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Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke: a systematic review and meta-analysis of prospective cohort studies.
Dybvik, JS, Svendsen, M, Aune, D
European journal of nutrition. 2023;62(1):51-69
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Cardiovascular disease (CVD) is mainly due to ischemic heart disease (IHD) and stroke. Plant-based diets are effective for improving CVD risk factors. This is further supported by the favourable cardiometabolic profile seen among vegetarians who predominantly exclude meat, fish and poultry from their diet, when compared to people consuming meat. The aim of this study was to analyse the association between vegetarian or vegan diets and risk of incidence and mortality from CVD, IHD and stroke, both overall and subtypes. This study is a systematic review and meta-analysis of thirteen prospective cohort studies. Results show a 15% and a 21% reduction in the relative risk of CVD and IHD, respectively, for vegetarians compared to nonvegetarians, but there wasn’t a clear association for total stroke or subtypes of stroke. Furthermore, an 18% reduction in the relative risk of IHD was observed among vegans when compared to nonvegetarians but the association lacked precision and no clear association was observed for CVD or stroke; however, there were few studies in the analyses of vegans. Authors conclude that their findings are consistent with existing guidelines recommending plant-based dietary patterns for CVD prevention. However, further studies are required to clarify the association between vegetarian diets and stroke risk, as well as the association between vegan diets and IHD.
Abstract
PURPOSE Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are less clear. We conducted a systematic review and meta-analysis of prospective cohort studies on CVD, IHD and stroke risk among vegetarians or vegans versus nonvegetarians to clarify these associations. METHODS PubMed and Ovid Embase databases were searched through August 12, 2021. Prospective cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for incidence or mortality from CVD, IHD and stroke, comparing vegetarians and vegans to nonvegetarians were included. Risk of bias (RoB) was assessed using ROBINS-I and the strength of evidence was assessed using World Cancer Research Fund (WCRF) criteria. Summary RRs (95% CIs) were estimated using a random effects model. RESULTS Thirteen cohort studies (844,175 participants, 115,392 CVD, 30,377 IHD, and 14,419 stroke cases) were included. The summary RR for vegetarians vs. nonvegetarians was 0.85 (95% CI: 0.79-0.92, I2 = 68%, n = 8) for CVD, 0.79 (95% CI: 0.71-0.88, I2 = 67%, n = 8) for IHD, 0.90 (95% CI: 0.77-1.05, I2 = 61%, n = 12) for total stroke, and for vegans vs. nonvegetarians was 0.82 (95% CI: 0.68-1.00, I2 = 0%, n = 6) for IHD. RoB was moderate (n = 8) to serious (n = 5). The associations between vegetarian diets and CVD and IHD were considered probably causal using WCRF criteria. CONCLUSIONS Vegetarian diets are associated with reduced risk of CVD and IHD, but not stroke, but further studies are needed on stroke. These findings should be considered in dietary guidelines. REVIEW REGISTRATION No review protocol registered.
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Effect of supplementation with Chlorella vulgaris on lipid profile in adults: A systematic review and dose-response meta-analysis of randomized controlled trials.
Sherafati, N, Bideshki, MV, Behzadi, M, Mobarak, S, Asadi, M, Sadeghi, O
Complementary therapies in medicine. 2022;66:102822
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Dyslipidaemia is a chronic metabolic disorder that is characterized by increased levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and reduced levels of high-density lipoprotein cholesterol (HDL-C). Patients with dyslipidaemia have an increased risk of coronary heart disease, stroke, non-alcoholic fatty liver disease, diabetes and even mortality. The aim of this study was to investigate the effect of Chlorella vulgaris supplementation on lipid profile in adults. This study is a systematic review and meta-analysis of ten randomised controlled trial studies. The studies included a total of 539 individuals (n= 264 in the Chlorella vulgaris group and n= 275 in the control group). Results show that Chlorella vulgaris supplementation resulted in a significant reduction in TC and LDL-C levels, while it had no significant effect on TG and HDL-C levels either in the overall analysis or in the subgroup analysis. Furthermore, the reducing effect of Chlorella vulgaris supplementation on LDL-C levels was significant between zero and 1500 mg/d and it was not significant at higher dosages. Authors conclude that future studies should examine the effect of Chlorella vulgaris supplementation on other biochemical parameters such as glycaemic measures and inflammatory biomarkers.
