Intervention Trials with the Mediterranean Diet in Cardiovascular Prevention: Understanding Potential Mechanisms through Metabolomic Profiling

The Mediterranean Diet, Its Microbiome Connections, and Cardiovascular Health: A Narrative Review

The Mediterranean diet (MD), rich in minimally processed plant foods and in monounsaturated fats but low in saturated fats, meat, and dairy products, represents one of the most studied diets for cardiovascular health. It has been shown, from both observational and randomized controlled trials, that MD reduces body weight, improves cardiovascular disease surrogates such as waist-to-hip ratios, lipids, and inflammation markers, and even prevents the development of fatal and nonfatal cardiovascular disease, diabetes, obesity, and other diseases. However, it is unclear whether it offers cardiovascular benefits from its individual components or as a whole. Furthermore, limitations in the methodology of studies and meta-analyses have raised some concerns over its potential cardiovascular benefits. MD is also associated with characteristic changes in the intestinal microbiota, mediated through its constituents. These include increased growth of species producing short-chain fatty acids, such as Clostridium leptum and Eubacterium rectale, increased growth of Bifidobacteria, Bacteroides, and Faecalibacterium prausnitzii species, and reduced growth of Firmicutes and Blautia species. Such changes are known to be favorably associated with inflammation, oxidative status, and overall metabolic health. This review will focus on the effects of MD on cardiovascular health through its action on gut microbiota.

Altered dietary behaviour during pregnancy impacts systemic metabolic phenotypes

Rationale

Evidence suggests consumption of a Mediterranean diet (MD) can positively impact both maternal and offspring health, potentially mediated by a beneficial effect on inflammatory pathways. We aimed to apply metabolic profiling of serum and urine samples to assess differences between women who were stratified into high and low alignment to a MD throughout pregnancy and investigate the relationship of the diet to inflammatory markers.

Methods

From the ORIGINS cohort, 51 pregnant women were stratified for persistent high and low alignment to a MD, based on validated MD questionnaires. 1H Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the urine and serum metabolite profiles of these women at 36 weeks of pregnancy. The relationship between diet, metabolite profile and inflammatory status was investigated.

Results

There were clear differences in both the food choice and metabolic profiles of women who self-reported concordance to a high (HMDA) and low (LMDA) Mediterranean diet, indicating that alignment with the MD was associated with a specific metabolic phenotype during pregnancy. Reduced meat intake and higher vegetable intake in the HMDA group was supported by increased levels of urinary hippurate (p = 0.044) and lower creatine (p = 0.047) levels. Serum concentrations of the NMR spectroscopic inflammatory biomarkers GlycA (p = 0.020) and GlycB (p = 0.016) were significantly lower in the HDMA group and were negatively associated with serum acetate, histidine and isoleucine (p < 0.05) suggesting a greater level of plant-based nutrients in the diet. Serum branched chain and aromatic amino acids were positively associated with the HMDA group while both urinary and serum creatine, urine creatinine and dimethylamine were positively associated with the LMDA group.

Conclusion

Metabolic phenotypes of pregnant women who had a high alignment with the MD were significantly different from pregnant women who had a poor alignment with the MD. The metabolite profiles aligned with reported food intake. Differences were most significant biomarkers of systemic inflammation and selected gut-microbial metabolites. This research expands our understanding of the mechanisms driving health outcomes during the perinatal period and provides additional biomarkers for investigation in pregnant women to assess potential health risks.

Plasma urea cycle metabolite levels and the risk of moyamoya disease

Background and purpose

Urea cycle metabolites are expected to be the biomarkers for cerebrovascular diseases. However, the effects of circulating urea cycle metabolites on the risk of MMD and its subcategories remain unclear. The aim of this study was to prospectively investigate the association between plasma urea cycle metabolites and the risk of MMD and its subcategories.

Methods

We measured plasma urea cycle metabolite levels for 360 adult MMD patients and 89 matched healthy controls. Clinical and laboratory characteristics were obtained from the medical record. The study was conducted from July 2020 to December 2021.

