LE Magazine November 2002
Page 2 of 2
Currently, long-term space travel is not possible for humans because the lack of gravity causes rapid resorption of bone along with suppression of new bone formation. This effect can be mimicked by suspending the tails of rats so that they are not subject to the pull of gravity. Another group of Japanese researchers used this animal model to examine the effects of vitamin K on bone mass. When vitamin K was given orally in high doses-22 mg/kg body weight-the structure of the bones in the rats' tails was maintained at almost normal levels.
Ovarian hormone production has a strong preservative effect on bone mass, and postmenopausal women have the greatest risk of ending up with osteoporosis. Following ovariectomy (removal of the ovaries) in rats, vitamin K was administered. The K supplement attenuated the decline in bone mineral density typically seen after ovariectomy.[20,21] In another study, researchers found that postmenopausal women given one milligram of vitamin K daily for two weeks showed an increase of 70% to 80% in carboxylated Gla-a good sign that calcium is going where it should.
One of the best ways to prevent osteoporosis in old age is to maximize bone density during youth. This can be accomplished with exercise and adequate nutrition during the height of a child's growth phase, and supplemental vitamin K may prove a valuable adjunct to these bone-building efforts. To determine whether nutrient supplementation in youth can increase peak bone mineral density, 168 three-month-old female rats were divided into five groups. One got a control diet; the other groups received either vitamin D, vitamin K, calcium, or vitamins D and K plus calcium. In all four groups with added nutrients, peak bone mineral density (BMD) was higher than in the control group. The greatest improvements in increasing bone density in the short-term was seen in the calcium-only group, but the smallest decreases in bone mineral density (BMD) over the course of the study was seen in the group that got the combination of nutrients. In other words, all three nutrients (calcium, vitamin D and vitamin K) taken together protected against bone loss better than any of them by themselves.
Bone loss is a common complication of cirrhosis of the liver. When patients were given vitamin K, carboxylation of osteocalcin-one of the Gla proteins-significantly improved.
Other benefits of vitamin K
Vitamin K and Coagulation
Coagulation-more commonly known as blood clotting-consists of two separate processes: platelet activation and fibrin formation. The latter process is where vitamin K plays its part, controlling the formation of coagulation factors in the liver. Without these coagulation factors, the fibrin filaments that bind platelets together into a clot cannot form. Vitamin K is also a component of proteins that act as anticoagulants, as well as two bone matrix proteins that are required for normal bone metabolism.* Vitamin K thus provides a crucial balancing effect in the body.
* Blackwell GJ, et al, Inhibition of human platelet aggregation by vitamin K. Thromb Res 1985; 37:103-14.
Furie B, et al, The molecular basis of blood coagulation. Cell 1988;53:505-18.
The benefits of vitamin K don't stop at osteoporosis and heart disease prevention. Further research has demonstrated that this nutrient also relieves inflammation. With age, concentrations in the body of a substance called interleukin-6 (IL-6) increase. IL-6 is a biochemical messenger called a cytokine. It accelerates inflammation when produced out of balance with other cytokines. People who suffer from arthritis and Alzheimer's disease have high IL-6 concentrations, as do blood vessels affected by atherosclerosis. A study performed at the National Research Institute in Italy revealed that subjects with the highest levels of IL-6 were nearly twice as likely to end up with a mobility-related disability.
Diabetics may be poised to benefit from vitamin K supplements more than any other segment of the population. Type II diabetics are more subject to all types of arteriosclerosis; the abundance of sugars and insulin in their systems accelerate the aging process that naturally predisposes people to pathological calcium deposition. The fact that the pancreas contains the second highest concentration of vitamin K in the body hints at its role in blood sugar regulation. Japanese researchers have found that when vitamin K deficiency is induced in rats, the clearance of blood glucose is impaired and insulin release increases-in other words, the rats developed the symptoms of early type II diabetes (i.e. hyperinsulinemia).
Vitamin K's benefits may also be linked to its antioxidant activity. Some research has indicated that vitamin K has free radical-scavenging power comparable to that of vitamin E and coenzyme CoQ10.[27,28] The livers of animals subjected to oxidative stress gained complete protection when given vitamin K, and vitamin K has been found to be 80% as effective as vitamin E at preventing the oxidation of polyunsaturated linoleic acid.
|Bone loss is a common complication of cirrhosis of the liver. When patients were given vitamin K, carboxylation of osteocalcin-one of the Gla proteins-significantly improved.|
If you are using ginger, garlic, ginkgo or aspirin to keep your blood thin and prevent clotting, don't worry that taking supplemental vitamin K will counteract this. While vitamin K does participate in blood coagulation, it prevents platelet aggregation-a process of blood cell clumping that is spurred by increases in oxidative stress. Keep in mind that K also plays a role in activating anti-clotting proteins, even while participating in the blood clotting cascade.
Supplementing vitamin K may also help to prevent Alzheimer's disease. Those with the E4 form of the lipoprotein apoE-about 25% of the population-are known to have increased risk of developing this dreaded disorder. What many don't know is that people who carry the apoE4 gene have been found to have low vitamin K levels. The calcification and development of lesions in blood vessels that feed brain tissues is believed to be one aspect of Alzheimer's development, and further research may reveal an important role for high-dose vitamin K in its prevention.
Vitamin K supplementation guidelines
Generally, 10 mg per day is a good dose for any person interested in optimal health and longevity. Those suffering from osteoporosis may consider taking up to 40 mg a day. Those taking higher doses may wish to have their vitamin K levels evaluated. Ask your doctor or nutritionist to administer the osteocalcin test. This test measures levels of carboxylated osteocalcin, yielding an excellent picture of vitamin K status.
