Effects of a typical acute oral calcium load on arterial properties and endothelial function in healthy subjects

BACKGROUND/OBJECTIVES: Often recommended, calcium supplements have been incriminated as increasing the risk of cardiovascular events, whereas dietary calcium has generally been exonerated. As a first step to address the vascular safety of Such dietary Measures at the clinical nutritionist toolbox, we sought to determine and compare the acute effects of a typical oral calcium load, provided either as a supplement or as food, on vascular parameters assessed noninvasively in healthy subjects. SUBJECTS/METHODS: In this acute, cross-over, random-order intervention, 11 young and healthy vitamin D-sufficient volunteers (8 women/3 Men, 35 +/- 6.1 years, body mass index 22.6 +/- 2.3 kg/m(2)), ingested 600 mg of calcium twite, Once as caldiurn, citrate and the Other time from dairy products. Biochemical; vascular and hemodynamic parameters, before and 2 h after each challenge, were compared. Arterial stiffness was studied by measuring pulse wave velocity, augmentation index and large (C1) and small (C2) arterial compliance. Endothelial function was assessed by flow-mediated dilation (FMD). RESULTS: Despite effective calcium loading accompanied by a significant 60% parathyroid hormone level reduction On both occasions, there were no clinically significant changes in the vascular parameters neither in comparison with baseline, nor between the studies. A decrease in heart rate with no change in cardiac output was noticed after the supplement. CONCLUSIONS: An effective calcium load has no clinically significant untoward effect on the vascular properties of young healthy subjects; regardless of its source. Additional studies should determine whether this holds true for Chronic-calcium supplementation, particularly in subjects with a priori vascular impairment.