Is vitamin C an effective antihypertensive supplement? A review and analysis of the literature

ObjectiveHypertension is a common condition with high mortality from associated diseases. Epidemiological evidence suggests that a dietary deficiency of vitamin C may be a risk factor for hypertension. However the literature on vitamin C interventional trials appears divided on the efficacy of vitamin C utilization clinically.MethodsA literature search and review of published trials using vitamin C in treating patients with hypertension was undertaken. Relevant references were located using MEDLINE (1966–2005) and the bibliographies of located articles.ResultsThirteen trials making up 14 separate groups were identified and analyzed providing a pooled population of 284 hypertensive patients (52% female), with a weighted mean age of 58.8 ± 9.5 years. Median vitamin C dose and study intervention duration was 500mg/day and 6 weeks respectively. The weighted mean baseline and post treatment systolic blood pressures across all 14 groups were 149.6 ± 11.1 and 145.7 ± 11.0 mmHg respectively. This represented a systolic blood pressure decrease of 3.9 mmHg. Seven of the 14 groups ascertained statistically significant reductions (p < .05) in systolic blood pressures. However only 2 of the 14 groups found significant reductions in diastolic blood pressure. The weighted mean baseline and post treatment diastolic blood pressures across all 14 groups were 84.6 ± 4.4 and 82.5 ± 4.1 mmHg respectively. This represented a diastolic blood pressure decrease of 2.1 mmHg.ConclusionVitamin C supplementation in hypertensive patients appears to possess modest effects on reducing systolic blood and diastolic blood pressure.