Abstract
OBJECTIVE To summarize available findings on the effect of Chlorella vulgaris supplementation on lipid profile in adults. DESIGN Systematic review and meta-analysis of randomized controlled trials (RCTs). SETTING This study followed 2020 PRISMA guideline. We performed a systematic search in the online databases to identify relevant articles and then, extracted required data from each paper for the meta-analysis. Random-effects models were used to obtain overall mean difference (MD) comparing Chlorella vulgaris supplementation with a control group. MAIN OUTCOME MEASURES Blood lipids including triglyceride (TG), total cholesterol (TC), LDL-C, and HDL-C. RESULTS In total, 10 RCTs with a total sample size of 539 adults (264 in the Chlorella vulgaris group and 275 in the control group) were included. Of the 10 RCTs, four had a low risk of bias for all aspects of the Cochrane risk of bias tool. Also, only two studies determined the chlorella content, purity, potency, and contamination of the supplements used in the intervention. Combining results from these studies showed a summary MD of -2.11 mg/dL (95% CI: -7.28 to 3.06) for TG, -7.47 mg/dL (95% CI: -12.98 to -1.96) for TC, -7.71 mg/dL (95% CI: -14.05 to -1.37) for LDL-C, and -0.45 mg/dL (95% CI: -0.67 to 1.57) for HDL-C, indicating a beneficial effect of Chlorella vulgaris supplementation on TC and LDL-C levels. Based on the dose-response analysis, the reducing effect of Chlorella vulgaris supplementation on LDL-C levels was seen at the dosages between zero and 1500 mg/d (P for non-linearity= 0.01), whereas in higher amounts, this effect was not significant. CONCLUSION We found that Chlorella vulgaris supplementation had a beneficial effect on TC and LDL-C levels with no significant effect on TG and HDL-C levels.
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Impact of α-Linolenic Acid, the Vegetable ω-3 Fatty Acid, on Cardiovascular Disease and Cognition.
Sala-Vila, A, Fleming, J, Kris-Etherton, P, Ros, E
Advances in nutrition (Bethesda, Md.). 2022;13(5):1584-1602
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α-Linolenic acid (ALA) is an omega-3 fatty acid found in seeds and nuts such as flaxseeds, chia seeds, and walnuts and in oils such as canola oil, soybean oil, flaxseed oil and walnut oil. It has been shown to reduce the risk of coronary heart disease and cardiovascular disease. This meta-analysis examined the results of various studies, including epidemiologic studies, randomized controlled trials, and systematic reviews, to evaluate the beneficial effects of ALA in improving cognitive function and reducing the risk of cardiovascular disease and coronary heart disease. The included studies showed a correlation between ALA intake and a decreased risk of cardiovascular disease and coronary heart disease, possibly due to ALA's anti-inflammatory properties, as well as its ability to reduce total cholesterol, LDL cholesterol, triglycerides, and blood pressure. The analysis also found that ALA intake may reduce the risk of type 2 diabetes and cognitive impairment. Healthcare professionals can leverage the findings of this analysis to educate individuals about the benefits of dietary ALA in improving cardiovascular and cognitive outcomes. However, further studies are necessary to establish definitive conclusions and determine therapeutic dosage.
Abstract
Given the evidence of the health benefits of plant-based diets and long-chain n-3 (ω-3) fatty acids, there is keen interest in better understanding the role of α-linolenic acid (ALA), a plant-derived n-3 fatty acid, on cardiometabolic diseases and cognition. There is increasing evidence for ALA largely based on its major food sources (i.e., walnuts and flaxseed); however, this lags behind our understanding of long-chain n-3 fatty acids. Meta-analyses of observational studies have shown that increasing dietary ALA is associated with a 10% lower risk of total cardiovascular disease and a 20% reduced risk of fatal coronary heart disease. Three randomized controlled trials (RCTs) [AlphaOmega trial, Prevención con Dieta Mediterránea (PREDIMED) trial, and Lyon Diet Heart Study] all showed benefits of diets high in ALA on cardiovascular-related outcomes, but the AlphaOmega trial, designed to specifically evaluate ALA effects, only showed a trend for benefit. RCTs have shown that dietary ALA reduced total cholesterol, LDL cholesterol, triglycerides, and blood pressure, and epidemiologic studies and some trials also have shown an anti-inflammatory effect of ALA, which collectively account for, in part, the cardiovascular benefits of ALA. A meta-analysis reported a trend toward diabetes risk reduction with both dietary and biomarker ALA. For metabolic syndrome and obesity, the evidence for ALA benefits is inconclusive. The role of ALA in cognition is in the early stages but shows promising evidence of counteracting cognitive impairment. Much has been learned about the health benefits of ALA and with additional research we will be better positioned to make strong evidence-based dietary recommendations for the reduction of many chronic diseases.