Results

After multivariate adjustment, the risk of MMD increased with each increment in ornithine level (per natural log [ornithine] increment: OR, 3.893; 95% CI, 1.366-11.090). The risk of MMD decreased with each increment in arginine level (per natural log [arginine] increment: OR, 0.109; 95% CI, 0.028-0.427), urea level (per natural log [urea] increment: OR, 0.261; 95% CI, 0.072-0.940), and global arginine bioavailability ratio (GABR) level (per natural log [GABR] increment: OR, 0.189; 95% CI, 0.074-0.484). The addition of plasma arginine (integrated discrimination improvement: 1.76%, p = 0.021) or GABR (integrated discrimination improvement: 1.76%, p = 0.004) to conventional risk factors significantly improved the risk reclassification for MMD.

Conclusion

Plasma ornithine levels are positively associated with the risk of MMD. By contrast, the levels of arginine, urea, and GABR are inversely related to the risk of MMD. Plasma urea cycle metabolites might be potential biomarkers for the risk of MMD.

Risk factors for depression in the elderly: An umbrella review of published meta-analyses and systematic reviews

BACKGROUND

Depression has been identified as one of the leading causes of the disease burden worldwide. Identification of the potential factors that increased or decreased the risk of depression could be important to provide prevention strategies. We aimed to conduct an umbrella review of risk factors for depression in the elderly and assessed the credibility of evidence of the association between each factor and depression.

METHODS

We searched PubMed and Web of Science from 1990 to April 11, 2021 for articles investigating associations between potential factors and depression. For each association, we recalculated the summary effect size and 95% confidence intervals using random effects models. The 95% prediction interval and between-heterogeneity were also reported. For publication bias, small-study effect and excess of significance bias were assessed.

RESULTS

Twenty-five publications met the inclusion criteria, including twenty-two meta-analyses and three qualitative systematic reviews. Approximately 1,199,927 participants and 82 unique factors were reported. Two factors were rated as convincing evidence and four factors showed highly suggestive evidence. These risk factors were aspirin use, individuals aged 80 years and above, sleep disturbances and persistent sleep disturbances, hearing problem, poor vision, and cardiac disease.

LIMITATIONS

Most studies that we included were of low quality.

CONCLUSIONS

We found several risk factors for depression with different levels of evidence, in which aspirin use and individuals aged 80 years and above presented the strongest evidence. Further research is warranted to support other findings from this umbrella review using a large, well-designed cohort study.

Mediterranean Diet and Genetic Determinants of Obesity and Metabolic Syndrome in European Children and Adolescents

Childhood obesity and metabolic syndrome (MetS) are multifactorial diseases influenced by genetic and environmental factors. The Mediterranean Diet (MD) seems to modulate the genetic predisposition to obesity or MetS in European adults. The FTO gene has also been shown to have an impact on the MD benefits to avoid obesity or MetS. Since these interaction effects have been scarcely analyzed in European youth, the aim was to describe the gene–MD interplay, analyzing the impact of the genetic factors to reduce the obesity and MetS risk through MD adherence, and the MD impact in the obesity and MetS genetic profile. From the limited evidence on gene–MD interaction studies in European youth, a study showed that the influence of high MD adherence on adiposity and MetS was only observed with a limited number of risk alleles; the gene–MD interplay showed sex-specific differences, being higher in females. Most results analyzed in European adults elucidate that, the relationship between MD adherence and both obesity and MetS risk, could be modulated by obesity genetic variants and vice versa. Further research is needed, to better understand the inter-individual differences in the association between MD and body composition, and the integration of omics and personalized nutrition considering MD.

Evaluation of pharmacy-led weight management service to minimise the risk of cardiovascular disease

AIMS

The primary aim of the programme was a minimum of a 5% weight reduction of the initial weight, while the secondary outcomes were a reduction in participants' body mass index (BMI), waist circumference (WC), blood pressure (BP), AUDIT-C score and an increase in the Mediterranean diet (MD) score and an improvement in physical activity levels.

METHODS

This 'before and after' study was a 10-week weight management (WM) programme and it was developed and delivered in community pharmacies in Patras chosen for convenience, thus consisting the first service of its type in Greece. The sample size was calculated (n = 96) based on the mean BMI for a Greek male and female individual, and the standard deviation (SD) of weight at baseline of 14 kg.

