Vitamin K and bone health
Approximately 54 million Americans have osteoporosis, or low bone density that puts them at higher risk for developing osteoporosis. According to the National Osteoporosis Foundation, approximately 50% of women and 25% of men age 50 and older will break a bone due to osteoporosis.1 After age 50, a woman’s risk of dying from a hip fracture is equal to her lifetime risk of dying from breast cancer.2
Osteoporosis is a bone disease that results in bones becoming weak and brittle and more prone to breaking due to a fall, or in serious cases, from sneezing or bumping into furniture. The word ‘osteoporosis’ actually means ‘porous bone’. When our bones lose density or mass, they are more likely to break. Osteoporotic bone breaks occur most often in the hip, spine or wrist but can happen in other bones as well. Osteoporosis causes 2 million broken bones and $19 billion dollars in related health costs every year. 20% of seniors who break a hip die within one year due to complications, and many people will require long-term nursing home care.1
Osteoporosis is not part of normal aging, and in fact we can start protecting our bones early in life by getting regular exercise, avoiding smoking, limiting alcohol, and eating an overall healthy diet that includes plenty of calcium, vitamin D, and other nutrients that support strong bones, including vitamin K.1
The role of vitamin K in healthy bones
Vitamin K is an essential nutrient that works with calcium to build strong bones.2 People who have higher blood levels of vitamin K have higher bone density, while at the opposite end of the spectrum people with low blood levels of vitamin K are more likely to have osteoporosis.3 In one study of hip fracture risk, women who consumed more than 109 µgm of Vitamin K per day, the amount found in ½ cup broccoli or 1 cup of endive, had a decreased risk of hip fracture compared to women with lower vitamin K intake.2
How much vitamin K do we need?
The optimum daily intake of vitamin K is 90 µgm (micrograms) per day for women and 120 µgm per day for men.2 According to the third National Health and Nutrition Examination Survey in 1994, approximately half of adults in the U.S. consume less than the recommended amount of vitamin K.4 Vitamin K plays an important role in blood clotting as well as working together with calcium to build stronger bones.3
Risks with increased vitamin K intake
Excessive amounts of vitamin K from food is not advised for people who take warfarin (Coumadin®) for anti-coagulation. Warfarin is a vitamin K antagonist, making your blood clot more slowly. Also, people who use dialysis for kidney disease need to monitor vitamin K intake closely.3
Food sources of vitamin K
Vitamin K is made by plants and is found in their chlorophyll, which also gives plants their green color.3 Good dietary sources of vitamin K include kale, collard greens, fresh spinach, Brussels sprouts, asparagus, and dark green lettuce. Due to food processing, the vitamin K2 content of food has significantly dropped.2 Freezing foods may destroy vitamin K, but heating does not affect it.3
Incorporate these 6 nutrition strategies for optimal bone strength to reduce your risk of developing osteoporosis5:
Include 3-4 servings of milk or yogurt each day for calcium and vitamin D. If you prefer non-dairy milk or yogurt, choose products fortified with calcium and vitamin D.
Canned sardines and salmon with bones are good sources of calcium.
Choose two servings per week of fatty fish that contain vitamin D: mackerel, salmon, tuna or sardines.
Include at least 4-6 cups per day of a wide variety of fruit and vegetables for magnesium and potassium, two nutrients that play an important role in overall health as well as bone density.
Choose at least 2 cups per day of dark green vegetables for optimum vitamin K intake.
Limit alcohol and caffeinated beverages which can decrease calcium absorption.
Vitamin K in foods6
|Food/serving size||Vitamin K µgm|
|½ cup broccoli||110|
|½ cup Brussels sprouts||150|
|½ cup cooked kale||550|
|½ cup raw kale||274|
|1 cup raw endive||116|
|½ cup beet greens||350|
|½ cup raw collard greens||418|
|½ cup cooked collard greens||530|
|½ cup cooked spinach||444|
|1 cup raw spinach||145|
|½ cup mustard greens||210|
|½ cup Swiss chard||287|
National Osteoporosis Foundation. What is Osteoporosis and What Causes It? https://www.nof.org/patients/what-is-osteoporosis/ Accessed 12-21-17
Price CT, Langford JR, Liporace FA. Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet. The Open Orthopaedics Journal. 2012;6:143-149. doi:10.2174/1874325001206010143.
University of Maryland Medical Center. Vitamin K. http://www.umm.edu/health/medical/altmed/supplement/vitamin-k Last reviewed 7/13/2013. Accessed 12-21-17
Burt VL, Harris T. The third National Health and Nutrition Examination Survey: contributing data on aging and health. Gerontologist. 1994 Aug;34(4):486-90.
National Osteoporosis Foundation. Nutrition. https://www.nof.org/patients/treatment/nutrition/ Assessed 12-26-17
VA Nutrition and Food Services. Vitamin K Content of Food. https://www.nutrition.va.gov/docs/UpdatedPatientEd/VitaminKContentofFoods-nationalboard03-2011.pdf Assessed 12-26-17