Find out more about Super K
1. Matschiner JT, et al, Mechanism of the effect of retinoic acid and squalene on vitamin K deficiency in the rat. J Nutr 1967;91:303-6.
2. Vermeer C, Schurgers LJ, A comprehensive review of vitamin K and vitamin K antagonists. Hematol Oncol Clin North Am 2000 Apr;14(2):339-53.
3. Wallin R, et al, Arterial calcification: a review of mechanisms, animal models, and the prospects for therapy. Med Res Rev 2001 Jul;21(4):274-301.
|Vitamin K's benefits may also be linked to its antioxidant activity. Some research has indicated that vitamin K has free radical-scavenging power comparable to that of vitamin E and coenzyme CoQ10.|
4. Witteman JC, et al, Aortic calcified plaques and cardiovascular disease (the Framingham Study). Am J Cardiol 1990;66:1060-4.
5. van Noord PA, et al, Mammograms may convey more than breast cancer risk: breast arterial calcification and arteriosclerotic related disease in women of the DOM cohort. Eur J Cancer Prev 1996 Dec;5(6):483-7.
6. NIAMS-NHBLI Working Group, New evidence connecting cardiovascular disease and osteoporosis. September 14-15, 1999, Bethesda, Maryland.
7. Luo G, Ducy P, McKee MD, et al, Spontaneous calcification of arteries and cartilage in mice lacking matrix GLA protein. Nature 1997;386:78-81.
8. Jie KSG, et al, Vitamin K status and bone mass in women with and without aortic atherosclerosis: a population-based study. Calcif Tissue Int 1996;59:352-6.
9. Seyama Y, et al, Comparative effects of vitamin K2 and vitamin E on experimental arteriosclerosis. Internat J Vit Nutr Res 1999;69:23-26.
10. Spronk HM, et al, Matrix Gla protein accumulates at the border of regions of calcification and normal tissue in the media of the arterial vessel wall. Biochem Biophys Res Commun 2001 Nov 30;289(2):485-90.
11. Howe AM, Webster WS, Warfarin exposure and calcification of the arterial system in the rat. Int J Exp Pathol 2000 Feb;81(1):51-6.
12. Browner WS, et al, Non-trauma mortality in elderly women with low bone mineral density. Study of Osteoporotic Fractures Research Group. Lancet 1991;338:355-58.
13. Cappuccio FP, et al, High blood pressure and bone-mineral loss in elderly white women: a prospective study. Lancet 1999;354:971-75.
14. Jie KSG, et al, Vitamin K status and bone mass in women with and without aortic atherosclerosis: a population-based study. Calcif Tissue Int 1996;59:352-6.
15. Kado DM, et al, Vertebral fractures and mortality in older women: a prospective study. Study of Osteoporotic Fractures Research Group. Arch Intern Med 1999;159:1215-20.
16. Yoshihiro S, et al, Long-term oral anticoagulation reduces bone mass in patients with previous hemispheric infarction and nonrheumatic atrial fibrillation. Stroke 1997;28:2390-94.
17. Feskanich D, et al, Vitamin K intake and hip fractures in women: a prospective study. Am J Clin Nutr 1999;69:74-79.
18. Hidaka T, et al, 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.
19. Iwasaki Y, et al, Maintenance of trabecular structure and bone volume by vitamin K(2) in mature rats with long-term tail suspension. J Bone Miner Metab 2002;20(4):216-22.
20. Iwamoto I, et al, Effects of vitamin K(2) on bone of ovariectomized rats and on a rat osteoblastic cell line. Gynecol Obstet Invest 2002;53(3):144-8.
21. Yamaguchi M, et al, Effect of vitamin K2 (menaquinone-7) in fermented soybean (natto) on bone loss in ovariectomized rats. J Bone Miner Metab 1999;17:23-9.
22. Knapen MHK, et al, The effects of vitamin K supplementation on circulating osteocalcin (bone Gla protein) and urinary calcium excretion. Ann Internal Med 1989;111:1001-5.
23. Hirano J, Ishii Y, Effects of vitamin K(2), vitamin D, and calcium on the bone metabolism of rats in the growth phase. J Orthop Sci 2002;7(3):364-9.
24. Shiomi S, et al, Vitamin K2 (menatrenone) for bone loss in patients with cirrhosis of the liver. Am J Gastroenterol 2002 Apr;97(4):978-81.
25. Ferrucci L, et al, Serum IL-6 level and the development of disability in older persons. J Am Geriatr Soc 1999. 47:639-46.
26. Sakamoto N, et al, Low vitamin K intake effects on glucose tolerance in rats. Int J Vit Nutr Res 1999;69:27-31.
27. Mukai K, et al, Stopped-flow kinetic study of vitamin E regeneration reaction with biological hydroquinones (reduced forms of ubiquinone, vitamin K, and tocopherolquinone) in solution. J Biol Chem 1992;267:22277-81.
28. Mukai K, et al, Kinetic study of free radical-scavening action of biological hydroquinones (reduced forms of ubiquinone, vitamin K and tocopherol quinone) in solution. Biochim Biophys Acta 1993,1157:313-17.
29. Ronden JE, et al, Modulation of arterial thrombosis tendency in rats by vitamin K and its side chains. Atherosclerosis 1997;132:61-7.
Back to the Magazine Forum