RESULTS

Nearly every participant enrolled in the 20 participating pharmacies, 97.4% (n = 114/117), achieved the programme's aim, losing at least 5% of their initial weight. The mean percentage of total weight loss of the 117 participants at the 10th week was 8.97% (SD 2.65), and the t-test showed statistically significant results (P-value < 0.001; 95% CI [8.48, 9.45]). A significant reduction in the waist-to-height ratio (WHtR) was observed in both male (P-value = 0.004) and female (P-value < 0.001) participants. The participants' BP and AUDIT-C score and physical activity levels significantly improved (P-value < 0.001), as well as their MD score.

CONCLUSION

This study provides the first evidence that Greek pharmacists have the potential to play an important role within primary healthcare and that after training they are able to provide public health services for both the public's benefit and their clinical role enhancement.

Characteristics of Blood Metabolic Profile in Coronary Heart Disease, Dilated Cardiomyopathy and Valvular Heart Disease Induced Heart Failure

Purpose: Metabolic impairment is one key contributor to heart failure (HF) pathogenesis and progression. The major causes of HF, coronary heart disease (CHD), dilated cardiomyopathy (DCM), and valvular heart disease (VHD) remains poorly characterized in patients with HF from the view of metabolic profile. We sought to determine metabolic differences in CHD-, VHD-, and DCM-induced HF patients and identify significantly altered metabolites and their correlations.

Procedure: In this study, a total of 96 HF cases and 97 controls were enrolled. The contents of 23 amino acids and 26 carnitines in fasting plasma were measured by a targeted liquid chromatography and mass spectrometry (LC-MS) approach.

Results: Nine metabolites (Histidine, Arginine, Citrulline, Glutamine, Valine, hydroxyhexadecenyl-carnitine, acylcarnitine C22, hydroxytetradecanoyl-carnitine, and carnitine) were found to be related with the occurrence of HF. Arginine, Glutamine and hydroxytetradecanoyl-carnitine could effectively distinguish CHD and DCM patients, and hydroxytetradecanoyl-carnitine and aspartic acid were able to classify CHD and VHD cohorts.

Conclusion: This study indicated that circulating amino acids and long-chain acylcarnitine levels were closely associated with progression of heart failure. Monitoring these metabolic alterations by LC-MS may help the differentiation of CHD, VHD, and DCM in the early stage, and provide new diagnostics targets or therapeutic interventions.

Plasma metabolomics are associated with metabolic syndrome: A targeted approach

OBJECTIVES

Advances in metabolomic tools have allowed us to gain a more comprehensive understanding of metabolic syndrome (MetS). The aim of this study was to evaluate the association between plasma metabolomic profiles and MetS.

METHODS

For this study, adults without diabetes, chronic kidney disease, stroke, heart disease, or cancer and with full metabolomics, biochemical, and dietetic data available, representing a subsample of the Health Survey of Sao Paulo study (ISA-Capital; N = 130), were included. The joint interim statement consensus criteria were used for diagnosing MetS. Absolute quantification (µmol/L) of blood metabolites was achieved by targeted quantitative profiling of annotated metabolites by electrospray ionization tandem mass spectrometry in plasma samples. Mean differences in the compounds for MetS were evaluated by linear regression adjusted for confounding factors.

RESULTS

Serine was inversely associated with MetS (β = -15.04; P = 0.014). In glycerophospholipids with acyl-alkyl bonds, there was an inverse association with MetS, including phosphatidylcholine (PC) ae C42:5 (β = -0.15; P = 0.040), PC ae C44:5 (β = -0.15; P = 0.046), PC ae C40:4 (β = -0.21; P = 0.014) and PC ae C44:4 (β = -0.04; P = 0.032).

CONCLUSION

Plasma metabolomic profiles were associated with MetS, especially the amino acid serine and some acyl-alkyl PCs.

