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Nuts and seeds consumption and risk of cardiovascular disease, type 2 diabetes and their risk factors: a systematic review and meta-analysis.
Arnesen, EK, Thorisdottir, B, Bärebring, L, Söderlund, F, Nwaru, BI, Spielau, U, Dierkes, J, Ramel, A, Lamberg-Allardt, C, Åkesson, A
Food & nutrition research. 2023;67
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Nuts and seeds consumption is associated with a reduced risk of coronary heart disease (CHD) and cardiovascular disease (CVD). Nuts and seeds contain beneficial components to reduce the risk of CVD and CHD; hence dietary addition may benefit heart health. This systematic review and meta-analysis included sixty studies to analyse the effects of the consumption of nuts and seeds on the incidence of mortality from type 2 diabetes (T2D) and CVD and intermediate cardiometabolic risk factors. High nuts and seed consumption showed a 19% reduction in CVD risk and a 23% reduction in CVD mortality. In addition, high consumption lowered the risk of CHD by 25%. Increased nut consumption up to 30 g/day showed a dose-dependent relationship with reduced risk of CVD. Healthcare professionals can use the results of this study to understand the association between nuts and seeds consumption and CHD, CVD and blood lipid levels. However, further robust studies are required to evaluate the effect of specific nuts and seeds on CHD and CVD risk reduction.
Abstract
OBJECTIVES We aimed to systematically review studies and evaluate the strength of the evidence on nuts/seeds consumption and cardiometabolic diseases and their risk factors among adults. METHODS A protocol was pre-registered in PROSPERO (CRD42021270554). We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Scopus up to September 20, 2021 for prospective cohort studies and ≥12-week randomized controlled trials (RCTs). Main outcomes were cardiovascular disease (CVD), coronary heart disease (CHD), stroke and type 2 diabetes (T2D), secondary total-/low density lipoprotein (LDL)-cholesterol, blood pressure and glycaemic markers. Data extraction and risk of bias (RoB) assessments (using RoB 2.0 and RoB-NObS) were performed in duplicate. Effect sizes were pooled using random-effects meta-analyses and expressed as relative risk (RR) or weighted mean differences with 95% confidence intervals (CI); heterogeneity quantified as I 2. One-stage dose-response analyses assessed the linear and non-linear associations with CVD, CHD, stroke and T2D. The strength of evidence was classified per the World Cancer Research Fund criteria. RESULTS After screening 23,244 references, we included 42 papers from cohort studies (28 unique cohorts, 1,890,573 participants) and 18 RCTs (2,266 participants). In the cohorts, mainly populations with low consumption, high versus low total nuts/seeds consumption was inversely associated with total CVD (RR 0.81; 95% CI 0.75, 0.86; I 2 = 67%), CVD mortality (0.77; 0.72, 0.82; I 2 = 59.3%), CHD (0.82; 0.76, 0.89; I 2 = 64%), CHD mortality (0.75; 0.65, 0.87; I 2 = 66.9%) and non-fatal CHD (0.85; 0.75, 0.96; I 2 = 62.2%). According to the non-linear dose-response analyses, consumption of 30 g/day of total nuts/seeds was associated with RRs of similar magnitude. For stroke and T2D the summary RR for high versus low intake was 0.91 (95% CI 0.85, 0.97; I 2 = 24.8%) and 0.95 (0.75, 1.21; I 2 = 82.2%). Intake of nuts (median ~50 g/day) lowered total (-0.15 mmol/L; -0.22, -0.08; I 2 = 31.2%) and LDL-cholesterol (-0.13 mmol/L; -0.21, -0.05; I 2 = 68.6%), but not blood pressure. Findings on fasting glucose, HbA1c and insulin resistance were conflicting. The results were robust to sensitivity and subgroup analyses. We rated the associations between nuts/seeds and both CVD and CHD as probable. There was limited but suggestive evidence for no association with stroke. No conclusion could be made for T2D. CONCLUSION There is a probable relationship between consumption of nuts/seeds and lower risk of CVD, mostly driven by CHD, possibly in part through effects on blood lipids. More research on stroke and T2D may affect the conclusions. The evidence of specific nuts should be further investigated.
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The effect of synbiotic supplementation on hypothyroidism: A randomized double-blind placebo controlled clinical trial.
