vitamin K and osteoporosis

Misleading information about vitamin K is everywhere, including magazine articles that tout green leafy veggies as a “great source for bone-building vitamin K.” Yes, green leafy vegetables are a source of vitamin K, but not the kind that most efficiently prevents osteoporosis. Research shows that it takes 1,000 micrograms of a highly absorbable pharmacological preparation of K1 daily to activate osteocalcin. Unfortunately, humans are incapable of absorbing even one-fifth of that amount from food. On the other hand, we are able to absorb large amounts of vitamin K2 from foods. Studies done in the Netherlands indicate that vitamin K2 was three times more effective than vitamin K1 at raising activated osteocalcin numbers over a 40-day period. Most interesting was that the impact of vitamin K1 leveled off after only three days, while the effect of K2 increased every day of the study.

Reference: Schurgers LJ, Teunissen KJF, Hamulyák K, et al. Vitamin K–containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood 2007, 109: 3279–83.)