Osteoporosis: Vitamin K for Bone Quality and Strength

Research has recognized an important role for vitamin K, which is to contribute substantially to the integrity of bones.

Vitamin K is a fat-soluble vitamin; therefore, poor absorption of fat can contribute to a deficiency of vitamin K. Some health conditions that can cause impaired absorption of fat include pancreatic disease, celiac disease, and gallbladder disease.

The World Health Organisation estimates there are 200 million Osteoporosis sufferers worldwide and, according to Osteoporosis Australia, 25 percent of Australian women and 17 percent of men will develop a bone fracture due to osteoporosis, with total incidence expected to rise 83 percent by 2011.

The Nurses Health Study followed 72,327 women between 38 and 63 years of age for 10 years. The researchers found that women with the lowest intake of vitamin K had a 30% higher risk of hip fracture than women with the highest intake of vitamin K. They concluded there was a lower risk of hip fracture in middle-aged and older women with moderate and high intakes of vitamin K than in those with a low intake. (Am J Clin Nutr. 1999;69(1):74-79)

Researchers reporting in The American Journal of Clinical Nutrition in May 2000 found that men and women with the highest intake of dietary vitamin K had only 35% of the risk of a hip fracture as opposed to those with the lowest intake of vitamin K (approximately 250 mcg per day compared to 50 mcg per day). The study involved over 800 elderly men and women participating in the Framingham Heart Study. (Am J Clin Nutr. 2000;71(5):1201-1208).

There are three forms of vitamin K:

Vitamin K1, or phylloquinone, is found naturally in plants. Vitamin K2, or menaquinone, is made by the bacteria that line the gastrointestinal tract. Vitamin K3, or menadione, is a synthetic form that is man made.

Although vitamin K2 is made by bacteria lining the gastrointestinal tract, it is not clear how much of it is absorbed into the body. Therefore, it is important to eat a diet with adequate amounts of vitamin K.

Researchers in Japan reporting in the Journal of Bone and Mineral Metabolism noted that recent studies have reported that vitamin K reduces vertebral and hip fractures without increasing bone mass in patients with osteoporosis, suggesting that vitamin K could affect bone quality. (J Bone Miner Metab. 2001;19(3):146-9).

Japanese researchers reporting in the journal Nutrition in 2001 observed a large geographic difference in blood levels of vitamin K2 in postmenopausal women. They noted that Japanese women in Tokyo had significantly higher levels of vitamin K2 than Japanese women in Hiroshima and British women have much lower levels than both.

They also noted that natto, which contains a large amount of vitamin K2, is eaten frequently in Tokyo but seldom in Hiroshima. Analysing the relationship between the regional difference in natto intake and the incidence of fractures they found a significant association between the incidence of hip fractures in women and natto consumption in each region throughout Japan.

As previously noted, British women have significantly lower levels of vitamin K2, suggesting the possibility that higher vitamin K2 blood levels from natto consumption may contribute to the relatively lower fracture risk in Japanese women. (Nutrition. 2001 Apr;17(4):315-21).

Norwegian researchers noted that the level of vitamin K1 in the Norwegian diet appears to be lower than the recommended dietary allowance and that it is possible that the high incidence of osteoporosis in Norway may be due to the low dietary intake of vitamin K. (Tidsskr Nor Laegeforen. 2004 Jun 17;124(12):1650-4).

In April 2004, a Japanese researcher reporting in the journal Clinical Calcium, reviewed the literature up to that date and noted that vitamin K intake from the diet is reduced with aging and low vitamin K intakes are associated with an increased incidence of hip fractures and an increase of under carboxylated osteocalcin in elderly men and women. He concluded that Vitamin K2 treatment is effective for the prevention of fractures, but not for the increase of bone mineral density in osteoporosis.

Although he came to the conclusion that vitamin K2 did not increase bone mineral density, he stated that vitamin K2 administration could be a potential treatment to improve bone quality. (Clin Calcium. 2004 Apr;14(4):621-6).

Low vitamin K nutritional status is associated with increased fracture risk but is inconsistently related to bone mineral density (BMD), suggesting that vitamin K may affect components of bone strength not measured by BMD, such as microarchitecture. (Osteoporos Int. 2006 Jan 6:1-8).

Vitamin D and Vitamin K for increased bone mineral density.

The following demonstrates the importance of vitamin D for bone mineral density. Vitamin D is needed for the absorption of calcium and is essential for bone health.

Combined administration of vitamin D3 and vitamin K2 potentially stimulates bone formation (mineralization) in patients with primary osteoporosis, resulting in an increase in lumbar bone mineral density. (Clin Calcium. 2002 Jul;12(7):955-65).

