to get proper amounts for your age and gender, you should add vitamin K to your diet through food. In healthy individuals, vitamin K deficiency is rare. Symptoms include bruising and bleeding easily. Bleeding gums and nosebleeds may be experienced. In infants, deficiency creates the risk of inter-cranial hemorrhaging -- bleeding in the skull -- which is why newborn babies commonly are given a vitamin K shot in the hospital.

RDAs for Children and Adolescents

The recommended dietary allowances, RDAs, for vitamin K changes by age, but they are the same for both genders in children and adolescents. In infants 0 to 6 months of age, the RDA is 2 mcg a day, and this amount goes up to 2.5 mcg a day from age 6 to 12 months, according to the Institute of Medicine Food and Nutrition Board. Children 1 to 3 years of age have an RDA of 30 mcg each day. At 4 to 8 years of age, the RDA is 55 mcg a day, and from age 9 to 13 years the RDA is 60 mcg a day. During age 14 to 18, the RDA is 75 mcg a day. This number remains constant for pregnant and lactating women under the age of 18.

RDAs for Adults

In adults, the RDA is different for men and women. For women age 19 and above, the RDA is 90 mcg a day. This number remains the same in the case of pregnancy and lactation. In men above the age of 19, the RDA is 90 mcg a day. It should be noted that no tolerable upper intake levels -- the maximum safe amount that can be consumed -- have been established. Large doses are not advisable, because excessive vitamin K can cause red blood cells to break down, and liver damage may occur, according to the Colorado State University Extension.

Role of Vitamin K

Vitamin K is important for blood clotting, as it helps to create four of the 13 proteins your body requires for blood to clot. Due to this substantial role vitamin K plays in blood clotting, if you take anticoagulants, such as warfarin, you should work with your healthcare provider to keep your vitamin K levels stable. Vitamin K also is important for building bone, and low levels of vitamin K in the body have been linked to low bone density, notes Harvard School of Public Health.

Sources of Vitamin K

Vitamin K is naturally found in a lot of plant-based foods. Green, leafy vegetables are especially high in vitamin K -- such as collard greens, turnip greens, parsley, Brussels sprouts, broccoli, mustard greens, spinach and kale. Vitamin K is also found in cauliflower, avocado, cabbage, asparagus and certain vegetable oils like olive oil, soybean oil, cottonseed oil and canola oil. Animal foods do not tend to contain significant amounts of vitamin K.