ascorbic-acid and Essential-Hypertension

Vitamin C as a supplement to treat hypertension has been proposed. However, it remains controversial whether vitamin C can improve blood pressure in patients with primary hypertension.. To analyze the effect of vitamin C (VitC) supplementation on systolic (SBP) and diastolic (DBP) blood pressure in patients with essential hypertension.. We searched the Chinese Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, WANFANG Data, Cochrane Library, National Library of Medicine's PubMed, EMBASE, and other databases until June 2019. Eight RCTs involving 614 participants were analyzed. SBP and DBP before and after VitC supplementation were compared between the intervention and control groups. The risk of bias of individual studies was assessed using the Cochrane Collaboration risk of bias tool. Two reviewers selected studies independently of each other. The Cochrane Collaboration Review Manager 5.3 was used to perform the meta-analysis.. There was a significant difference in the change of SBP (weighted mean difference [WMD] = -4.09; 95% confidence interval [CI] -5.56, -2.62; P < .001) and DBP (WMD = -2.30; 95% CI -4.27, -.331; P = .02) between the groups. Further, there was a significant difference in the SBP (WMD = -3.75, 95% CI -6.24, -1.26, P = .003) and DBP (WMD = -3.29, 95% CI -5.98, -.60, P = .02) for the subgroup with an age ≥60 years and that with ≥35 participants. In the subgroup analysis, result for SBP with a study duration ≥6 weeks was statistically significant different (WMD = -4.77; 95% CI -6.46, -3.08; P < .001). For an intervention dose of VitC ≥500 mg daily, SBP was statistically significant (WMD = -5.01; 95% CI -8.55, -1.48; P = .005).. VitC supplementation resulted in a significant reduction of blood pressure in patients with essential hypertension.

Topics: Antioxidants; Ascorbic Acid; Essential Hypertension; Humans

Abstract Oxidative stress (OS) plays a key role in the pathophysiology of essential hypertension and is associated with changes in the cell membrane fatty acid composition and fluidity. As (Na,K)-ATPase is modulated by the surrounding lipid microenvironment, lipid peroxidation could alter the interactions of this enzyme with the membrane components. Thus, modifications in the membrane fatty acid profile will translate into effects on (Na,K)-ATPase activity. Accordingly, a decrease in this enzyme activity has been reported in hypertensive patients. The aim of this study was to evaluate the relationship between membrane fluidity and fatty acid composition and (Na,K)-ATPase activity in erythrocytes of essential hypertensive patients supplemented with antioxidant vitamins C and E. A double-blind, randomized, placebo-controlled study was conducted in 120 men with essential hypertension assigned to receive vitamin C (1 g/day) +E (400 IU/day) or placebo for 8 weeks. Measurements included OS related parameters: GSH/GSSG ratio, F2-isoprostanes and antioxidant capacity of plasma, (Na,K)-ATPase activity and erythrocytes membrane fatty acid composition (PUFA, polyunsaturated fatty acids; SAFA, saturated fatty acids). Associations were assessed by Pearson correlation and the differences by Student t-test (p<0.05). Supplemented hypertensive patients showed higher activity of (Na,K)-ATPase and proportion of PUFA, and lower blood pressure, OS markers and proportion of SAFA, versus placebo. The activity of (Na,K)-ATPase correlated negatively with the proportion of SAFA, but positively with that of PUFA in both groups. Supplementation with vitamins C+E resulted in decreased OS and increased fluidity and PUFA proportion in the membrane, both of which positively modulate (Na,K)-ATPase activity, accounting for the blood pressure reduction.

Topics: Adult; Antioxidants; Ascorbic Acid; Blood Pressure; Double-Blind Method; Erythrocyte Membrane; Erythrocytes; Essential Hypertension; Fatty Acids; Fatty Acids, Unsaturated; Humans; Hypertension; Male; Membrane Fluidity; Membrane Lipids; Middle Aged; Oxidative Stress; Sodium-Potassium-Exchanging ATPase; Vitamin E; Vitamins

Evidence for blood pressure-lowering effects of vitamin C (VC) supplementation in clinical trials is inconsistent and limited studies have examined the effect of VC supplementation on hypertension (HTN) control. In this study, eligible patients were cluster assigned to receive 300 mg VC per day or nothing for 6 months. During the 6-month follow-up period, a questionnaire survey was obtained and standardized blood pressure measurements were performed on all subjects. Oral administration of VC significantly decreased the diastolic blood pressure and pulse pressure with a significant increase in HTN control. After adjusting for confounding variables, treatment with VC was associated with ~ 0.5 risk reduction of uncontrolled HTN in subjects received anti-hypertensive medications, whereas lower indoor and outdoor and ground temperature were significantly associated with an increased risk of uncontrolled HTN in all patients. Our results warrant further studies investigating the mechanisms underlying the association between VC and HTN control.

Topics: Aged; Antihypertensive Agents; Antioxidants; Ascorbic Acid; Blood Pressure; Dietary Supplements; Essential Hypertension; Female; Humans; Male; Middle Aged; Risk Factors; Temperature

This study aimed to investigate the influence of acute glycemic load on vascular endothelial function in patients with hypertension and to evaluate the protective effect of vitamins C and E during the acute glycemic phase. We randomly selected 39 hypertensive patients and 21 normal subjects and divided them into 3 groups: 75 g oral glucose (glycemic load group), 75 g glucose+0.9 g vitamin C (VC group), 75 g glucose+2 g vitamin C+0.8 g vitamin E (VC+VE group). Extravascular color Doppler ultrasound was used to detect brachial artery flow-mediated vasodilation at 0, 1, 2, and 3 h, and, at the same time, serum anti-oxidant products were measured. Basic endothelial functions in patients with hypertension were decreased in the glycemic load group (9.48±3.33 versus 13.09±6.78%, P<0.05), and was even more depressed in the hypertensive group (9.48±3.33 versus 14.20±6.48%, P<0.05). Antioxidant vitamins played a dose-dependent protective role on acute damage of endothelial function due to glycemic load. Acute high blood sugar damaged vascular endothelial functions, especially in hypertensive patients, but this effect can be reversed by large doses of vitamin C and E.

Topics: Adult; Antioxidants; Ascorbic Acid; Blood Glucose; Cohort Studies; Endothelium, Vascular; Essential Hypertension; Female; Glucose; Humans; Hypertension; Male; Middle Aged; Risk Factors; Superoxide Dismutase; Superoxides; Vasodilation; Vitamin E

Topics: Arteriosclerosis; Ascorbic Acid; Atherosclerosis; Essential Hypertension; Humans; Hypertension; Lipids