As can be seen by the above studies and studies below, vitamin K improves bone quality and strength. The addition of vitamin D3 (with or without increased calcium intake) also helps increase bone mineral density.

In 2002 researchers at Osaka Medical College in Japan demonstrated this fact. Women with low vertebral bone mineral density (osteopenia and osteoporosis) were enrolled for the study. One group (43 participants) was given vitamin K2 supplementation. Another group (43 participants) were supplemented with vitamin K2 and vitamin D3 combined. The study lasted 2 years, and bone mineral density was measured prior to therapy and after.

The group supplemented with both vitamin K2 and vitamin D3 for 24 months showed significantly increased bone mineral density, while the group given vitamin K2 alone showed only a small increase. (Maturitas. 2002 Mar 25;41(3):211-21).

In July 2005, Japanese researchers reviewed the literature to date. Reporting in the journal Clinical Calcium, they noted that recent clinical studies have shown that the occurrence of new fractures does not always depend on bone mineral density. Therefore bone quality has become an important issue in osteoporosis research.

They carried out a study to investigate the effectiveness of treating rats with a low magnesium diet. Results revealed that the low magnesium diet resulted in reduced bone strength without decreasing bone mineral content. Vitamin K2 increased bone strength without influencing bone mineral content suggesting that the vitamin may improve bone quality. (Clin Calcium. 2005 Jul;15(7):49-55).

In August 2005 American researchers reported in a review that the results of two dose-response studies have indicated that the amount of vitamin K needed for optimal gamma-carboxylation of osteocalcin is significantly higher than what is provided through diet alone and that current dosage recommendations should be increased to optimize bone mineralization. (Am J Health Syst Pharm. 2005 Aug 1;62(15):1574-81. Review).

Evidence suggests that dietary phylloquinone (vitamin K1) intake of less than 100 micrograms daily might not be optimal for bone health. Low intake of vitamin K could contribute to osteoporosis and subsequent fracture due to the undercarboxylation of osteocalcin. (Canadian family physician. 2004 Jul;50:993-7).

The vitamin K that I recommend is vitamin K1, which is natural and not toxic at even 500 times the RDA. Vitamin K2, which is made in your body and also produced by fermented foods, is also a superior form of vitamin K. (Dr Mercola).

Vitamin K levels tend to decrease with age whilst the risk of fracture increases.

Family physicians need to be aware of the importance of encouraging adequate vitamin K intake, particularly among institutionalized elderly people, to prevent increased bone resorption. (Canadian family physician. 2004 Jul;50:993-7).

Does Hormone Replacement Therapy (HRT) increase bone mineral density?

Researchers at Toyama Medical and Pharmaceutical University, Japan, noted in 2002 that estrogen increases bone mineral density (BMD) for 2 or 3 years, and only maintains BMD thereafter.

They carried out a study involving 94 patients with postmenopausal osteoporosis. All patients were placed on HRT for more than 1 year. Ten patients whose bone mineral density had increased up to a plateau and showed a decreasing trend thereafter while they were receiving HRT were placed on HRT in combination with vitamin K2.

After supplementation with vitamin K2 for 12 months their bone mineral density increased significantly. They concluded that vitamin K2 is a good therapeutic option for patients with postmenopausal osteoporosis who are placed on HRT. (J Bone Miner Metab. 2002;20(4):235-9).

Astronauts suffer from osteoporosis, being in a weightless environment which results in a calcium, vitamin D, and vitamin K deficiency.

Japanese researchers wrote in a review that high calcium intake and vitamin D supplementation during space flight prevents an elevation of blood calcium levels through increased calcitriol levels, while vitamin K counteracts the decrease in bone formation. A note of importance here is that vitamin D supplementation increases calcium absorption thereby preventing the elevation of blood calcium levels. (Keio J Med. 2005 Jun;54(2):55-9. Review).

In a study done on Russian cosmonauts, levels of free osteocalcin skyrocketed within 4 days. This means it was not being utilized. During the 179 day Euromir 95 mission, investigators administered 10 mg of vitamin K from in-flight day 86 to day 136 to one astronaut. During and after supplementation, bone formation markers increased significantly during this part of the mission (his levels returned to normal). Therefore, vitamin K seems to play a significant role in bone turnover during space flight. (Nutrition. 2002 Oct;18(10):853-6. Review).

Vitamin K2 (menatetrenone, MK-4) has been clinically used in the treatment of patients with osteoporosis in Japan, Korea and Thailand. (Clin Calcium. 2005 Apr;15(4):605-10. Review).

