Mechanisms underlying the cardiometabolic protective effect of walnut consumption in obese people: A cross-over, randomized, double-blind, controlled inpatient physiology study

Multidimensional plasma lipid composition and its causal association with type 2 diabetes mellitus: A Mendelian randomization study

BACKGROUND AND AIM

Recent research extends our knowledge of plasma lipid species, building on established links between serum lipid levels and Type 2 Diabetes Mellitus (T2DM) risk. Identifying the causal roles of these lipid species is key to improving T2DM risk assessment.

METHODS AND RESULTS

This study employs Mendelian randomization (MR) to investigate the causal relationship between 179 lipid species across 13 lipid categories and T2DM. Summary-level data were sourced from genome-wide association studies. The primary analytical methods included the inverse variance weighted (IVW) approach and the Wald ratio, complemented by a series of sensitivity analyses to ensure the robustness of results. The IVW analysis reveals a significant causal association between elevated levels of ceramide (d40:2) (OR = 1.071, 95% CI 1.034-1.109, P = 1.36 × 10-4), sphingomyelin (d38:1) (OR = 1.052, 95% CI 1.028-1.077, P = 1.80 × 10-5), and triacylglycerol (56:8) (OR = 1.174, 95% CI 1.108-1.243, P = 4.65 × 10-8), and an increased risk of T2DM. Conversely, Wald ratio analysis indicates that higher levels of phosphatidylcholine (O-16:1_16:0) (OR = 0.928, 95% CI 0.892-0.966, P = 2.37 × 10-4), phosphatidylcholine (O-16:1_20:4) (OR = 0.932, 95% CI 0.897-0.967, P = 2.37 × 10-4), and phosphatidylcholine (O-18:2_20:4) (OR = 0.872, 95% CI 0.812-0.935, P = 1.24 × 10-4) are significantly associated with a reduced risk of T2DM. Furthermore, suggestive causal evidence for 22 additional lipid species was identified.

CONCLUSIONS

This MR study establishes a causal relationship between specific lipid classes in modulating the risk of T2DM. It offers new insights for risk assessment and potential therapeutic targets in T2DM.

Rethinking weight loss treatments as cardiovascular medicine in obesity, a comprehensive review

The global escalation of obesity has made it a worldwide health concern, notably as a leading risk factor for cardiovascular disease (CVD). Extensive evidence corroborates its association with a range of cardiac complications, including coronary artery disease, heart failure, and heightened vulnerability to sudden cardiac events. Additionally, obesity contributes to the emergence of other cardiovascular risk factors including dyslipidaemia, type 2 diabetes, hypertension, and sleep disorders, further amplifying the predisposition to CVD. To adequately address CVD in patients with obesity, it is crucial to first understand the pathophysiology underlying this link. We herein explore these intricate mechanisms, including adipose tissue dysfunction, chronic inflammation, immune system dysregulation, and alterations in the gut microbiome.Recent guidelines from the European Society of Cardiology underscore the pivotal role of diagnosing and treating obesity to prevent CVD. However, the intricate relationship between obesity and CVD poses significant challenges in clinical practice: the presence of obesity can impede accurate CVD diagnosis while optimizing the effectiveness of pharmacological treatments or cardiac procedures requires meticulous adjustment, and it is crucial that cardiologists acknowledge the implications of excessive weight while striving to enhance outcomes for the vulnerable population affected by obesity. We, therefore, sought to overcome controversial aspects in the clinical management of heart disease in patients with overweight/obesity and present evidence on cardiometabolic outcomes associated with currently available weight management interventions, with the objective of equipping clinicians with an evidence-based approach to recognize and address CVD risks associated with obesity.

Can daily consumption of enriched fatty acids diet be effective in improving metabolic syndrome? An attractive paradox for walnut kernel

Imagine consuming a daily diet rich in fatty acids to help treat diseases such as hypertension and obesity. This concept presents an attractive paradox. In particular, consuming walnut kernels is beneficial for treating diseases associated with metabolic syndrome (MetS), including type 2 diabetes, cardiovascular disease, dyslipidemia, and obesity. Different parts of the Juglans regia tree (family Juglandaceae), including its leaves, green husks, bark, and septum, have shown promising effects on pathological conditions related to MetS. The therapeutic advantages of consuming walnut kernels for MetS can be attributed to the presence of polyunsaturated fatty acids and polyphenolic compounds such as juglone and ellagic acid. Diets enriched with walnut kernel have a positive impact on MetS complications by reducing diastolic blood pressure, improving blood lipid profiles, lowering fasting blood sugar levels, and increasing insulin sensitivity. The potential cellular mechanisms responsible for these benefits involve activating the cholesterol hemostasis pathway by inhibiting sterol regulatory element-binding proteins (SREBPs), proprotein convertase subtilisin/kexin type 9 (PCSK9), and cholesteryl ester transfer protein (CETP). Furthermore, other by-products of walnuts, such as leaves and green husks, have also demonstrated effectiveness in managing MetS. These findings highlight the potential of incorporating walnut-based products into our diets as a natural approach to combating MetS and its complications.

Effects of n-3 polyunsaturated fatty acid supplementation on appetite: a systematic review and meta-analysis of controlled clinical trials

BACKGROUND

The current studies explore the effect of omega-3 polyunsaturated fatty acids (PUFAs) on appetite.

