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Controlled trial of low calcium versus high calcium intake in mild hypertension
A Siani1, P Strazzullo, S Guglielmi
1Institute of Internal Medicine and Metabolic Disease, 2nd Medical School, University of Naples, Italy.
Insights
This study found that moderate changes in dietary calcium intake did not significantly alter blood pressure in patients with mild essential hypertension over a short period.
Area of Science:
- Cardiovascular Health
- Nutritional Science
- Hypertension Management
Background:
- Essential hypertension is a prevalent cardiovascular condition.
- Dietary factors, including calcium, are investigated for their role in blood pressure regulation.
- Understanding calcium's impact is crucial for developing non-pharmacological hypertension treatments.
Purpose of the Study:
- To investigate the effect of low versus high oral calcium intake on blood pressure in patients with mild essential hypertension.
- To assess changes in serum ionized calcium and urinary calcium, sodium, and potassium excretion.
Main Methods:
- A double-blind, randomized crossover trial involving 15 patients with mild essential hypertension.
- Patients received either a low (400 mg/day) or high (1400 mg/day) calcium intake for 4 weeks each, following a standard intake baseline.
- Blood pressure, serum ionized calcium, and 24-hour urinary electrolyte excretion were monitored.
Main Results:
- No significant changes in blood pressure were observed between the low and high calcium intake periods.
- Serum ionized calcium was slightly lower, and 24-hour urinary calcium excretion was significantly reduced during the low-calcium diet.
- Urinary sodium and potassium excretion remained unchanged between the two dietary periods.
Conclusions:
- Moderate modifications in oral calcium intake do not appear to affect blood pressure in patients with mild essential hypertension within the study's timeframe.
- Further research may be needed to explore longer-term effects or different patient populations.
Abstract:
A controlled trial of the effect of low versus high calcium intake on blood pressure was performed in 15 patients with mild essential hypertension (supine blood pressure after a 1-month run-in period: 145.7 +/- 2.6/97.8 +/- 0.9 mmHg, mean +/- s.e.m.). After a 1-week baseline period on a standard calcium intake (900 mg/day, obtained by giving a 500-mg calcium tablet daily, in addition to a 400-mg calcium diet), the patients were randomly entered into a double-blind crossover study of 4-week low calcium intake (400 mg calcium diet plus two placebo tablets/day) and 4-week high calcium intake (1400 mg/day: 400-mg calcium diet plus two 500-mg calcium tablets/day). Compliance with the diets appeared to be satisfactory, based on the results of food record analysis. No significant blood pressure change was observed at the end of the low-compared to the high-calcium regimen. Serum ionized calcium was slightly, but not significantly lower, while 24-h urinary calcium excretion was significantly reduced during the low-calcium diet. No difference was found in urinary sodium and potassium excretion between the two study periods. We conclude that moderate modifications of oral calcium intake are not associated with changes in blood pressure within the time span of this study.