title: Effects of a typical acute oral calcium load on arterial properties and endothelial function in healthy subjects.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  In this acute, cross-over, random-order intervention, 11 young and healthy vitamin D-sufficient volunteers (8 women/3 men, 33±6.1 years, body mass index 22.6±2.3 kg/m(2)), ingested 600 mg of calcium twice, once as calcium 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.
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Yaron
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: V
authors.initials: V
authors.lastname: Roach
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Izkhakov
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Ish-Shalom
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: J
authors.initials: J
authors.lastname: Sack
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Sofer
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Azzam
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Ray
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Stern
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: K M
authors.initials: KM
authors.lastname: Tordjman
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000097:blood / Q000652:urine; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D064368:Healthy Volunteers; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000097:blood / Q000209:etiology; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D011897:Random Allocation; D064167:Recommended Dietary Allowances; D014807:Vitamin D / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; D003404:Creatinine