Pistachios and cardiometabolic risk factors: a systematic review and meta-analysis of randomized controlled clinical trials.
Background: Previous experimental studies have reported that pistachios can elicit positive effects on lipid profile, blood pressure, and inflammation; however, a meta-analysis of the available evidence has yet to be performed. Objective: the aim of this study was to conduct systematic review and meta-analysis of the effect of pistachio enriched diets on cardiometabolic risk factors, such as weight, BMI, blood pressure, serum lipids, blood glucose, and inflammatory biomarkers. Design: A literature search was carried out for RCTs in medical databases, including PubMed/MEDLINE, Scopus, and Cochrane databases, with no time limitation up to August 2019, and conducted in accordance with the Preferred Reporting Items of Systematic Reviews and Meta-Analysis guidelines. Results: 11 RCTs, with 506 participants, that reported the effect of pistachios consumption on cardiometabolic risk factors were included in this systematic review and meta-analysis. Our findings indicated that pistachios consumption significantly reduced FBS (WMD: -3.73, 95 % CI: -6.99, -0.46, I2 = 99 %), TC/HDL (WMD: -0.46, 95 % CI: -0.76, -0.15, I2 = 95 %), LDL/HDL (WMD: -0.24, 95 % CI: -0.38, -0.11, I2 = 96 %), HbA1C (WMD: -0.14, 95 % CI: -0.26, -0.02, I2 = 60 %), Insulin (WMD: -2.43, 95 % CI: -4.85, -0.001, I2 = 58 %), SBP (WMD: -3.10, 95 % CI: -5.35, -0.85, I2 = 63 %), and MDA (WMD: -0.36, 95 % CI: -0.49, -0.23, I2 = 0%). Importantly, we did not observe adverse effects of pistachios consumption on BMI or blood pressure. Conclusion: This systematic review and meta-analysis demonstrates that pistachios consumption can elicit a beneficial effect on some cardiometabolic risk factors. All previous clinical studies are well designed but some points have still remained unclear including the effects of different pistachios dosages on cardio metabolic risk factors and efficacy of pistachios consumption in preventing endothelial dysfunction. Further examination is required to determine the effect of pistachios consumption on further endothelial function risk factors.
The effectiveness of pistachio on glycemic control and insulin sensitivity in patients with type 2 diabetes, prediabetes and metabolic syndrome: A systematic review and meta-analysis.
Background and aims: Pistachio nuts have been considered to improve dysglycemia. However, there are controversial results. This systematic review and meta-analysis carried out to evaluate the effects of pistachio nuts on glycemic control and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM), prediabetes, and metabolic syndrome. Methods: Medline/PubMed, ProQuest, Web of Knowledge, Scopus, Cochrane library, and ScienceDirect were systematically searched to find randomized controlled trials (RCTs). Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist was used to conduct the study. Results: Six RCTs were included in the review. Treatment with pistachio nuts exerted a significant reduction in fasting blood glucose (FBG) level (OR = 1.7, 95% CI; 1.2-2.4, P = 0.002, I2 = 0.0%, P = 0.731) and homeostasis model assessment of insulin resistance (HOMA-IR) index (OR = 1.5, 95% CI; 1.0-2.4, P = 0.043, I2 = 0.0%, P = 0.617), but no significant improvement was observed in regard to hemoglobin A1c (HbA1c) level (OR = 1.4, 95% CI; 0.9-2.1 P = 0.089, I2 = 0.0%, P = 0.957) and fasting plasma insulin (FPI) level (OR = 1.3, 95% CI; 0.9-1.9, P = 0.133, I2 = 0.0%, P = 0.776). Conclusions: Pistachio nuts might cause a significant reduction in FBG and HOMA-IR, although HbA1c and FPI might not significantly improve in patients suffering from or at risk of T2DM.