Lysine pathway metabolites and the risk of type 2 diabetes and cardiovascular disease in the PREDIMED study: results from two case-cohort studies

Background

The pandemic of cardiovascular disease (CVD) and type 2 diabetes (T2D) requires the identification of new predictor biomarkers. Biomarkers potentially modifiable with lifestyle changes deserve a special interest. Our aims were to analyze: (a) The associations of lysine, 2-aminoadipic acid (2-AAA) or pipecolic acid with the risk of T2D or CVD in the PREDIMED trial; (b) the effect of the dietary intervention on 1-year changes in these metabolites, and (c) whether the Mediterranean diet (MedDiet) interventions can modify the effects of these metabolites on CVD or T2D risk.

Methods

Two unstratified case-cohort studies nested within the PREDIMED trial were used. For CVD analyses, we selected 696 non-cases and 221 incident CVD cases; for T2D, we included 610 non-cases and 243 type 2 diabetes incident cases. Metabolites were quantified using liquid chromatography–tandem mass spectrometry, at baseline and after 1-year of intervention.

Results

In weighted Cox regression models, we found that baseline lysine (HR_{+1 SD increase} = 1.26; 95% CI 1.06–1.51) and 2-AAA (HR_{+1 SD increase} = 1.28; 95% CI 1.05–1.55) were both associated with a higher risk of T2D, but not with CVD. A significant interaction (p = 0.032) between baseline lysine and T2D on the risk of CVD was observed: subjects with prevalent T2D and high levels of lysine exhibited the highest risk of CVD. The intervention with MedDiet did not have a significant effect on 1-year changes of the metabolites.

Conclusions

Our results provide an independent prospective replication of the association of 2-AAA with future risk of T2D. We show an association of lysine with subsequent CVD risk, which is apparently diabetes-dependent. No evidence of effects of MedDiet intervention on lysine, 2-AAA or pipecolic acid changes was found.

Trial registration ISRCTN35739639; registration date: 05/10/2005; recruitment start date 01/10/2003

Extra Virgin Olive Oil: Lesson from Nutrigenomics

Extra virgin olive oil (EVOO) consumption has a beneficial effect on human health, especially for prevention of cardiovascular disease and metabolic disorders. Here we underscore the peculiar importance of specific cultivars used for EVOO production since biodiversity among cultivars in terms of fatty acids and polyphenols content could differently impact on the metabolic homeostasis. In this respect, the nutrigenomic approach could be very useful to fully dissect the pathways modulated by different EVOO cultivars in terms of mRNA and microRNA transcriptome. The identification of genes and miRNAs modulated by specific EVOO cultivars could also help to discover novel nutritional biomarkers for prevention and/or prognosis of human disease. Thus, the nutrigenomic approach depicts a novel scenario to investigate if a specific EVOO cultivar could have a positive effect on human health by preventing the onset of cardiovascular disease and/or chronic inflammatory disorders also leading to cancer.

Benefits of the Mediterranean diet: Epidemiological and molecular aspects

More than 50 years after the Seven Countries Study, a large number of epidemiological studies have explored the relationship between the Mediterranean diet (MD) and health, through observational, case-control, some longitudinal and a few experimental studies. The overall results show strong evidence suggesting a protective effect of the MD mainly on the risk of cardiovascular disease (CVD) and certain types of cancer. The beneficial effects have been attributed to the types of food consumed, total dietary pattern, components in the food, cooking techniques, eating behaviors and lifestyle behaviors, among others. The aim of this article is to review and summarize the knowledge derived from the literature focusing on the benefits of the MD on health, including those that have been extensively investigated (CVD, cancer) along with more recent issues such as mental health, immunity, quality of life, etc. The review begins with a brief description of the MD and its components. Then we present a review of studies evaluating metabolic biomarkers and genotypes in relation to the MD. Other sections are dedicated to observation and intervention studies for various pathologies. Finally, some insights into the relationship between the MD and sustainability are explored. In conclusion, the research undertaken on metabolomics approaches has identified potential markers for certain MD components and patterns, but more investigation is needed to obtain valid measures. Further evaluation of gene-MD interactions are also required to better understand the mechanisms by which the MD diet exerts its beneficial effects on health. Observation and intervention studies, particularly PREDIMED, have provided invaluable data on the benefits of the MD for a wide range of chronic diseases. However further research is needed to explore the effects of other lifestyle components associated with Mediterranean populations, its environmental impact, as well as the MD extrapolation to non-Mediterranean contexts.

