A Double-Blind, Placebo-Controlled Parallel Trial of Vitamin C Treatment in Middle Aged Patients

An evaluation of the effect of vitamin C on blood pressure is very important because hypertension is a major risk factor for cardiovascular, cerebral and renal diseases. We studied the effect of vitamin C on the blood pressure of patients between 35-50 years old with mild primary hypertension in Kerman.We conducted a prospective one-year double-blind, placebo controlled parallel trial on 42 middle aged patients with mild primary hypertension at the hypertension clinic inKerman University of Medical Sciences. Following a 2-week run-in phase, two age and sex matched groups of untreated hypertensive subjects received 8 weeks oral treatment with either vitamin C, 250 mg twice daily (n=21; 8 M/13F, mean age 42.7 ± 5.3 years) or lacebo one tablet twice daily (n=21; 10 M/11F, mean age 42.7 ± 5.9 years). Bloodpressure was measured in the sitting position on three occasions during the run-in phase,and again at 1, 2, 4 and 8 weeks after commencing treatment. Venous blood samples forthe measurement of plasma ascorbic acid were measured at baseline and at 1, 2, 4, 8weeks after treatment.Plasma ascorbic acid level in vitamin C group significantly changed from 8.8 ± 3umol/l at baseline to 32.3 ± 12 umol/l at 8 weeks, but in placebo-treated group, it changedfrom 13.8 ± 6 umol/l at baseline to 9.01 ± 4.1 umol/l at 8 weeks during the study period.A more significant fall in mean blood pressure was observed in the vitamin C group thanthe placebo-treated group such that the mean systolic blood pressure decreased from153.1± 5 to 144±5.3 mmHg in vitamin C group and from 154.1±4.9 to 149±4.9 mmHg inthe placebo group. The mean diastolic blood pressure decreased from 95.7±1.4 to91.4±1.7 mmHg in the vitamin C group and from 96.2±1.6 to 94.0±1.6 mmHg in theother group.At 8 weeks, the significant difference in the reduction of systolic blood pressure (p<0.05)and diastolic blood pressure (p<0.001) between the two groups became apparent.Vitamin C intake has a useful effect on lowering blood pressure. (Iranian Heart