1.
Impact of dietary anthocyanins on systemic and vascular inflammation: Systematic review and meta-analysis on randomised clinical trials.
Fallah, AA, Sarmast, E, Fatehi, P, Jafari, T
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2020;135:110922
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Low-grade chronic inflammation contributes to the development of various chronic conditions like diabetes mellitus type2, chronic kidney disease, stroke, atherosclerosis, cardiovascular diseases, and cancer. Anthocyanins, a member of the flavonoid family, are water-soluble pigments that give plants their red-orange to blue-violet colours and have been shown to have antioxidant properties. The aim of this review and meta-analysis of 32 randomised controlled trials was to evaluate the impact of pure anthocyanins or anthocyanin-rich extracts/powders on inflammatory markers. The quality of studies for the meta-analysis was high for the inflammatory markers CRP (C-reactive protein), IL-6, TNF-alpha, adiponectin, and VCAM-1. There was a significant reduction in the pro-inflammatory CRP, IL-6, TNF-alpha and VCAM-1, and a significant increase in the anti-inflammatory adinopectin. Quality of studies was poor for other inflammatory markers evaluated. Higher doses tended to have a bigger positive effect. The authors conclude that anthocyanins may reduce inflammation.
Abstract
Anthocyanins are natural bioactive compounds that have several health benefits. This systematic review and meta-analysis assessed the impact of dietary anthocyanins on markers of systemic and vascular inflammation. Meta-analysis of 32 randomised controlled trials indicated that dietary anthocyanins significantly decreased levels of C-reactive protein (CRP; -0.33 mg/l, 95% CI: -0.55 to -0.11, P = 0.003), interleukin-6 (IL-6; -0.41 ρg/ml, 95% CI: -0.70 to -0.13, P = 0.004), tumor necrosis factor-alpha (TNF-α; -0.64 ρg/ml, 95% CI: -1.18 to -0.09, P = 0.023), intercellular adhesion molecule-1 (-52.4 ng/ml, 95% CI: -85.7 to -19.1, P = 0.002), and vascular adhesion molecule-1 (VCAM-1; -49.6 ng/ml, 95% CI: -72.7 to -26.5, P < 0.001) while adiponectin level was significantly increased (0.75 μg/ml, 95% CI: 0.23 to 1.26, P = 0.004). The levels of interleukin-1β (IL-1β; -0.45 ρg/ml, 95% CI: -3.77 to 2.88, P = 0.793) and P-selectin (-6.98 ng/ml, 95% CI: -18.1 to 4.15, P = 0.219) did not significantly change. Subgroup analyses showed that administration of higher doses of anthocyanins (>300 mg/day) significantly decreased levels of CRP, IL-6, TNF-α, and VCAM-1. The results indicate that dietary anthocyanins reduce the levels of systemic and vascular inflammation in the subjects.
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Prevention of Type 2 Diabetes by Lifestyle Changes: A Systematic Review and Meta-Analysis.
Uusitupa, M, Khan, TA, Viguiliouk, E, Kahleova, H, Rivellese, AA, Hermansen, K, Pfeiffer, A, Thanopoulou, A, Salas-Salvadó, J, Schwab, U, et al
Nutrients. 2019;11(11)
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With Type 2 Diabetes growing globally this paper analyses whether T2D is preventable with lifestyle measures including diet. Seven RCTs were included for review with a total of 4090 participants, and 2466 incidents of T2D, and were chosen on the basis that the lifestyle interventions included both physical exercise and diet (typically Mediterranean Diet). They found that diet and lifestyle intervention reduced the risk of T2D by 47%. Sustained risk reduction was also found in follow-up studies up to 10 years later with participants maintaining improved blood glucose control. Lifestyle interventions may also reduce risk factors for cardiovascular disease. Weight reduction was considered a cornerstone of preventing T2D and adherence to lifestyle changes a key element in long term prevention. Dietary foods reviewed include processed meats, white rice and sugars which correlated highly with T2D whilst leafy greens, berries, wholegrains, legumes, dietary fibre and yoghurt correlate with a lower risk of T2D. Dietary patterns of skipping breakfast and snacking correlate higher with T2D. Different criteria for evaluating physical activity estimate that it reduces risk factors by 50%. In conclusion there is high evidence that lifestyle factors which optimise diet, increase physical activity and promote weight reduction are preventative factors for T2D and can be sustained long term.
