Effect of a nut-enriched low-calorie diet on body weight and selected markers of inflammation in overweight and obese stable coronary artery disease patients: a randomized controlled study

Brazil Nut (Bertholletia excelsa H.B.K.) Consumption in Energy-Restricted Intervention Decreases Proinflammatory Markers and Intestinal Permeability of Women with Overweight/Obesity: A Controlled Trial (Brazilian Nuts Study)

BACKGROUND

Obesity is associated with low-grade inflammation and increased intestinal permeability (IP). The Brazil nut (BN) (Bertholletia excelsa H.B.K.) appears to be a promising dietary intervention to control inflammation by enhancing antioxidant defenses.

OBJECTIVES

We aimed to assess the effect of daily BN consumption on inflammatory biomarkers and IP in the context of an energy-restricted intervention. Furthermore, we evaluated the correlation between the changes in these inflammatory markers and the changes in serum selenium and IP.

METHODS

In this 8-wk nonrandomized controlled trial, 56 women with overweight or obesity were allocated into 2 groups, both following an energy-restricted diet (-500 kcal/d). The control group (CO) consumed a nut-free diet, while the BN group consumed 8 g BN/d, providing 347.2 μg selenium (Se). Inflammatory cytokines were analyzed in plasma and Se in serum. IP was assessed using the lactulose/mannitol test (LM ratio).

RESULTS

Forty-six women completed the intervention. Both groups achieved similar energy restriction (CO Δ= -253.7 ± 169.4 kcal/d; BN Δ= -265.8 ± 141.8 kcal/d) and weight loss (CO Δ= -2.5 ± 0.5 kg; BN Δ= -3.5 ± 0.5 kg). The BN group showed lower values of C-reactive protein, tumor necrosis factor, interleukin (IL)1-β, IL-8, percentage lactulose excretion, and LM ratio than the CO group. Additionally, changes in serum Se concentration were predictive of changes in IL-8 concentration (β: -0.054; adjusted R2: 0.100; 95% confidence interval [CI]: -0.100; -0.007; P = 0.025), and changes in IL-8 were predictive of changes in the LM ratio (β: 0.006; adjusted R2: 0.101; 95% CI: 0.001, 0.011; P = 0.024).

CONCLUSIONS

Regular intake of BNs can be a promising complementary dietary strategy for controlling low-grade inflammation and improving IP in women with overweight/obesity undergoing energy-restricted treatment. However, the effects of BNs seem to be Se status-dependent. This trial was registered at the Brazilian Registry of Clinical Trials (ReBEC: https://ensaiosclinicos.gov.br/rg/RBR-3ntxrm/.

Effect of nuts on lipid profile and inflammatory biomarkers in atherosclerotic cardiovascular disease: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Nut-enriched diets are related to improve lipid and inflammatory biomarkers in meta-analyses in the context of primary cardiovascular prevention. However, primary studies on secondary cardiovascular prevention are scarce and controversial. This systematic review and meta-analysis aimed to evaluate the effect of nut supplementation on lipid and inflammatory profiles in individuals with atherosclerotic cardiovascular disease, and the frequency of adverse events.

METHODS

Six databases were used for research: PubMed, EMBASE, BVS, Cochrane Library, Web of Science, and ClinicalTrials.gov, until February 2023, with no language restrictions. We performed random-effects meta-analyses to compare nut-enriched diets vs. control diets for pre-post intervention changes. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system assessed the evidence's certainty.

RESULTS

From the 5187 records identified, eight publications containing data referring to five randomized clinical trials involving 439 participants were included in the final analyses. The nuts evaluated were almonds, pecans, Brazil nuts, and mixed nuts, with doses ranging between 5 g and 85 g (median: 30 g/day). The intervention time varied between 6 and 12 weeks. Compared to nut-free diets, nut intake did not have a statistically significant effect on lipid profile biomarkers, except on the atherogenic index (MD: -0.32 [95% CI -0.58 to -0.06], I2 = 0% - moderate certainty of the evidence). Similarly, there was no effect of nuts on inflammatory profile biomarkers. It was not possible to aggregate data on adverse events.

CONCLUSIONS

Nut supplementation did not change lipid and inflammatory profiles in the secondary cardiovascular prevention setting.