Lipid metabolic networks, Mediterranean diet and cardiovascular disease in the PREDIMED trial

Background

Perturbed lipid metabolic pathways may play important roles in the development of cardiovascular disease (CVD). However, existing epidemiological studies have focused more on discovering individual lipid metabolites for CVD risk prediction rather than assessing metabolic pathways.

Methods

This study included a subcohort of 787 participants and all 230 incident CVD cases from the PREDIMED trial. Applying a network-based analytical method, we identified lipid subnetworks and clusters from a global network of 200 lipid metabolites and linked these subnetworks/clusters to CVD risk.

Results

Lipid metabolites with more double bonds clustered within one subnetwork, whereas lipid metabolites with fewer double bonds clustered within other subnetworks. We identified 10 lipid clusters that were divergently associated with CVD risk. The hazard ratios [HRs, 95% confidence interval (CI)] of CVD per a 1-standard deviation (SD) increment in cluster score were 1.39 (1.17-1.66) for the hydroxylated phosphatidylcholine (HPC) cluster and 1.24 (1.11-1.37) for a cluster that included diglycerides and a monoglyceride with stearic acyl chain. Every 1-SD increase in the score of cluster that included highly unsaturated phospholipids and cholesterol esters was associated with an HR for CVD of 0.81 (95% CI, 0.67-0.98). Despite a suggestion that MedDiet modified the association between a subnetwork that included most lipids with a high degree of unsaturation and CVD, changes in lipid subnetworks/clusters during the first-year follow-up were not significantly different between intervention groups.

Conclusions

The degree of unsaturation was a major determinant of the architecture of lipid metabolic network. Lipid clusters that strongly predicted CVD risk, such as the HPC cluster, warrant further functional investigations.

Patterns of plant and animal protein intake are strongly associated with cardiovascular mortality: the Adventist Health Study-2 cohort

Background

Current evidence suggests that plant and animal proteins are intimately associated with specific large nutrient clusters that may explain part of their complex relation with cardiovascular health. We aimed at evaluating the association between specific patterns of protein intake with cardiovascular mortality.

Methods

We selected 81 337 men and women from the Adventist Health Study-2. Diet was assessed between 2002 and 2007, by using a validated food frequency questionnaire. Dietary patterns based on the participants' protein consumption were derived by factor analysis. Cox regression analysis was used to estimate multivariate-adjusted hazard ratios (HRs) adjusted for sociodemographic and lifestyle factors and dietary components.

Results

There were 2276 cardiovascular deaths during a mean follow-up time of 9.4 years. The HRs for cardiovascular mortality were 1.61 [98.75% confidence interval (CI), 1.12 2.32; P-trend < 0.001] for the 'Meat' protein factor and 0.60 (98.75% CI, 0.42 0.86; P-trend < 0.001) for the 'Nuts & Seeds' protein factor (highest vs lowest quintile of factor scores). No significant associations were found for the 'Grains', 'Processed Foods' and 'Legumes, Fruits & Vegetables' protein factors. Additional adjustments for the participants' vegetarian dietary pattern and nutrients related to cardiovascular disease outcomes did not change the results.

Conclusions

Associations between the 'Meat' and 'Nuts & Seeds' protein factors and cardiovascular outcomes were strong and could not be ascribed to other associated nutrients considered to be important for cardiovascular health. Healthy diets can be advocated based on protein sources, preferring low contributions of protein from meat and higher intakes of plant protein from nuts and seeds.

