Garlic powder intake and cardiovascular risk factors: a meta-analysis of randomized controlled clinical trials

BACKGROUND/OBJECTIVES

Although preclinical studies suggest that garlic has potential preventive effects on cardiovascular disease (CVD) risk factors, clinical trials and reports from systematic reviews or meta-analyses present inconsistent results. The contradiction might be attributed to variations in the manufacturing process that can markedly influence the composition of garlic products. To investigate this issue further, we performed a meta-analysis of the effects of garlic powder on CVD risk factors.

MATERIALS/METHODS

We searched PubMed, Cochrane, Science Direct and EMBASE through May 2014. A random-effects meta-analysis was performed on 22 trials reporting total cholesterol (TC), 17 trials reporting LDL cholesterol (LDL-C), 18 trials reporting HDL cholesterol (HDL-C), 4 trials reporting fasting blood glucose (FBG), 9 trials reporting systolic blood pressure (SBP) and 10 trials reporting diastolic blood pressure (DBP).

RESULTS

The overall garlic powder intake significantly reduced blood TC and LDL-C by -0.41 mmol/L (95% confidence interval [CI], -0.69, -0.12) (-15.83 mg/dL [95% CI, -26.64, -4.63]) and -0.21 mmol/L (95% CI, -0.40, -0.03) (-8.11 mg/dL [95% CI, -15.44, -1.16]), respectively. The mean difference in the reduction of FBG levels was -0.96 mmol/L (95% CI, -1.91, -0.01) (-17.30 mg/dL [95% CI, -34.41, -0.18]). Evidence for SBP and DBP reduction in the garlic supplementation group was also demonstrated by decreases of -4.34 mmHg (95% CI, -8.38, -0.29) and -2.36 mmHg (95% CI, -4.56, -0.15), respectively.

CONCLUSIONS

This meta-analysis provides consistent evidence that garlic powder intake reduces the CVD risk factors of TC, LDL-C, FBG and BP.     

Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials

BACKGROUND: The beneficial effects of flavonoid consumption on cardiovascular risk are supported by mechanistic and epidemiologic evidence. OBJECTIVE: We aimed to systematically review the effectiveness of different flavonoid subclasses and flavonoid-rich food sources on cardiovascular disease (CVD) and risk factors--ie, lipoproteins, blood pressure, and flow-mediated dilatation (FMD). DESIGN: Methods included a structured search strategy on MEDLINE, EMBASE, and Cochrane databases; formal inclusion or exclusion, data extraction, and validity assessment; and meta-analysis. RESULTS: One hundred thirty-three trials were included. No randomized controlled trial studied effects on CVD morbidity or mortality. Significant heterogeneity confirmed differential effects between flavonoid subclasses and foods. Chocolate increased FMD after acute (3.99%; 95% CI: 2.86, 5.12; 6 studies) and chronic (1.45%; 0.62, 2.28; 2 studies) intake and reduced systolic (-5.88 mm Hg; -9.55, -2.21; 5 studies) and diastolic (-3.30 mm Hg; -5.77, -0.83; 4 studies) blood pressure. Soy protein isolate (but not other soy products or components) significantly reduced diastolic blood pressure (-1.99 mm Hg; -2.86, -1.12; 9 studies) and LDL cholesterol (-0.19 mmol/L; -0.24, -0.14; 39 studies). Acute black tea consumption increased systolic (5.69 mm Hg; 1.52, 9.86; 4 studies) and diastolic (2.56 mm Hg; 1.03, 4.10; 4 studies) blood pressure. Green tea reduced LDL (-0.23 mmol/L; -0.34, -0.12; 4 studies). For many of the other flavonoids, there was insufficient evidence to draw conclusions about efficacy. CONCLUSIONS: To date, the effects of flavonoids from soy and cocoa have been the main focus of attention. Future studies should focus on other commonly consumed subclasses (eg, anthocyanins and flavanones), examine dose-response effects, and be of long enough duration to allow assessment of clinically relevant endpoints.     