Ramezani, M, Reisian, M, Sajadi Hezaveh, Z
PloS one. 2023;18(2):e0277213
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Despite the increased awareness and the improvements in medical management of hypothyroidism; depression, mood disturbance and poor health-related quality of life (QoL) is common among hypothyroid patients. Synbiotics have been advocated as being beneficial to patients with metabolic diseases. Synbiotics are a mixture of probiotics and prebiotics that beneficially affect the host by improving the survival and stimulating the growth of advantageous and health promoting microbial species in the gastrointestinal tract. The aim of this study was to examine whether synbiotic supplementation could enhance depression, QoL, and blood pressure, as well as thyroid hormones in hypothyroid patients. This study is a 10-week parallel design randomised placebo-controlled trial. Participants – adults with hypothyroidism - were randomly assigned to the synbiotic (n = 28) or the placebo (n = 28) group. Results show that following 10 weeks supplementation with synbiotics (500 mg of 10⁹ CFU/g probiotics plus fructo-oligosaccharide) in comparison to placebo does not affect serum thyroid stimulating hormone level and depression. However, it significantly improved blood pressure levels and various domains and areas of QoL. Authors conclude that further clinical trials are needed to assess the effectiveness of a synbiotic supplementation along with the current routine treatment for hypothyroid patients.
Abstract
OBJECTIVE We hypothesize that synbiotic supplementation could modulate the intestinal microbiota and subsequently, improve the condition of hypothyroid patients. METHODS Fifty-six adult hypothyroid patients were recruited to this double-blind, placebo-controlled, randomized clinical trial. The intervention was 10 weeks of synbiotic (500 mg of 109 CFU/g probiotics plus fructo-oligosaccharide, n = 28) compared to placebo (lactose, magnesium stearate, talc, and silicon dioxide, n = 28). Randomization and allocation to trial groups were carried out using random number sequences drawn from https://sealedenvelope.com/. Primary outcomes were serum thyroid stimulating hormone (TSH) and free thyroxine (FT4), and secondary outcomes were depression, quality of life, and blood pressure (BP). P-values< 0.05 were considered statistically significant. RESULTS Analysis on 51 patients who completed the trial showed that TSH and depression (p> 0.05) did not change significantly, while serum FT4 significantly increased in both groups (p = 0.03 and p = 0.02 in symbiotic and placebo respectively). A significant decrease in systolic BP occurred only in the synbiotic group (p = 0.05). Significant improvements occurred regarding different domains and areas of quality of life in the crude and adjusted analysis, including perceived mental health (p = 0.02), bodily pain (p = 0.02), general health perception (p = 0.002), and wellbeing (p = 0.002), which were significantly higher in the synbiotic group. CONCLUSIONS Ten-week supplementation with synbiotic had no favorable effect on depression and TSH, but it improved blood pressure and quality of life in patients with hypothyroidism. More trials are needed to support or reject these findings. TRIAL REGISTRATION IRCT20210926052583N1, Iranian Registry of Clinical Trials (IRCT), registered October 1st, 2021.
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Is Extra Virgin Olive Oil the Critical Ingredient Driving the Health Benefits of a Mediterranean Diet? A Narrative Review.
Flynn, MM, Tierney, A, Itsiopoulos, C
Nutrients. 2023;15(13)
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Cardiovascular diseases (CVDs) are the largest contributor to deaths globally, followed by cancers, chronic respiratory diseases and diabetes. It is estimated that 90% of deaths from CVD can be prevented with modifiable risk factors such as diet. The Mediterranean diet, which is rich in extra virgin olive oil (EVOO), is important in the prevention of chronic diseases. There is however very little focus on differentiating healthy fats such as EVOO from other fats and oils in dietary guidelines. This review of 34 studies aims to compare the effect of diets that include EVOO on cardiometabolic risk factors for heart disease, metabolic syndrome, and type 2 diabetes. It looks at the effects on blood pressure (SBP), low- and high-density lipoprotein cholesterol, (HDP-c and LDD-c) fasting blood glucose (FBG) and body weight. It also assesses from published studies the minimum daily amount of EVOO and the shortest time needed to see improvements in the risk factors. There is evidence to support EVOO in improving SBP in patients with high blood pressure, with studies suggesting that specific phenols in the oil may be important compared with a refined olive oil. Compared with other dietary fats or low-fat diets, EVOO can decrease LDL-c and increase HDL-c. Diets including daily EVOO are effective for weight loss. The effect of EVOO on FBG compared with other diets is not yet clear. The authors state that EVOO would be a far superior choice compared with other dietary fats, low-fat diets, or refined olive oil. The daily use of EVOO starting at approximately two tablespoons a day will improve a range of risk factors in as few as three weeks.