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Metabolic dysfunction-associated fatty liver disease and cardiovascular disease: A meta-analysis.
Wen, W, Li, H, Wang, C, Chen, C, Tang, J, Zhou, M, Hong, X, Cheng, Y, Wu, Q, Zhang, X, et al
Frontiers in endocrinology. 2022;13:934225
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Non-alcoholic fatty liver disease (NAFLD) is a multi-system disease that not only affects the structure and function of the liver but also increases the incidence of type 2 diabetes, cardiovascular disease (CVD), cerebrovascular disease, and chronic kidney disease. In 2020, experts reached a consensus to recommend a more appropriate term to more accurately and positively define fatty liver disease associated with metabolic disorders, namely, metabolic dysfunction-associated fatty liver disease (MAFLD). The aim of this study was to investigate the risk of CVD incidence or CVD mortality in patients diagnosed with MAFLD. This study is a meta-analysis of ten cohort studies. Results show that patients in the MAFLD group had a significantly increased relative risk of CVD or death from CVD during the follow-up compared with the control group. Authors conclude that even though there is a positive association between MAFLD and the risk of CVD or death from CVD, further studies are needed to demonstrate different effects of the newly defined MAFLD on CVD compared with previous NAFLD.
Abstract
BACKGROUND Metabolic dysfunction-associated fatty liver disease [MAFLD, formerly known as nonalcoholic fatty liver disease (NAFLD)] is one of the most important causes of liver disease worldwide, while cardiovascular disease (CVD) is still one of the main causes of morbidity and mortality worldwide, and the two are closely related. This study aimed to investigate the risk of CVD incidence or CVD-related mortality (CVD mortality) in patients diagnosed with MAFLD under new concepts and new diagnostic criteria. METHODS We searched English databases PubMed, Web of Science, Embase, and Cochrane Library for relevant literature. The language was restricted to English. RESULTS By 22 January 2022, 556 published studies were obtained through preliminary retrieval, and 10 cohort studies were included in this study. All statistical analyses were performed using Review Manager 5.2 software. Compared with the control group, patients in the MAFLD group had a significantly higher relative risk of CVD incidence or CVD mortality during the follow-up, with an RR rate of 1.95 (95% CI 1.76-2.17, p < 0.01). The incidence of CVD in the MAFLD group was more than twice that in the control group (RR 2.26, 95% CI 2.00-2.54, p < 0.01). The mortality rate of CVD was 1.57 times higher than that in the control group (RR 1.57, 95% CI 1.42-1.72, p < 0.01). CONCLUSIONS Patients diagnosed with MAFLD alone had higher cardiovascular mortality than those diagnosed with NAFLD alone based on the available data.
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Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials.
Bernasconi, AA, Wiest, MM, Lavie, CJ, Milani, RV, Laukkanen, JA
Mayo Clinic proceedings. 2021;96(2):304-313
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There is mixed evidence to support the use of omega-3 fatty acids for the prevention and treatment of cardiovascular disease. Animal studies have shown promising results, but randomised control trials are inconsistent, possibly due to differing doses used, or differences in the subject’s omega-3 levels at the start of the trial. This meta-analysis of 40 studies with over 135,000 subjects aimed to determine whether omega-3 supplementation reduces heart disease risk and whether dosage has a role. The results showed that omega-3 supplementation reduced the risk of heart attacks, death from heart attacks and deaths due to heart disease, and the higher the dose, the greater the protection. The majority of studies were on individuals who had already had a heart attack or who had suffered from a related condition. It was concluded that supplementation with omega-3 is effective in preventing heart disease and heart attacks and the protective effect increases with dosage. This study could be used by healthcare professionals to prevent further heart disease and heart attacks in individuals who have already suffered from one of these conditions.
