Almonds ameliorate glycemic control in Chinese patients with better controlled type 2 diabetes: a randomized, crossover, controlled feeding trial

Effects of Almond Consumption on Selected Markers of Inflammation and Oxidative Stress: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the effectiveness of almond consumption on serum C-reactive protein (CRP) and malondialdehyde (MDA) levels in individuals at risk of cardiovascular disease (CVD). An electronic database search was performed on PubMed, Web of Science, Scopus, and the Cochrane Library from inception through October 2024. Summary effect size measurements were calculated using random effects model estimation and were reported as weighted mean differences (WMDs) along with 95% confidence intervals (CIs). A total of 258 articles were identified, and 13 randomized controlled trials (RCTs) were included in the systematic review and meta-analysis. The meta-analysis of eleven RCTs, which involved a total of 544 participants, indicated that almonds significantly reduced levels of CRP (WMD, -0.28 mg/L; 95% CI, -0.52, -0.04; p = 0.02). However, we found no significant benefit of almond consumption in improving serum MDA levels, and due to the limited number of studies, the examination of MDA was conducted only qualitatively. This study supports the conclusion that almond consumption has favorable effects on CRP levels in individuals with CVD risk factors. More high-quality trials are needed to confirm these findings.

Effect of nut consumption on blood lipids: An updated systematic review and meta-analysis of randomized controlled trials

AIMS

Nuts are nutrient-dense foods touted for their health-promoting effects, especially regarding cardiovascular health, yet inconsistencies in the literature remain in relation to their effect on blood lipids. Hence, a systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to determine the effect of nut intake on blood lipids.

DATA SYNTHESIS

MEDLINE-PubMed and Cochrane databases were searched. 113 unique trials met eligibility criteria (n = 8060 adults with various health status) assessing the effect of a median daily dose of 45.5 g/d of nuts compared to a non-nut control on blood lipid outcomes met inclusion criteria. Overall, nut consumption resulted in moderate reductions in total cholesterol (mean difference, -0.14 mmol/L [95 % confidence interval, -0.18 to -0.10 mmol/L]) and LDL-C (-0.12 mmol/L [-0.14 to -0.09 mmol/L]), with small reductions in triglycerides (-0.05 mmol/L [-0.07 to -0.03 mmol/L]), TC:HDL-C (-0.11 [-0.16 to -0.06]), LDL-C:HDL-C (-0.19 [-0.24 to -0.12]), and apolipoprotein B (-0.04 g/L [-0.06 to -0.02 g/L]). There was no significant impact on HDL-cholesterol or other assessed measures. Certainty of evidence was high for apolipoprotein A, and generally moderate/low for all other outcomes. Sensitivity analysis did not change the evidence on the main outcomes. Significant effect modifications in subgroup analysis were shown for most of the lipid parameters assessed. None of these subgroup effects altered the evidence of heterogeneity for any primary outcome.

CONCLUSIONS

Current evidence provides a good indication that consuming nuts may advantageously affect blood lipids in adults with a mix of health status.

PROSPERO REGISTRATION

PROSPERO identifier, CRD42022358688.

Effects of almond consumption on lipid profile in patients with type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials

The aim of this meta-analysis was to assess the effects of almond consumption on the lipid profiles of type 2 diabetes mellitus (T2DM) patients. Eligible trials were searched from four electronic databases until Jan 2020. Five eligible articles were included in the final quantitative analysis. Overall, meta-analysis could not show any beneficial effect of almond consumption on total cholesterol (TC) weighted mean difference (WMD: 0.65 mg/dL, 95% CI: -7.52-8.82, p = .87), triglyceride (TG; WMD: 1.59 mg/dL, 95% CI: -21.77-24.96, p = .89), low-density lipoprotein cholesterol (LDL-C; WMD: -5.40 mg/dL, 95% CI: -13.30-2.50, p = .18), and high-density lipoprotein cholesterol (HDL-C; WMD: 1.57 mg/dL, 95% CI: -0.95-4.10, p = .22). However, subgroup analyses showed that serum LDL-C levels were significantly reduced in trials administered > 50 g/d almond. The data suggest that consumption of almond could not improve lipid profile in patients with T2DM.

Can different types of tree nuts and peanuts induce varied effects on specific blood lipid parameters? A systematic review and network meta-analysis

Tree nuts and peanuts have shown cardioprotective effects through the modulation of blood lipid levels. Despite the abundance of scientific evidence available, it remains uncertain whether the type of nut consumed influences these changes. The objective of this study was to evaluate and rank the effects of six types of nuts on total cholesterol (total-c), low-density lipoprotein (LDL-c), triglyceride (TG) and high-density lipoprotein (HDL-c) levels through a systematic search of randomized controlled trials (RCTs), a frequentist network meta-analysis (NMA), and the estimation of SUCRA values. A total of 76 RCTs were ultimately analyzed. The total c for pistachios, almond, and walnuts; LDL-c for cashews, walnuts, and almond; and TG for hazelnuts and walnuts significantly decreased, while only peanuts exhibited a significant increase in HDL-c levels. According to the rankings, the most effective type of nut for reducing total cholesterol was pistachio, cashew for LDL-c, hazelnut for TG, and peanut for increasing HDL-c levels. It should be noted that every type of nut analyzed exhibited a significant positive impact on some parameters, and specific types demonstrated enhanced advantages for particular blood lipids. These results endorse the use of personalized nutritional strategies to address and prevent dyslipidemia.Registration: PROSPERO database CRD42021270779.

Association of nut consumption with insulin resistance and blood lipid profile in Spanish university students

AIMS

To examine whether nut consumption was associated with insulin resistance and blood lipid parameters in a sample of young healthy adults.