Abstract
Most chronic diseases are preventable with a healthy diet, although there is debate about the optimal dietary approach. Increasingly more countries are focusing on food-based guidelines rather than the traditional nutrient-based approach. Although there is good agreement on plant foods, controversy remains about the types and amounts of fats and oils. This narrative review aims to systematically summarize and evaluate the latest evidence on the protective effects of extra virgin olive oil (EVOO) on disease risk factors. A systematic search of the relevant literature using PubMed, Cochrane Library, and Embase databases was conducted for the years 2000 through December 2022. A narrative synthesis was then undertaken. Of 281 retrieved articles, 34 articles fulfilled our inclusion criteria and were included. Compared with other dietary fats and low-fat diets, EVOO is superior in the management of clinical biomarkers including lowering blood pressure and LDL-c, increasing protective HDL-c, improving glycemic control, and weight management. The protective effects of EVOO are likely due to its polyphenol content rather than the monounsaturated fat content. It is therefore important to promote the regular use of EVOO in the context of healthy dietary patterns such as the Mediterranean diet for maximal health benefit.
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Coffee Consumption and Risk of Hypertension in Adults: Systematic Review and Meta-Analysis.
Haghighatdoost, F, Hajihashemi, P, de Sousa Romeiro, AM, Mohammadifard, N, Sarrafzadegan, N, de Oliveira, C, Silveira, EA
Nutrients. 2023;15(13)
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High blood pressure (hypertension) is the main risk factor for cardiovascular diseases. Over the past decades the number of people experiencing high blood pressure has steadily increased, making it a serious concern for public health. Many dietary factors influence the development of high blood pressure, either increasing of decreasing the risk. Coffee is a widely consumed beverage. The caffeine in coffee can stimulate stress hormones like adrenaline. Adrenaline increases blood pressure, inflammation and decreases sensitivity to insulin, which are all regarded as risk factors for cardiovascular diseases. At the same time coffee contains many blood pressure lowering nutrients and compounds. Whether coffee contributes or diminishes the risks of developing high blood pressure has remained controversial. Hence, this systematic review and meta-analysis aimed to summarise the current evidence on coffee and hypertension risk. The analysis included 25 observational studies published between 2002 and 2023. The results concluded that coffee consumption was associated with a small reduction in risk for high blood pressure development. An inverse association was found, suggesting that as coffee consumption rose, high blood pressure risk falls. However, upon closer examination this inverse relationship was only found in the USA, but not in Europe and Asia. The authors suggested that geographics, genetics, gender, coffee preparation methods, and differences in lifestyle habits (smoking, salt consumption etc.) may contribute to the discrepancies between outcomes and make it harder to compare studies to form a uniform consensus. Hence, they urged for a cautious interpretation of the findings. In the absence of clear, consistent evidence, coffee consumption and cardiovascular risk may need to be assessed on an individual basis in clinical practice.
Abstract
OBJECTIVES The association between coffee intake and hypertension (HTN) risk is controversial. Therefore, this systematic review and meta-analysis aimed at summarizing the current evidence on the association of coffee with hypertension risk in observational studies. METHODS PubMed/Medline and Web of Science were searched for observational studies up to February 2023. Observational studies which assessed the risk of HTN in the highest category of coffee consumption in comparison with the lowest intake were included in the current meta-analysis (registration number: CRD42022371494). The pooled effect of coffee on HTN was evaluated using a random-effects model. RESULTS Twenty-five studies i.e., thirteen cross-sectional studies and twelve cohorts were identified to be eligible. Combining 13 extracted effect sizes from cohort studies showed that higher coffee consumption was associated with 7% reduction in the risk of HTN (95% CI: 0.88, 0.97; I2: 22.3%), whereas combining 16 effect sizes from cross-sectional studies illustrated a greater reduction in HTN risk (RR = 0.79, 95% CI: 0.72, 0.87; I2 = 63.2%). These results varied by studies characteristics, such as the region of study, participants' sex, study quality, and sample size. CONCLUSIONS An inverse association was found between coffee consumption and hypertension risk in both cross-sectional and cohort studies. However, this association was dependent on studies characteristics. Further studies considering such factors are required to confirm the results of this study.
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Effect of Peanut Consumption on Cardiovascular Risk Factors: A Randomized Clinical Trial and Meta-Analysis.