Abstract
OBJECTIVES To quantify the effect of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on cardiovascular disease (CVD) prevention and the effect of dosage. METHODS This study is designed as a random effects meta-analysis and meta-regression of randomized control trials with EPA/DHA supplementation. This is an update and expanded analysis of a previously published meta-analysis which covers all randomized control trials with EPA/DHA interventions and cardiovascular outcomes published before August 2019. The outcomes included are myocardial infarction (MI), coronary heart disease (CHD) events, CVD events (a composite of MI, angina, stroke, heart failure, peripheral arterial disease, sudden death, and non-scheduled cardiovascular surgical interventions), CHD mortality and fatal MI. The strength of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework. RESULTS A total of 40 studies with a combined 135,267 participants were included. Supplementation was associated with reduced risk of MI (relative risk [RR], 0.87; 95% CI, 0.80 to 0.96), high certainty number needed to treat (NNT) of 272; CHD events (RR, 0.90; 95% CI, 0.84 to 0.97), high certainty NNT of 192; fatal MI (RR, 0.65; 95% CI, 0.46 to 0.91]), moderate certainty NNT = 128; and CHD mortality (RR, 0.91; 95% CI, 0.85 to 0.98), low certainty NNT = 431, but not CVD events (RR, 0.95; 95% CI, 0.90 to 1.00). The effect is dose dependent for CVD events and MI. CONCLUSION Cardiovascular disease remains the leading cause of death worldwide. Supplementation with EPA and DHA is an effective lifestyle strategy for CVD prevention, and the protective effect probably increases with dosage.
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Effects of Vegetarian Diets on Blood Pressure Lowering: A Systematic Review with Meta-Analysis and Trial Sequential Analysis.
Lee, KW, Loh, HC, Ching, SM, Devaraj, NK, Hoo, FK
Nutrients. 2020;12(6)
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High blood pressure or hypertension is defined as systolic blood pressure of 140 mmHg or higher, and diastolic blood pressure of 90 mmHg or higher. It is an independent and major risk factor for cardiovascular disease and chronic kidney failure. The aim of this study was to determine the effect of a vegetarian diet on the reduction of blood pressure. This study is a systematic review together with trial sequential analysis. A total of 15 studies involving 856 individuals met the eligibility criteria and were included in the final analyses. Results show that a vegetarian dietary pattern significantly reduced systolic and diastolic blood pressure. Furthermore, dietary patterns based solely on plant sources are more effective in reducing blood pressure than other types of vegetarian diet which still include animal products or by-products, such as eggs and dairy products. Authors conclude that vegetarian diets, especially vegan diets, reduce blood pressure when compared with omnivorous diets. Thus, suggesting that they may be crucial in the primary prevention and overall management of hypertension.
Abstract
The beneficial effects of a vegetarian diet on blood pressure (BP) control have been reported in previous systematic reviews; however, so far, their relative effectiveness is not well established. Here, we performed a systematic review together with trial sequential analysis to determine the effect of a vegetarian diet on the reduction of blood pressure. We searched the randomized controlled trial (RCT) through Medline, PubMed and Cochrane Central Register. Fifteen eligible RCTs with 856 subjects were entered into the analysis. The pooled results demonstrated that vegetarian diet consumption significantly lowered the systolic blood pressure (weighted mean difference (WMD), -2.66 mmHg (95% confidence interval (CI) = -3.76, -1.55, p < 0.001) and diastolic BP was WMD, -1.69 95% CI = -2.97, -0.41, p < 0.001) as compared to an omnivorous diet. In subgroup analysis, a vegan diet demonstrated a greater reduction in systolic BP (WMD, -3.12 mm Hg; 95% CI = -4.54, -1.70, p < 0.001) as compared with a lacto-ovo-vegetarian diet (WMD, -1.75 mm Hg, 95% CI -5.38, 1.88, p = 0.05). The vegan diet has showed a similar trend in terms of diastolic blood pressure reduction (WMD, -1.92 mm Hg (95% CI = -3.18, -0.66, p < 0.001) but those with a lacto-ovo-vegetarian diet showed no changes in diastolic BP reduction (WMD, 0.00, 95% CI = 0.00, 0.00), p =0.432). In conclusion, vegetarian diets are associated with significant reductions in BP compared with omnivorous diets, suggesting that they may play a key role in the primary prevention and overall management of hypertension.
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Blood pressure, hypertension and the risk of sudden cardiac death: a systematic review and meta-analysis of cohort studies.
Pan, H, Hibino, M, Kobeissi, E, Aune, D
European journal of epidemiology. 2020;35(5):443-454
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Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Sudden cardiac death (SCD) accounts for more than 60% of all cardiovascular deaths. This study is a systematic review and meta-analysis of 18 cohort studies on the association between hypertension or blood pressure and the risk of SCD with an aim of clarifying the presence and strength of the association as well as to investigate the dose–response relationship and potential sources of heterogeneity in the results. Results show a twofold increase in risk for SCD with prevalent hypertension and a 28% increase in risk for SCD per 20 mmHg increment in systolic blood pressure. Whereas, there wasn’t a significant association between diastolic blood pressure and SCD. Authors conclude that public health policies and interventions to further address the hypertension epidemic are recommended to reduce the burden of SCD.
