Written by Jessica Patella, ND. This study has shown that supplementing a diet with a form of vitamin K2 in healthy postmenopausal women improved bone health over a period of 6-12 months.
Osteoporosis is a major concern for postmenopausal women, effecting over 4.5 million women over the age of 50 years (1). Menaquinone-4 (MK-4) is administered in high doses as a pharmaceutical drug in Japan for the treatment of osteoporosis (2). Recent research found supplementing low dosages of menaquinone-4 (MK-4), improved bone health in healthy postmenopausal women over a period of 6-12 months (2).
There are two major forms of vitamin K: vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K 1 is found in green leafy vegetables and vitamin K2 is produced by bacteria or found in animal tissues (2).
A total of 48 postmenopausal women 50-65 years of age from Japan participated in the study (2). The women were randomly divided into two groups: the placebo group and the menaquinone-4 group. The menaquinone-4 group received 1.5 mg per day of menaquinone-4, a type of vitamin K2 (a total of 6 tablets, daily, after breakfast) (2). The Recommended Daily intake for Vitamin K is 80 mcg.
Blood and urine samples were collected at baseline, 6 months and 12 months (2). After 6 and 12 months, blood levels of osteocalcin (uncarboxylated) were significantly lower in the menaquinone-4 group than in the control group (6 months: 2.8 +/- 1.0 vs. 4.2 +/- 2.1 ng/ml, p<0.005; 12-months: 3.6 +/-1.5 vs. 4.9 +/-2.3 ng/ml, p=0.018). High levels of blood osteocalcin are an indicator of vitamin K deficiency in the bone (3). High levels of osteocalcin (uncarboxylated) are associated with low bone mineral density and increased risk of fractures due to osteoporosis (4). These results indicate improvement with the menaquinone-4 supplementation (2). There was no change in the control group from baseline (2).
Pentosidine, a marker for increased fracture risk, was significantly lower in the mentaquinone-4 group compared to the control group at 6 and 12-months (P=0.009 and P=0.007), indicating improvement with supplementation of mentaquinone-4 (2).
The final marker of improvement was observed in the bone mineral density in the forearm, which significantly decreased in the control group from 6 months to 12 months (p<0.001), while there was no significant decrease in the menaquinone-4 group. This indicates a bone loss in the control group and no bone loss in the supplemented group in the forearm (2).
In conclusion, a low dose (1.5 mg per day) of menaquinone-4, a form of vitamin K2, in postmenopausal women improved bone health. Improvement was observed by decreasing blood concentrations osteocalcin (uncarboxylated) and pentosidine (2). This was the first study of its kind to research a low-dose of menaquinone-4 in healthy postmenopausal women. Future research with more participants should still be conducted.
Source: Koitaya, Noriko, et al. “Low-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese women.” Journal of bone and mineral metabolism 32.2 (2014): 142-150.
© 2013, The Japanese Society for Bone and Mineral Research and Springer Japan
Posted July 15, 2013.
Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health. She earned her ND from Southwest College of Naturopathic Medicine in Tempe, AZ, and is a member of the North Carolina Association of Naturopathic Physicians. Visit her website at www.awarenesswellness.com.
References:
- Centers for Disease Control and Prevention. Osteoporosis. Fast Stats.
- Koitaya N, et al. Low-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese women. J Bone Miner Metab. 2013 doi: 10.1007/s00774-013-0472-7.
- Szulc P, Chapuy MC, Meunier PJ, Delmas PD (1993) Serum undercarboxylated osteocalcin is a marker of the risk of hip fracture in elderly women. J Clin Invest 91:17–74.
- Knapen MH, Jie KS, Hamulyak K, Vermeer C (1993) Vitamin K-induced changes in markers for osteoblast activity and urinary calcium loss. Calcif Tissue Int 53:81–85.