Parilli-Moser, I, Hurtado-Barroso, S, Guasch-Ferré, M, Lamuela-Raventós, RM
Frontiers in nutrition. 2022;9:853378
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Peanuts contain bioactive substances that are beneficial for cardiovascular health. This three-arm, parallel-group randomised controlled trial (ARISTOTLE) and meta-analysis evaluated the beneficial effects of high-oleic peanuts and peanut butter in improving cardiometabolic health. Participants in the randomised controlled trial consumed 25 g of skin-roasted peanuts or 32 g of peanut butter, or a control butter made with peanut oil without fibre and polyphenols for six months. The skin-roasted peanuts group showed a reduction in total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios. The meta-analysis was highly heterogeneous in participant ethnicity, health status, peanut intervention dosage and duration. The dosage of peanuts, peanut butter and high oleic peanuts used was between 25 and 200 g/day. The participants were healthy, with metabolic syndrome (MeS), or at risk of MeS. There was a significant increase in body weight among those with or at risk of MeS. In addition, healthy participants showed reduced triglycerides, total cholesterol, and LDL-cholesterol/HDL-cholesterol ratios. Healthcare professionals can use the results of this research to understand the beneficial impact of peanut consumption on the lipid profile. However, further robust studies are required due to the high heterogeneity of the included studies in the meta-analysis.
Abstract
UNLABELLED Although numerous studies have reported the protective effect of nut consumption on cardiovascular risk, evidence for the role of peanuts in maintaining cardiometabolic health is inconclusive. Presented here are the results from the ARISTOTLE study, a parallel randomized controlled trial evaluating the impact of regular peanut intake on anthropometric, biochemical, and clinical measurements. The 63 healthy subjects that completed the study consumed their habitual diet plus either: a) 25 g/day of skin roasted peanuts (SRP, n = 21), b) two tablespoons (32 g)/day of peanut butter (PB, n = 23) or c) two tablespoons (32 g)/day of a control butter based on peanut oil (CB, n = 19) for 6 months. In addition, a meta-analysis of clinical trials, including data from the ARISTOTLE study, was carried out to update the evidence for the effects of consuming peanuts, including high-oleic peanuts, and peanut butter on healthy subjects and those at high cardiometabolic risk. After a systematic search on PubMed, Web of Science, Cochrane Library and Scopus databases up to July 2021, 11 studies were found to meet the eligibility criteria. In the ARISTOTLE study, lower total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios were found in the SRP group compared to the CB group (p = 0.019 and p = 0.008). The meta-analysis of clinical trials revealed that peanut consumption is associated with a decrease in triglycerides (MD: -0.13; 95% CI, -0.20 to -0.07; p < 0.0001) and that healthy consumers had lower total cholesterol and LDL-cholesterol/HDL-cholesterol ratios compared to the control groups (MD: -0.40; 95% CI, -0.71 to -0.09; p = 0.01 and MD: -0.19; 95% CI, -0.36 to -0.01; p = 0.03, respectively). However, individuals at high cardiometabolic risk experienced an increase in body weight after the peanut interventions (MD: 0.97; 95% CI, 0.54 to 1.41; p < 0.0001), although not in body fat or body mass index. According to the dose-response analyses, body weight increased slightly with higher doses of peanuts. In conclusion, a regular consumption of peanuts seems to modulate lipid metabolism, reducing triglyceride blood levels. SYSTEMATIC REVIEW REGISTRATION https://osf.io/jx34y/, identifier: 10.17605/OSF.IO/MK35Y.
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Comparative analysis of the efficacies of probiotic supplementation and glucose-lowering drugs for the treatment of type 2 diabetes: A systematic review and meta-analysis.
Liang, T, Xie, X, Wu, L, Li, L, Yang, L, Gao, H, Deng, Z, Zhang, X, Chen, X, Zhang, J, et al
Frontiers in nutrition. 2022;9:825897
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Type 2 diabetes (T2D) is a serious medical condition often requiring antidiabetic drug management. Although commonly used antidiabetic drugs effectively control glucose levels, their tolerability profiles differ, causing various side effects. Probiotics can be used as single or multi strains to reduce glycaemic and lipid indicators and avoid the negative effects of antidiabetic medications. The study included twenty-five randomised controlled trials, of which fourteen studies assessed the effectiveness of probiotics (single probiotics, multi-strain probiotics, and probiotics with co-supplements), and eleven studies included different antidiabetic drugs such as Thiazolidinedione (TZD), Glucagon-like peptide-1 receptor agonists (GLP-1 RA), Dipeptidyl peptidase IV inhibitors (DPP-4i), and Sodium-glucose co-transporter 2 inhibitors (SGLT-2i). This systematic review and meta-analysis compared the effectiveness of probiotic and antidiabetic drugs on glycaemia, lipid profile and blood pressure in T2D patients. Probiotics were less effective than specific antidiabetic drugs in reducing fasting blood sugar levels (FBS), HbA1c levels, and triglycerides. Different probiotic formulations were effective in reducing the HOMA-IR index, total cholesterol (TC), triglycerides (TG), and systolic and diastolic pressure (SBP and DBP). A subgroup analysis showed a greater reduction in FBS, HbA1c, TC, TG, and SBP in obese and elderly participants, those who participated for a longer duration, and those from Eastern origins. Considering the high heterogeneity in baseline study characteristics among the studies included in this systematic review and meta-analysis, further studies are required to evaluate the effects of probiotics and antidiabetic drugs. However, healthcare professionals can use the study to understand the effect of probiotics and antidiabetic drugs in reducing glycaemic, lipid and hypertension profiles.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Glucose-lowering drugs, except for DPP-4i, reduced FBS and HbA1c more than probiotics; and SGLT-2i induced the greatest decrease in HbA1c
- A BMI ≥ 30 kg/m2 showed a significant decrease in FBS and the HOMA-IR index compared with those with lower BMI
- Weight loss induced by glucose-lowering drugs and probiotic supplementation plays an important role in glycaemic control in obese patients with type 2 diabetes.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This meta-analysis compared the effects of probiotics and glucose-lowering drugs thiazolidinedione [TZD], glucagon-like pep-tide-1 receptor agonists [GLP-1 RA], dipeptidyl peptidase IV inhibitors, and sodium glucose co-transporter 2 inhibitors [SGLT-2i]) on various outcome measures in patients with type 2 diabetes (T2D).
