Wednesday May 27, 2009 (foodconsumer.org) -- High doses of Vitamin K help reduce the risk of bone fractures in post-menopausal women, according to a recent article in Nutrition Research.

Though scientists found that high doses of vitamins K1 and K2 had only “moderate increase in bone mineral density,” they stated that use of the vitamins helped “reduce the incidence of clinical fractures.”

Vitamin K1 is found in green leafy vegetables such as lettuce and spinach and provides about 90 percent of the vitamin K in a normal Western diet. Vitamin K2 can be found in meat and makes up about 10 percent of the vitamin K in the diet.

Japanese scientists, led by Jun Iwamotoa from Keio University School of Medicine in Tokyo, reviewed seven clinical trials for the vitamins in relation to bone health in post-menopausal women. The randomized trials involved at least 50 post-menopausal women with a study period of two years or longer. The women were given doses of vitamin K1 ranging from 200 micrograms to 5 milligrams per day and 45 milligrams of vitamin K2, according to nutraingredients.com.

“The review of the reliable literature confirmed the effect of vitamin K1 and vitamin K2 supplementation on the skeleton of post-menopausal women,” wrote researchers, “mediated by mechanisms other than bone mineral density and bone turnover.”