OBJECTIVE

To examine the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on appetite using a systematic review and meta-analysis of controlled clinical trials (CTs).

PATIENTS AND METHODS

Online databases including PubMed, Scopus, ISI Web of Science, and Google Scholar were searched up to January 2022. A random-effects model was used to compare the overall standardized mean difference in appetite scores between n-3 PUFAs supplemented and control individuals.

RESULTS

Fifteen eligible CTs with 1504 participants (872 for n-3 PUFA supplementation and 632 for placebo groups) were included in our systematic review. The meta-analysis showed no significant difference in overall appetite score between n-3 PUFAs supplemented and control groups (standardized mean difference [SMD] = 0.458, 95% confidence interval [CI] - 0.327, 1.242, P value = 0.25). However, the n-3 PUFA supplementation significantly increased the desire to eat (SMD = 1.07, 95% CI 0.116, 2.029, P = 0.02) compared to control.

CONCLUSION

Although we found no effect of omega-3 supplementation on overall appetite score, it modestly increases the desire to eat. Further CTs evaluating the effect of PUFAs on appetite are still needed to confirm these findings.

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.

Ceramides in Autoimmune Rheumatic Diseases: Existing Evidence and Therapeutic Considerations for Diet as an Anticeramide Treatment

Autoimmune rheumatic diseases (AIRDs) constitute a set of connective tissue disorders and dysfunctions with akin clinical manifestations and autoantibody responses. AIRD treatment is based on a comprehensive approach, with the primary aim being achieving and attaining disease remission, through the control of inflammation. AIRD therapies have a low target specificity, and this usually propels metabolic disturbances, dyslipidemias and increased cardiovascular risk. Ceramides are implicated in inflammation through several different pathways, many of which sometimes intersect. They serve as signaling molecules for apoptosis, altering immune response and driving endothelial dysfunction and as regulators in the production of other molecules, including sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P). With lipid metabolism being severely altered in AIRD pathology, several studies show that the concentration and variety of ceramides in human tissues is altered in patients with rheumatic diseases compared to controls. As a result, many in vitro and some in vivo (animal) studies research the potential use of ceramides as therapeutic targets in rheumatoid arthritis (RA), ankylosing spondylitis, systemic lupus erythematosus, fibromyalgia syndrome, primary Sjögren's syndrome, systemic sclerosis, myositis, systemic vasculitis and psoriatic arthritis. Furthermore, the majority of ceramide synthesis is diet-centric and, as a result, dietary interventions may alter ceramide concentrations in the blood and affect health. Subsequently, more recently several clinical trials evaluated the possibility of distinct dietary patterns and nutrients to act as anti-ceramide regimes in humans. With nutrition being an important component of AIRD-related complications, the present review details the evidence regarding ceramide levels in patients with AIRDs, the results of anti-ceramide treatments and discusses the possibility of using medical nutritional therapy as a complementary anti-ceramide treatment in rheumatic disease.

The Lard Works in Mysterious Ways: Ceramides in Nutrition-Linked Chronic Disease

Diet influences onset, progression, and severity of several chronic diseases, including heart failure, diabetes, steatohepatitis, and a subset of cancers. The prevalence and clinical burden of these obesity-linked diseases has risen over the past two decades. These metabolic disorders are driven by ectopic lipid deposition in tissues not suited for fat storage, leading to lipotoxic disruption of cell function and survival. Sphingolipids such as ceramides are among the most deleterious and bioactive metabolites that accrue, as they participate in selective insulin resistance, dyslipidemia, oxidative stress and apoptosis. This review discusses our current understanding of biochemical pathways controlling ceramide synthesis, production and action; influences of diet on ceramide levels; application of circulating ceramides as clinical biomarkers of metabolic disease; and molecular mechanisms linking ceramides to altered metabolism and survival of cells. Development of nutritional or pharmacological strategies to lower ceramides could have therapeutic value in a wide range of prevalent diseases.

Valorization of Traditional Italian Walnut (Juglans regia L.) Production: Genetic, Nutritional and Sensory Characterization of Locally Grown Varieties in the Trentino Region

Juglans regia (L.) is cultivated worldwide for its nutrient-rich nuts. In Italy, despite the growing demand, walnut cultivation has gone through a strong decline in recent decades, which led to Italy being among the top five net importing countries. To promote the development of local high-quality Italian walnut production, we devised a multidisciplinary project to highlight the distinctive traits of three varieties grown in the mountainous region Trentino (northeast of Italy): the heirloom ‘Bleggiana’, a second local accession called local Franquette and the French cultivar ‘Lara’, recently introduced in the local production to increase yield. The genetic characterization confirmed the uniqueness of ‘Bleggiana’ and revealed local Franquette as a newly described autochthonous variety, thus named ‘Blegette’. The metabolic profiles highlighted a valuable nutritional composition of the local varieties, richer in polyphenols and with a lower ω-6/ω-3 ratio than the commercial ‘Lara’. ‘Blegette’ obtained the highest preference scores from consumers for both the visual aspect and tasting; however, the volatile organic compound profiles did not discriminate among the characterized cultivars. The described local varieties represent an interesting reservoir of walnut genetic diversity and quality properties, which deserve future investigation on agronomically useful traits (e.g., local adaptation and water usage) for a high-quality and sustainable production.