Methods
A search was performed on PubMed, Web of science, Embase, and Cochrane Library between January 2015 - April 2021.
Results
25 randomised controlled trials (RCT) were included (2843 participants). 14 RCTs (842 participants) involved the administration of single probiotics, multi-strain probiotics, and probiotics with co-supplements, and 11 RCTs (2001 participants) involved TZD, GLP-1 RA, SGLT-2i, and DPP-4i. Participants in 7 of the studies had T2D, aged ≤ 55 years old. 8 RCTs included participants with a mean BMI ≥ 30 kg/m2, and 11 RCTs participants had a mean BMI < 30 kg/m2.
Effects of probiotics:
- Fasting Blood Sugar (FBS): A reduction (−1.42, −0.32 mg/dL, p=0.000)
- Glycated hemaglobin (HbA1c): No reduction (p = 0.000)
- Insulin Resistance (HOMA-IR): A decrease (−0.64, −0.31; p = 0.780), regardless of probiotic strain or with a co-supplement
- Insulin: Not significant (p = 0.000). Subgroup analysis: no reduction
- Total Cholesterol (TC): No difference (p = 0.941). Subgroup analysis: reduction from multi-species probiotics (−0.36, −0.01 mg/dL, p = 0.871)
- Triglycerides: Difference (−0.25 mg/dL, p = 0.958)
- LDL-C: No changes (p = 0.189)
- HDL-C: No increase (p = 0.014)
- Systolic Blood Pressure (SBP): A decrease (−6.44, −0.08 mmHg, p = 0.044)
- Diastolic Blood Pressure (DBP): A reduction (−4.53, −0.80 mmHg, p = 0.206).
Effects of glucose-lowering drugs:
- FBS: A decrease (−4.22 mg/dL, −1.24 mg/dL, p = 0.000)
- HbA1c: A decrease (−2.51%, −0.52%, p = 0.000) with TZD, GLP-1 RA, SGLT-2i, and DPP- 4i; a reduction with SGLT-2i (p = 0.003)
- TC: No difference (p = 0.000). Subgroup: no decrease with single species probiotics and probiotics with co-supplements, TZD, GLP-1 RA, and DPP-4i)
- TG: No difference (p = 0.000)
- . HDL-C: No increase (p = 0.000). Subgroup: a decrease with TZDs (−2.37, −0.72 mg/dL). No difference with probiotic strains, or probiotics with co-supplements, GLP-1 RA, and DPP-4i
- LDL-C: No changes (p = 0.000), Subgroups: no difference with probiotic strains, probiotics with co-supplements, TZD, GLP-1 RA, and DPP-4i).
Limitations
Limited number of studies for TZD and SGLT-2i, making results potentially unreliable.
Conclusions
Multi species probiotics are worth considering as an adjunct to glucose-lowering drugs, and for improving lipid profiles and hypertension.
Clinical practice applications:
- Probiotic supplementation reduced the HOMA-IR index
- Multi-species probiotics were associated with reduction in TC and TG levels
- DPP-4i only decreased TG levels
- TZD was associated with decrease in HDL-C, whereas probiotic supplementation was associated with higher decrease in SBP and DBP and that GLP-1 RA increases the risk of hypoglycaemia.