Abstract
Prevention of type 2 diabetes (T2D) is a great challenge worldwide. The aim of this evidence synthesis was to summarize the available evidence in order to update the European Association for the Study of Diabetes (EASD) clinical practice guidelines for nutrition therapy. We conducted a systematic review and, where appropriate, meta-analyses of randomized controlled trials (RCTs) carried out in people with impaired glucose tolerance (IGT) (six studies) or dysmetabolism (one study) to answer the following questions: What is the evidence that T2D is preventable by lifestyle changes? What is the optimal diet (with a particular focus on diet quality) for prevention, and does the prevention of T2D result in a lower risk of late complications of T2D? The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was applied to assess the certainty of the trial evidence. Altogether seven RCTs (N = 4090) fulfilled the eligibility criteria and were included in the meta-analysis. The diagnosis of incident diabetes was based on an oral glucose tolerance test (OGTT). The overall risk reduction of T2D by the lifestyle interventions was 0.53 (95% CI 0.41; 0.67). Most of the trials aimed to reduce weight, increase physical activity, and apply a diet relatively low in saturated fat and high in fiber. The PREDIMED trial that did not meet eligibility criteria for inclusion in the meta-analysis was used in the final assessment of diet quality. We conclude that T2D is preventable by changing lifestyle and the risk reduction is sustained for many years after the active intervention (high certainty of evidence). Healthy dietary changes based on the current recommendations and the Mediterranean dietary pattern can be recommended for the long-term prevention of diabetes. There is limited or insufficient data to show that prevention of T2D by lifestyle changes results in a lower risk of cardiovascular and microvascular complications.
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Effect of High-Dose Marine Omega-3 Fatty Acids on Atherosclerosis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Sekikawa, A, Cui, C, Sugiyama, D, Fabio, A, Harris, WS, Zhang, X
Nutrients. 2019;11(11)
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This systematic review and meta-analysis reports that high dose omega 3 at a dose of 3g/day with 90% purity significantly slowed the progression of atherosclerosis and is a promising mechanism for reducing cardiovascular (CVD) incidents. The study reviewed 6 articles from 2016-2017 with a total of 693 participants, which met the criteria of omega 3 and a primary outcome on atherosclerosis. Only one trial was placebo controlled with the remaining five open-label trials with no placebo. Four of the trials were conducted in Japan using a highly purified EPA whilst the remaining trials used an EPA / DHA combination. The effect of high dose omega 3 was significant even after removing the two most influential studies. Preclinical studies in animal models show that Omega 3 slows atherosclerosis progression through various molecular mechanisms. In humans there is less conclusive evidence and observational studies report that dietary intake of Omega 3 has no significant correlation with coronary artery calcification, the measure used to assess atherosclerosis. The limitation of this study is that different technologies were used to assess atherosclerosis across the selected trials. However, the authors conclude that the anti-atherosclerotic properties of high-dose OM3 are one potential mechanism in reducing CVD risk.
Abstract
A recent randomized controlled trial (RCT), the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT), reported that high-dose marine omega-3 fatty acids (OM3) significantly reduce cardiovascular disease (CVD) outcomes, yet the mechanisms responsible for this benefit remain unknown. To test the hypothesis that high-dose OM3 is anti-atherosclerotic, we performed a systematic review and meta-analysis of RCT of high-dose OM3 on atherosclerosis. The protocol of this systematic review was registered with PROSPERO (CRD42019125566). PubMed, Embase, Cochran Central Register for Controlled Trials, and Clinicaltrials.gov databases were searched using the following criteria: adult participants, high-dose OM3 (defined as ≥3.0 g/day, or in Japan 1.8 g/day and purity ≥90%) as the intervention, changes in atherosclerosis as the outcome, and RCTs with an intervention duration of ≥6 months. A random-effects meta-analysis was used to pool estimates across studies. Among the 598 articles retrieved, six articles met our criteria. Four RCTs evaluated atherosclerosis in the coronary and two in the carotid arteries. High-dose OM3 significantly slowed the progression of atherosclerosis (standardized mean difference -1.97, 95% confidence interval -3.01, -0.94, p < 0.001). The results indicate that anti-atherosclerotic effect of high-dose OM3 is one potential mechanism in reducing CVD outcomes demonstrated in the REDUCE-IT trial.
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Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.
Abdelhamid, AS, Brown, TJ, Brainard, JS, Biswas, P, Thorpe, GC, Moore, HJ, Deane, KH, AlAbdulghafoor, FK, Summerbell, CD, Worthington, HV, et al
The Cochrane database of systematic reviews. 2018;7:CD003177
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Dietary intake or supplementation with omega-3 fats from fish and some plant foods such as flaxseed, are commonly believed to reduce the risk of cardiovascular disease. This systematic review of 79 trials, including 112,000 individuals, aimed to assess the impacts of greater omega-3 intake versus lower or no omega-3 intake for heart and circulatory disease. The results of this systematic review showed that increasing EPA and DHA (omega-3 oils from fish) had little or no effect on all cause death or cardiovascular events and probably little or no effect on cardiovascular deaths (evidence mainly from supplement trials). EPA and DHA were found to reduce blood fat levels (triglycerides) and raise HDL (good cholesterol). Eating more ALA (omega-3 fats from walnuts for example) probably makes little or no difference to all-cause or cardiovascular death but probably slightly reduce cardiovascular events.