The effect of coffee consumption on serum lipids: a meta-analysis of randomized controlled trials

Background/objectives:Numbers of epidemiological studies assessing coffee consumption and serum lipids have yielded inconsistent results. We aimed to evaluate the effects of coffee intake on serum lipids.Subjects/methods:We searched several English and Chinese electronic databases up to September 2011 for randomized controlled trials of coffee on serum lipids. Weighted mean effect size was calculated for net changes in serum lipids by using random-effect models or fixed-effect models. Subgroup and meta-regression analyses were conducted to explore possible explanations for heterogeneity among trials.Results:Twelve studies conducted in Western countries with a total of 1017 subjects were identified. Meta-analyses showed, on average, drinking coffee for 45 days was associated with an increase of 8.1?mg/dl (95% confidence interval (CI): 4.5, 11.6; P<0.001) for total cholesterol (TC), 5.4?mg/dl (95% CI: 1.4, 9.5; P=0.009) for low-density lipoprotein cholesterol (LDL-C) and 12.6?mg/dl (95% CI: 3.5, 12.6; P=0.007) for triglyceride (TG). The increase in TC were greater in trials using unfiltered coffee and caffeinated coffee as the treatment group. Those who had hyperlipidemia were more sensitive to the cholesterol-raising effect of coffee. Meta-regression analysis revealed a positive dose-response relation between coffee intake and TC, LDL-C and TG.Conclusion:The intake of coffee especially unfiltered coffee is contributed significantly to the increase in TC, LDL-C and TG, and the changes were related to the level of intake. Studies of coffee intake on serum lipids in Asian populations should be performed.     

Can dietary interventions change diet and cardiovascular risk factors? A meta-analysis of randomized controlled trials.

OBJECTIVES: This study evaluated the effectiveness of dietary advice in primary prevention of chronic disease. METHODS: A meta-analysis was conducted of 17 randomized controlled trials of dietary behavior interventions of at least 3 months' duration. Results were analyzed as changes in reported dietary fat intakes and biomedical measures (serum cholesterol, urinary sodium, systolic and diastolic blood pressure) in the intervention group minus changes in the control group at 3 to 6 months and 9 to 18 months of follow-up. RESULTS: After 3 to 6 months, mean net changes in each of the five outcomes favored intervention. For dietary fat as a percentage of food energy, the change was -2.5% (95% confidence interval [CI] = -3.9%, -1.1%). Mean net changes over 9 to 18 months were as follows: serum cholesterol, -0.22 (95% CI = -0.39, -0.05) mmol/L; urinary sodium, -45.0 (95% CI = -57.1, -32.8) mmol/24 hours; systolic blood pressure, -1.9 (95% CI = -3.0, 0.8) mm Hg; and diastolic blood pressure, -1.2 (95% CI = -2.6, 0.2) mm Hg. CONCLUSIONS: Individual dietary interventions in primary prevention can achieve modest improvements in diet and cardiovascular disease risk status that are maintained for 9 to 18 months.     

老年人应用他汀致癌风险Meta分析

目的评价老年人(≥60岁)应用他汀是否会增加致癌风险。方法全面检索2015年12月前发表的关于老年人(≥60岁)应用他汀治疗的随机对照研究(RCTs),筛选出其中有关他汀与安慰剂比较,并有癌症风险报道的研究,评价所纳入研究的文献质量,提取有效数据。采用Rev Man 5.3软件进行Meta分析,评价文献的发表偏倚及异质性,采用相对危险度(RR)分析统计量,各效应量均给出其95%可信区间(CI)。结果共纳入12项研究,合计62 927例患者(他汀治疗组31 517例,对照组31 410例),随访1.9~5.4年。Meta分析结果显示,他汀治疗组与对照组相比,癌症的发生率并没有显著增加(RR=1.04,95%CI 0.98~1.10,P=0.19),水溶性他汀(RR=1.06,95%CI 0.93~1.21,P=0.35)、脂溶性他汀(RR=0.99,95%CI 0.88~1.11,P=0.83)均不会增加致癌风险。结论老年人应用他汀不会增加致癌风险,无论水溶性他汀还是脂溶性他汀,都不会增加致癌风险,但还需随访时间更长的研究进一步证实。     

Physical activity and cardiovascular risk factors in children: meta-analysis of randomized clinical trials