Considerations for future research:
- Semaglutide was associated with an increased risk for hypoglycaemia compared with a placebo, indicating that the safety of semaglutide needs further study
- Dietary and physical activity should be considered in future studies
- Heterogeneity in some indicators may be due to differences in study baseline characteristics,Larger trials needed to support the results of this meta-analysis.
Abstract
The aim of this systematic review and meta-analysis was to evaluate the effects of probiotics and glucose-lowering drugs (thiazolidinedione [TZD], glucagon-like pep-tide-1 receptor agonists [GLP-1 RA], dipeptidyl peptidase IV inhibitors, and sodium glucose co-transporter 2 inhibitors [SGLT-2i]) in patients with type 2 diabetes from randomized con-trolled trials (RCTs). The PubMed, Web of science, Embase, and Cochrane Library databases were searched on the treatment effects of probiotics and glucose-lowering drugs on glycemia, lipids, and blood pressure metabolism published between Jan 2015 and April 2021. We performed meta-analyses using the random-effects model. We included 25 RCTs (2,843 participants). Overall, GLP-1RA, SGLT-2i, and TZD significantly reduce fasting blood sugar (FBS) and glycated hemoglobin (HbA1c), whereas GLP-1 RA increased the risk of hypoglycaemia. Multispecies probiotics decrease FBS, total cholesterol (TC), and systolic and diastolic blood pressure (SBP, DBP). Moreover, subgroup analyses indicated that participants aged >55 years, BMI ≥30 kg/m2, longer duration of intervention, and subjects from Eastern countries, showed significantly higher reduction in FBS and HbA1c, TC, TG and SBP. This meta-analysis revealed that including multiple probiotic rather than glucose-lowering drugs might be more beneficial regarding T2D prevention who suffering from simultaneously hyperglycemia, hypercholesterolemia, and hypertension.
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Effects of camelina oil supplementation on lipid profile and glycemic control: a systematic review and dose‒response meta-analysis of randomized clinical trials.
Jalili, C, Talebi, S, Mehrabani, S, Bagheri, R, Wong, A, Amirian, P, Zarpoosh, M, Ghoreishy, SM, Kermani, MAH, Moradi, S
Lipids in health and disease. 2022;21(1):132
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Research indicates that alpha-linolenic acid (ALA) can reduce the risk of cardiovascular disease by improving blood lipids, blood pressure, and haemostatic factors, among others. Camelina oil, considered a good source of ALA compared to other edible oils, is one of the richest dietary sources of omega-3 fatty acids, with a polyunsaturated fatty acid content over 50%. The aim of this study was to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycaemic control in human studies. This study is a systematic review and meta-analysis of seven randomised controlled trials with a total of 428 individuals (202 participants in the COS group and 226 in the control group). Results did not show any affects of COS on lipid profile and glycaemic indices compared with placebo intake. However, subgroup analysis showed that COS for more than 8 weeks and at a dose lower than 30g/d could decrease total cholesterol. Authors conclude that COS may be a beneficial nonpharmacological strategy for the improvement of this lipid marker. However, further studies are required to confirm the findings of this study.
Abstract
BACKGROUND This systematic review and dose-response meta-analysis of published randomized controlled trials (RCTs) was conducted to determine the effectiveness of camelina oil supplementation (COS) on lipid profiles and glycemic indices. METHODS Relevant RCTs were selected by searching the ISI Web of Science, PubMed, and Scopus databases up to July 1, 2022. RTCs with an intervention duration of less than 2 weeks, without a placebo group, and those that used COS in combination with another supplement were excluded. Weighted mean differences and 95% confidence intervals were pooled by applying a random-effects model, while validated methods examined sensitivity analyses, heterogeneity, and publication bias. RESULTS Seven eligible RCTs, including 428 individuals, were selected. The pooled analysis revealed that COS significantly improved total cholesterol in studies lasting more than 8 weeks and utilizing dosages lower than 30 g/d compared to the placebo group. The results of fractional polynomial modeling indicated that there were nonlinear dose-response relations between the dose of COS and absolute mean differences in low-density cholesterol, high-density cholesterol, and total cholesterol, but not triglycerides. It appears that the greatest effect of COS oil occurs at the dosage of 20 g/day. CONCLUSION The present meta-analysis indicates that COS may reduce cardiovascular disease risk by improving lipid profile markers. Based on the results of this study, COS at dosages lower than 30 g/d may be a beneficial nonpharmacological strategy for lipid control. Further RCTs with longer COS durations are warranted to expand on these results.
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Effects of lifestyle interventions on cardiovascular risk factors in South Asians: a systematic review and meta-analysis.
