Effect of garlic on blood pressure: a meta-analysis.
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ABSTRACT:
SUBMITTER: Wang HP
PROVIDER: S-EPMC8031974 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundNon-pharmacological treatment options for hypertension have the potential to reduce the risk of cardiovascular disease at a population level. Animal studies have suggested that garlic reduces blood pressure, but primary studies in humans and non-systematic reviews have reported mixed results. With interest in complementary medicine for hypertension increasing, it is timely to update a systematic review and meta-analysis from 1994 of studies investigating the effect of garlic preparations on blood pressure.MethodsWe searched the Medline and Embase databases for studies published between 1955 and October 2007. Randomised controlled trials with true placebo groups, using garlic-only preparations, and reporting mean systolic and/or diastolic blood pressure (SBP/DBP) and standard deviations were included in the meta-analysis. We also conducted subgroup meta-analysis by baseline blood pressure (hypertensive/normotensive), for the first time. Meta-regression analysis was performed to test the associations between blood pressure outcomes and duration of treatment, dosage, and blood pressure at start of treatment.ResultsEleven of 25 studies included in the systematic review were suitable for meta-analysis. Meta-analysis of all studies showed a mean decrease of 4.6 +/- 2.8 mm Hg for SBP in the garlic group compared to placebo (n = 10; p = 0.001), while the mean decrease in the hypertensive subgroup was 8.4 +/- 2.8 mm Hg for SBP (n = 4; p < 0.001), and 7.3 +/- 1.5 mm Hg for DBP (n = 3; p < 0.001). Regression analysis revealed a significant association between blood pressure at the start of the intervention and the level of blood pressure reduction (SBP: R = 0.057; p = 0.03; DBP: R = -0.315; p = 0.02).ConclusionOur meta-analysis suggests that garlic preparations are superior to placebo in reducing blood pressure in individuals with hypertension.
| S-EPMC2442048 | biostudies-literature
Project description:BACKGROUND: Patients with nocturnal hypertension are at higher risk for cardiovascular complications such as myocardial infarction and cerebrovascular insult. Published studies inconsistently reported decreases in nocturnal blood pressure with melatonin. METHODS: A meta-analysis of the efficacy and safety of exogenous melatonin in ameliorating nocturnal blood pressure was performed using a random effects model of all studies fitting the inclusion criteria, with subgroup analysis of fast-release versus controlled-release preparations. RESULTS: Seven trials (three of controlled-release and four of fast-release melatonin) with 221 participants were included. Meta-analysis of all seven studies did not reveal significant effects of melatonin versus placebo on nocturnal blood pressure. However, subgroup analysis revealed that controlled-release melatonin significantly reduced nocturnal blood pressure whereas fast-release melatonin had no effect. Systolic blood pressure decreased significantly with controlled-release melatonin (-6.1 mmHg; 95% confidence interval [CI] -10.7 to -1.5; P = 0.009) but not fast-release melatonin (-0.3 mmHg; 95% CI -5.9 to 5.30; P = 0.92). Diastolic blood pressure also decreased significantly with controlled-release melatonin (-3.5 mmHg; 95% CI -6.1 to -0.9; P = 0.009) but not fast-release melatonin (-0.2 mmHg; 95% CI -3.8 to 3.3; P = 0.89). No safety concerns were raised. CONCLUSION: Add-on controlled-release melatonin to antihypertensive therapy is effective and safe in ameliorating nocturnal hypertension, whereas fast-release melatonin is ineffective. It is necessary that larger trials of longer duration be conducted in order to determine the long-term beneficial effects of controlled-release melatonin in patients with nocturnal hypertension.
| S-EPMC3180511 | biostudies-other
Project description:Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals.We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P < 0.05.Fifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change +/- SE: SBP: -3.2 +/- 1.9 mmHg, P = 0.001; DBP: -2.0 +/- 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 +/- 3.0 mmHg; P = 0.0009; DBP: -2.7 +/- 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 +/- 2.3 mmHg, P = 0.17; DBP: -1.3 +/- 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors for blood pressure outcome.Our meta-analysis suggests that dark chocolate is superior to placebo in reducing systolic hypertension or diastolic prehypertension. Flavanol-rich chocolate did not significantly reduce mean blood pressure below 140 mmHg systolic or 80 mmHg diastolic.