Nutrition knowledge, attitudes, and practice towards breast cancer prevention among the female population of Iran University of medical science students

Diet plays a measurable role in breast cancer (BC) prevention. The aims of this study were to assess nutrition-related BC prevention Knowledge, attitudes and practice (KAP) of female university students and to examine the relationship between demographic characteristics of students and their KAP. We conducted a cross-sectional study among 500 female students from Iran University of Medical Science (IUMS). A pretested self-administered questionnaires were used to assess the participants' nutrition-related BC prevention KAP. A total of 500 students completed the survey. Students' knowledge with the mean score of 16.97, significantly varied by age (P= 0.03), the field of study (P= 0.001) and family history of BC (P= 0.01). The mean score of attitudes and practice toward nutrition-related BC prevention factors were 24.86 and 39.39, respectively. A significant relationship was observed between nutrition knowledge and attitude (r = 0.27, P < 0.001). Also, Nutrition-related attitudes were positively correlated with the BC prevention dietary practices (r = 0.23, P < 0.001). Nutrition KAP about BC prevention factors was found to be influenced by individual factors such as age, field of study, familial history of BC, job and residency status. Together, our findings confirm that increasing nutrition knowledge is not sufficient for dietary behavior change, but is necessary.

Metabolomics and Microbiomes as Potential Tools to Evaluate the Effects of the Mediterranean Diet

The approach to studying diet–health relationships has progressively shifted from individual dietary components to overall dietary patterns that affect the interaction and balance of low-molecular-weight metabolites (metabolome) and host-enteric microbial ecology (microbiome). Even though the Mediterranean diet (MedDiet) has been recognized as a powerful strategy to improve health, the accurate assessment of exposure to the MedDiet has been a major challenge in epidemiological and clinical studies. Interestingly, while the effects of individual dietary components on the metabolome have been described, studies investigating metabolomic profiles in response to overall dietary patterns (including the MedDiet), although limited, have been gaining attention. Similarly, the beneficial effects of the MedDiet on cardiometabolic outcomes may be mediated through gut microbial changes. Accumulating evidence linking food ingestion and enteric microbiome alterations merits the evaluation of the microbiome-mediated effects of the MedDiet on metabolic pathways implicated in disease. In this narrative review, we aimed to summarize the current evidence from observational and clinical trials involving the MedDiet by (1) assessing changes in the metabolome and microbiome for the measurement of diet pattern adherence and (2) assessing health outcomes related to the MedDiet through alterations to human metabolomics and/or the microbiome.

Breakthroughs in the Health Effects of Plant Food Bioactives: A Perspective on Microbiomics, Nutri(epi)genomics, and Metabolomics

Plant bioactive compounds consumed as part of our diet are able to influence human health. They include secondary metabolites like (poly)phenols, carotenoids, glucosinolates, alkaloids, and terpenes. Although much knowledge has been gained, there is still need for studies unravelling the effects of plant bioactives on cardiometabolic health at the individual level, using cutting-edge high-resolution and data-rich holistic approaches. The aim of this Perspective is to review the prospects of microbiomics, nutrigenomics and nutriepigenomics, and metabolomics to assess the response to plant bioactive consumption while considering interindividual variability. Insights for future research in the field toward personalized nutrition are discussed.

Olive oil and prevention of chronic diseases: Summary of an International conference

Olive oil is the foremost source of fat in the Mediterranean area and, among other features, sets the Mediterranean diet apart from other dietary regimens. In January 2018, the International Olive Council convened several worldwide experts at the Robert Mondavi Institute (Davis, CA), to discuss and summarize the available data on the effects of olive oil consumption on human health. In this paper, we critically provide a synthesis of the main reported findings, which underscore how and why consuming this oil as part of a balanced diet and healthful lifestyle improves prognosis and extends life- and health-spans.

Inflammation, not Cholesterol, Is a Cause of Chronic Disease

Since the Seven Countries Study, dietary cholesterol and the levels of serum cholesterol in relation to the development of chronic diseases have been somewhat demonised. However, the principles of the Mediterranean diet and relevant data linked to the examples of people living in the five blue zones demonstrate that the key to longevity and the prevention of chronic disease development is not the reduction of dietary or serum cholesterol but the control of systemic inflammation. In this review, we present all the relevant data that supports the view that it is inflammation induced by several factors, such as platelet-activating factor (PAF), that leads to the onset of cardiovascular diseases (CVD) rather than serum cholesterol. The key to reducing the incidence of CVD is to control the activities of PAF and other inflammatory mediators via diet, exercise, and healthy lifestyle choices. The relevant studies and data supporting these views are discussed in this review.