Limbachia, J, Ajmeri, M, Keating, BJ, de Souza, RJ, Anand, SS
BMJ open. 2022;12(12):e059666
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The prevalence of cardiovascular disease (CVD) and associated mortality risk is high in the South Asian population in western countries. Regular physical activity and a healthy diet may modify the risk factors of CVD, such as abdominal fat, high cholesterol, and blood sugar irregularities. This systematic review and meta-analysis included thirty-five randomised controlled trials to evaluate the effectiveness of diet, physical activity interventions or a combination of diet and physical activity interventions on CVD risk factors and compared it against usual care. Combining diet and physical activity interventions reduced CVD risk factors such as systolic and diastolic blood pressure, BMI, weight, waist circumference and fasting plasma glucose (FPG). Dietary interventions reduced diastolic blood pressure, triglycerides, low-density lipoprotein cholesterol, BMI, weight and FPG. Physical activity modifications improved diastolic and systolic blood pressure and high-density lipoprotein cholesterol. Healthcare professionals can use the study results to understand how tailored diet and physical activity modifications improve the CVD risk factors in South Asians. However, further robust studies are required as most of these evidences were of moderate quality and lacked clinical significance.
Abstract
BACKGROUND The cardiovascular disease (CVD) burden among South Asians is high. Lifestyle interventions have been effective in the primary prevention of CVD, but this has not been replicated, through a synthesis of randomised trials, in South Asians. METHODS Four electronic databases (MEDLINE, Embase, CENTRAL and CINAHL), two clinical trial registries and references of included articles were searched through June 2022 (featuring ≥90% South Asian participants). Random-effects pairwise meta-analyses were performed, and heterogeneity was quantified with the I2 statistic. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework was used to report on the quality of evidence (International Prospective Register of Systematic Reviews registration (PROSPERO). RESULTS Thirty-five studies were included. Twelve tested diet and physical activity interventions; 18 tested diet alone; and 5 tested physical activity alone. All reported effects of the intervention(s) on at least one established risk factor for CVD, including blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP) and blood lipids (high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc) or triglycerides). No trials reported clinical CVD. There is moderate-quality evidence that diet and physical activity interventions improve SBP (mean difference (MD) -2.72 mm Hg, 95% CI -4.11 to -1.33) and DBP (MD -1.53 mm Hg, 95% CI -2.57 to -0.48); high-quality to moderate-quality evidence that diet-only interventions improve DBP (MD -2.05 mm Hg, 95% CI -2.93 to -1.16) and blood lipids (triglycerides (MD -0.10 mmol/L, 95% CI -0.14 to -0.06) and LDLc (MD -0.19 mmol/L, 95% CI -0.32 to -0.06)); and moderate-quality evidence that physical activity-only interventions improve SBP (MD -9.7 mm Hg, 95% CI -11.05 to -8.35), DBP (MD -7.29 mm Hg, 95% CI -8.42 to -6.16) and HDLc (MD 0.08 mmol/L, 95% CI 0.04 to 0.11) compared with usual care. CONCLUSIONS Lifestyle interventions improve blood pressure and blood lipid profiles in adult South Asians at risk of CVD. Tailored interventions should be used to modify cardiovascular risk factors in this at-risk group. PROSPERO REGISTRATION NUMBER CRD42018090419.
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Efficacy and safety of oral alpha-lipoic acid supplementation for type 2 diabetes management: a systematic review and dose-response meta-analysis of randomized trials.
Jibril, AT, Jayedi, A, Shab-Bidar, S
Endocrine connections. 2022;11(10)
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Many studies have shown that type 2 diabetes is associated with increased formation of free radicals and decreased antioxidant potential, leading to oxidative damage of cell components. Increased formation of free radicals and decreased antioxidant potential, coupled with lipid abnormalities, are substantial risk factors for developing complications, especially microvascular ones. The aim of this study was to investigate the effect of oral supplementation of alpha-lipoic acid (ALA) on cardiometabolic risk factors in patients with type 2 diabetes. This study is a systematic review and dose–response meta-analysis of 16 randomised controlled trials with a total of 1035 patients with type 2 diabetes. Results show that: - each 500 mg/day oral ALA supplementation reduced haemoglobin A1c and body weight but did not affect low-density lipoprotein cholesterol concentration. - ALA supplementation reduced c-reactive protein, fasting plasma glucose, serum triglycerides, and diastolic blood pressure but it had no affect on serum total cholesterol and high-density lipoprotein cholesterol concentrations and systolic blood pressure. Authors conclude that their findings do not support ALA supplementation in clinical practice for patients with type 2 diabetes.
