A review published in the American Journal of Health-System Pharmacy (2005;62(15):1574–1581) examined the growing body of research on vitamin K and its potential role in preventing both osteoporosis and arterial calcification. Vitamin K is required to activate proteins involved in bone structure and mineralization. The review noted that vitamin K1 and vitamin K2 supplements may help maintain bone mass and reduce bone loss, based on both animal and human studies. Several trials also suggest that vitamin K combined with vitamin D may enhance bone-preserving effects.

Vitamin K Intake and Bone Loss in Japanese Women

Research from the Journal of Nutrition (2006;136(5):1323–1328) examined data from the Japanese Population-Based Osteoporosis Study (JPOS), a three-year cohort involving 944 healthy women aged 20–79. Participants completed dietary questionnaires, including measurements of natto consumption—a fermented soybean food naturally rich in vitamin K2 (menaquinone).

Over the three-year follow-up:

  • Postmenopausal women who consumed 160 grams of natto per week experienced less bone loss compared with those who consumed less.

These findings highlight the potential importance of vitamin K–rich foods in skeletal health.

Earlier Evidence Linking Vitamin K With Bone Strength

An earlier article published in the Journal of Nutrition (1995;125:1812–1821) reported that individuals with bone fractures tended to have lower circulating vitamin K levels. The authors noted that vitamin K supplementation was associated with reduced bone loss and lower calcium excretion, though they emphasized that additional research was needed.

Together, these studies suggest that vitamin K status may influence bone metabolism and bone density, especially in postmenopausal women.

Educational only — not medical advice.