Effects of tree nut and groundnut consumption compared with those of L-arginine supplementation on fasting and postprandial flow-mediated vasodilation: Meta-analysis of human randomized controlled trials
Introduction: l-arginine supplementation may improve vascular endothelial function. As tree nuts and groundnuts are a source of the amino acid l-arginine, we performed a meta-analysis of human randomized controlled trials (RCTs) to compare effects of tree nut and groundnut consumption with those of l-arginine supplementation on fasting and postprandial endothelial function as assessed by flow-mediated vasodilation of the brachial artery (FMD). Methods: Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses. Results: A total of thirteen RCTs focusing on tree nut and groundnut consumption and nineteen RCTs investigating effects of l-arginine supplementation were included. Longer-term consumption of tree nuts and groundnuts increased fasting FMD by 1.09 %-point (PP) (95% CI: 0.49, 1.69, P < 0.001; I2: 76.7%, P < 0.001), while l-arginine supplementation (daily range: 3-21 g) increased fasting FMD by 0.53 PP (95% CI: 0.12, 0.93; P = 0.012; I2: 91.6%, P < 0.001). Effects between treatments were not statistically different (P = 0.31). Tree nut and groundnut consumption did not affect postprandial FMD responses (1.25 PP, 95% CI: -0.31, 2.81, P = 0.12; I2: 91.4%, P < 0.001), whereas l-arginine supplementation (range: 3-15 g) improved FMD during the postprandial phase by 2.02 PP (95% CI: 0.92, 3.13, P < 0.001; I2: 99.1%, P < 0.001). However, treatment effects did not differ significantly (P = 0.60). Overall, these results derive from high-quality evidence. Conclusion: Longer-term consumption of tree nuts and groundnuts, as well as l-arginine supplementation did improve fasting endothelial function, as assessed by FMD. However, the positive effects of tree nuts and groundnuts could not be fully explained by the amount of l-arginine in these nuts. Only l-arginine supplementation did improve postprandial FMD, but effects were not different from those of tree nuts and groundnuts. Future studies should focus on the identifications of the bioactive nutrients in tree nuts and groundnuts and mechanistic pathways behind differences in postprandial and longer-term fasting changes in FMD.
Sperm DNA methylation changes after short‐term nut supplementation in healthy males consuming a Western‐style diet.
Background. Many environmental and lifestyle factors have been implicated in the decline of sperm quality, with diet being one of the most plausible factors identified in recent years. Moreover, several studies have reported a close association between the alteration of specific sperm DNA methylation signatures and semen quality. Objectives. To evaluate the effect of tree nuts consumption on sperm DNA methylation patterns in healthy individuals reporting eating a Western‐style diet. Material and Methods. This is a post‐hoc analysis conducted in a subset of participants (healthy, non‐smoking, and young) from the FERTINUTS 14‐wk randomized‐controlled, parallel‐trial, recruited between December 2015 and February 2017. The participants included in the current study (n=72) were randomly selected in a proportion 2:1 from the original FERTINUTS trial between the 98 participants that completed the entire dietary intervention (nut group, n=48; control group, n=24). Sperm DNA methylation patterns were examined at baseline and after 14 weeks in 48 individuals consuming 60 g/d of mixed nuts (nuts group) and in 24 individuals following the usual Western‐style diet avoiding consumption of nuts (control group). Results. Over the course of the trial, no significant changes in global methylation were observed between groups. However, in the nuts group, we identified 36 genomic regions that were significantly differentially methylated between the baseline and the end of the trial and 97.2% of the regions displayed hypermethylation. We identified no such change in the control group over the same period of time. We also utilized the recently developed germ line age calculator to determine if nut consumption resulted in alterations to the epigenetic age of cells and no significant differences were found. Discussion and Conclusion. Adding nuts to a regular Western‐style diet subtly impacts sperm DNA methylation in specific regions, demonstrating that there are some sperm epigenome regions that could respond to diet.
Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials.