| S-EPMC2908554 | biostudies-other
Project description:BACKGROUND/OBJECTIVES: Hypertension affects about 30% of adults worldwide. Garlic has blood pressure-lowering properties and the mechanism of action is biologically plausible. Our trial assessed the effect, dose-response, tolerability and acceptability of different doses of aged garlic extract as an adjunct treatment to existing antihypertensive medication in patients with uncontrolled hypertension. SUBJECTS/METHODS: A total of 79 general practice patients with uncontrolled systolic hypertension participated in a double-blind randomised placebo-controlled dose-response trial of 12 weeks. Participants were allocated to one of three garlic groups with either of one, two or four capsules daily of aged garlic extract (240/480/960 mg containing 0.6/1.2/2.4 mg of S-allylcysteine) or placebo. Blood pressure was assessed at 4, 8 and 12 weeks and compared with baseline using a mixed-model approach. Tolerability was monitored throughout the trial and acceptability was assessed at 12 weeks by questionnaire. RESULTS: Mean systolic blood pressure was significantly reduced by 11.8±5.4 mm Hg in the garlic-2-capsule group over 12 weeks compared with placebo (P=0.006), and reached borderline significant reduction in the garlic-4-capsule group at 8 weeks (-7.4±4.1 mm Hg, P=0.07). Changes in systolic blood pressure in the garlic-1-capsule group and diastolic blood pressure were not significantly different to placebo. Tolerability, compliance and acceptability were high in all garlic groups (93%) and highest in the groups taking one or two capsules daily. CONCLUSIONS: Our trial suggests aged garlic extract to be an effective and tolerable treatment in uncontrolled hypertension, and may be considered as a safe adjunct treatment to conventional antihypertensive therapy.
| S-EPMC3561616 | biostudies-other
Project description:Herbal supplements rich in phenolic compounds are evidenced to have a protective effect against cardiovascular diseases. Therefore, they are suggested to be included in diets for people with hypertension (HT). HT is a global health problem and is estimated to affect billions of people until the end of 2025. For this reason, every possible and effective solution preventing HT should be considered. The aim was to perform an updated meta-analysis and review of recently published studies to evaluate the effect of selected herbal supplements on blood pressure reduction. We searched the PubMed database with specified selection criteria, analysing the RCT studies from 2011 to 2021. A total of 31 studies were included in the analysis, and the meta-analysis was conducted on the data from 16 of them. The general effect size of all the supplements via placebo was d = 1.45, p < 0.05 for systolic blood pressure (SBP) and d = 0.31, p < 0.05 for diastolic blood pressure (DBP). The meta-analysis and review of the literature demonstrated that herbal supplements, such as resveratrol, cherry juice, beetroot juice, bergamot extracts, barberry, and pycnogenol, can be effective in blood pressure reduction and cardiovascular prevention, but attention should be paid to their appropriate dosage due to the possibility of side effects from the digestive system.
| S-EPMC9332300 | biostudies-literature
Project description:Shinrin-yoku (experiencing the forest atmosphere or forest bathing) has received increasing attention from the perspective of preventive medicine in recent years. Some studies have reported that the forest environment decreases blood pressure. However, little is known about the possibility of anti-hypertensive applications of Shinrin-yoku. This study aimed to evaluate preventive or therapeutic effects of the forest environment on blood pressure.We systematically reviewed the medical literature and performed a meta-analysis.Four electronic databases were systematically searched for the period before May 2016 with language restriction of English and Japanese. The review considered all published, randomized, controlled trials, cohort studies, and comparative studies that evaluated the effects of the forest environment on changes in systolic blood pressure. A subsequent meta-analysis was performed.Twenty trials involving 732 participants were reviewed. Systolic blood pressure of the forest environment was significantly lower than that of the non-forest environment. Additionally, diastolic blood pressure of the forest environment was significantly lower than that of the non-forest environment.This systematic review shows a significant effect of Shinrin-yoku on reduction of blood pressure.
| S-EPMC5559777 | biostudies-other
Project description:BackgroundAlthough a number of clinical studies have investigated the effectiveness and safety of auricular therapy for treating hypertension, the overall evidence remains uncertain.AimsWe aimed to evaluate the evidence for the effect of auricular therapy on blood pressure using meta-analysis methodology.MethodsWe searched PubMed, Embase, Cochrane Library databases, Clinicalkey, China National Knowledge Infrastructure, China Scientific Journal Database and Wanfang Database and Chinese Biomedicine for trials that compared the effects of auricular therapy to that of sham auricular therapy, antihypertensive drugs, or no intervention on blood pressure. Blood pressure values before and after treatment, magnitude of blood pressure change between baseline and post-intervention, and the efficacy rate, as outcomes, were synthesized by RevMan 5.3. Continuous outcomes were expressed as weighted mean differences, and dichotomous data were expressed as relative risks with 95% confidence intervals.ResultsWe systematically reviewed 44 randomized controlled trials (involving 5022 patients through June 2018). Auricular acupressure plus antihypertensive drugs might be more effective than antihypertensive drugs alone in both reducing systolic blood pressure value after treatment (n=464 patients; mean difference, -5.06 mm Hg; 95% confidence interval, -6.76- -3.36, p<0.00001; I2=32%), decreasing diastolic blood pressure after treatment (n=464 patients; mean difference, -5.30 mm Hg; 95% confidence interval, -6.27- -4.33, p<0.00001; I2=0%) and the efficacy rate (relative risk, 1.22; 95% confidence interval, 1.17-1.26; p<0.00001; I2=0%).ConclusionAuricular therapy could be provided to patients with hypertension as an adjunct to antihypertensive drugs for lowering blood pressure value and achieving blood pressure targets.