MATERIAL AND METHODS

A cross-sectional study was conducted involving 306 first-year students (aged 18-30 years) from the University of Castilla-La Mancha, Spain. Biochemical variables related to insulin resistance and blood lipid profile (glucose, insulin, HbA1c, total cholesterol (total-c), LDL-c, HDL-c, and triglycerides) were determined from morning fasting blood samples. Nut consumption was estimated using a 137-item Food-Frequency Questionnaire. The associations of walnuts, other nuts and total nut intakes with insulin resistance and lipid profile variables and surrogates were assessed by linear regression analysis. Differences in insulin resistance and lipid profiles between participants meeting or not meeting the nut consumption recommendations were examined by analysis of covariance (ANCOVA). Logistic regressions were used to analyze the likelihood of having higher levels of blood lipids or insulin resistance in participants who met or did not meet the recommended intake of nuts.

RESULTS

There was no association found between nut consumption, whether walnuts or other nut varieties, and insulin resistance and lipid profile variables. Additionally, there were no significant differences in insulin resistance or blood lipid profile variables between university students meeting or not meeting nut consumption recommendations. Finally, stratified analyses based on sex were consistent and did not substantially modify our estimates in the fully adjusted models.

CONCLUSIONS

In conclusion, our results suggest that walnuts, other types of nuts, and total nut consumption did not adversely influence metabolic or lipid profile variables among healthy young adults. Although nuts are recommended among healthy dietary patterns, our findings showed that nut consumption has a null effect on the cardiometabolic risk parameters explored in young healthy adults.

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.

Premeal almond load decreases postprandial glycaemia, adiposity and reversed prediabetes to normoglycemia: A randomized controlled trial

BACKGROUND

Asian Indians show rapid conversion from prediabetes to type 2 diabetes (T2D). Novel dietary strategies are needed to arrest this progression, by targeting postprandial hyperglycaemia (PPHG).

DESIGN

We conducted a free-living randomized controlled open-label parallel arm study to evaluate the effect of a premeal load of almonds (20 g) 30 min before major meals on anthropometric, glycaemic, and metabolic parameters over 3 months. Sixty-six participants with prediabetes in the age range of 18-60 yrs were recruited. The study was registered at clinicaltrials.gov (registration no. NCT04769726).

RESULTS

Thirty participants in each arm completed the study. As per 'intention-to-treat' analysis, overall additional mean reductions were statistically significant for body weight, BMI, waist circumference (WC), subscapular and suprailiac skinfolds, and improved handgrip strength (Kg) (p < 0·001 for all) in the treatment arm vs. the control arm (after multiple adjustments). In the blood parameters, the additional mean reduction in the treatment arm vs. control arm was statistically significant for fasting and post-75 g oral glucose-load blood glucose, postprandial insulin, HOMA-IR, HbA1c, proinsulin, total cholesterol, and very low-density lipoprotein cholesterol (p < 0·001 for all). Most importantly, we observed a reversal to normoglycemic state (fasting blood glucose and 2 h post-OGTT glucose levels) in 23.3% (7 out of 30) of participants in the treatment arm which is comparable to that seen with Acarbose treatment (25%).

CONCLUSION

Incorporation of 20 g of almonds, 30 min before each major meal leads to significant improvement in body weight, WC, glycemia (particularly PPHG), and insulin resistance and shows potential for reversal of prediabetes to normal glucose regulation over 3 months.

Almond Consumption for 8 Weeks Altered Host and Microbial Metabolism in Comparison to a Control Snack in Young Adults

Almond consumption can improve cardiometabolic (CM) health. However, the mechanisms underlying those benefits are not well characterized. This study explored the effects of consuming a snack of almonds vs. crackers for 8 weeks on changes in metabolomic profiles in young adults (clinicaltrials.gov ID: NCT03084003).

Participants (n = 73, age: 18-19 years, BMI: 18-41 kg/m2) were randomly assigned to consume either almonds (2 oz/d, n = 38) or an isocaloric control snack of graham crackers (325 kcal/d, n = 35) daily for 8 weeks. Blood samples were collected at baseline prior to and at 4 and 8 weeks after the intervention. Metabolite abundances in the serum were quantified by hydrophilic interaction chromatography quadrupole (Q) time-of-flight (TOF) mass spectrometry (MS/MS), gas chromatography (GC) TOF MS, CSH-ESI (electrospray) QTOF MS/MS, and targeted analyses for free PUFAs, total fatty acids, oxylipins and endocannabinoids. Linear mixed model analyses with baseline-adjustment were conducted, and those results were used for enrichment and network analyses. Microbial community pathway predictions from 16S rRNA sequencing of fecal samples was done using PICRUST2.

Almond consumption enriched unsaturated triglycerides, unsaturated phosphatidylcholines, saturated and unsaturated lysophosphatidylcholines, tricarboxylic acids, and tocopherol clusters (p < 0.05). Targeted analyses reveal lower levels of omega-3 total fatty acids (TFAs) overall in the almond group compared to the cracker group (p < 0.05). Microbial amino acid biosynthesis, and amino sugar and nucleotide sugar metabolism pathways were also differentially enriched at the end of the intervention (p < 0.05).

The study demonstrates the differential effects of almonds on host tocopherol, lipid, and TCA cycle metabolism with potential changes in microbial metabolism, which may interact with host metabolism to facilitate the CM benefits.

The effect of nuts consumption on circulating oxidized low-density lipoproteins: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis evaluated the effect of nuts in decreasing circulating levels of oxidized low-density lipoproteins (ox-LDL). A literature search was performed of major electronic databases (MEDLINE/PubMed, Scopus, and ISI Web of Science) from inception up to November 15th, 2021 to find randomized controlled trials (RCTs) evaluating the effect of different nuts on circulating levels of ox-LDL. The effect size was determined using standardized mean difference (SMD) and corresponding 95% confidence intervals (CI). Evaluation of funnel plot, Begg's rank correlation, and Egger's weighted regression tests were used to assess the presence of publication bias in the meta-analysis. This systematic review and meta-analysis included 15 RCTs involving 997 subjects. Meta-analysis showed that nuts significantly decreased serum levels of ox-LDL. Besides, meta-regression results of the association between confounders such as duration of nuts consumption or delta LDL-cholesterol and levels of ox-LDL, were not significant. The correlation between nuts type and ox-LDL levels was significant in subgroup analyses suggesting the most significant effect of pistachios consumption on reducing the circulating concentrations of ox-LDL. To conclude, nuts consumption decreases the circulating concentrations of ox-LDL which might be beneficial for the prevention and/or progression of ASCVD.

