A Double-Blind, Placebo-Controlled Parallel Trial of Vitamin C Treatment in Elderly Patients with HypertensionGhosh S.K. · Ekpo E.B. · Shah I.U. · Girling A.J. · Jenkins C. · Sinclair A.J.
aWrexham Maelor Hospital, Clwyd; bUniversity Department of Mathematics and Statistics, University of Birmingham; cUniversity Department of Geriatric Medicine, Cardiff, UK
We have investigated the effect on blood pressure of treatment with vitamin C (an antioxidant and free radical scavenger) in patients with both systolic and essential hypertension. Following a 2-week run-in phase, two age- and sex-matched groups of untreated hypertensive subjects were randomised in a double-blind study to receive 6 weeks’ oral treatment with either vitamin C, 250 mg twice daily (n = 22; 8M/14F, mean age 73.7 ± 4.9 years) or placebo, one capsule twice daily (n = 26; 10M/16F, mean age 73.8 ± 5.3 years). Blood pressure was measured in the sitting position using a random zero sphygmomanometer on three occasions during the run-in phase, and again at 2, 4 and 6 weeks after commencing treatment. Venous blood samples for measurement of plasma ascorbic acid (AA) and lipid peroxides (LP) were measured in all subjects at baseline and at 4 and 6 weeks after the start of vitamin C or placebo treatment. During the study period, significant falls in both systolic (vitamin C group, mean change -10.3 (95% CI 0.7-20.0) mm Hg, p = 0.05) and diastolic (vitamin C group, mean change -5.9 (95% CI 0.2-11.5) mm Hg, p = 0.03; placebo group, mean change -4.7 (95% CI 0.3-9.1) mm Hg, p = 0.05) blood pressure occurred. However, no statistical difference between the effects of either treatment on blood pressure was observed. At baseline, AA concentrations were lower in the vitamin C-treated group compared with the placebo group (44.6 ± 2.4 vs. 57.7 ± 4.2 μmol/l, p < 0.05). At 6 weeks, AA concentrations were similar to baseline in the placebo group (50.8 ± 4.6 μmol/l) but were significantly higher than at baseline in the vitamin C-treated group (80.7 ± 7.5 μmol/lp < 0.001). At baseline, LP concentrations were similar in the vitamin C and placebo-treated groups (5.0 ± 1.0 vs. 3.6 ± 0.8 nmol/l, respectively). After 6 weeks’ treatment with vitamin C, LP concentrations fell significantly to 1.6 ± 0.4 nmol/l, but no significant change after placebo was observed (4.4 ± nmol/l). We conclude: (1) No significant fall in blood pressure occurred after 6 weeks’ treatment with vitamin C in comparison with placebo; (2) vitamin C treatment is associated with a marked antioxidant action but further studies are required to relate whether this action is relevant to any hypotensive action of this vitamin; (3) the small fall in systolic blood pressure after vitamin C may have wider implications in population-based studies in reducing stroke incidence in elderly patients and suggests the need for large long-term studies to be established.
Dr. AJ. Sinclair, BSc MSc MD MRCP, Senior Lecturer and Consultant Physician, University Department of Geriatric Medicine, Cardiff Royal Infirmary (West Wing), Cardiff CF2 1SZ (UK)
Received: December 20, 1993
Accepted: January 20, 1994
Published online: April 14, 2009
Number of Print Pages : 5
Gerontology (International Journal of Experimental, Clinical, Behavioural and Technological Gerontology)
Vol. 40, No. 5, Year 1994 (Cover Date: 1994)
Journal Editor: Wick G. (Innsbruck)
ISSN: 0304-324X (Print), eISSN: 1423-0003 (Online)
For additional information: http://www.karger.com/GER