Excellent sources of vitamin K include: spinach, Brussels sprouts, Swiss chard, carrots, green string beans, asparagus, red bell peppers, strawberries and eggs. Very good sources include tomatoes, and green peas. Freezing food can decrease its vitamin K content. (World’s Healthiest Foods).

Vitamin K levels tend to decrease with age whilst the risk of fracture increases. Therefore, it is important for older individuals to include foods containing vitamin K in their diet. Leafy green vegetables are also rich sources of calcium and boron which are important for bone health.

Anticoagulant medications, such as Coumadin, are designed to decrease clotting by interfering with vitamin K.

Vitamin K participates in bone metabolism and, since oral anticoagulants antagonize vitamin K, their use may increase the risk of osteoporosis. Long-term exposure to oral anticoagulation is associated with an increased risk of vertebral and rib fractures. (Arch Intern Med. 1999 Aug 9-23;159(15):1750-6).

References

Feskanich D, Weber P, Willett WC, Rockett H, Booth SL, Colditz GA. Vitamin K intake and hip fractures in women: a prospective study. Am J Clin Nutr. 1999;69(1):74-79.

Booth SL, Tucker KL, Chen H, et al. Dietary vitamin K intakes are associated with hip fracture but not with bone mineral density in elderly men and women. Am J Clin Nutr. 2000;71(5):1201-1208.

Kaneki M. [Vitamin K2 as a protector of bone health and beyond] Clin Calcium. 2005 Apr;15(4):605-10. Review. Japanese.

Kaneki M, Hedges SJ, Hosoi T, Fujiwara S, Lyons A, et al. Japanese fermented soybean food as the major determinant of the large geographic difference in circulating levels of vitamin K2: possible implications for hip-fracture risk. Nutrition. 2001 Apr;17(4):315-21.

Drevon CA, Henriksen HB, Sanderud M, Gundersen TE, Blomhoff R. [Biological effects of vitamin K and concentration of vitamin K in Norwegian food] Tidsskr Nor Laegeforen. 2004 Jun 17;124(12):1650-4.

Sugiyama T, Kawai S. Carboxylation of osteocalcin may be related to bone quality: a possible mechanism of bone fracture prevention by vitamin K. J Bone Miner Metab. 2001;19(3):146-9.

Kishimoto H. [Vitamin K and bone quality] Clin Calcium. 2004 Apr;14(4):621-6.

Kobayashi M, Hara K, Akiyama Y. [Vitamin K2 and bone quality] Clin Calcium. 2005 Jul;15(7):49-55.

Iwamoto J. [Efficacy of combined administration of vitamin D3 and vitamin K2 for primary osteoporosis] Clin Calcium. 2002 Jul;12(7):955-65. Japanese.

Adams J, Pepping J. Vitamin K in the treatment and prevention of osteoporosis and arterial calcification. Am J Health Syst Pharm. 2005 Aug 1;62(15):1574-81. Review.

Iwamoto J, Takeda T, Sato Y. Interventions to prevent bone loss in astronauts during space flight. Keio J Med. 2005 Jun;54(2):55-9. Review.

Heer M. Nutritional interventions related to bone turnover in European space missions and simulation models. Nutrition. 2002 Oct;18(10):853-6. Review.

Ryan-Harshman M, Aldoori W. Bone health. New role for vitamin K? Can Fam Physician. 2004 Jul;50:993-7. Review.

Hidaka T, Hasegawa T, Fujimura M, Sakai M, Saito S. Treatment for patients with postmenopausal osteoporosis who have been placed on HRT and show a decrease in bone mineral density: effects of concomitant administration of vitamin K(2). J Bone Miner Metab. 2002;20(4):235-9.

Caraballo PJ, Heit JA, Atkinson EJ, Silverstein MD, O'Fallon WM, Castro MR, Melton LJ 3rd. Long-term use of oral anticoagulants and the risk of fracture. Arch Intern Med. 1999 Aug 9-23;159(15):1750-6.

McLean RR, Booth SL, Kiel DP, Broe KE, Gagnon DR, Tucker KL, Cupples LA, Hannan MT. Association of dietary and biochemical measures of vitamin K with quantitative ultrasound of the heel in men and women. Osteoporos Int. 2006 Jan 6;:1-8.

Ushiroyama T, Ikeda A, Ueki M. Effect of continuous combined therapy with vitamin K(2) and vitamin D(3) on bone mineral density and coagulofibrinolysis function in postmenopausal women. Maturitas. 2002 Mar 25;41(3):211-21.

Copyright 2007 Kevin Flatt. Disclaimer: The information contained in this article is presented for information purposes only and is in no way intended to replace professional medical care or attention by a qualified practitioner. It cannot and should not be used as a basis for diagnosis or choice of treatment.