Effects of almond intake on oxidative stress parameters: A systematic review and meta-analysis of clinical trials

BACKGROUND AND AIMS

Several randomized controlled trials (RCTs) have shown that almonds can improve oxidative stress indices, but the results are controversial. Therefore, the goal of this research was to carry out a systematic review and meta-analysis of all RCTs that evaluated the effect of almonds on selected oxidative stress indices.

METHODS

A systematic search was conducted up to April 2022 on PubMed, Scopus, Web of Science, and Google Scholar. We have selected the studies that investigated the effects of almonds on malondialdehyde (MDA), and oxidized low-density lipoprotein (Ox-LDL) levels in adults. Data were pooled by using the random-effects model. The risk of bias in individual studies was assessed using the Cochrane Collaboration risk of bias tool.

RESULTS

Seven RCTs involving 424 participants were analyzed. The results indicated that almond intake led to a significant decrease in MDA levels (WMD: - 6.63 nmol/ml; 95 % CI: - 8.72 to - 4.54; P < 0.001). However, no significant effect was observed on Ox-LDL (Hedges' g: - 0.12; 95 % CI: - 0.34 to 0.10; P = 0.28). Sensitivity analysis showed that overall estimates were not affected by the elimination of any study. We did not observe any evidence regarding publication bias.

CONCLUSION

The present meta-analysis suggests that almond intake can improve MDA levels and might play a beneficial role in the reinforcement of the antioxidant defense system and amelioration of oxidative stress in adults. There is a need for more studies with larger groups to better estimate this effect.

Beneficial effects of premeal almond load on glucose profile on oral glucose tolerance and continuous glucose monitoring: randomized crossover trials in Asian Indians with prediabetes

BACKGROUND

Rapid conversion from prediabetes to diabetes and frequent postprandial hyperglycemia (PPHG) is seen in Asian Indians. These should be the target of dietary strategies.

OBJECTIVES

We hypothesized that dietary intervention of preloading major meals with almonds in participants with prediabetes will decrease overall glycemia and PPHG.

DESIGN

The study included two phases: (1) an oral glucose tolerance test (OGTT)-based crossover randomized control study, the effect of a single premeal almond load (20 g) given before OGTT was evaluated (n = 60, 30 each period). (2) The continuous glucose monitoring system (CGMS)-based study for 3 days including premeal almond load before three major meals was a free-living, open-labeled, crossover randomized control trial, where control and premeal almond load diets were compared for glycaemic control (n = 60, 30 in each period). The study was registered at clinicaltrials.gov (registration no. NCT04769726).

RESULTS

In the OGTT-based study phase, the overall AUC for blood glucose, serum insulin, C-peptide, and plasma glucagon post-75 g oral glucose load was significantly lower for treatment vs. control diet (p < 0.001). Specifically, with the former diet, PPHG was significantly lower (18.05% in AUC on OGTT, 24.8% at 1-h, 28.9% at 2-h post OGTT, and 10.07% during CGMS). The CGMS data showed that premeal almond load significantly improved 24-glucose variability; SD of mean glucose concentration and mean of daily differences. Daily glycaemic control improved significantly as per the following: mean 24-h blood glucose concentration (M), time spent above 7.8 mmol/L of blood glucose, together with the corresponding AUC values. Premeal almond load significantly decreased following: overall hyperglycemia (glucose AUC), PPHG, peak 24-h glycaemia, and minimum glucose level during night.

CONCLUSION

Incorporation of 20 g of almonds, 30 min before each major meal led to a significant decrease in PPHG (as revealed in OGTT-based study phase) and also improved insulin, C-peptide, glucagon levels, and improved glucose variability and glycemic parameters on CGMS in participants with prediabetes.

CLINICAL TRIAL REGISTRY

The study was registered at clinicaltrials.gov (registration no. NCT04769726).

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.

Effects of almond on cardiometabolic outcomes in patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

An enhanced risk for cardiovascular disease (CVD) still exists even when T2DM patients have tight control on blood sugar. Thus, identification of treatment approaches that address CVD risk factors may be useful for patients beyond the blood sugar management. Although emerging evidence suggests that nuts consumption have beneficial effects on cardiometabolic health, the effects of almond intake in patients with type 2 diabetes are still controversial. Therefore, our objective was to investigate the effect of almond on cardiometabolic outcomes in patients with T2DM through a systematic review and meta-analysis of available randomized controlled trials (RCTs). A systematic search was conducted in PubMed, Web of Science, Scopus, Embase, and Google Scholar to identify relevant RCTs up to March 2021. There was no language and time limitation. Weighted mean difference (WMD) was pooled using a random effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods. Nine RCTs were included in the final analysis. Almond intake resulted in significant reduction in low-density lipoprotein cholesterol (LDL-C) (WMD: -5.28 mg/dL; 95% CI, -9.92, -0.64; p = .026) compared with the control group. This lowering effect of LDL-C was robust in subgroups with almond consumption >50 g/day, and baseline LDL-C level <130 mg/dL. However, the effect of almond on total cholesterol, triglycerides, high-density lipoprotein cholesterol, fasting plasma glucose, insulin, hemoglobin A1c, body mass index, weight, body fat, systolic and diastolic blood pressure, and CRP was not significant compared with the control group. In summary, the current meta-analysis indicated that almond consumption decreased LDL-C, and had no favorable effect on other cardiometabolic outcomes in patients with T2DM. However, further high-quality studies are needed to firmly establish the clinical efficacy of the almond.

Nuts as a Part of Dietary Strategy to Improve Metabolic Biomarkers: A Narrative Review

Background

Nuts are in the spotlight because of their association with improved health outcomes. We aimed to summarize the findings of previous studies to evaluate the impact of nuts consumption on glycaemic and lipid profile, inflammation, and oxidative stress.

Methods

Electronic searches for observational and intervention studies were undertaken in PubMed, Embase, Web of Science, and Science Direct until 2022 for searching the studies aiming the application of different types of nuts and the beneficial effects of nuts in improving glycemia, dyslipidemia, inflammation, and oxidative stress.