Mediterranean Diet and Health Outcomes in the SUN Cohort

The Mediterranean Dietary (MedDiet) Pattern has been linked to many beneficial health effects. This review summarizes the main findings of a prospective cohort study, the Seguimiento Universidad de Navarra (SUN) cohort, specifically focused on MedDiet and the risk of major chronic disease. It is an open cohort in which 22,786 Spanish university graduates have participated since 1999 until February 2018. Data on diet, lifestyle and clinical diagnosis are collected at baseline and every two years. After reviewing 21 publications from the SUN cohort on the effects of the MedDiet, we conclude that this cohort has provided good evidence that a high MedDiet adherence is associated with a reduced incidence of all-cause mortality, fatal and non-fatal major cardiovascular disease (CVD), type 2 diabetes, weight gain, metabolic syndrome, depression, cognitive decline, and nephrolithiasis. An inverse dose-response relationship was found for many of these associations. The MedDiet was also associated with lower average heart rate, a mitigation of the harmful effects of overweight/obesity on the risk of CVD, and an attenuation of the effects of obesity on type 2 diabetes. A suggestion that the MedDiet may enhance fertility was also found.

Gut microbiota-dependent trimethylamine N-oxide in acute coronary syndromes: a prognostic marker for incident cardiovascular events beyond traditional risk factors

Aims

Systemic levels of trimethylamine N-oxide (TMAO), a pro-atherogenic and pro-thrombotic metabolite produced from gut microbiota metabolism of dietary trimethylamine (TMA)-containing nutrients such as choline or carnitine, predict incident cardiovascular event risks in stable primary and secondary prevention subjects. However, the prognostic value of TMAO in the setting of acute coronary syndromes (ACS) remains unknown.

Methods and results

We investigated the relationship of TMAO levels with incident cardiovascular risks among sequential patients presenting with ACS in two independent cohorts. In the Cleveland Cohort, comprised of sequential subjects (n = 530) presenting to the Emergency Department (ED) with chest pain of suspected cardiac origin, an elevated plasma TMAO level at presentation was independently associated with risk of major adverse cardiac events (MACE, including myocardial infarction, stroke, need for revascularization, or death) over the ensuing 30-day (4th quartile (Q4) adjusted odds ratio (OR) 6.30, 95% confidence interval (CI), 1.89-21.0, P < 0.01) and 6-month (Q4 adjusted OR 5.65, 95%CI, 1.91-16.7; P < 0.01) intervals. TMAO levels were also a significant predictor of the long term (7-year) mortality (Q4 adjusted HR 1.81, 95%CI, 1.04-3.15; P < 0.05). Interestingly, TMAO level at initial presentation predicted risk of incident MACE over the near-term (30 days and 6 months) even among subjects who were initially negative for troponin T (< 0.1 ng/mL) (30 days, Q4 adjusted OR 5.83, 95%CI, 1.79-19.03; P < 0.01). The prognostic value of TMAO was also assessed in an independent multicentre Swiss Cohort of ACS patients (n = 1683) who underwent coronary angiography. Trimethylamine N-oxide again predicted enhanced MACE risk (1-year) (adjusted Q4 hazard ratios: 1.57, 95% CI, 1.03-2.41; P <0.05).

Conclusion

Plasma TMAO levels among patients presenting with chest pain predict both near- and long-term risks of incident cardiovascular events, and may thus provide clinical utility in risk stratification among subjects presenting with suspected ACS.