Role of Phytoestrogen-Rich Bioactive Substances (Linum usitatissimum L., Glycine max L., Trifolium pratense L.) in Cardiovascular Disease Prevention in Postmenopausal Women: A Systematic Review and Meta-Analysis

The aim of this report was to determine the impact of flaxseed, soy and red clover, and their bioactive substances on the lipid profile in postmenopausal women in cardiovascular diseases prevention. We used the following databases: MEDLINE (PubMed), EMBASE and the Cochrane Library. Meta-analysis indicates that the intake of flaxseed by postmenopausal women is associated with a statistically significant reduction in total cholesterol (TC) levels (weighted-mean difference (WMD) = -0.26; 95% confidence interval (95% CI): -0.38 to -0.13; p = 0.0001), low-density lipoprotein cholesterol (LDL-C) levels (WMD = -0.19; 95% CI: -0.30 to -0.08; p = 0.0006), and high-density lipoprotein cholesterol (HDL-C) levels (WMD = -0.06; 95% CI: -0.11 to -0.01; p = 0.0150). The effect of soy protein on the lipid profile showed a significant decrease in TC levels: WMD = -0.15; 95% CI: -0.25-0.05; p = 0.0048, LDL-C levels: WMD = -0.15; 95% CI: -0.25-0.05; p = 0.0067, as well as a significant increase in HDL-C levels: WMD = 0.05; 95% CI: 0.02-0.08; p = 0.0034. Changes in the lipid profile showed a significant reduction in TC levels after the use of red clover (WMD = -0.11; 95% CI: -0.18--0.04; p = 0.0017) and a significant increase in HDL-C levels (WMD = 0.04; 95% CI: 0.01 to 0.07; p = 0.0165). This meta-analysis provides evidence that consuming flaxseed, soy and red clover can have a beneficial effect on lipids in postmenopausal women and suggest a favorable effect in preventing cardiovascular diseases.

Walnut Meal Extracts Rich In Polyphenols Mitigate Insulin Resistance and Modulate Gut Microbiota in High Fat Diet-Fed Rats

Walnut kernel is a traditional Chinese herb recorded in the Chinese Pharmacopoeia with the efficacies of invigorating kidney, tonifying lung, and relaxing bowel. However, the potential mechanisms were unclear. This article aims to uncover the interdict mechanisms of walnut meal extracts (WMP) on high-fat diet (HFD) induced metabolic disorders in rats and reveal how the WMP benefits are associated with changes in the intestinal flora. Sprague-Dawley (SD) rats were fed a standard chow diet or an HFD for 18 weeks. After 6 weeks, the HFD rats were supplemented with 750 mg WMP/kg body weight or the vehicle for 12 weeks. The structure of gut microbiota was assessed by analyzing 16S rDNA sequences. WMP suppressed the weight gain and visceral obesity. WMP treatment also improved lipid profiles and increased antioxidative activities. WMP fully reversed hepatic steatosis with the upregulation of adipocytokines involved in lipid catabolism (e.g., adiponectin, PPAR-γ, visfatin, CEBPα) and the increased activities of lipoprotein lipase and hormone-sensitive lipase, which were associated with glucose tolerance improvement and insulin resistance (IR) mitigation. As revealed by 16S rDNA sequencing, WMP restored the diversity of intestinal flora reduced by HFD. WMP dramatically reduced the abundance of Gram-negative bacteria, especially Fusobacterium varium and Bacteroides vulgatus, and sharply increased the abundance of Lactobacillus animalis decreased by HFD. Our findings demonstrated that WMP suppressed the weight gain and adiposity in HFD-fed rats and fully reversed HFD induced IR and hepatic steatosis while dramatically reducing the abundance of Fusobacteriaceae and Enterobacteriaceae, underscoring the gut-liver axis as a primary target of walnut polyphenols.

Novel Pharmaceutical and Nutraceutical-Based Approaches for Cardiovascular Diseases Prevention Targeting Atherogenic Small Dense LDL

Compelling evidence supports the causative link between increased levels of low-density lipoprotein cholesterol (LDL-C) and atherosclerotic cardiovascular disease (CVD) development. For that reason, the principal aim of primary and secondary cardiovascular prevention is to reach and sustain recommended LDL-C goals. Although there is a considerable body of evidence that shows that lowering LDL-C levels is directly associated with CVD risk reduction, recent data shows that the majority of patients across Europe cannot achieve their LDL-C targets. In attempting to address this matter, a new overarching concept of a lipid-lowering approach, comprising of even more intensive, much earlier and longer intervention to reduce LDL-C level, was recently proposed for high-risk patients. Another important concern is the residual risk for recurrent cardiovascular events despite optimal LDL-C reduction, suggesting that novel lipid biomarkers should also be considered as potential therapeutic targets. Among them, small dense LDL particles (sdLDL) seem to have the most significant potential for therapeutic modulation. This paper discusses the potential of traditional and emerging lipid-lowering approaches for cardiovascular prevention by targeting sdLDL particles.

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.

An extra virgin olive oil-enriched chocolate spread positively modulates insulin-resistance markers compared with a palm oil-enriched one in healthy young adults: A double-blind, cross-over, randomised controlled trial

AIMS

To investigate if extra virgin olive oil (EVOO) or palm oil enriched chocolate spreads consumption leads to different results in terms of plasma ceramides concentration, glucose and lipid metabolism, inflammatory markers and appetite regulation in young healthy subjects.

