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

Abstract

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 (p0.01) 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.

Keywords

• Calcium
• Blood pressure
• Normotensive
• NaCl Sensitivity, Vitamin D