ObjectiveTo assess the effects of physical activity interventions in preventing cardiovascular risk factors in childhood through a systematic review and meta-analysis of randomized clinical trials (RCTs).MethodsA search of online databases (PubMed, EMBASE and Cochrane CENTRAL) was conducted from inception until June 2013. RCTs enrolling children 6–12 years old conducted physical activity interventions longer than 6 months, assessing their effect on body mass index (BMI), systolic (SBP) and diastolic blood pressure (DBP), total cholesterol (TC) and triglycerides (TG) were included. Data analysis was performed using a random-effects model.ResultsOf 23.091 articles retrieved, 11 RCTs (10.748 subjects) were included. Physical activity interventions were not associated with reductions of BMI [− 0.03 kg/m² (95%CI − 0.16, 0.13) I² 0%]. However, there was an association between the interventions and reduction of SBP [− 1.25 mmHg (95%CI − 2.47, − 0.02) I² 0%], DBP [− 1.34 mmHg (95%CI − 2.57, − 0.11) I² 43%] and TG [− 0.09 mmol/L (95%CI − 0.14, − 0.04) I² 0%], and increase of TC [0.14 mmol/L (95%CI 0.01, 0.27) I² 0%].ConclusionAs physical activity intervention programs lasting longer than 6 months are associated with reductions in blood pressure levels and triglycerides, they should be considered to be included in prevention programs for cardiovascular diseases in schoolchildren.     

维生素E补充对心脑血管疾病影响随机对照试验meta分析

目的 探讨维生素E补充剂对心脑血管疾病事件(中风、心肌梗死、短暂性脑缺血发作)发生的影响,为心脑血管疾病的防治提供参考依据。方法 检索Pubmed、EMBASE、OVID、Healthstar、Cochrane database、Google Scholar、Science Citation Index等外文数据库和万方数据知识平台、中国知网系列数据库、中国生物医学文献数据库、维普期刊资源整合服务系统等中文数据库,全面收集1980-2014年间维生素E补充与心脑血管疾病事件发生关系的随机对照试验文献,采用Revman 5.1软件对纳入的文献进行Meta分析。结果 最终纳入13篇英文文献,累计维生素E组干预人数62871例,安慰剂组对照人数62837例;Meta分析结果显示,维生素E补充对心脑血管疾病事件的发生无显著影响(RR=0.99,95% CI=0.96~1.02),对中风的发生无显著影响(RR=1.03,95% CI=0.96~1.10),对心肌梗死的发生无显著影响(RR=0.99,95% CI=0.93~1.04),对短暂性脑缺血发作无显著影响(RR=0.94,95% CI=0.82~1.09);亚组分析结果显示,性别、随访时间、是否有其他干预措施和维生素E的剂量均对心脑血管疾病事件的发生无显著影响(均P>0.05)。结论 补充维生素E对心脑血管疾病事件的发生无显著影响。     

Low-protein diet for diabetic nephropathy: a meta-analysis of randomized controlled trials

BACKGROUND: A low-protein diet (LPD) has been proposed for many years to delay the progression of diabetic nephropathy. However, the efficacy of an LPD with respect to renal outcome is disputed. OBJECTIVE: We aimed to determine the effect of an LPD on renal function in patients with type 1 or 2 diabetic renal diseases by using a meta-analysis of randomized controlled trials. DESIGN: Medline, EMBASE, and the Cochrane Central Register of Controlled Trials were searched. Eight studies met the inclusion criteria for our meta-analysis: a duration of >6 mo, use of a randomized control group, availability of outcome data for changes in glomerular filtration rate (GFR) or creatinine clearance rate (CCR), and albuminuria or proteinuria in patients with type 1 or 2 diabetic nephropathy. Data were combined by means of a fixed-effects model. Weighted mean differences (WMD) were calculated for the change in GFR or CCR, glycated hemoglobin (HbA(1c)), and serum albumin between the LPD and control groups. A random-effects model was also used to calculate the standardized mean difference for the change in urinary albumin excretion or proteinuria. RESULTS: Overall, a change in WMD for GFR or CCR was not significantly associated with an LPD, but a decrease in WMD for HbA(1c) was significant in the LPD group (P = 0.005). Although the benefit of LPD therapy on proteinuria was significant (P = 0.003), great heterogeneity was observed. In a subgroup analysis, LPD resulted in lower serum albumin concentrations. CONCLUSION: LPD was not associated with a significant improvement of renal function in patients with either types 1 or 2 diabetic nephropathy.     