METHODS

In a 2-week, double-blind, cross-over, randomised controlled trial, 20 healthy, normal-weight subjects with a mean age of 24.2 years (SD: 1.2), consumed chocolate spread snacks (73% of energy [%E] from fat, 20% from carbohydrates and 7% from proteins), providing 570 Kcal/day added to an isocaloric diet. The chocolate spreads were identical, except for the type of fat: EVOO oil, rich in monounsaturated fatty acids (MUFAs), or palm oil, rich in Saturated Fatty Acids (SFAs).

RESULTS

EVOO-enriched chocolate spread consumption led to better circulating sphingolipids and glucose profile, with reduced plasma ceramide C16:0, ceramide C16:0/ceramide C22:0-ceramide C24:0 ratio and sphingomyelin C18:0 (P = 0.030, P= 0.032 and P = 0.042, respectively) compared to the palm oil-enriched chocolate spread diet. HOMA-IR and plasma insulin were lower, while the Quicki and the McAuley Index were higher after the EVOO diet compared to the palm oil diet (P = 0.046, P = 0.045, P = 0.018 and P = 0.039 respectively). Subjects maintained a stable weight throughout the study. No major significant changes in total cholesterol, triglycerides, HDL, inflammatory markers, and appetite-regulating hormones/visual analogue scale were observed between the groups.

CONCLUSIONS

Partially replacing SFAs with MUFAs in a chocolate-based snack as part of a short-term isocaloric diet in healthy individuals may limit SFAs detrimental effects on insulin sensitivity and decrease circulating harmful sphingolipids in young adults.

Triglyceride-Rich Lipoproteins and Glycoprotein A and B Assessed by 1H-NMR in Metabolic-Associated Fatty Liver Disease

High plasma triglyceride (TG) levels and chronic inflammation are important factors related to metabolic-associated fatty liver disease in patients at cardiovascular risk. Using nuclear magnetic resonance (1H-NMR), we aimed to study the triglyceride-rich lipoprotein (TRL) and acute-phase glycoprotein profiles of a cohort of patients with metabolic disease and their relationship with fatty liver. Plasma samples of 280 patients (type 2 diabetes, 81.1%; obesity, 63.3%; and metabolic syndrome, 91.8%) from the University Hospital Lipid Unit were collected for the measurement of small, medium and large TRL particle numbers and sizes and glycoprotein profiles (Glyc-A and Glyc-B) by 1H-NMR. Liver function parameters, including the fatty liver index (FLI) and fibrosis-4 (FIB-4) score, were assessed. Hepatic echography assessment was performed in 100 patients, and they were followed up for 10 years. TRL particle concentrations showed a strong positive association with Glyc-A and Glyc-B (ρ=0.895 and ρ=0.654, p<0.001, respectively) and with the liver function-related proteins ALT ρ=0.293, p<0.001), AST (ρ=0.318, p<0.001) and GGT (ρ=0.284, p<0.001). Likewise, TRL concentrations showed a positive association with FLI (ρ=0.425, p<0.001) but not with FIB-4. During the follow-up period of 10 years, 18 new cases of steatosis were observed among 64 patients who were disease-free at baseline. Baseline TRL particle numbers and glycoprotein levels were associated with the new development of metabolic-associated fatty liver disease (MAFLD) (AUC=0.692, p=0.018 and AUC=0.669, p=0.037, respectively). Overall, our results indicated that TRL number and acute-phase glycoproteins measured by 1H-NMR could be potential biomarkers of the development of hepatic steatosis in patients at metabolic risk.

Effect of carbohydrate-restricted dietary interventions on LDL particle size and number in adults in the context of weight loss or weight maintenance: a systematic review and meta-analysis

BACKGROUND

LDL particle size and number (LDL-P) are emerging lipid risk factors. Nonsystematic reviews have suggested that diets lower in carbohydrates and higher in fats may result in increased LDL particle size when compared with higher-carbohydrate diets.

OBJECTIVES

This study aimed to systematically review available evidence and conduct meta-analyses of studies addressing the association of carbohydrate restriction with LDL particle size and LDL-P.

METHODS

We searched 6 electronic databases on 4 January, 2021 for randomized trials of any length that reported on dietary carbohydrate restriction (intervention) compared with higher carbohydrate intake (control). We calculated standardized mean differences (SMDs) in LDL particle size and LDL-P between the intervention and control groups of eligible studies, and pooled effect sizes using random-effects models. We performed prespecified subgroup analyses and examined the effect of potential explanatory factors. Internal validity and publication bias were assessed using Cochrane's risk-of-bias tool and funnel plots, respectively. Studies that could not be meta-analyzed were summarized qualitatively.

RESULTS

This review summarizes findings from 38 randomized trials including a total of 1785 participants. Carbohydrate-restricted dietary interventions were associated with an increase in LDL peak particle size (SMD = 0.50; 95% CI: 0.15, 0.86; P < 0.01) and a reduction in LDL-P (SMD = -0.24; 95% CI: -0.43, -0.06; P = 0.02). The effect of carbohydrate-restricted dietary interventions on LDL peak particle size appeared to be partially explained by differences in weight loss between intervention groups and exploratory analysis revealed a shift from small dense to larger LDL subclasses. No statistically significant association was found between carbohydrate-restricted dietary interventions and mean LDL particle size (SMD = 0.20; 95% CI: -0.29, 0.69; P = 0.37).