Zinc Supplementation in Individuals with Prediabetes and type 2 Diabetes: a GRADE-Assessed Systematic Review and Dose-Response Meta-analysis

Zinc supplementation has therapeutic effects on cardiovascular disease (CVD) risk factors, including dyslipidemia, hyperglycemia, and inflammation as the main contributors to CVD pathogenesis. Since CVD is a major cause of mortality among people with type 2 diabetes mellitus (T2DM), this study aimed to overview the potential effects of zinc supplementation on CVD risk factors in T2DM patients. To determine appropriate randomized clinical trials (RCTs) investigating the effects of zinc supplementation on CVD risk factors, electronic sources including PubMed, Web of Science, and Scopus were systematically searched until January 2023. The heterogeneity of trials was checked using the I2 statistic. According to the heterogeneity tests, random-effects models were estimated, and pooled data were defined as the weighted mean difference (WMD) with a 95% confidence interval (CI). Of the 4004 initial records, 23 studies that met inclusion criteria were analyzed in this meta-analysis. The pooled findings indicated the significant lowering effects of zinc supplementation on triglycerides (TG), total cholesterol (TC), fasting blood glucose (FBG), hemoglobin A1C (HbA1C), and C-reactive protein (CRP), while high-density cholesterol (HDL) concentrations showed an elevation after zinc supplementation. In addition to statistical significance, the effect of zinc supplementation on most of the variables was clinically significant; however, the quality of evidence in the included studies is regarded as low or very low for most variables. Our study demonstrated that zinc supplementation has beneficial effects on glycemic control markers, lipid profile, and CRP levels as a classic marker of inflammation in T2DM. Due to the high degree of heterogeneity between studies and the low rate of quality in them, further well-designed studies are necessitated to strengthen our findings.

Effect of Nuts on Anthropometric and Glycemic Indexes and Blood Pressure in Secondary Cardiovascular Prevention: A Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Nut-enriched diets have a positive impact on cardiovascular risk factors, such as body mass, blood pressure, and fasting blood glucose. However, studies in individuals undergoing secondary cardiovascular prevention show controversial results.

OBJECTIVE

This systematic review with meta-analysis assessed the effect of nut supplementation on anthropometric, glycemic, and blood pressure indices in patients with atherosclerotic cardiovascular disease, as well as the frequency of adverse events.

DATA SOURCES

Six databases were used for the search-PubMed, Cochrane Library, EMBASE, BVS (Biblioteca Virtual da Saude), Web of Science, and ClinicalTrials.gov-until February 2023, with no language restrictions.

DATA EXTRACTION

The Cochrane Handbook for Systematic Reviews of Interventions methodology and the PICOS (Population, Intervention, Comparison, Outcome, Setting/design) strategy were used. Seven independent reviewers were involved in data extraction and resolution of disagreements. Certainty of the evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system.

DATA ANALYSIS

From 5187 records identified, 6 publications containing data referring to 5 randomized clinical trials (n = 436) were included in the final analyses. The nuts evaluated were almonds, pecans, Brazil nuts, and mixed nuts, with portions that varied between 5 g and 85 g (median: 30 g/day). The intervention period varied between 6 and 12 weeks. The nuts had no effect on fasting glucose and anthropometric indices, although the certainty of the evidence for most of these outcomes was low or very low. They also had no effect on systolic (mean difference [MD]: -1.16 mmHg [95% CI, -5.68 to 3.35], I2 = 0%-moderate certainty of evidence) or diastolic (MD: 0.10 mmHg [95% CI, -2.30 to 2.51], I2 = 0%-high certainty of evidence) blood pressure. It was not possible to aggregate data on adverse events.

CONCLUSION

Nut supplementation had no effect on blood pressure, fasting glucose, or anthropometric profile in the context of atherosclerotic cardiovascular disease.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020163456.

Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Cardiovascular disease (CVD) is the leading cause of death globally. Habitual consumption of tree nuts and peanuts is associated with cardioprotective benefits. Food-based dietary guidelines globally recommend nuts as a key component of a healthy diet. This systematic review and meta-analysis were conducted to examine the relationship between tree nut and peanut consumption and risk factors for CVD in randomized controlled trials (RCTs) (PROSPERO: CRD42022309156). MEDLINE, PubMed, CINAHL, and Cochrane Central databases were searched up to 26 September, 2021. All RCT studies that assessed the effects of tree nut or peanut consumption of any dose on CVD risk factors were included. Review Manager software was used to conduct a random effect meta-analysis for CVD outcomes from RCTs. Forest plots were generated for each outcome, between-study heterogeneity was estimated using the I2 test statistic and funnel plots and Egger's test for outcomes with ≥10 strata. The quality assessment used the Health Canada Quality Appraisal Tool, and the certainty of the evidence was assessed using grading of recommendations assessment, development, and evaluation (GRADE). A total of 153 articles describing 139 studies (81 parallel design and 58 cross-over design) were included in the systematic review, with 129 studies in the meta-analysis. The meta-analysis showed a significant decrease for low-density lipoprotein (LDL) cholesterol, total cholesterol (TC), triglycerides (TG), TC:high-density lipoprotein (HDL) cholesterol, LDL cholesterol:HDL cholesterol, and apolipoprotein B (apoB) following nut consumption. However, the quality of evidence was "low" for only 18 intervention studies. The certainty of the body of evidence for TC:HDL cholesterol, LDL cholesterol:HDL cholesterol, and apoB were "moderate" because of inconsistency, for TG were "low," and for LDL cholesterol and TC were "very low" because of inconsistency and the likelihood of publication bias. The findings of this review provide evidence of a combined effect of tree nuts and peanuts on a range of biomarkers to create an overall CVD risk reduction.

A systematic review and meta-analysis of almond effect on C-reactive protein and interleukin-6 in adults

BACKGROUND

The previous articles have shown that the almond might reduce the serum concentration of inflammatory mediators. Therefore, the studies reported in this article aimed to assess the almond effect on serum concentration of C-reactive protein (CRP) and interleukin-6 (IL-6) in adults.

METHOD AND MATERIALS

To find the related English-language studies, an electronic search was run in databases including Web of Science, PubMed, SCOPUS, ClinicalTrials.gov, and Cochrane library with no time limit (up to August 2022). The effect sizes were calculated based on the mean changes for both intervention and comparison groups. DerSimonian and Laird random-effects model was used to determine the summary of overall effects and their heterogeneity. Cochran's Q test and I-squared statistic were used to explore the statistical heterogeneity.

RESULTS

In total, eleven studies were included in this study. The overall estimate indicated that the almond consumption had no significant effect on serum CRP level (weighted mean difference (WMD) = -0.28 mg/l, 95 % confidence interval (CI): - 0.81, 0.25; p = 0.29). Regarding IL-6, almond consumption significantly decreased serum IL-6 level (WMD = -0.1 pg/ml, 95 % CI: -0.15, -0.05; p < 0.001).

CONCLUSION

The overall results support the beneficial effects of almond consumption on serum concentration of IL-6; but even so, our study revealed that the almond consumption non-significantly reduced serum concentration of CRP. We still need more well-designed trials to confirm the beneficial effects of almond.

Effect of Nuts on Markers of Inflammation and Oxidative Stress: A Narrative Review

Oxidative stress and inflammation are mediators in the pathophysiology of several non-communicable diseases (NCDs). Tree nuts and peanuts lower risk factors of cardiometabolic disease, including blood lipids, blood pressure and insulin resistance, among others. Given their strong antioxidant/anti-inflammatory potential, it is plausible that nuts may also exert a favorable effect on inflammation and oxidative stress. Evidence from systematic reviews and meta-analyses of cohort studies and randomized controlled trials (RCTs) suggest a modest protective effect of total nuts; however, the evidence is inconsistent for specific nut types. In this narrative review, the state of evidence to date is summarized for the effect of nut intake on biomarkers of inflammation and oxidative stress, and an attempt is made to define the gaps in research while providing a framework for future research. Overall, it appears that some nuts, such as almonds and walnuts, may favorably modify inflammation, and others, such as Brazil nuts, may favorably influence oxidative stress. There is a pressing need for large RCTs with an adequate sample size that consider different nut types, and the dose and duration of nut intervention, while evaluating a robust set of biomarkers for inflammation and oxidative stress. Building a stronger evidence base is important, especially since oxidative stress and inflammation are mediators of many NCDs and can benefit both personalized and public health nutrition.