The effect of multiple micronutrient supplementation on mortality and morbidity of HIV-infected adults: a meta-analysis of randomized controlled trials

Numerous preclinical studies have suggested that micronutrient status is associated with the progression of human immunodeficiency virus (HIV) disease, but results from observational studies are still controversial. The objective was to systematically review the efficacy of multiple micronutrient supplementation on mortality and morbidity in HIV-infected adults. A comprehensive search of the PubMed/MEDLINE, EMBASE and Cochrane Library was performed. Six randomized controlled trials assessing the effect of multiple micronutrient supplementation on HIV-infected adults were included. Relative risk was used as an effect measure to compare the intervention and control groups with fixed-effects or random effects models. Sensitivity analyses were applied to further evaluate heterogeneity. Multiple micronutrient supplementation decreased the mortality and morbidity of HIV-infected adults nonstatistically significantly (RR=0.90; 95% CI, 0.80 to 1.02; p=0.09). Sensitivity analyses revealed that multiple micronutrient supplementation decreased the mortality and morbidity of adults infected with HIV alone statistically significantly (RR=0.75; 95% CI, 0.58 to 0.95; p=0.02), but not adults infected with both HIV and pulmonary tuberculosis (RR=0.97; 95% CI, 0.84 to 1.11; p=0.65). Multiple micronutrient consumption was correlated with reduction of the mortality and morbidity of HIV-infected adults, at least those in developing countries and infected with HIV alone, and should be prescribed by local doctors for those in earlier stages especially.Numerous preclinical studies have suggested that micronutrient status is associated with the progression of human immunodeficiency virus (HIV) disease, but results from observational studies are still controversial. The objective was to systematically review the efficacy of multiple micronutrient supplementation on mortality and morbidity in HIV-infected adults. A comprehensive search of the PubMed/MEDLINE, EMBASE and Cochrane Library was performed. Six randomized controlled trials assessing the effect of multiple micronutrient supplementation on HIV-infected adults were included. Relative risk was used as an effect measure to compare the intervention and control groups with fixed-effects or random effects models. Sensitivity analyses were applied to further evaluate heterogeneity. Multiple micronutrient supplementation decreased the mortality and morbidity of HIV-infected adults nonstatistically significantly (RR=0.90; 95% CI, 0.80 to 1.02; p=0.09). Sensitivity analyses revealed that multiple micronutrient supplementation decreased the mortality and morbidity of adults infected with HIV alone statistically significantly (RR=0.75; 95% CI, 0.58 to 0.95; p=0.02), but not adults infected with both HIV and pulmonary tuberculosis (RR=0.97; 95% CI, 0.84 to 1.11; p=0.65). Multiple micronutrient consumption was correlated with reduction of the mortality and morbidity of HIV-infected adults, at least those in developing countries and infected with HIV alone, and should be prescribed by local doctors for those in earlier stages especially.     

The effect of probiotics on inflammatory biomarkers: a meta-analysis of randomized clinical trials

European Journal of Nutrition - No study has summarized earlier findings on the effect of probiotic supplementation on inflammatory biomarkers. This systematic review and meta-analysis was...     

Effect of milk tripeptides on blood pressure: a meta-analysis of randomized controlled trials

OBJECTIVE: To better understand and summarize the relation between milk peptide intake and blood pressure (BP), we conducted a meta-analysis of randomized controlled trials to assess the effects of the milk-derived tripeptides isoleucine-proline-proline and valine-proline-proline on BP in prehypertensive and hypertensive subjects. METHODS: Nine studies including 12 trials published between 1996 and 2005 with a total of 623 participants were included. Two researchers independently extracted data from the original publications. A fixed-effects model was used for meta-analysis because of the homogeneity among trials. RESULTS: Significant decreases of 4.8 mmHg (95% confidence interval 3.7-6.0) in systolic BP and 2.2 mmHg (95% confidence interval 1.3-3.1) in diastolic BP were found after the pooling of these trials. When trials were separated by BP status, hypotensive effects appeared to be larger in hypertensive subjects than in prehypertensive subjects. As a trend, the hypotensive effects became more obvious as the intervention lengthened. CONCLUSION: Our analysis provided evidence that milk-derived tripeptides have hypotensive effects in prehypertensive and hypertensive subjects.     

