It's "Hip" to Get Enough Vitamin K

By Rosalie Marion Bliss
February 26, 2003

Low dietary vitamin K intake has been associated with an increased risk of hip fracture in men and women. But until recently, little has been known about the association between dietary vitamin K intake and bone mineral density (BMD).

Now scientists funded by the Agricultural Research Service have reported findings which suggest that low dietary vitamin K intake is associated with low BMD in women, though not in men. The lead researcher, Sarah L. Booth, is director of the Vitamin K Research Program at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Mass. She reported the findings in the February issue of The American Journal of Clinical Nutrition. ARS is the U.S. Department of Agriculture's chief scientific research agency.

BMD was measured at the hip and spine in 2,591 men and women, aged 29 to 86 years old, who participated in the Framingham Heart Study 1996-2000. Dietary and supplemental intakes of vitamin K were assessed with the use of a food-frequency questionnaire.

Women with the lowest vitamin K intakes had significantly lower mean BMD at the femoral neck and spine than did those with the highest intakes of the vitamin. The data contribute to an expanding body of research that supports a probable role of dietary vitamin K in reducing age-related bone loss, though more studies are required.

Vitamin K helps certain proteins bind calcium and is required for proper bone mineralization. The study results provide further evidence that a healthy diet containing adequate vitamin K may help to assure adequate bone density and protect against osteoporosis and hip fractures in postmenopausal women. The current recommendation for vitamin K is 90 micrograms (mcgs) a day for women and 120 mcgs for men. Green leafy vegetables and vegetable-derived oils and spreads are good sources of fat-soluble vitamin K.