CONCLUSIONS

The available evidence indicates that dietary interventions restricted in carbohydrates increase LDL peak particle size and decrease the numbers of total and small LDL particles.This review was registered at www.crd.york.ac.uk/prospero/ as CRD42020188745.

The Mediterranean diet increases glucagon-like peptide 1 and oxyntomodulin compared with a vegetarian diet in patients with type 2 diabetes: A randomized controlled cross-over trial

AIM

To compare a Mediterranean diet (MED) with a high-fibre vegetarian diet (HFV) in terms of hunger-satiety perception through post-prandial assessment of appetite-related hormones glucagon-like peptide 1 (GLP-1) and oxyntomodulin, as well as self-rated visual analogue scale (VAS) quantification, in overweight/obese subjects with type 2 diabetes (T2D).

MATERIALS AND METHODS

Twelve T2D subjects (Male to female ratio = 7:5), mean age 63 ± 8.5 years, were enrolled in a randomized, controlled, crossover study. Participants consumed an MED meal as well as an isocaloric meal rich in complex carbohydrate as well as an isocaloric MED meal in two different visits with a 1-week washout period between the two visits. Appetite ratings, glucose/insulin, and gastrointestinal hormone concentrations were measured at fasting and every 30' until 210' following meal consumption.

RESULTS

GLP-1 and oxyntomodulin levels were significantly higher following MED meal compared with HFV meals (210' area under the curve, p < 0.022 and p < 0.023, respectively). Both MED and HFV meal resulted in a biphasic pattern of GLP-1 and oxyntomodulin, although MED meal was related to a delayed, significantly higher second GLP-1 peak at 150' compared with that of HFV meal (p < 0.05). MED meal was related to lower glucose profile compared with HFV meal (p < 0.039), whereas we did not observe significant changes in terms of self-reported VAS scores and insulin trend.

CONCLUSIONS

In T2D overweight/obese subjects, an MED meal is more effective than a HFV meal in terms of post-prandial plasma glucose homoeostasis and GLP-1 and oxyntomodulin release. These changes were not confirmed by VAS appetite self-assessment over a 210' period.

The psychological impact of COVID-19 pandemic on patients included in a bariatric surgery program

PURPOSE

The COVID-19 pandemic has radically impacted the world lifestyle. Epidemics are well-known to cause mental distress, and patients with a current or past history of obesity are at increased risk for the common presence of psychological comorbidities. This study investigates the psychological impact of the current pandemic in patients participating in a bariatric surgery program.

METHODS

Patients were consecutively enrolled during the Italian lockdown among those waiting for bariatric surgery or attending a post-bariatric follow-up, and were asked to complete through an online platform the Depression Anxiety Stress Scales-21 and a self-assessment questionnaire of 22 items evaluating the resilience, change in eating behavior and emotional responses referring to the ongoing pandemic.

RESULTS

59% of the 434 enrolled subjects reported of being worried about the pandemic, and 63% specifically reported of being worried about their or their relatives' health. 37% and 56% felt lonelier and more bored, respectively. 66% was hungrier with increased frequency of snacking (55%) and 39% reported more impulse to eat. Noteworthy, 49% felt unable to follow a recommended diet. No difference in terms of psychological profile was recorded among pre and post-bariatric subjects. Logistic regression analysis on post-bariatric patients showed a relationship between snacking, hunger, eating impulsivity, and anxiety, stress, and/or depression symptoms.

CONCLUSION

The pandemic led to increased psychological distress in patients with a current or past history of obesity, reducing quality of life and affecting dietary compliance. Targeted psychological support is warranted in times of increased stress for fragile subjects such as pre- and post-bariatric patients.

LEVEL OF EVIDENCE

Level V: cross-sectional descriptive study.

The gastro-jejunal anastomosis site influences dumping syndrome and weight regain in patients with obesity undergoing Laparoscopic Roux-en-Y Gastric Bypass

PURPOSE

The Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) is an effective weight loss procedure. The gastro-jejunal (GJ) anastomosis required can be performed on the anterior or posterior gastric pouch wall. No studies have compared these variants in terms of efficacy and onset of dumping syndrome (DS) and weight regain (WR). We aimed at assessing the prevalence of DS in relation to the site of anastomosis together with identifying prognostic factors of DS and WR.

METHODS

Patients who had undergone LRYGB with anterior (AGJ) or posterior (PGJ) anastomosis in 2010-2019 were retrospectively analyzed. We collected demographic data, medical history and the prevalence of DS evaluated through the Sigstad Score, together with WR data.

RESULTS

213 patients were enrolled, of which 51.6% had an AGJ and 48.4% had a PGJ. The mean follow-up time was 81 ± 18 and 27 ± 13 months in the AGJ and PGJ group, respectively (p < 0.0001). Excess weight loss was 77.59% and 94.13% in patients with AGJ and PGJ, respectively (p < 0.001). WR rate was 16% and 4% in the AGJ and PGJ population, respectively (p < 0.001). DS prevalence was 38% and 76% in the AGJ and the PGJ population, respectively (p < 0.0001). The site of anastomosis was identified as an independent predictor of DS (OR5.15; 95% CI 2.82-9.41; p < 0.0001) and WR (OR5.31; 95% CI 2.32-12.15; p < 0.0001). Obesity-related complications significantly improved after surgery independent of the anastomosis site.

