Letter to the editor

DOI: https://doi.org/10.4414/smw.2011.13300

I read with great interest the excellent review article “Calcium supplementation, osteoporosis and cardiovascular disease” by Drs. Meier and Kraenzlin [1]. They note several mechanisms linking calcium supplements with cardiovascular disease and I would like to add an additional point to this review. In recent years, several authors have included vitamin K as a possible protective factor, interacting with calcium and vitamin D in the maintenance of both bone and cardiovascular health [2]. There are two main forms of vitamin K: vitamin K1 (found in vegetables) and vitamin K2 (produced by bacteria in the intestine and in fermented foods) [2]. From a theoretical point of view, vitamin K might potentially decrease the burden of vascular calcifications by maintaining an adequate activity of matrix Gla protein, a vitamin K2 dependent, gamma-carboxylated protein which inhibits vascular calcification [3]. In the Rotterdam Study, an adequate intake of vitamin K2 was associated with reduced risk of coronary heart disease and severe aortic calcification [4]. Likewise, oral anticoagulant treatment with warfarin antagonises vitamin K, and several studies have shown an association between warfarin therapy and severe cardiovascular calcifications [5–7]. It is therefore plausible that, among other mechanisms, without an adequate vitamin K2 intake, the increased calcium intake through supplementation could have a detrimental effect on cardiovascular health through increased vascular calcification.

Reply to this Letter to the Editor:http://www.smw.ch/content/smw-2011-13301/

References

  1 Meier C, Kraenzlin ME. Calcium supplementation, osteoporosis and cardiovascular disease. Swiss Med Wkly. 2011;141:w13260 http://www.smw.ch/content/smw-2011-13260/ .

  2 Vermeer C, Braam L. Role of K vitamins in the regulation of tissue calcification. J Bone Miner Metab. 2001;19:201–6.

  3 Fusaro M, et al. Vitamin K, bone fractures, and vascular calcifications in chronic kidney disease: an important but poorly studied relationship. J Endocrinol Invest. 2011;34:317–23.

  4 Geleijnse JM, et al. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: The Rotterdam Study. J Nutr. 2004;134:3100–5.

  5 Holden RM, et al. Warfarin and aortic valve calcification in hemodialysis patients. J Nephrol. 2007;20:417–22.

  6 Krüger T, Floege J. Coumarin use in dialysis patients with atrial fibrillation – more harm than benefit? Nephrol Dial Transplant. 2009;24:3284–5.

  7 Schurgers LJ, Aebert H, Vermeer C, Bültmann B, Janzen J. Oral anticoagulant treatment: friend or foe in cardiovascular disease? Blood. 2004;104:3231–2.