Results

Results from 56 interventional, 9 narrative and 3 systematic reviews, and 12 meta-analysis studies, aiming at the evaluating beneficial effects of different types of nuts on metabolic markers, showed that nut consumption could improve metabolic markers, including glycaemic factors, lipid profile, and inflammatory and oxidative stress parameters in both healthy and individuals with metabolic disorders in a type-, dose- and duration-dependent manner. According to their unique nutrient components, nuts can be known as a part of a healthy diet, resulting in improved metabolic biomarkers.

Conclusion

Considering the efficacy of nuts in improving metabolic markers, incorporation of, incorporating nuts the effectiveness of nuts in improving metabolic markers, incorporating nuts in the diet may prevent the incidence or aggravation of chronic metabolic diseases. Considering the health benefits of the nuts' components, including essential micronutrients, if consumed in the appropriate dose and duration to provide the necessary amount of effective micronutrients to improve health, we will see an improvement in metabolic factors. At the same time, more research is required to determine the optimal type, dose, and duration of nut intervention with regards to metabolic control and reducing the risk of developing metabolic disorders.

Effects of nut consumption on blood lipid profile: A meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Several randomized controlled trials (RCTs) have assessed the effects of nut consumption on blood lipid profile. The aim of this study was to conduct a meta-analysis to quantitatively estimate the effects of nut consumption on blood lipid profile.

METHODS AND RESULTS

The PubMed, EMBASE, Cochrane Library, and Google Scholar databases were systematically searched to identify RCTs examining the effects of nut intake on blood total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) from inception until March 2021. A random-effects model was used to pool standardized mean differences (SMDs) and 95% confidence intervals (CIs). Potential publication bias was assessed using Begg's test and Egger's test. Sensitivity analysis was performed to assess the impact of each individual study on the pooled results. The meta-analysis showed that nut consumption had no significant effect on the blood lipid profile. However, there was a significant reduction in TC (SMD: -2.89, 95% CI: -4.80, -0.98, I² = 97.4) for pistachio consumption, and cashew consumption significantly increased HDL-C (SMD: 0.24, 95% CI: 0.04, 0.43, I² = 0.0) compared with that in controls. There was no significant publication bias in the meta-analysis. The sensitivity analysis showed that removing one study at a time did not change the significance of the results.

CONCLUSION

There was no overall effect of nut consumption on lipid profile, and the results may vary depending on nut type. We found that pistachio consumption may reduce TC levels, while cashew consumption increases HDL-C.

REGISTRY NUMBER

PROSPERO CRD42021249147.

The Effects of Peanuts and Tree Nuts on Lipid Profile in Type 2 Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized, Controlled-Feeding Clinical Studies

Background: Type 2 diabetes mellitus was found to be associated with metabolic disorders, particularly abnormal glucose and lipid metabolism. Dietary food choices may have profound effects on blood lipids. The primary objective of this study was to examine the effects of peanuts and tree nuts intake on lipid profile in patients with type 2 diabetes.

Methods: According to preferred reporting items for systematic reviews and meta-analysis guidelines, we performed a systematic search of randomized controlled clinical trials and systematic reviews published in PubMed, Web of Science, Embase, Scopus, and Cochrane library, from inception through June 2021. Studies in populations with type 2 diabetes, which compare nuts or peanuts to a controlled-diet group were included. We used the mean difference with 95% CIs to present estimates for continuous outcomes from individual studies. In addition, we used the GRADEpro tool to evaluate the overall quality of evidence.

Results: Sixteen studies involving 1,041 participants were eligible for this review. The results showed that peanuts and tree nuts supplementation did not induce significant changes in low-density lipoprotein-cholesterol (LDL-C) (mean difference = −0.11; 95%CI: −0.25 – 0.03, p = 0.117) and high-density lipoprotein-cholesterol (HDL-C) (mean difference = 0.01; 95%CI: −0.01 – 0.04, p = 0.400) in patients with type 2 diabetics. In addition, we found that peanuts and tree nuts intake may cause a significantly reduction in total cholesterol (TC) (mean difference = −0.14; 95%CI: −0.26 – −0.02, p = 0.024) and triglyceride (TG) (mean difference = −0.10; 95%CI: −0.17 – −0.02, p = 0.010). In the subgroup analysis, a significantly greater reduction in TC was observed in studies which duration was <12 weeks (mean difference = −0.22; 95%CI: −0.37 – −0.08, p = 0.002). The quality of the body of evidence was “moderate” for TC and TG, the quality of evidence for LDL-C and HDL-C were “low.”

Conclusion: Our findings suggest that consuming peanuts and tree nuts might be beneficial to lower TC concentration and TG concentration in type 2 diabetics subjects. Furthermore, peanuts and tree nuts supplementation could be considered as a part of a healthy lifestyle in the management of blood lipids in patients with type 2 diabetes. Given some limits observed in the current studies, more well-designed trials are still needed.

The effect of almond intake on glycemic control: A systematic review and dose-response meta-analysis of randomized controlled trials

Number trials have evaluated the effect of almond intake on glycemic control in adults; however, the results remain equivocal. Therefore, the present meta-analysis aims to examine the effectiveness of almond intake on glycemic parameters. Online databases including PubMed, Scopus, ISI web of science, Embase, and Cochrane Library were searched up to August 2021 for trials that examined the effect of almond intake on glycemic control parameters including fasting blood sugar (FBS), insulin, HOMA-IR, and HbA1C. Treatment effects were expressed as mean difference (MD) and the standard deviation (SD) of outcomes. To estimate the overall effect of almond intake, we used the random-effects model. In total, 24 studies with 31 arms were included in our analysis. The meta-analysis revealed that almond intake did not significantly change the concentrations of FBS, HbA1c, insulin levels, and HOMA-IR. In conclusion, there is currently no convincing evidence that almonds have a clear beneficial effect on glycemic control. Future studies are needed before any confirmed conclusion could be drowned.