Several clinical interventions report that consuming nuts will not cause weight gain. However, it is unclear if the type of instructions provided for how to incorporate nuts into the diet impacts weight outcomes. We performed a systematic review and meta-analysis of published nut-feeding trials with and without dietary substitution instructions to determine if there are changes in body weight (BW) or composition. PubMed and Web of Science were searched through 31 December 2019 for clinical trials involving the daily consumption of nuts or nut-based snacks/meals by adults (≥18 y) for >3 wk that reported BW, BMI, waist circumference (WC), or total body fat percentage (BF%). Each study was categorized by whether or not it contained dietary substitution instructions. Within these 2 categories, an aggregated mean effect size and 95% CI was produced using a fixed-effects model. Quality of studies was assessed through the Cochrane risk-of-bias tool. Fifty-five studies were included in the meta-analysis. In studies without dietary substitution instructions, there was no change in BW [standardized mean difference (SMD): 0.01 kg; 95% CI: −0.07, 0.08; I2 = 0%] or BF% (SMD: −0.05%; 95% CI: −0.19, 0.09; I2 = 0%). In studies with dietary substitution instructions, there was no change in BW (SMD: −0.01 kg; 95% CI: −0.11, 0.09; I2 = 0%); however, there was a significant decrease in BF% (SMD: −0.32%; 95% CI: −0.61%, −0.03%; I2 = 35.4%; P < 0.05). There was no change in BMI or WC for either category of studies. Nut-enriched diet interventions did not result in changes in BW, BMI, or WC in studies either with or without substitution instructions. Slight decreases in BF% may occur if substitution instructions are used, but more research is needed. Limitations included varying methodologies between included studies and the frequency of unreported outcome variables in excluded studies.
The Effect of Grape Products Containing Polyphenols on C-reactive protein Levels: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
Although grape polyphenols can decrease chronic inflammations, their effect on C-reactive protein (CRP) levels is still controversial. So, this meta-analysis was conducted to investigate the effect of grape products containing polyphenols on CRP concentrations. In order to collect the relevant randomized controlled trials (RCTs), the data bases of PubMed, Scopus, Web of Science, and Google Scholar were searched up to March 30, 2020. The random-effects model, standardized mean difference, and 95% confidence interval were applied in data analysis. Meta-analysis was conducted over 17 eligible RCTs containing a total of 668 participants. The study registration number is CRD42018110169. Based on the results, grape products containing polyphenol decreased the CRP levels significantly (SMD = -0.229; 95% CI: -0.41, -0.05; P = 0.013). The sensitivity analysis was performed by removing each individual study and the results did not change. According to the subgroup analysis, higher doses of grape polyphenols (˃ 500 mg/d) and longer intervention periods (≥ 12 wk) had significant effects on CRP levels. Furthermore, grape polyphenols significantly reduced the CRP levels in patients with a clinical condition. In the same vein, grape seed extract and other grape products, such as grape extract, juice, and raisin, decreased the CRP levels significantly. According to the meta-regression results, the CRP level depends on the dose and duration of the grape polyphenols supplementation. Based on the findings, grape products containing polyphenols had a significant effect on CRP levels. Further well-designed and long-term clinical trials are highly recommended to achieve more comprehensive and accurate results.
Investigating walnut consumption and cognitive trajectories in a representative sample of older US adults.
Objective: Existing research suggests walnut intake may be associated with better cognitive function in older adults, yet few studies utilise longitudinal data from observational studies of ageing populations. Our objective was to estimate the association between whole walnut intake and cognitive change in a representative sample of older Americans. Design: Secondary analysis of the Health and Retirement Study and Health Care and Nutrition Study. Walnut consumption was defined as a categorical measure (none, low intake (0·01–0·08 1 oz. servings per day) and moderate intake (>0·08 1 oz. servings per day)) and cognitive function was measured using the Telephone Interview for Cognitive Status. Latent growth modelling estimated the association between walnut consumption and trajectories of cognitive status over a 4-year observational period. Sensitivity analyses assessing non-random dropout and Monte Carlo power analyses were conducted to contextualise results. Setting: The USA. Participants: A sample of 3632 US adults aged 65 years and older. Results: Those reporting any walnut consumption had greater cognitive scores at baseline than those not consuming walnuts (low walnut consumption, b = 1·53, se = 0·21, P < 0·001; moderate walnut consumption, b = 2·22, se = 0·27, P < 0·001), but walnut consumption was not associated with cognitive change. Walnut consumption was positively associated with socioeconomic status and health behaviours as well as intake of nutrients identified to have neuroprotective benefits. Conclusions: We identified an association between walnut consumption and cognitive function in older adults, although we did not find that walnut consumption was protective against age-related cognitive decline.