CONCLUSION

LRYGB is effective in determining long-term weight loss and improvement of complications. AGJ is associated with lower prevalence of DS but more frequent WR. The anastomosis site is a factor to be considered when performing LRYGB.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

Small dense low-density lipoprotein-lowering agents

Metabolic disorders, including obesity, diabetes, and hyperlipidemia, as well as cardiovascular diseases (CVD), particularly atherosclerosis, are still leading causes of death worldwide. Plasma levels of low-density lipoprotein (LDL) are currently being considered as a critical risk factor for the diseases mentioned above, especially atherosclerosis. Because of the heterogeneous nature of LDL, many studies have already been conducted on its subclasses, especially small dense LDL (sdLDL). According to available evidence, sdLDL levels can be considered as an ideal alternative to LDL levels for monitoring CVD and early diagnosis of atherosclerosis. Recently, several researchers have focused on factors that are able to decrease sdLDL levels and improve health quality. Therefore, the purpose of this study is to describe the production process of sdLDL particles and review the effects of pharmaceutical and dietary agents as well as lifestyle on sdLDL plasma levels. In brief, their mechanisms of action are discussed. Apparently, cholesterol and LDL-lowering compounds are also effective in the reduction of sdLDL levels. In addition, improving lipid profile, especially the reduction of triglyceride levels, appropriate regimen, and lifestyle can decrease sdLDL levels. Therefore, all the aforementioned parameters should be taken into consideration simultaneously in sdLDL levels reducing strategies.

Effects of Mediterranean Diet on plasma metabolites and their relationship with insulin resistance and gut microbiota composition in a crossover randomized clinical trial

BACKGROUND & AIMS

The Mediterranean Diet (MedDiet) may decrease the cardiometabolic risk through modulation of metabolic pathways. Furthermore, the interplay between MedDiet, metabolites and microbial metabolism may improve our understanding on the metabolic effects of this diet. We aimed to evaluate the effect of the MedDiet compared to nuts supplementation on circulating metabolites and their relationship with cardiometabolic health. We further examined whether changes in the metabolomic profiles were associated with changes in gut microbiota composition in a multi-omics integrative approach.

METHODS

Forty-four adults with Metabolic Syndrome (MetS), (aged 37-65) participated in a randomized controlled, crossover 2-months dietary-intervention trial with a 1-month wash-out period, consuming a MedDiet or a non MedDiet plus nuts (50 g/day). Nutritional data were collected at the beginning and the end of each intervention period using 3-day dietary records, as well as fasting blood and fecal samples. Plasma metabolites (m = 378) were profiled using targeted metabolomics. Associations of these metabolites with the interventions were assessed with elastic net regression analyses. Gut microbiota composition was assessed by 16S rRNA sequencing. A sparse least regression analysis combined with a canonical correlation analysis was conducted between the plasma selected metabolites and genera in order to identify the relevant dual-omics signatures discriminating the dietary interventions.

RESULTS

Changes in 65 circulating metabolites were significantly associated with the MedDiet (mainly lipids, acylcarnitines, amino acids, steroids and TCA intermediates). Importantly, these changes were associated with decreases in glucose, insulin and HOMA-IR. The network analysis identified two main clusters of genera with an opposite behaviour towards selected metabolites, mainly PC species, ChoE(20:5), TGs and medium/long-chain acylcarnitines.

CONCLUSION

Following a MedDiet, rather than consuming nuts in the context of a non-MedDiet was associated with a specific plasma metabolomic profile, which was also related to metabolic improvements in adults with MetS. The identified correlated network between specific bacteria and metabolites suggests interplay between diet, circulating metabolites and gut microbiota. The trial was registered in the ISRCTN with identifier ISRCTN88780852, https://doi.org/10.1186/ISRCTN88780852.

Socioeconomic and lifestyle factors modifies the association between nut consumption and metabolic syndrome incidence

BACKGROUND & AIMS

The aim of this study was to evaluate the association of nut consumption and its various types with metabolic syndrome (MetS) risk and to investigate whether lifestyle factors (physical activity and smoking status) and socioeconomic status (education and occupation) modulate the association of nut consumption and the risk of MetS.

METHODS

We prospectively studied 1915 participants of the Tehran Lipid and Glucose study, among whom 591 were diagnosed with MetS during 8.9 years of follow-up. Nut consumption and its various types were assessed using a validated semi-quantitative food frequency questionnaire. Multivariable adjusted Cox regression was used to estimate Hazard Ratios (HRs) for MetS events across tertiles of nut consumption and its various types. Regarding interaction between nut consumption and physical activity levels, education levels, and smoking status on the risk of MetS, using joint classification, the effect modification of lifestyle factors and socioeconomic status on the association between nut consumption (<median and ≥ median) and risk of MetS was assessed by Cox regression.