Abstract
OBJECTIVE To examine the dose-dependent influence of oral alpha-lipoic acid (ALA) supplementation on cardiometabolic risk factors in patients with type 2 diabetes (T2D). DESIGN We followed the instructions outlined in the Cochrane Handbook for Systematic Reviews of Interventions and the Grading of Recommendations, Assessment, Development, and Evaluation Handbook to conduct our systematic review. The protocol of the study was registered in PROSPERO (CRD42021260587). METHOD We searched PubMed, Scopus, and Web of Science to May 2021 for trials of oral ALA supplementation in adults with T2D. The primary outcomes were HbA1c, weight loss, and LDL cholesterol (LDL-C). Secondary outcomes included fasting plasma glucose (FPG), triglyceride (TG), C-reactive protein (CRP), and blood pressure. We conducted a random-effects dose-response meta-analysis to calculate the mean difference (MD) and 95% CI for each 500 mg/day oral ALA supplementation. We performed a nonlinear dose-response meta-analysis using a restricted cubic spline. RESULTS We included 16 trials with 1035 patients. Each 500 mg/day increase in oral ALA supplementation significantly reduced HbA1c, body weight, CRP, FPG, and TG. Dose-response meta-analyses indicated a linear decrement in body weight at ALA supplementation of more than 600 mg/day (MD600 mg/day: -0.30 kg, 95% CI: -0.04, -0.57). A relatively J-shaped effect was seen for HbA1c (MD: -0.32%, 95% CI: -0.45, -0.18). Levels of FPG and LDL-C decreased up to 600 mg/day ALA intake. The point estimates were below minimal clinically important difference thresholds for all outcomes. CONCLUSION Despite significant improvements, the effects of oral ALA supplementation on cardiometabolic risk factors in patients with T2D were not clinically important.
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Effects of the Treatment with Flavonoids on Metabolic Syndrome Components in Humans: A Systematic Review Focusing on Mechanisms of Action.
Gouveia, HJCB, Urquiza-Martínez, MV, Manhães-de-Castro, R, Costa-de-Santana, BJR, Villarreal, JP, Mercado-Camargo, R, Torner, L, de Souza Aquino, J, Toscano, AE, Guzmán-Quevedo, O
International journal of molecular sciences. 2022;23(15)
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Metabolic syndrome is a condition characterised by at least three of the five risk factors, such as abdominal obesity, elevated fasting glucose, blood pressure and triglycerides and reduced high-density lipoprotein cholesterol (HDL-c). There is a strong link between metabolic syndrome and the development of cardiovascular disease and Type 2 diabetes. Research suggests that increasing consumption of flavonoid-rich foods can be beneficial in reducing cardiovascular morbidity and mortality. Flavonoids are bioactive compounds that possess antioxidative, anti-inflammatory, anti-cancerous, anti-mutagenic, and enzymatic properties. This systematic review of 29 randomised controlled trials evaluated the beneficial effects of long-term flavonoid supplementation in reducing the risk factors of metabolic syndrome. This review included a variety of flavonoid supplements, such as anthocyanin, hesperidin, quercetin, epigallocatechin gallate (egcg), genistein, theaflavin, catechin, and eriocitrin. Additionally, this research investigated the mechanisms behind the beneficial effects of flavonoid supplementation. Results showed that flavonoid supplementation for at least three weeks improved metabolic parameters and inflammatory markers, with hesperidin showing the greatest improvements in metabolic parameters. Healthcare professionals can use these findings to understand the potential benefits of long-term flavonoid supplementation in improving metabolic parameters. However, more robust studies are needed to determine the therapeutic dosages of different flavonoids.
Abstract
Diets high in bioactive compounds, such as polyphenols, have been used to mitigate metabolic syndrome (MetS). Polyphenols are a large group of naturally occurring bioactive compounds, classified into two main classes: non-flavonoids and flavonoids. Flavonoids are distributed in foods, such as fruits, vegetables, tea, red wine, and cocoa. Studies have already demonstrated the benefits of flavonoids on the cardiovascular and nervous systems, as well as cancer cells. The present review summarizes the results of clinical studies that evaluated the effects of flavonoids on the components of the MetS and associated complications when offered as supplements over the long term. The results show that flavonoids can significantly modulate several metabolic parameters, such as lipid profile, blood pressure, and blood glucose. Only theaflavin and catechin were unable to affect metabolic parameters. Moreover, only body weight and body mass index were unaltered. Thus, the evidence presented in this systematic review offers bases in support of a flavonoid supplementation, held for at least 3 weeks, as a strategy to improve several metabolic parameters and, consequently, reduce the risk of diseases associated with MetS. This fact becomes stronger due to the rare side effects reported with flavonoids.