Influence of pistachios on force production, subjective ratings of pain, and oxidative stress following exercise-induced muscle damage in moderately trained athletes: A randomized, crossover trial

Although previous studies have focused on the role of pistachios on metabolic health, the ergogenic effects of the nut must be elucidated. This study evaluated the impact of ingesting raw, shelled, unsalted pistachios on subjective pain ratings, force production, vertical jump, and biochemical indices of recovery from eccentrically biased exercise. Using a crossover design, 27 moderately trained, male athletes completed 3 trials in a randomized counterbalanced fashion. Control received water only, low dose (1.5 oz/d; PL) and high dose (3.0 oz/d; PH) consumed pistachios for 2 weeks with a 3-4-week washout between trials. PH had lower pain ratings in most muscles after 72 h of recovery (p < 0.05). PH prevented a decrease in force production at 120°/s of knee flexion (p > 0.05); whereas force was diminished in the other trials. Creatine kinase, myoglobin, and C-reactive protein increased over time following exercise (p < 0.05); however, there were no advantages following pistachio consumption. No significant changes in vertical jump or superoxide dismutase were elicited during any trial. This study demonstrates that 3.0 oz/d of pistachios can reduce delayed onset of muscle soreness and maintain muscle strength, potentially promoting exercise tolerance and training adaptations.

ClinicalTrialsgov Identifier

NCT03698032.

The Effects of Almond Consumption on Inflammatory Biomarkers in Adults: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Conflicting findings have been reported regarding the effects of almond consumption on inflammatory markers. This study aimed to summarize the current literature to determine whether almonds can affect inflammatory markers. A systematic search was carried out in PubMed, Scopus, and ISI Web of Science up to March 2021. Randomized clinical trials that compared almond with no almond consumption were included. The outcomes of interest were changes in circulating C-reactive protein (CRP), IL-6, TNF-α, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) concentrations. The random-effects model was used to find the mean differences. In total, 18 trials with 847 participants were eligible for the current analysis. Participants' ages ranged from 26.3 to 69.6 y. Combining 16 studies, almond consumption significantly reduced serum concentrations of CRP [weighted mean difference (WMD): -0.25 mg/L; 95% CI: -0.43, -0.06 mg/L; I2 = 0.0%; P-heterogeneity = 0.633]. However, the beneficial effect of almond intake only occurred at doses <60 g/d. Pooling 11 effect sizes, almond interventions significantly decreased circulating IL-6 concentrations (WMD: -0.11 pg/mL; 95% CI: -0.21, -0.01 pg/mL; I2 = 19.9%; P-heterogeneity = 0.254). In subgroup analyses, effects on CRP and IL-6 were nonsignificant in unhealthy participants or those with obesity. In addition, almond consumption had no significant effect on TNF-α (WMD: -0.05 pg/mL; 95% CI: -0.11, 0.01 pg/mL; I2 = 0.0%; P-heterogeneity = 0.893; n = 6), ICAM-1 (WMD: 6.39 ng/mL; 95% CI: -9.44, 22.22 ng/mL; I2 = 66.6%; P-heterogeneity = 0.006; n = 7), or VCAM-1 (WMD: -8.31 ng/mL; 95% CI: -35.32, 18.71 ng/mL; I2 = 58.8%; P-heterogeneity = 0.033; n = 6). In conclusion, almond consumption beneficially affects CRP and IL-6 concentrations in adults. However, it has no beneficial effect on TNF-α, ICAM-1, or VCAM-1. More trials are needed to determine the effects of almonds on inflammation.