The Effects of Almonds on Gut Microbiota, Glycometabolism, and Inflammatory Markers in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

The use of nutritional interventions for managing diabetes is one of the effective strategies aimed at reducing the global prevalence of the condition, which is on the rise. Almonds are the most consumed tree nut and they are known to be rich sources of protein, monounsaturated fatty acids, essential minerals, and dietary fibre. Therefore, the aim of this review was to evaluate the effects of almonds on gut microbiota, glycometabolism, and inflammatory parameters in patients with type 2 diabetes.

METHODS

This systematic review and meta-analysis was carried out according to the preferred reporting items for systematic review and meta-analysis (PRISMA). EBSCOhost, which encompasses the Health Sciences Research Databases; Google Scholar; EMBASE; and the reference lists of articles were searched based on population, intervention, control, outcome, and study (PICOS) framework. Searches were carried out from database inception until 1 August 2021 based on medical subject headings (MesH) and synonyms. The meta-analysis was carried out with the Review Manager (RevMan) 5.3 software.

RESULTS

Nine randomised studies were included in the systematic review and eight were used for the meta-analysis. The results would suggest that almond-based diets have significant effects in promoting the growth of short-chain fatty acid (SCFA)-producing gut microbiota. Furthermore, the meta-analysis showed that almond-based diets were effective in significantly lowering (p < 0.05) glycated haemoglobin (HbA1c) levels and body mass index (BMI) in patients with type 2 diabetes. However, it was also found that the effects of almonds were not significant (p > 0.05) in relation to fasting blood glucose, 2 h postprandial blood glucose, inflammatory markers (C-reactive protein and Tumour necrosis factor α, TNF-α), glucagon-like peptide-1 (GLP-1), homeostatic model assessment of insulin resistance (HOMA-IR), and fasting insulin. The biological mechanisms responsible for the outcomes observed in this review in relation to reduction in HbA1c and BMI may be based on the nutrient composition of almonds and the biological effects, including the high fibre content and the low glycaemic index profile.

CONCLUSION

The findings of this systematic review and meta-analysis have shown that almond-based diets may be effective in promoting short-chain fatty acid-producing bacteria and lowering glycated haemoglobin and body mass index in patients with type 2 diabetes compared with control. However, the effects of almonds were not significant (p > 0.05) with respect to fasting blood glucose, 2 h postprandial blood glucose, inflammatory markers (C-reactive protein and TNF-α), GLP-1, HOMA-IR, and fasting insulin.

Nut consumption, body weight, and adiposity in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

It seems that nut consumption does not lead to weight gain in the general population. However, fewer studies have explored this relationship in individuals with type 2 diabetes (T2D).

PURPOSE

To synthesize evidence on the effects of nut (specifically, tree nuts and peanuts) consumption on adiposity-related measures in individuals diagnosed with T2D.

DATA SOURCES AND STUDY SELECTION

Four databases were searched up to December 31, 2020. Randomized controlled trials that examined the effects of nut consumption vs a control diet on body weight, body mass index, waist circumference, and percent body fat were included.

DATA EXTRACTION

The pooled effect sizes (p-ESs) and 95%CIs of nut consumption were estimated using random effects models.

DATA SYNTHESIS

A total of 15 randomized controlled trials including 899 individuals were included. No significant effects of nut-enriched interventions were found for body weight (p-ES = -0.04; 95%CI: -0.16 to 0.08), body mass index (p-ES = -0.05; 95%CI: -0.17 to 0.08), waist circumference (p-ES = -0.02; 95%CI: -0.20 to 0.15), or percent body fat (p-ES = -0.03; 95%CI: -0.28 to 0.21).

CONCLUSION

Nut consumption has no effect, positive or negative, on weight or adiposity parameters in people with T2D.

The Relationship of Tree Nuts and Peanuts with Adiposity Parameters: A Systematic Review and Network Meta-Analysis

The network meta-analysis and systematic review conducted aim to comparatively assess the effects of tree nuts and peanuts on body weight (BW), body mass index (BMI), waist circumference (WC), and body fat percentage (BF%). A systematic search up to 31 December 2020 was performed. A random-effects network meta-analysis was conducted following the PRISMA-NMA statement. A total of 105 randomized controlled trials (RCTs) with measures of BW (n = 6768 participants), BMI (n = 2918), WC (n = 5045), and BF% (n = 1226) were included. The transitivity assumption was met based on baseline characteristics. In the comparisons of nut consumption versus a control diet, there was no significant increase observed in any of the adiposity-related measures examined except for hazelnut-enriched diets, which raised WC. Moreover, almond-enriched diets significantly reduced WC compared to the control diet and to the pistachio-, mixed nuts-, and hazelnut-enriched diets. In subgroup analyses with only RCTs, designed to assess whether nut consumption affected weight loss, almonds were associated with reduced BMI and walnuts with reduced %BF. The evidence supports that: (1) tree nut and peanut consumption do not influence adiposity, and (2) compared to a control diet, the consumption of almond-enriched diets was associated with a reduced waist circumference.

A Comprehensive Review of Almond Clinical Trials on Weight Measures, Metabolic Health Biomarkers and Outcomes, and the Gut Microbiota

This comprehensive narrative review of 64 randomized controlled trials (RCTs) and 14 systematic reviews and/or meta-analyses provides an in-depth analysis of the effect of almonds on weight measures, metabolic health biomarkers and outcomes, and the colonic microbiota, with extensive use of figures and tables. Almonds are a higher energy-dense (ED) food that acts like a lower ED food when consumed. Recent systematic reviews and meta-analyses of nut RCTs showed that almonds were the only nut that had a small but significant decrease in both mean body mass and fat mass, compared to control diets. The biological mechanisms for almond weight control include enhanced displacement of other foods, decreased macronutrient bioavailability for a lower net metabolizable energy (ME), upregulation of acute signals for reduced hunger, and elevated satiety and increased resting energy expenditure. The intake of 42.5 g/day of almonds significantly lowered low-density lipoprotein cholesterol (LDL-C), 10-year Framingham estimated coronary heart disease (CHD) risk and associated cardiovascular disease (CVD) medical expenditures. Diastolic blood pressure (BP) was modestly but significantly lowered when almonds were consumed at >42.5 g/day or for >6 weeks. Recent RCTs suggest possible emerging health benefits for almonds such as enhanced cognitive performance, improved heart rate variability under mental stress, and reduced rate of facial skin aging from exposure to ultraviolet (UV) B radiation. Eight RCTs show that almonds can support colonic microbiota health by promoting microflora richness and diversity, increasing the ratio of symbiotic to pathogenic microflora, and concentrations of health-promoting colonic bioactives. Almonds are a premier healthy snack for precision nutrition diet plans.