Effects of safflower seed extract supplementation on oxidation and cardiovascular risk markers in healthy human volunteers

We previously demonstrated that safflower seed extract (SSE) and its major antioxidant constituents, serotonin hydroxycinnamic acid amides, suppressed LDL oxidation in vitro, decreased plasma autoantibody titres to oxidized LDL and attenuated atherosclerotic lesion formation in apoE-deficient mice. In this report, we examined whether SSE, rich in serotonin derivatives, could affect markers of oxidative stress, inflammation and aortic stiffness in healthy human subjects. Twenty Japanese male volunteers were studied at baseline, after 2.1 g SSE supplementation daily (providing 290 mg serotonin derivatives/d) for 4 weeks, and after a 4-week washout period. Significant reductions in circulating oxidized LDL, autoantibody titres to malondialdehyde-modified LDL, the soluble form of vascular cell adhesion molecule-1 (sVCAM-1), and urinary 8-isoprostane were observed after a 4-week intervention. Although there were no statistically significant differences in blood pressure or brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, baPWV was lower than baseline in eleven of twenty subjects and was accompanied by a reduction in blood pressure. Statistically significant negative correlations were observed between the extent of initial cardiovascular risk markers (autoantibody titres, 8-isoprostane, sVCAM-1 and baPWV) and the effect of intervention. This suggested that individuals with elevated oxidative stress, inflammation, and/or arterial stiffness may receive more benefit from SSE supplementation.     

Walking, lipids, and lipoproteins: a meta-analysis of randomized controlled trials

BACKGROUND: The purpose of this study was to use the meta-analytic approach to examine the effects of walking on lipids and lipoproteins in adults. METHODS: Randomized controlled trials that examined the effects of walking on total cholesterol (TC), high- and low-density lipoprotein cholesterol (HDL-C and LDL-C), the ratio of TC/HDL, and triglycerides (TG) in adults ages 18 years and older were retrieved via computerized literature searches, cross-referencing, hand-searching, and expert review of our reference list. RESULTS: Twenty-five studies that included 1,176 subjects (692 walkers, 484 controls) and up to 33 outcomes were available for pooling. Using random-effects modeling, statistically significant, walking-induced decreases of 5% and 6% were observed for LDL-C and TC/HDL-C (LDL-C, mean +/- SE, -5.5 +/- 2.2 mg/dL, 95% CI, -9.9 to -1.2 mg/dL; TC/HDL-C, mean +/- SE, -0.3 +/- 0.1, 95% CI, -0.6 to -0.1). No statistically significant changes were observed for TC, HDL, or TG (P > 0.05), although changes were in the direction of benefit. No statistically significant changes occurred in body composition (P > 0.05). CONCLUSIONS: Walking reduces LDL-C and TC/HDL-C in adults independent of changes in body composition.     

Coffee consumption and serum lipids: a meta-analysis of randomized controlled clinical trials

Coffee drinking has been associated with increased serum cholesterol levels in some, but not all, studies. A Medline search of the English-language literature published prior to December 1998, a bibliography review, and consultations with experts were performed to identify 14 published trials of coffee consumption. Information was abstracted independently by two reviewers using a standardized protocol. With a random-effects model, treatment effects were estimated by pooling results from individual trials after weighting the results by the inverse of total variance. A dose-response relation between coffee consumption and both total cholesterol and LDL cholesterol was identified (p < 0.01). Increases in serum lipids were greater in studies of patients with hyperlipidemia and in trials of caffeinated or boiled coffee. Trials using filtered coffee demonstrated very little increase in serum cholesterol. Consumption of unfiltered, but not filtered, coffee increases serum levels of total and LDL cholesterol.