The effect of inositol supplementation on blood pressure: A systematic review and meta-analysis of randomized-controlled trials.
Potential effects of inositol supplementation on blood pressure (BP) have been examined in several interventional studies. Nevertheless, findings in this context are controversial. Therefore, the current systematic review and meta-analysis aimed to comprehensively assess the impact of inositol supplementation on BP.
Five online databases including Web of Science, Scopus, Embase, Cochrane, Google Scholar, and PubMed were systematically searched from inception to March 2020. We included all randomized clinical trials (RCTs) evaluating the effects of inositol supplementation on systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) in humans.
The random-effects meta-analysis of 7 eligible RCTs demonstrated the significant decline in both SBP (WMD - 5.69 mmHg; 95% CI - 7.35 to - 4.02, P < 0.001) and DBP (WMD - 7.12 mmHg; 95% CI - 10.18 to - 4.05, P < 0.001) following supplementation with inositol. Subgroup analysis showed that studies performed in individuals with metabolic syndrome with a longer duration (>8 weeks) and a dose of 4000 mg resulted in a more effective reduction in SBP and DBP with acceptable homogeneity.
The current meta-analysis, indicated that supplementation with inositol significantly decrease SBP and DBP. Further large-scale RCTs with better design are needed to confirm these findings.
Hashemi Tari S
,Sohouli MH
,Lari A
,Fatahi S
,Rahideh ST
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《Clinical Nutrition ESPEN》
Effect of proanthocyanidins on blood pressure: A systematic review and meta-analysis of randomized controlled trials.
Hypertension is a common chronic disease that can lead to serious health problems. Previous studies have not drawn a consistent conclusion about the effect of proanthocyanidins (PCs) on blood pressure (BP). This systematic review and meta-analysis aims to evaluate the effect of PCs supplementation on blood pressure (BP).
A comprehensive literature search was performed in 6 databases (Pubmed, Scopus, ISI Web of Science, the Cochrane Library, Embase and Google Scholar) to identify the randomized controlled trials (RCTs) that evaluated the BP-lowering effect of PCs. Subgroup and sensitivity analyses were conducted to evaluate the potential heterogeneity. Meta-regression analysis was used to evaluate dose effects of PCs on BP.
A total of 6 studies comprising 376 subjects were included in our meta-analysis to estimate the pooled effect size. This meta-analysis suggested that PCs supplementation could significantly reduce systolic blood pressure (SBP) (WMD: -4.598 mmHg; 95 % CI: -8.037, -1.159; I2 = 33.7 %; p = 0.009), diastolic blood pressure (DBP) (WMD: -2.750 mmHg; 95 % CI: -5.087, -0.412; I2 = 0.0 %; p = 0.021) and mean arterial pressure (MAP) (WMD: -3.366 mmHg; 95 % CI: -6.719, -0.041 mmHg; I2 = 0.0 %; p = 0.049), but had no significant effect on pulse pressure (PP) (WMD: -2.131 mmHg; 95 % CI: -6.292, 2.030; I2 = 0.0 %; p = 0.315). When the studies were stratified according to the duration of the study, there was a significant reduction on SBP in the subset of the trials with <12 weeks of duration. On the contrary, there was a significant reduction on DBP in the subset of the trials with ≥12 weeks of duration. The Subgroup analysis by BMI indicated that a significant reduction on SBP for people with a higher BMI (BMI ≥ 25) and a significant reduction on DBP for people with a lower BMI (BMI < 25). Additional subgroup analysis revealed low-dose-PCs (<245 mg/day) could significantly reduce SBP, DBP and MAP. The meta-regression analyses did not indicate the dose effects of PCs on SBP, DBP, PP and MAP.
Based on the current findings, PCs supplementation may be a useful treatment of hypertensive patients as well as a preventive measure in the prehypertensive and healthy subjects. However, further investigation is needed to confirm these results.
Ren J
,An J
,Chen M
,Yang H
,Ma Y
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Effects of flaxseed supplements on blood pressure: A systematic review and meta-analysis of controlled clinical trial.
Many experimental and clinical trials suggested that flaxseed might be a potent antihypertensive, but the evidences concerning the effects of flaxseed supplements on blood pressure (BP) has not been fully conclusive. We aimed to assess the impact of the effects of flaxseed supplements on blood pressure through systematic review of literature and meta-analysis of available randomized controlled trials (RCTs).
The literature search included PUBMED, Cochrane Library, Scopus, and EMBASE up to February 2015 to identify RCTs investigating the effect of flaxseed supplements on plasma blood pressure. Effect size was expressed as weighed mean difference (WMD) and 95% confidence interval (CI).
15 trials (comprising 19 treatment arms) with 1302 participants were included in this meta-analysis. Random-effects meta-analysis suggested significant reductions in both systolic BP (SBP) (WMD: -2.85 mmHg, 95%CI: -5.37 to -0.33, p = 0.027) and diastolic BP (DBP) (WMD: -2.39 mmHg, 95%CI: -3.78 to -0.99, p = 0.001) following supplementation with flaxseed products. When the studies were stratified according to their duration, there was a greater effect on both SBP and DBP in the subset of trials with ≥12 weeks of duration (WMD: -3.10 mmHg, 95%CI: -6.46 to 0.27, p = 0.072 and -2.62 mmHg, 95%CI: -4.39 to -0.86, p = 0.003, respectively) vs the subset lasting <12 weeks (WMD: -1.60 mmHg, 95%CI: -5.44 to 2.24, p = 0.413, and -1.74 mmHg, 95%CI: -4.41 to 0.93, p = 0.202, respectively). Another subgroup analysis was performed to assess the impact of flaxseed supplement type on BP. Reduction of SBP was significant with flaxseed powder (WMD: -1.81 mmHg, 95% CI: -2.03 to -1.59, p < 0.001) but not oil (WMD: -4.62 mmHg, 95%CI: -11.86 to 2.62, p = 0.211) and lignan extract (WMD: 0.28 mmHg, 95% CI: -3.49 to 4.04, p = 0.885). However, DBP was significantly reduced with powder and oil preparations (WMD: -1.28 mmHg, 95% CI: -2.44 to -0.11, p = 0.031, and -4.10 mmHg, 95%CI: -6.81 to -1.39, p = 0.003, respectively), but not with lignan extract (WMD: -1.78 mmHg, 95% CI: -4.28 to 0.72, p = 0.162).
This meta-analysis of RCTs showed significant reductions in both SBP and DBP following supplementation with various flaxseed products.
Ursoniu S
,Sahebkar A
,Andrica F
,Serban C
,Banach M
,Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group
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