RESULTS

Nut consumption was inversely associated with MetS risk in multivariable-adjusted models. The highest tertiles of the constituents of nuts including fiber, polyphenol, MUFA and PUFA reduced MetS risk compared with the lowest tertiles, after adjustment for confounders. Among various types of nuts, the multivariable-adjusted HRs of MetS were 0.78 (0.63-0.96) for walnuts, and 0.77 (0.63-0.94) for pistachios, compared with the lowest intake. Among adult population, consuming nuts higher than the median and having moderate to high physical activity levels resulted in significant reduction in the MetS risk (HRs: 0.74, CI: 0.55-0.98 for moderate and HRs: 0.63, CI: 0.47-0.86 for high physical activity level). Participants who did not smoke had lower risk of MetS regardless of their amount of nuts consumption (HRs: 0.67, CI: 0.47-0.94 for intakes < median and HRs: 0.71, CI: 0.53-0.93 for intakes ≥ median). Stratification based on education status resulted in reduction in the risk of MetS in participants consuming nuts ≥ median in both educated and not-educated group (HRs: 0.81, CI: 0.66-0.98 for the non-educated group and HRs: 0.63, CI: 0.47-0.84 for the educated group).

CONCLUSIONS

Incorporating nuts, especially walnuts, into dietary patterns reduced the risk of MetS, especially among individuals with more physical activity levels.

Branched-Chain Amino Acids in relation to food preferences and insulin resistance in obese subjects consuming walnuts: A cross-over, randomized, double-blind, placebo-controlled inpatient physiology study

BACKGROUND&AIMS

To assess whether the concentrations of circulating Branched-Chain Amino Acids (BCAAs) change after walnut consumption and, whether these changes are associated with alterations in markers of insulin resistance and food preferences.

METHODS

In a crossover, randomized, double-blind, placebo-controlled study, ten subjects participated in two 5-day inpatient study admissions, during which they had a smoothie containing 48 g walnuts or a macronutrient-matched placebo smoothie without nuts every morning. Between the two phases there was a 1-month washout period.

RESULTS

Fasting valine and isoleucine levels were reduced (p = .047 and p < .001) and beta-hydroxybutyrate levels were increased after 5-days of walnut consumption compared to placebo (p = .023). Fasting valine and isoleucine correlated with HOMA-IR while on walnut (r = 0.709, p = .032 and r = 0.679, p = .044). The postprandial area under the curve (AUC) of leucine in response to the smoothie consumption on day 5 was higher after walnut vs placebo (p = .023) and correlated negatively with the percentage of Kcal from carbohydrate and protein consumed during an ad libitum buffet meal consumed the same day for lunch (r = -0.661, p = .037; r = -0.628, p = .05, respectively).

CONCLUSION

The fasting and postabsorptive profiles of BCAAs are differentially affected by walnut consumption. The reduction in fasting valine and isoleucine may contribute to the longer-term benefits of walnuts on insulin resistance, cardiovascular risk and mortality, whereas the increase in postabsorptive profiles with walnuts may influence food preference. TRIAL REGISTRATION CLINICALTRIALS.GOV: Number: NCT02673281, Website: https://clinicaltrials.gov/ct2/show/NCT02673281.

Can Walnut Serve as a Magic Bullet for the Management of Non-Alcoholic Fatty Liver Disease?

Walnut contains many nutrients and bioactive components such as essential fatty acids, polyphenols, fiber, ɤ-tocopherol, folate, minerals, and vegetable protein, and has therefore been regarded as a natural functional food. Walnut-enriched diets have been demonstrated to be useful for heart health, cancer prevention, and metabolic disorders owing to their anti-oxidative and anti-inflammatory properties as well as for the maintenance of a healthy metabolism and immune function. Walnut extracts, either phenolic or lipid, also demonstrated the health effects in animal and cultured cell studies. More recently, the beneficial effects of walnut consumption on non-alcoholic fatty liver disease, which is a hepatic manifestation of obesity, hyperlipidemia, type 2 diabetes mellitus, and metabolic syndrome with substantial hepatic accumulation of triglyceride, have been proposed because walnut and a walnut-containing diet can modulate the etiologic mechanism such as ameliorating systemic and hepatic dyslipidemia, reducing lipotoxicity and inflammation, enhancing immune function, and maintaining gut microbiota balance. Through the extensive literature review we discuss the preventive roles of walnut in the development and progression of non-alcoholic fatty liver disease (NAFLD) and provide mechanistic insights into these effects.

Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review

The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.

Mass spectrometry-based lipidomics in food science and nutritional health: A comprehensive review

With the advance in science and technology as well as the improvement of living standards, the function of food is no longer just to meet the needs of survival. Food science and its associated nutritional health issues have been increasingly debated. Lipids, as complex metabolites, play a key role both in food and human health. Taking advantages of mass spectrometry (MS) by combining its high sensitivity and accuracy with extensive selective determination of all lipid classes, MS-based lipidomics has been employed to resolve the conundrum of addressing both qualitative and quantitative aspects of high-abundance and low-abundance lipids in complex food matrices. In this review, we systematically summarize current applications of MS-based lipidomics in food field. First, common MS-based lipidomics procedures are described. Second, the applications of MS-based lipidomics in food science, including lipid composition characterization, adulteration, traceability, and other issues, are discussed. Third, the application of MS-based lipidomics for nutritional health covering the influence of food on health and disease is introduced. Finally, future research trends and challenges are proposed. MS-based lipidomics plays an important role in the field of food science, promoting continuous development of food science and integration of food knowledge with other disciplines. New methods of MS-based lipidomics have been developed to improve accuracy and sensitivity of lipid analysis in food samples. These developments offer the possibility to fully characterize lipids in food samples, identify novel functional lipids, and better understand the role of food in promoting healt.

