How Vitamin K Affects Bones

Vitamin K's most prominent role in health is making proteins important in the blood-clotting process. Vitamin K may also play an important role in bone health, and consuming increased amounts of vitamin K could reduce the risk for bone conditions such as osteoporosis.

Significance

Vitamin K helps the blood clot normally, particularly important when an injury occurs. While some intestinal bacteria in the human body make vitamin K, most of it comes from diet. Symptoms of a vitamin K deficiency usually involve abnormal bleeding, such as excessive nosebleeds or blood in the urine and stools. The Food and Nutrition Board recommends women consume 90 mcg of vitamin K daily, while men should have 120 mcg.

Bone Health

Calcium is the most important mineral for bone health, and vitamin K plays a role in normal calcium absorption. The University of Maryland Medical Center notes that lower levels of vitamin K have been found in osteoporosis patients, while higher levels of vitamin K correlate with more bone density. The National Osteoporosis Foundation also notes that vitamin K, along with other minerals such as magnesium and phosphorus, are important to bone health.

Research

A 2001 article in the journal "Nutrition" states that vitamin K may work alongside vitamin D -- a nutrient instrumental in calcium absorption in the bones -- to increase bone density. A 2007 study review in "Nutrition in Clinical Practice" notes that studies consistently link vitamin K with greater bone density and reduced bone fracture risk. The review also finds that typical vitamin K consumption doesn't provide enough vitamin K to provide benefits to bone health; the author recommends more research looking into how to optimize and increase vitamin K intake for bone health.

Sources of Vitamin K

Vitamin K is found mainly in green and leafy vegetables, particularly turnip greens, collard greens, broccoli, spinach, lettuce and kale. Other sources include avocados and prunes as well as soybean, canola and olive oil. One cup of cooked turnip greens contains 851 mcg of vitamin K. A diet rich in leafy greens is recommended to get adequate vitamin K. Vitamin K supplements are currently recommended mainly for individuals with symptoms of vitamin K deficiency.