Hypothesis: Phytate is an important unrecognised nutrient and potential intravenous drug for preventing vascular calcification

Abstract

Cardiovascular calcification (CVC) associated with conditions such as ageing, diabetes or renal impairment, results from the deposition of hydroxyapatite in the endothelium or media of blood vessels. Key medical management options are directed towards controlling plasma calcium and phosphate concentrations (e.g. parathormone inhibition, phosphate binders, dialysis), enhancing the effect of calcification inhibitors (e.g. fetuin-A, pyrophosphate, vitamin K, osteopontin, matrix Gla protein) and decreasing the effect of promoters of calcification (e.g. vitamin D, lipids, cytokines). Dietary phytate prevents the calcification of ageing in rats and epidemiological data suggest that phytate rich diets are associated with a lower incidence of CVC in the elderly. Intravenous phytate prevents aggressive CVC induced by vitamin D in rats. We propose that phytate should be added to the list of inhibitors of vascular calcification. We further suggest that adequate dietary phytate could prevent mild forms of calcification and that the low phytate content of diets for patients with renal disease can contribute to the increased risk of vascular calcification. It is also our contention that supra-physiological systemic phytate concentrations not achievable orally, might prevent aggressive vascular calcification. Appropriate epidemiological (to determine nutritional value) and clinical studies (evaluating safety and efficacy) are required to confirm, modify or reject our hypothesis.

Keywords: Calciphylaxis; End stage renal disease; Haemodialysis; Hydroxyapatite; Phytate; Vascular calcification.