Adipokines and Adipose Tissue-Related Metabolites, Nuts and Cardiovascular Disease

Adipose tissue is a complex structure responsible for fat storage and releasing polypeptides (adipokines) and metabolites, with systemic actions including body weight balance, appetite regulation, glucose homeostasis, and blood pressure control. Signals sent from different tissues are generated and integrated in adipose tissue; thus, there is a close connection between this endocrine organ and different organs and systems such as the gut and the cardiovascular system. It is known that functional foods, especially different nuts, may be related to a net of molecular mechanisms contributing to cardiometabolic health. Despite being energy-dense foods, nut consumption has been associated with no weight gain, weight loss, and lower risk of becoming overweight or obese. Several studies have reported beneficial effects after nut consumption on glucose control, appetite suppression, metabolites related to adipose tissue and gut microbiota, and on adipokines due to their fatty acid profile, vegetable proteins, l-arginine, dietary fibers, vitamins, minerals, and phytosterols. The aim of this review is to briefly describe possible mechanisms implicated in weight homeostasis related to different nuts, as well as studies that have evaluated the effects of nut consumption on adipokines and metabolites related to adipose tissue and gut microbiota in animal models, healthy individuals, and primary and secondary cardiovascular prevention.

Metabolic and Vascular Effect of the Mediterranean Diet

Several studies indicated how dietary patterns that were obtained from nutritional cluster analysis can predict disease risk or mortality. Low-grade chronic inflammation represents a background pathogenetic mechanism linking metabolic risk factors to increased risk of chronic degenerative diseases. A Mediterranean diet (MeDi) style has been reported as associated with a lower degree of inflammation biomarkers and with a protective role on cardiovascular and cerebrovascular events. There is heterogeneity in defining the MedDiet, and it can, owing to its complexity, be considered as an exposome with thousands of nutrients and phytochemicals. Recently, it has been reported a novel positive association between baseline plasma ceramide concentrations and cardiovascular events and how adherence to a Mediterranean Diet-style may influence the potential negative relationship between elevated plasma ceramide concentrations and cardiovascular diseases (CVD). Several randomized controlled trials (RCTs) showed the positive effects of the MeDi diet style on several cardiovascular risk factors, such as body mass index, waist circumference, blood lipids, blood pressure, inflammatory markers and adhesion molecules, and diabetes and how these advantages of the MeDi are maintained in comparison of a low-fat diet. Some studies reported a positive effect of adherence to a Mediterranean Diet and heart failure incidence, whereas some recent studies, such as the PREDIMED study, showed that the incidence of major cardiovascular events was lower among those assigned to MeDi supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet. New studies are needed to better understand the molecular mechanisms, whereby the MedDiet may exercise its effects. Here, we present recent advances in understanding the molecular basis of MedDiet effects, mainly focusing on cardiovascular diseases, but also discussing other related diseases. We review MedDiet composition and assessment as well as the latest advances in the genomic, epigenomic (DNA methylation, histone modifications, microRNAs, and other emerging regulators), transcriptomic (selected genes and whole transcriptome), and metabolomic and metagenomic aspects of the MedDiet effects (as a whole and for its most typical food components). We also present a review of the clinical effects of this dietary style underlying the biochemical and molecular effects of the Mediterranean diet. Our purpose is to review the main features of the Mediterranean diet in particular its benefits on human health, underling the anti-inflammatory, anti-oxidant and anti-atherosclerotic effects to which new knowledge about epigenetic and gut-microbiota relationship is recently added.

The Postprandial Appearance of Features of Cardiometabolic Risk: Acute Induction and Prevention by Nutrients and Other Dietary Substances

The purpose of this review is to provide an overview of diets, food, and food components that affect postprandial inflammation, endothelial function, and oxidative stress, which are related to cardiometabolic risk. A high-energy meal, rich in saturated fat and sugars, induces the transient appearance of a series of metabolic, signaling and physiological dysregulations or dysfunctions, including oxidative stress, low-grade inflammation, and endothelial dysfunction, which are directly related to the amplitude of postprandial plasma triglycerides and glucose. Low-grade inflammation and endothelial dysfunction are also known to cluster together with insulin resistance, a third risk factor for cardiovascular diseases (CVD) and type-II diabetes, thus making a considerable contribution to cardiometabolic risk. Because of the marked relevance of the postprandial model to nutritional pathophysiology, many studies have investigated whether adding various nutrients and other substances to such a challenge meal might mitigate the onset of these adverse effects. Some foods (e.g., nuts, berries, and citrus), nutrients (e.g., l-arginine), and other substances (various polyphenols) have been widely studied. Reports of favorable effects in the postprandial state have concerned plasma markers for systemic or vascular pro-inflammatory conditions, the activation of inflammatory pathways in plasma monocytes, vascular endothelial function (mostly assessed using physiological criteria), and postprandial oxidative stress. Although the literature is fragmented, this topic warrants further study using multiple endpoints and markers to investigate whether the interesting candidates identified might prevent or limit the postprandial appearance of critical features of cardiometabolic risk.

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.

Study designs: Part 4 - Interventional studies

In the fourth piece of this series on research study designs, we look at interventional studies (clinical trials). These studies differ from observational studies in that the investigator decides whether or not a participant will receive the exposure (or intervention). In this article, we describe the key features and types of interventional studies.