Effect of dietary calcium and vitamin D supplementation on blood pressure control following salt loading

Epidemiological and animal studies assert an inverse relationship between calcium intake and risk of clinical hypertension. Nonetheless, there is a paucity of information on the effect of calcium and vitamin D co-administration on sodium chloride (NaCl)induced blood pressure (BP) elevation in apparently healthy normotensive subjects. Hence, this study evaluated this relationship. For a 5-day study period, a group of 10 subjects (Group A) was placed on placebo while another group of 5 subjects (Group B) had dietary NaCl (200 mmol/day) and a third group of 5 subjects (Group C) had dietary NaCl (200 mmol/day) with calcium/vitamin D supplement (625 mg/200 IU). Before and after the 5-day regimen, blood pressure (BP) was measured, and blood, as well as urine samples, were collected from the subjects for evaluation of electrolyte status. Mean arterial BP (MABP) increased (p < 0.01) in group B, but decreased in group C (p < 0.01). Plasma potassium level increased in both groups B and C (p < 0.01). However, while plasma calcium decreased in the two groups (p 0.01), plasma sodium decreased (p < 0.01) only in group C, after the 5-day regimen. Urinary excretion of calcium increased and decreased (p < 0.01) in groups B and C, respectively, a converse of the trend in urinary potassium. Whereas that of sodium increased in both groups B and C (p < 0.01). These results suggest that oral Ca and Vitamin D supplementation may prevent a rise in BP in subjects on a high NaCl diet by attenuating plasma Na retention, with an augmented urinary excretion. (c) 2021 The Authors. Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.

Automated summary

This study examined the effect of calcium and vitamin D supplementation on blood pressure in subjects on a high salt diet. The results suggest that oral supplementation of calcium and Vitamin D may prevent a rise in blood pressure by reducing plasma sodium retention and increasing urine excretion in subjects on a high NaCl diet.