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Dietary calcium induces regression of left ventricular hypertrophy in hypertensive non-insulin-dependent diabetic
M B Zemel1, P C Zemel, R J Bryg
1Department of Nutrition and Food Science, Wayne State University, Detroit, Michigan.
Insights
Calcium supplementation in type II diabetic hypertensives reduced blood pressure and vascular resistance. This intervention also led to partial regression of left ventricular hypertrophy (LVH) in these patients.
Area of Science:
- Cardiovascular Medicine
- Endocrinology
- Nephrology
Background:
- Dietary calcium may influence intracellular calcium levels in type II diabetic hypertensives.
- Left ventricular hypertrophy (LVH) is a common complication in hypertensive individuals.
Purpose of the Study:
- To assess the effects of calcium supplementation on forearm blood flow (FBF), vascular resistance (FVR), and left ventricular mass (LVM) in type II diabetic hypertensive men with LVH.
Main Methods:
- Seven type II diabetic hypertensive black men with LVH received 600 mg calcium daily for three months.
- Forearm blood flow (FBF), vascular resistance (FVR), and left ventricular mass (LVM) were measured before and after supplementation.
- A control group received atenolol (50 mg).
Main Results:
- Calcium supplementation decreased mean arterial pressure, increased FBF by 18%, and reduced FVR by 20%.
- Left ventricular mass (LVM) decreased by approximately 17% (from 289 to 240 g).
- A significant correlation was observed between changes in FBF and LVM (r = 0.82).
Conclusions:
- Calcium supplementation, sufficient to normalize dietary intake, significantly reduces vascular resistance in black hypertensive diabetic men.
- This intervention promotes partial regression of left ventricular hypertrophy (LVH).
Abstract:
Recent data from this laboratory indicate that dietary calcium supplementation causes reduced intracellular calcium in type II diabetic hypertensives. Consequently, we have assessed the effects of calcium supplementation on forearm blood flow (FBF) and vascular resistance (FVR) and left ventricular mass (LVM) in seven type II diabetic hypertensive black men with left ventricular hypertrophy (LVH) maintained off antihypertensive treatment for four weeks and then supplemented with 600 mg calcium per day for three months. A comparable group of black diabetic hypertensive patients treated with atenolol (50 mg) served as controls. LVM was determined by M-mode echocardiography and FBF and FVR by electrical impedance plethysmography at the end of the four week baseline and the 12 week supplementation periods. Calcium supplementation resulted in a decrease (P less than .05) in mean arterial pressure (from 121 +/- 4 to 114 +/- 3 mm Hg) which was accompanied by an 18% increase in FBF and a 20% reduction in FVR (P less than .05). LVM decreased from 289 +/- 22 at baseline to 240 +/- 22 g at the end of the supplementation period (P less than .02) and there was a significant correlation between changes in FBF and LVM (r = 0.82). Left ventricular end diastolic dimension decreased by 11% (P less than .05). These data indicate that calcium supplementation sufficient to normalize dietary calcium in black hypertensive diabetic men significantly reduces vascular resistance and causes partial regression of LVH.