| S-EPMC6927068 | biostudies-literature
Project description:BackgroundThe effect of grape polyphenols on blood pressure remains unclear, which we aimed to address via a meta-analysis study.MethodsWe conducted study trial searches in PubMed, Embase, and the Cochrane Library databases. Summary estimates of weighted mean differences and 95% confidence intervals were obtained by using fixed-effects models. Subgroup analyses were performed to identify the source of heterogeneity. The protocol details of our meta-analysis have been submitted to the international database of prospectively registered systematic reviews (registration number CRD42015019196).ResultsTen studies were included in the present meta-analysis. Our results showed daily grape polyphenol intake could significantly reduce systolic blood pressure by 1.48 mmHg when compared to control subjects (12 comparisons; -1.48 [-2.79 to -0.16] mmHg; P = 0.03). Subgroup analyses indicated larger reduction was identified in the intake of low-dose of grape polyphenols (< 733 mg/day, median level of the included studies) or patients with metabolic syndrome. Contrarily, diastolic blood pressure was not significantly decreased in the grape polyphenols group as compared to controls. No significant heterogeneity or publication bias was detected in the meta-analysis of either systolic or diastolic blood pressure.ConclusionsDaily grape polyphenol intake can significantly reduce the systolic blood pressure in humans, although the reduction is modest when compared with anti-hypertensive medications. Larger, better designed trials, that specifically include hypertensive subjects, are required to verify our results in the future.
| S-EPMC4572713 | biostudies-literature
Project description:BackgroundFermented milk has over the last decade been intensively studied because of the putative antihypertensive effect. The aim of our study is to investigate the role of probiotics support therapy in blood pressure and, as a kind of convenient and economic drugs for prevention and auxiliary treatment of hypertension.Materials and methodsWe performed a systemic review and meta-analysis to examine the effect of probiotics consumption on blood pressure. Databases including MEDLINE, EMBASE, Clinical trials, CNKI and the Cochrane library were searched. Also, the grey literature and references were searched.ResultsTwenty-three randomized controlled trials (RCTs) involving 2037 participants met the inclusion criteria and were included. Probiotic consumption significantly changed systolic blood pressure (SBP) by - 3.05 mmHg (95%CI: - 4.67, - 1.44; P < 0.001) and diastolic blood pressure (DBP) by - 1.51 mmHg (95%CI: - 2.38, - 0.65; P = 0.001). Subgroup analysis indicated that the benefit effect of probiotics supplementation in SBP was only observed in hypertension [weight mean difference (WMD) = - 3.31 mmHg, 95%CI: - 5.71, - 0.92; P = 0.007] or type 2 diabetes (WMD = -4.85 mmHg, 95%CI: - 9.28, - 0.42; P = 0.032) patients, and the decreased DBP level by probiotics supplementation was only observed in hypertension patients (WMD = -2.02 mmHg, 95%CI: - 3.68, - 0.36; P = 0.017).This effect could only last for a short-term time of 8 or 10 weeks, but not for a long-term time.ConclusionThis meta-analysis found a moderate and statistically significant reduction for either SBP or DBP with probiotics supplement compared with controls. Thus, probiotics is a potential for the dietary treatment of hypertension.
| S-EPMC7183137 | biostudies-literature
Project description:Childhood overweight and obesity are associated with elevated blood pressure (BP). However, little is known about how childhood obesity lifestyle prevention programs affect BP. We assessed the effects of childhood obesity prevention programs on BP in children in developed countries.We searched databases up to April 22, 2013, for relevant randomized, controlled trials, quasi-experimental studies, and natural experiments. Studies were included if they applied a diet or physical activity intervention(s) and were followed for ? 1 year (or ? 6 months for school-based intervention studies); they were excluded if they targeted only overweight/obese subjects or those with a medical condition. In our meta-analysis, intervention effects were calculated for systolic BP and diastolic BP with the use of weighted random-effects models. Of the 23 included intervention studies (involving 18 925 participants), 21 involved a school setting. Our meta-analysis included 19 studies reporting on systolic BP and 18 on diastolic BP. The pooled intervention effect was -1.64 mm Hg (95% confidence interval, -2.56 to -0.71; P=0.001) for systolic BP and -1.44 mm Hg (95% confidence interval, -2.28 to -0.60; P=0.001) for diastolic BP. The combined diet and physical activity interventions led to a significantly greater reduction in both systolic BP and diastolic BP than the diet-only or physical activity-only intervention. Thirteen interventions (46%) had a similar effect on both adiposity-related outcomes and BP, whereas 11 interventions (39%) showed a significant desirable effect on BP but not on adiposity-related outcomes.Obesity prevention programs have a moderate effect on reducing BP, and those targeting both diet and physical activity seem to be more effective.
| S-EPMC4346224 | biostudies-literature