Almond consumption decreases android fat mass percentage in adults with high android subcutaneous adiposity but does not change HbA1c in a randomised controlled trial

The purpose of this study was to determine if the mixed evidence of almond consumption on HbA1c stems from testing people with different body fat distributions (BFD) associated with different risks of glucose intolerance. A 6-month randomised controlled trial in 134 adults was conducted. Participants were randomly assigned to the almond (A) or control (C) group based on their BFD. Those in the almond group consumed 1·5 oz of almonds with their breakfast and as their afternoon snack daily. Those in the control group continued their habitual breakfast and afternoon snack routines. Body weight and composition were measured and blood samples were collected for determination of HbA1c, glycaemia and lipaemia at 0 and 6 months. Appetite ratings, energy intake and diet quality were collected at 0, 2, 4 and 6 months. Participants consuming almonds ingested 816 (sem 364) kJ/d more than participants in the control group (P = 0·03), but this did not result in any differences in body weight (A: –0·3 (sem 0·4), C: –0·4 (sem 0·4); P > 0·3). Participants in the almond, high android subcutaneous adipose tissue (SAT) group had a greater reduction in android fat mass percentage (A: –1·0 (sem 0·6), C: 1·1 (sem 0·6); P = 0·04), preserved android lean mass percentage (A: 0·9 (sem 0·6), C: –1 (sem 0·6); P = 0·04) and tended to decrease android visceral adipose tissue mass (A: –13 (sem 53) g, C: 127 (sem 53) g; P = 0·08) compared with those in the control, high SAT group. There were no differences in HbA1c between groups (A: 5·4 (sem 0·04), C: 5·5 (sem 0·04); P > 0·05). Thus, BFD may not explain the mixed evidence on almond consumption and HbA1c. Long-term almond consumption has limited ability to improve cardiometabolic health in those who are overweight and obese but otherwise healthy.

The effect of almond intake on anthropometric indices: a systematic review and meta-analysis

This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of almond intake on anthropometric indices in adult subjects. We searched PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar databases until January 2020 to identify relevant RCTs. Data were reported as weighted mean differences (WMDs) and standard deviations (SDs) to show the magnitude of effects of almond on body weight (BW), body mass index (BMI), waist circumference (WC), fat mass (FM), and fat-free mass (FFM). Out of 2983 reports, 28 RCTs (37 arms) were eligible for including in our meta-analysis. The pooled results, obtained using a random-effects model, showed that almond intake significantly decreased BW (WMD: -0.38 kg, 95% CI: -0.65, -0.10, p = 0.007, I2 = 30.5%) and FM (WMD: -0.58 kg, 95% CI: -0.87, -0.28, p < 0.001, I2 = 4.9%). However, we found no significant effect of almond administration on BMI (WMD: -0.30 kg m-2, 95% CI: -0.67, 0.06, p = 0.101, I2 = 62.6%), WC (WMD: -0.60 cm, 95% CI: -1.28, 0.06, p = 0.078, I2 = 0.0%), and FFM (WMD: 0.23 kg, 95% CI: -0.04, 0.50, p = 0.097, I2 = 49.5%). Overall, the current meta-analysis demonstrated that resveratrol almond intake significantly reduced weight and FM, but did not affect BMI, WC, and FFM. Further studies are still required to confirm our results.

The effect of almond intake on lipid profile: a systematic review and meta-analysis of randomized controlled trials

A number of clinical trials have examined the effect of almond intake on lipid profile in recent years; however, the results remain equivocal. Therefore, the present study aims to summarize and quantitatively examine the available evidence on the effectiveness of almond intake on lipid parameters by employing a systematic review and meta-analytic approach. Online databases including PubMed, Scopus, Embase, and Cochrane Library were searched up to September 2020 for randomized controlled trials that examined the effect of almond intake on lipid profile in adults. Treatment effects were expressed as weighted mean difference (WMD) and the corresponding standard error (SE) in the concentrations of serum lipids. To estimate the overall effect of almond intake, we employed the random-effect model. In total, 27 studies with 36 effect sizes were included in our analysis (1154 cases and 904 control subjects). The meta-analysis revealed that almond intake significantly changed the concentrations of triglycerides (WMD = -6.68 mg dL-1; 95% CI: -11.62, -1.75, p = 0.008), total cholesterol (WMD = -4.92 mg dL-1; 95% CI: -7.81, -2.03, p = 0.001), and low-density lipoproteins (WMD = -5.65 mg dL-1; 95% CI: -8.75, -2.55, p < 0.001); however it did not have a significant effect on high-density lipoprotein (WMD = -0.21 mg dL-1; 95% CI: -1.26, 0.84, p = 0.697) levels. Meta-regression analysis indicated a linear relationship between the dose of almond and change in TG (P = 0.021). This meta-analysis concludes that almond intake can significantly reduce lipid parameters. To draw straightforward conclusions regarding generalized recommendations for almond intake for improving lipid profile, there is a need for more well-controlled trials exclusively targeting patients with dyslipidaemia.

The effect of almond intake on blood pressure: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The present systematic review and meta-analysis aimed determine the efficacy of almond intake on blood pressure (BP).

METHODS

PubMed, Scopus, ISI Web of Science, Cochrane library and Google Scholar were comprehensively searched to infinity until December 2019. Randomized clinical trials (RCTs) reporting effects of almond intake on aortic and brachial BP were included. Weighted mean differences (WMDs) were pooled using a random-effects model. Standard methods were used for assessment of heterogeneity, sensitivity analysis, and publication bias.

