Combination oral antioxidant supplementation reduces blood pressure.
1. Hypertension affects 30% of adults and low intakes of antioxidants have been associated with increased risk of hypertension and cardiovascular disease. To investigate the effect of short-term high-dose antioxidant supplementation on blood pressure in hypertensive and normotensive outpatients, we undertook a randomized, double-blind, crossover design placebo-controlled study. 2. Forty subjects were recruited from medical outpatient clinics, of whom 38 completed the study. Twenty-one were attending for treatment of hypertension and 17 were normotensive, attending for minor gastrointestinal complaints. Subjects were randomly assigned to receive either 8 weeks placebo followed by 2 weeks washout then 8 weeks antioxidants or vice versa. The combination of antioxidants consisted of 200 mg of zinc sulphate, 500 mg of ascorbic acid, 600 mg of alpha-tocopherol (sodium succinate salt) and 30 mg of beta-carotene daily. 3. Systolic blood pressure fell at the end of the antioxidant phase compared with the placebo phase both in subjects receiving anti-hypertensive therapy (P < 0.01) and those who were normotensive (P = 0.067). Circulating levels of beta-carotene and alpha-tocopherol increased in all subjects during supplementation (P < 0.01) and urine nitrite increased in hypertensive patients (P < 0.05). 4. Short-term oral high-dose combination antioxidant therapy reduces blood pressure, possibly via increased availability of nitric oxide. This study may have implications for the innovative use of antioxidants as an adjunct to anti-hypertensive therapy.
Galley
H F
HF
Clinical Oxidant Research Group, St James's University Hospital, Leeds, UK.
Thornton
J
J
Howdle
P D
PD
Walker
B E
BE
Webster
N R
NR
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000652:urine; D014810:Vitamin E / Q000008:administration & dosage; D019287:Zinc Sulfate / Q000008:administration & dosage; D019207:beta Carotene / Q000008:administration & dosage
D000975:Antioxidants; D009573:Nitrites; D019207:beta Carotene; D014810:Vitamin E; D009569:Nitric Oxide; D019287:Zinc Sulfate; D001205:Ascorbic Acid