Abstract
Cardiovascular disease is the leading cause of death worldwide, while sudden cardiac death (SCD) accounts for over 60% of all cardiovascular deaths. Elevated blood pressure and hypertension have been associated with increased risk of SCD, but the findings have not been consistent. To clarify whether blood pressure or hypertension is associated with increased risk of SCD and to quantify the size and the shape of any association observed. PubMed and Embase databases were searched for published prospective studies on blood pressure or hypertension and SCD up to 30 April 2018. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random effects model. The meta-analysis included 2939 SCDs among 418,235 participants from 18 studies. The summary RRs were 2.10 (95% CI 1.71-2.58, I2 = 56.7%, pheterogeneity = 0.018, n = 10) for prevalent hypertension, 1.28 (95% CI 1.19-1.38, I2 = 45.5%, pheterogeneity = 0.07, n = 10) per 20 mmHg increment in systolic blood pressure (SBP) and 1.09 (95% CI 0.83-1.44, I2 = 83.4%, pheterogeneity = 0.002, n = 3) per 10 mmHg increment in diastolic blood pressure (DBP). A nonlinear relationship was suggested between SBP and SCD. The results persisted in most subgroup and sensitivity analyses. There was no evidence of publication bias. This meta-analysis found an increased risk of SCD with hypertension diagnosis and increasing SBP. Future studies should clarify the association for DBP and the shape of the dose-response relationship between blood pressure and SCD.
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The effects of coenzyme Q10 supplementation on biomarkers of inflammation and oxidative stress in among coronary artery disease: a systematic review and meta-analysis of randomized controlled trials.
Jorat, MV, Tabrizi, R, Kolahdooz, F, Akbari, M, Salami, M, Heydari, ST, Asemi, Z
Inflammopharmacology. 2019;27(2):233-248
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Cardiovascular disease is the leading cause of death worldwide. Systemic inflammation and oxidative stress significantly contribute to the narrowing of the blood supply to the heart leading to coronary artery disease (CAD). Increased levels of several markers of inflammation, such as C-reactive protein (CRP), tumour necrosis factor-α (TNF- α), and interleukin-6 (IL-6), appear to be indicative of heart attack risk. Coenzyme Q10 (CoQ10) is a naturally occurring nutrient made in the body but can also be found in some foods or taken via supplements. It is an antioxidant that protects cell membranes and mitochondria against oxidative damage and also does so in the heart by preventing endothelial damage and the associated narrowing of blood vessels. Several trials investigated the effects of CoQ10 on inflammation and oxidative stress, with some noteworthy results and yet also some conflicting evidence. Hence this systematic review and meta-analysis aimed to shed some light on the controversial findings regarding coenzyme Q10 (CoQ10) supplementation on biomarkers of inflammation and oxidative stress amongst patients with CAD. The authors included 13 clinical randomised controlled trials, amounting to 364 cardiac patients in the intervention groups. The treatment duration ranged from 4 to 48 weeks, and the dosage of CoQ10 varied between 60 to 300 mg/day. In conclusion, the meta-analysis showed that CoQ10 supplementation increased antioxidant markers of superoxide dismutase (SOD) and catalase (CAT), and decreased the oxidative stress marker malondialdehyde (MDA) and its derivative forms. There was no consistent effect on inflammatory markers of CRP, TNF-α, IL-6 or the levels of the antioxidant glutathione peroxidase. The discrepancies amongst the different studies may be a result of the divergent study designs, different population characteristics, the dosage of CoQ10 used and the duration of intervention.