RESULTS

A total of 16 RCTs (1128 participants) were included in the meta-analysis. Pooled analysis suggested that almond intake can reduced diastolic BP (DBP) (WMD = -1.30 mmHg; 95 % CI: -2.31,-0.30, p = 0.01, I² = 0.0 %). However, there was not any impact of almond intake on systolic BP (SBP) (WMD = -0.83 mmHg; 95 % CI: -2.55, 0.89, p = 0.34, I² = 58.9 %). Subgroup analysis revealed a significant reduction in SBP levels in subjects with lower SBP and lower dose of almonds.

CONCLUSION

We found that almonds might have a considerable favorite effect in BP and especially in DBP, and it could be encouraged as part of a healthy diet; however due to the high calorie content, the intake should be part of healthy diet.

Does Nut Consumption Reduce Mortality and/or Risk of Cardiometabolic Disease? An Updated Review Based on Meta-Analyses

Aim We aimed to determine if nut consumption decreases mortality and/or the risk of cardiometabolic diseases based on updated meta-analyses of epidemiological and intervention studies. Methods. An updated electronic search was conducted in PubMed/MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Library databases for original meta-analyses to investigate the effects of nut consumption on cardiometabolic disease in humans. Results. Seven new meta-analyses were included in this updated review. Findings similar to our previous review were observed, showing that nut consumption significantly decreased cardiovascular disease (CVD) mortality (−19% to −25%; n = 4), coronary heart disease (CHD) mortality (−24% to −30%; n = 3), stroke mortality (−17% to −18%; n = 3), CVD incidence (−15% to −19 %; n = 4), CHD [or coronary artery disease (CAD)] incidence (−17% to −34%; n = 8), and stroke incidence (−10% to −11%; n = 6) comparing high with low categories of nut consumption. Fasting glucose levels (0.08 to 0.15 mmol/L; n = 6), total cholesterol (TC; 0.021 to 0.30 mmol/L; n = 10), and low-density lipoprotein cholesterol (LDL-C; 0.017 to 0.26 mmol/L; n = 10) were significantly decreased with nut consumption compared with control diets. Body weight and blood pressure were not significantly affected by nut consumption. Conclusion. Nut consumption appears to exert a protective effect on cardiometabolic disease, possibly through improved concentrations of fasting glucose, total cholesterol, and LDL-C.

Evaluation of white sweet potato tube-feeding formula in elderly diabetic patients: a randomized controlled trial

BACKGROUND

Elderly people with type 2 diabetes mellitus (T2DM) have an increased risk of diabetes-related microvascular and macrovascular complications, thus diabetic patients with a functioning gastrointestinal tract but without sufficient oral intake require enteral nutrition (EN) formulas to control blood glucose. White sweet potato (WSP) was a kind of sweet potato could provide a healthy carbohydrate source to EN formula. The aim of this study was to examine at risk of malnutrition T2DM patients whether a WSP-EN would attenuate glucose response and elevate nutritional index compared to a standard polymeric formulas.

METHODS

In this randomized, parallel, placebo-controlled, pilot clinical trial to investigate the effects of EN with WSP on aged residents with T2DM in long-term care institutions. In total, 54 eligible participants were randomly assigned to either the non-WSP-EN or WSP-EN group. For 60 days, the WSP-EN group received a WSP formula through nasogastric tube via a stoma with a large-bore syringe. The participants received EN of standard polymeric formulas without WSP in the non-WSP-EN group.

RESULTS

The body weight, body mass index, Mini Nutritional Assessment score, and Geriatric Nutritional Risk Index were significantly higher in the WSP-EN group (p < 0.05). Moreover, the WSP-EN intervention reduced glycated hemoglobin levels (6.73% ± 1.47% vs. 6.40% ± 1.16%), but increased transferrin (223.06 ± 38.85 vs. 245.85 ± 46.08 mg/dL), high-density lipoprotein cholesterol (42.13 ± 10.56 vs. 44.25 ± 8.43 mg/dL), and vitamin A (2.45 ± 0.77 vs 2.74 ± 0.93 μM) levels (p < 0.05). In addition, there was no important side effects including gastrointestinal intolerance with prescribed doses in our WSP-EN treated patients when compared with control ones.

CONCLUSIONS

The results suggest WSP incorporated into enteral formulas can improve nutrition status and glycemic control in elderly diabetic patients.

TRIAL REGISTRATION

NCT02711839, registered 27 May 2015.

Health Benefits of Nut Consumption in Middle-Aged and Elderly Population

Aging is considered the major risk factor for most chronic disorders. Oxidative stress and chronic inflammation are two major contributors for cellular senescence, downregulation of stress response pathways with a decrease of protective cellular activity and accumulation of cellular damage, leading in time to age-related diseases. This review investigated the most recent clinical trials and cohort studies published in the last ten years, which presented the influence of tree nut and peanut antioxidant diets in preventing or delaying age-related diseases in middle-aged and elderly subjects (≥55 years old). Tree nut and peanut ingestion has the possibility to influence blood lipid count, biochemical and anthropometric parameters, endothelial function and inflammatory biomarkers, thereby positively affecting cardiometabolic morbidity and mortality, cancers, and cognitive disorders, mainly through the nuts' healthy lipid profile and antioxidant and anti-inflammatory mechanisms of actions. Clinical evidence and scientific findings demonstrate the importance of diets characterized by a high intake of nuts and emphasize their potential in preventing age-related diseases, validating the addition of tree nuts and peanuts in the diet of older adults. Therefore, increased consumption of bioactive antioxidant compounds from nuts clearly impacts many risk factors related to aging and can extend health span and lifespan.

The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials

Background

Observational evidence suggests higher nut consumption is associated with better glycemic control; however, it is unclear if this association is causal.

Objectives

We aimed to conduct a systematic review and meta-analysis of randomized controlled trials to examine the effect of tree nuts and peanuts on markers of glycemic control in adults.

Methods

A systematic review and meta-analysis of randomized controlled trials was conducted. A total of 1063 potentially eligible articles were screened in duplicate. From these articles, 40 were eligible for inclusion and data from these articles were extracted in duplicate. The weighted mean difference (WMD) between the nut intervention and control arms was determined for fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR) using the DerSimonian and Laird random-effects method. For outcomes where a limited number of studies were published, a qualitative synthesis was presented.