Abstract
BACKGROUND Researchers have suggested that omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this. OBJECTIVES To assess effects of increased intake of fish- and plant-based omega-3 for all-cause mortality, cardiovascular (CVD) events, adiposity and lipids. SEARCH METHODS We searched CENTRAL, MEDLINE and Embase to April 2017, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to September 2016, with no language restrictions. We handsearched systematic review references and bibliographies and contacted authors. SELECTION CRITERIA We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation and/or advice to increase LCn3 or ALA intake versus usual or lower intake. DATA COLLECTION AND ANALYSIS Two review authors independently assessed studies for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression. MAIN RESULTS We included 79 RCTs (112,059 participants) in this review update and found that 25 were at low summary risk of bias. Trials were of 12 to 72 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most studies assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet.Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (RR 0.98, 95% CI 0.90 to 1.03, 92,653 participants; 8189 deaths in 39 trials, high-quality evidence), cardiovascular mortality (RR 0.95, 95% CI 0.87 to 1.03, 67,772 participants; 4544 CVD deaths in 25 RCTs), cardiovascular events (RR 0.99, 95% CI 0.94 to 1.04, 90,378 participants; 14,737 people experienced events in 38 trials, high-quality evidence), coronary heart disease (CHD) mortality (RR 0.93, 95% CI 0.79 to 1.09, 73,491 participants; 1596 CHD deaths in 21 RCTs), stroke (RR 1.06, 95% CI 0.96 to 1.16, 89,358 participants; 1822 strokes in 28 trials) or arrhythmia (RR 0.97, 95% CI 0.90 to 1.05, 53,796 participants; 3788 people experienced arrhythmia in 28 RCTs). There was a suggestion that LCn3 reduced CHD events (RR 0.93, 95% CI 0.88 to 0.97, 84,301 participants; 5469 people experienced CHD events in 28 RCTs); however, this was not maintained in sensitivity analyses - LCn3 probably makes little or no difference to CHD event risk. All evidence was of moderate GRADE quality, except as noted.Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and it may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low-quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low-quality evidence), and probably reduces risk of CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs), and arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear.Sensitivity analysis retaining only trials at low summary risk of bias moved effect sizes towards the null (RR 1.0) for all LCn3 primary outcomes except arrhythmias, but for most ALA outcomes, effect sizes moved to suggest protection. LCn3 funnel plots suggested that adding in missing studies/results would move effect sizes towards null for most primary outcomes. There were no dose or duration effects in subgrouping or meta-regression.There was no evidence that increasing LCn3 or ALA altered serious adverse events, adiposity or lipids, although LCn3 slightly reduced triglycerides and increased HDL. ALA probably reduces HDL (high- or moderate-quality evidence). AUTHORS' CONCLUSIONS This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia.
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The effects of probiotics on total cholesterol: A meta-analysis of randomized controlled trials.
Wang, L, Guo, MJ, Gao, Q, Yang, JF, Yang, L, Pang, XL, Jiang, XJ
Medicine. 2018;97(5):e9679
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Total cholesterol levels are commonly used as a marker of cardiovascular disease risk. The impact of probiotics on total cholesterol has been controversial. This meta-analysis of 32 randomised controlled trials including 1971 patients aimed to explore the effects of different probiotic strains on serum total cholesterol. The results of the meta-analysis showed that total cholesterol levels were significantly reduced in the probiotic group when compared with controls. Lactobacillus acidophilus, Bifidobacterium lactis, VSL#3 and Lactobacillus plantarum were found to have the most significant effects. In addition, a higher total cholesterol at the start of probiotic supplementation, a supplementation duration of longer than 8 weeks and taking the probiotics in capsule form as opposed to yoghurt, were found to have a greater impact. Nutrition practitioners wishing to support clients in the reduction of total cholesterol levels may want to consider the use of targeted probiotic therapy in their nutrition protocols.
Abstract
BACKGROUND Probiotics supplements provide a new nonpharmacological alternative to reduce cardiovascular risk factors. The impact of probiotics on the reduction of total cholesterol (TC) remains controversial. We conducted a meta-analysis to showcase the most updated and comprehensive evaluation of the studies. METHODS Randomized controlled trials (RCTs) were searched from electronic databases, including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wanfang database dating from January 2007 to January 2017. The curative effects of probiotics on the reduction of TC were assessed using mean difference (MD), as well as their 95% confidence interval (CI). RevMan software (version 5.3) was used to carry out this meta-analysis. RESULTS Thirty-two RCTs including 1971 patients met the inclusion criteria. Results of this analysis showed that compared with the control group serum TC was significantly reduced in probiotics group [MD = -13.27, 95% CI (-16.74 to 9.80), P < .05]. In addition, specific strains also significantly reduced serum TC, L acidophilus and B lactis [MD = -8.30, 95% CI (-10.44, -6.15), P < .05]; VSL#3 [MD = -11.04, 95% CI (-19.61, -2.48), P < .05]; L plantarum t ≤ 6 weeks: [MD = -1.56, 95% CI (-6.97, -3.86), P < .05] or t > 6 weeks: [MD = -22.18, 95% CI (-28.73, -15.63), P < .05]. Subgroup analysis indicated that the difference of baseline TC, probiotics forms and intervention duration might have a significant impact on the results. However, strains and doses of probiotics had no significant influence on curative effects. CONCLUSION Available evidence indicates that probiotics supplements can significantly reduce serum TC. Furthermore, higher baseline TC, longer intervention time, and probiotics in capsules form might contribute to a better curative effect.