Abstract
OBJECTIVE Systemic inflammation and oxidative stress significantly contribute in developing coronary artery disease (CAD). This systematic review and meta-analysis was aimed to determine the effects of coenzyme Q10 (CoQ10) supplementation on biomarkers of inflammation and oxidative stress among patients with CAD. METHODS The electronic databases including MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library databases were systematically searched until Oct 2018. The quality assessment and heterogeneity of the selected randomized clinical Trials (RCTs) were examined using the Cochrane Collaboration risk of bias tool, and Q and I2 tests, respectively. Given the presence of heterogeneity, random-effects model or fixed-effect model were used to pool standardized mean differences (SMDs) as summary effect sizes. RESULTS A total of 13 clinical RCTs of 912 potential citations were found to be eligible for the current meta-analysis. The pooled findings for biomarkers of inflammation and oxidative stress demonstrated that CoQ10 supplementation significantly increased superoxide dismutase (SOD) (SMD 2.63; 95% CI, 1.17, 4.09, P < 0.001; I2 = 94.5%) and catalase (CAT) levels (SMD 1.00; 95% CI, 0.57, 1.43, P < 0.001; I2 = 24.5%), and significantly reduced malondialdehyde (MDA) (SMD - 4.29; 95% CI - 6.72, - 1.86, P = 0.001; I2 = 97.6%) and diene levels (SMD - 2.40; 95% CI - 3.11, - 1.68, P < 0.001; I2 = 72.6%). We did not observe any significant effect of CoQ10 supplementation on C-reactive protein (CRP) (SMD - 0.62; 95% CI - 1.31, 0.08, P = 0.08; I2 = 87.9%), tumor necrosis factor alpha (TNF-α) (SMD 0.22; 95% CI - 1.07, 1.51, P = 0.73; I2 = 89.7%), interleukin-6 (IL-6) (SMD - 1.63; 95% CI - 3.43, 0.17, P = 0.07; I2 = 95.2%), and glutathione peroxidase (GPx) levels (SMD 0.14; 95% CI - 0.77, 1.04, P = 0.76; I2 = 78.7%). CONCLUSIONS Overall, this meta-analysis demonstrated CoQ10 supplementation increased SOD and CAT, and decreased MDA and diene levels, but did not affect CRP, TNF-α, IL-6, and GPx levels among patients with CAD.
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Association between plant-based diets and plasma lipids: a systematic review and meta-analysis.
Yokoyama, Y, Levin, SM, Barnard, ND
Nutrition reviews. 2017;75(9):683-698
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Plasma lipids play a prominent role in heart disease and modifiable factors such as diet and lifestyle can facilitate in preventing or developing hyperlipidemia. Previous research has suggested that vegetarian diets are associated with lower plasma lipid concentrations, however long-term impacts of consuming a plant-based diet (PBD) has not been studied. The aim of this research was to conduct a systematic review and meta-analysis for studies that have examined the relationship between PBDs and plasma lipids. Thirty observational studies and 19 clinical trials were included in this analysis and showed consumption of a PBD was significantly associated with lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), but not in triglyceride concentrations. Based on these results, the authors conclude PBDs could offer individuals and healthcare professionals an effective option for reducing heart disease. They also add that while dietary changes may not be as powerful as pharmaceutical drugs in reducing plasma lipids, dietary and pharmacologic interventions can work together.
Abstract
CONTEXT Although a recent meta-analysis of randomized controlled trials showed that adoption of a vegetarian diet reduces plasma lipids, the association between vegetarian diets and long-term effects on plasma lipids has not been subjected to meta-analysis. OBJECTIVE The aim was to conduct a systematic review and meta-analysis of observational studies and clinical trials that have examined associations between plant-based diets and plasma lipids. DATA SOURCES MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for articles published in English until June 2015. STUDY SELECTION The literature was searched for controlled trials and observational studies that investigated the effects of at least 4 weeks of a vegetarian diet on plasma lipids. DATA EXTRACTION Two reviewers independently extracted the study methodology and sample size, the baseline characteristics of the study population, and the concentrations and variance measures of plasma lipids. Mean differences in concentrations of plasma lipids between vegetarian and comparison diet groups were calculated. Data were pooled using a random-effects model. RESULTS Of the 8385 studies identified, 30 observational studies and 19 clinical trials met the inclusion criteria (N = 1484; mean age, 48.6 years). Consumption of vegetarian diets was associated with lower mean concentrations of total cholesterol (-29.2 and -12.5 mg/dL, P < 0.001), low-density lipoprotein cholesterol (-22.9 and -12.2 mg/dL, P < 0.001), and high-density lipoprotein cholesterol (-3.6 and -3.4 mg/dL, P < 0.001), compared with consumption of omnivorous diets in observational studies and clinical trials, respectively. Triglyceride differences were -6.5 (P = 0.092) in observational studies and 5.8 mg/dL (P = 0.090) in intervention trials. CONCLUSIONS Plant-based diets are associated with decreased total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, but not with decreased triglycerides. SYSTEMATIC REVIEW REGISTRATION PROSPERO number CRD42015023783. Available at: https://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015023783.