Microbial safety of oily, low water activity food products: A review.
Oily, low water activity (OL aw) products including tahini (sesame seed paste), halva (tahini halva), peanut butter, and chocolate, have been recently linked to numerous foodborne illness outbreaks and recalls. This review discusses the ingredients used and processing of OL aw products with a view to provide greater understanding of the routes of their contamination with foodborne pathogens and factors influencing pathogen persistence in these foods. Adequate heat treatment during processing may eliminate bacterial pathogens from OL aw foods; however, post-processing contamination commonly occurs. Once these products are contaminated, their high fat and sugar content can enhance pathogen survival for long periods. The physiological basis and survival mechanisms used by pathogens in these products are comprehensively discussed here. Foodborne outbreaks and recalls linked to OL aw foods are summarized and it was observed that serotypes of Salmonella enterica were the predominant pathogens causing illnesses. Further, intervention strategies available to control foodborne pathogens such as thermal inactivation, use of natural antimicrobials, irradiation and hydrostatic pressure are assessed for their usefulness to achieve pathogen control and enhance the safety of OL aw foods. Sanitation, hygienic design of manufacturing facilities, good hygienic practices, and environmental monitoring of OL aw food industries were also discussed.
Potential probiotic and food protection role of wild yeasts isolated from pistachio fruits (Pistacia vera).
Background: The biotechnological potential of yeasts from nuts such as pistachio, not only for health applications but also for industry use, is scarcely studied. Interest in the probiotic capability of yeasts has increased in the past years as well as their utilisation as food or feed preservatives. Their capabilities as biocontrol against problematic (spoilage or toxigenic) microorganisms or as antioxidants have been revalued. As a result, both abilities would be desirable to develop a new potential probiotic microorganism which could be added to food or feed to improve their properties. Results: Molecular techniques allowed the identification of a total of 7 different species and 15 strains. A screening of the probiotic potential of these strains was carried out. It was found that 65% of the strains resisted the gastrointestinal conditions as well as presented a generation time of < 22h. Additionally, some strains showed better kinetic parameters than Saccharomyces boulardii (positive control). Complementary tests were done to determine their auto-aggregation capacity, cell surface hydrophobicity, behaviour in a sequential simulated digestion, biofilm formation capability and carbon source assimilation. Finally, 67% and 13% of the studied yeasts showed biocontrol and antioxidant activities, respectively. Conclusions: Diutina rugosa 14 followed by Diutina rugosa 8 were the best wild yeast from Pistacia vera as potential probiotic and in carbon source utilisation. On the other hand, Hanseniaspora guilliermondii 6 and Aureobasidium proteae 5 could be used to improve food or feed product preservation because of their notable biocontrol and antioxidant capabilities.
Spray Drift Mitigation Using Opposing Synchronized Air‐Blast Sprayers.
Background: Pesticide drift is a serious environmental and safety concern that affects all of U.S. agriculture. A number of mitigation techniques to reduce pesticide drift have been recommended by industry, academic and government agencies. These techniques are very costly or reduce the efficacy of the pest control product and have not been implemented by U.S. agriculture. Results: When using a novel spray technique (Air-in), pesticide drift was significantly reduced between 53% to 99% at 7.6 m from the orchard drip line when compared to the grower standard. This technique not only reduced pesticide drift but also maintained or improved the amount of pesticide residue deposited (0.7 to 2.6 times) and the percent pesticide coverage (1.0 to 1.4 times) with different air-blast speed sprayers on almond, walnut and pistachio. Conclusion: The Air-in technique shows great promise in reducing pesticide drift while maintaining or improving pesticide coverage with minimal cost to the grower.