A calorie-restricted diet enriched with tree nuts and peanuts reduces the expression of CX3CR1 in peripheral blood mononuclear cells in patients with coronary artery disease

Background: The modification of the gut microbiome has been proposed to alter immune response which is a key driver in low-grade inflammation as well as metabolic markers. This study was conducted to determine the effects of a low-calorie diet with and without nuts on some gut bacterial abundance, metabolic markers, and gene expression in peripheral blood mononuclear cells (PBMCs) in stable coronary artery disease patients with overweight or obesity. Methods: Overweight or obese patients with stable coronary artery disease of both genders were randomly allocated to a nut-free calorie-restricted diet as 25% of energy deficit (CRD) or a CRD enriched with 39-60 gr/d of mixed nuts (CRDEN) for 8 weeks (32 patients in CRD and 35 patients in CRDEN). Mixed nuts consisted of equal amounts of unsalted pistachios, almonds, and peanuts. Microbiota analysis was performed by quantitative real-time polymerase chain reaction method on feces collected before and after the intervention, using primers targeting 16S ribosomal DNA of 4 different bacterial genera, including Bacteroides, Prevotella, Bifidobacterium, and Lactobacillus. We examined the plasma concentrations of glucose, insulin, adiponectin as well as expression of toll-like receptor-4 (TLR4) and fractalkine receptor (CX3CR1) in PBMCs. Results: A significant reduction in expression of CX3CR1 (p=0.04) and a tendency to lower expression of TLR4 in PBMCs (p=0.06) was observed in the CRDEN group at the end of the study compared to the CRD group. The abundance of fecal Prevotella also tended to increase in CRDEN compared to the CRD group (p=0.06). Plasma insulin and adiponectin had no significant changes. There was a positive correlation between fecal Prevotella abundance and plasma adiponectin at baseline (r=0.315, p=0.015) and the end of the study (r=0.380, p=0.003). Conclusion: Our results suggest that the inclusion of mixed tree nuts and peanuts in a low-calorie diet for 8 weeks led to a lower CX3CR expression in PBMCs in a cohort of overweight or obese patients with stable CAD. This finding provides another beneficial effect of diet supplemented with nuts on factors associated with inflammation. Trial registration: this clinical study has been registered at the clinical trial registration center (clinicaltrial.gov): NCT04078919 on September 6, 2019.

A calorie-restricted diet with nuts favourably raises plasma high-density lipoprotein-cholesterol in overweight and obese patients with stable coronary heart disease: A randomised controlled trial

BACKGROUND

Weight loss and consumption of nuts may both improve plasma lipids and lipoproteins. However, their effects in patients with coronary artery disease (CAD) who are under treatment with statins remain unclear. This study was conducted to determine plasma lipid and lipoprotein responses to a low-calorie (25% of energy deficit) nuts containing diet (NELCD) compared with a nut-free energy-restricted diet (NFLCD) in stable CAD patients who were overweight or obese (n = 67).

METHODS

Plasma lipids and lipoproteins and ATP-binding cassette (ABC) A1 and ABCG1 mRNA expressions in peripheral blood mononuclear cells (PBMCs) isolated from patients were assessed at baseline and after 8 weeks.

RESULTS

Plasma high-density lipoprotein (HDL) cholesterol and apoA1 increased significantly in the NELCD group at the end of Week 8 compared with those in NFLCD group (in NELCD group, mean change and 95% confidence interval (CI) were 1.17 [-1.31, 3.66] mg/dL, P = 0.012, and 2.55 [-2.10, 7.20] mg/dL, P = 0.011, for HDL cholesterol and apoA1, respectively). In both groups, the concentrations of total cholesterol, low-density lipoprotein cholesterol and triglyceride reduced significantly at Week 8 compared with those in baseline with no significant difference between the two groups. ABCA1 and ABCG1 mRNA expressions non-significantly decreased in both groups.

CONCLUSION

This study indicates that inclusion of nuts as part of a calorie-restricted diet improves the concentrations of HDL cholesterol and apoA-1 in patients with stable, established CHD receiving statins.

Health Benefits Related to Tree Nut Consumption and Their Bioactive Compounds

Long-term studies with regular tree nut consumption have indicated positive outcomes for multiple health benefits. Here, we review the beneficial effects of tree nuts, highlighting the impact on glucose modulation, body weight management, cardiovascular risk, inflammation, oxidative stress, cognitive performance, and gut microbiota. Nuts are important sources of nutrients and phytochemicals, which, together with a healthy lipid profile, could help prevent certain chronic diseases, protect against oxidative stress and inflammation, and improve cognitive performance, thus reducing the impact of aging and neurodegeneration.