Results

A total of 40 randomized controlled trials including 2832 unique participants, with a median duration of 3 mo (range: 1-12 mo), were included. Overall consumption of tree nuts or peanuts had a favorable effect on HOMA-IR (WMD: -0.23; 95% CI: -0.40, -0.06; I2 = 51.7%) and fasting insulin (WMD: -0.40 μIU/mL; 95% CI: -0.73, -0.07 μIU/mL; I2 = 49.4%). There was no significant effect of nut consumption on fasting blood glucose (WMD: -0.52 mg/dL; 95% CI: -1.43, 0.38 mg/dL; I2 = 53.4%) or HbA1c (WMD: 0.02%; 95% CI: -0.01%, 0.04%; I2 = 51.0%).

Conclusions

Consumption of peanuts or tree nuts significantly decreased HOMA-IR and fasting insulin; there was no effect of nut consumption on HbA1c or fasting glucose. The results suggest that nut consumption may improve insulin sensitivity. In the future, well-designed clinical trials are required to elucidate the mechanisms that account for these observed effects.

Nuts and Cardio-Metabolic Disease: A Review of Meta-Analyses

OBJECTIVES

Accumulating epidemiological and intervention evidence suggest that nut consumption is associated with reduced incidence of some cardiometabolic diseases. However, to date no review of meta-analyses of epidemiological and intervention studies has evaluated the effects of nut consumption on cardiometabolic disease. Design/Results: Electronic searches for meta-analyses of epidemiological and intervention studies were undertaken in PubMed®/MEDLINE®. Meta-analyses of prospective studies show that nut consumption appears to be associated with reduced all-cause mortality by 19⁻20% (n = 6), cardiovascular disease (CVD) incidence (19%; n = 3) and mortality (25%; n = 3), coronary heart disease (CHD) incidence (20⁻34%; n = 2) and mortality (27⁻30%; n = 2) and stroke incidence (10⁻11%; n = 7) and mortality (18%; n = 2). No association between nut consumption and the risk of type 2 diabetes mellitus (T2DM) was observed in meta-analyses of prospective studies, whereas a decrease in fasting blood glucose ranging from 0.08 to 0.15 mmol/L was observed in 3 meta-analyses of intervention studies. In the interventions, nut consumption also had favorable effects on total cholesterol (0.021 to 0.28 mmol/L reduction from 8 meta-analyses of interventions) and low-density lipoprotein cholesterol (0.017 to 0.26 mmol/L reduction from 8 meta-analyses of interventions) and endothelial function (0.79 to 1.03% increase in flow-mediated dilation from 4 meta-analyses of interventions). Nut consumption did not significantly affect body weight. Nut consumption had no effect on inflammatory markers in intervention studies. The effect on blood pressure was inconsistent. A higher nut consumption was associated with a lower incidence of hypertension in prospective studies, while nut consumption did not improve blood pressure in intervention studies.

CONCLUSIONS

Nut consumption appeared to be associated with lower all-cause mortality and CVD and CHD mortality. There was no association between nut consumption and the incidence of T2DM although fasting blood glucose is decreased in intervention studies. In intervention studies nuts lower total cholesterol and low-density lipoprotein cholesterol (LDL-C).

Nuts and Cardiovascular Disease Prevention

PURPOSE OF REVIEW

We review recent epidemiological and clinical studies investigating the consumption of tree nuts and peanuts and cardiovascular disease (CVD) mortality as well as CVD risk factors.

RECENT FINDINGS

A greater consumption of tree nuts and peanuts is associated with a reduced risk of CVD mortality, as well as lower CVD events. Furthermore, risk factors associated with the development of CVD such as dyslipidemia, impaired vascular function, and hypertension are improved with regular tree nut and peanut consumption through a range of mechanism associated with their nutrient-rich profiles. There is weak inconsistent evidence for an effect of nut consumption on inflammation. There is emerging evidence that consuming tree nuts reduces the incidence of non-alcoholic fatty liver disease (NAFLD) and promotes diversity of gut microbiota, which in turn may improve CVD outcomes. Evidence for CVD prevention is strong for some varieties of tree nuts, particularly walnuts, and length of supplementation and dose are important factors for consideration with recommendations.

Nut consumption and risk of metabolic syndrome and overweight/obesity: a meta-analysis of prospective cohort studies and randomized trials

Background

Nut consumption has been shown to reduce the risk of cardiovascular disease. However, its role in the prevention of metabolic disorders, such as metabolic syndrome (Mets) and overweight/obesity, remains controversial. We therefore conducted a meta-analysis to determine the association of nut consumption with Mets and overweight/obesity.

Methods

Eligible studies were identified by searching the PubMed and Embase databases and by reviewing the references of relevant literatures. We used random effect models to pool the studies-specific risk ratio (RR) and weighted mean difference (WMD).

Results

This meta-analysis included six prospective cohort studies with 420,890 subjects and 62 randomized feeding trials with 7184 participants. Among the cohort studies, the summary RR for every 1-serving/week increase in nut intake was 0.96 (95% confidence interval [CI]: 0.92 to 0.99; n = 3) for Mets, 0.97 (95% CI: 0.95 to 0.98; n = 2) for overweight/obesity, and 0.95 (95% CI: 0.89 to 1.02; n = 2) for obesity. Pooling of randomized trials indicated that nut consumption was related to a significant reduction in body weight (WMD: - 0.22 Kg, 95% CI: -0.40 to - 0.04), body mass index (WMD: - 0.16 Kg/m², 95% CI: -0.31 to - 0.01), and waist circumference (WMD: - 0.51 cm, 95% CI: -0.95 to - 0.07). These findings remained stable in the sensitivity analysis, and no publication bias was detected.

Conclusion

Nut consumption may be beneficial in the prevention of Mets and overweight/obesity. Additional prospective studies are needed to enhance these findings and to explore the metabolic benefits for specific subclasses of nut.