Oleic Acid and Hydroxytyrosol Inhibit Cholesterol and Fatty Acid Synthesis in C6 Glioma Cells

Recently, the discovery of natural compounds capable of modulating nervous system function has revealed new perspectives for a healthier brain. Here, we investigated the effects of oleic acid (OA) and hydroxytyrosol (HTyr), two important extra virgin olive oil compounds, on lipid synthesis in C6 glioma cells. OA and HTyr inhibited both de novo fatty acid and cholesterol syntheses without affecting cell viability. The inhibitory effect of the individual compounds was more pronounced if OA and HTyr were administered in combination. A reduction of polar lipid biosynthesis was also detected, while triglyceride synthesis was marginally affected. To clarify the lipid-lowering mechanism of these compounds, their effects on the activity of key enzymes of fatty acid biosynthesis (acetyl-CoA carboxylase-ACC and fatty acid synthase-FAS) and cholesterologenesis (3-hydroxy-3-methylglutaryl-CoA reductase-HMGCR) were investigated in situ by using digitonin-permeabilized C6 cells. ACC and HMGCR activities were especially reduced after 4 h of 25 μM OA and HTyr treatment. No change in FAS activity was observed. Inhibition of ACC and HMGCR activities is corroborated by the decrease of their mRNA abundance and protein level. Our results indicate a direct and rapid downregulatory effect of the two olive oil compounds on lipid synthesis in C6 cells.

Panomics for Precision Medicine

Medicine is poised to undergo a digital transformation. High-throughput platforms are creating terabytes of genomic, transcriptomic, proteomic, and metabolomic data. The challenge is to interpret these data in a meaningful manner - to uncover relationships that are not readily apparent between molecular profiles and states of health or disease. This will require the development of novel data pipelines and computational tools. The combined analysis of multi-dimensional data is referred to as 'panomics'. The ultimate hope of integrative panomics is that it will lead to the discovery and application of novel markers and targeted therapeutics that drive forward a new era of 'precision medicine' where inter-individual variation is accounted for in the treatment of patients.

Plasma lipidomic profiles and cardiovascular events in a randomized intervention trial with the Mediterranean diet

Background: Lipid metabolites may partially explain the inverse association between the Mediterranean diet (MedDiet) and cardiovascular disease (CVD).Objective: We evaluated the associations between 1) lipid species and the risk of CVD (myocardial infarction, stroke, or cardiovascular death); 2) a MedDiet intervention [supplemented with extra virgin olive oil (EVOO) or nuts] and 1-y changes in these molecules; and 3) 1-y changes in lipid species and subsequent CVD.Design: With the use of a case-cohort design, we profiled 202 lipid species at baseline and after 1 y of intervention in the PREDIMED (PREvención con DIeta MEDiterránea) trial in 983 participants [230 cases and a random subcohort of 790 participants (37 overlapping cases)].Results: Baseline concentrations of cholesterol esters (CEs) were inversely associated with CVD. A shorter chain length and higher saturation of some lipids were directly associated with CVD. After adjusting for multiple testing, direct associations remained significant for 20 lipids, and inverse associations remained significant for 6 lipids. When lipid species were weighted by the number of carbon atoms and double bonds, the strongest inverse association was found for CEs [HR: 0.39 (95% CI: 0.22, 0.68)] between extreme quintiles (P-trend = 0.002). Participants in the MedDiet + EVOO and MedDiet + nut groups experienced significant (P < 0.05) 1-y changes in 20 and 17 lipids, respectively, compared with the control group. Of these changes, only those in CE(20:3) in the MedDiet + nuts group remained significant after correcting for multiple testing. None of the 1-y changes was significantly associated with CVD risk after correcting for multiple comparisons.Conclusions: Although the MedDiet interventions induced some significant 1-y changes in the lipidome, they were not significantly associated with subsequent CVD risk. Lipid metabolites with a longer acyl chain and higher number of double bonds at baseline were significantly and inversely associated with the risk of CVD.

Mediterranean Diet Improves High-Density Lipoprotein Function in High-Cardiovascular-Risk Individuals: A Randomized Controlled Trial

BACKGROUND

The biological functions of high-density lipoproteins (HDLs) contribute to explaining the cardioprotective role of the lipoprotein beyond quantitative HDL cholesterol levels. A few small-scale interventions with a single antioxidant have improved some HDL functions. However, to date, no long-term, large-scale, randomized controlled trial has been conducted to assess the effects of an antioxidant-rich dietary pattern (such as a traditional Mediterranean diet [TMD]) on HDL function in humans.

METHODS

This study was performed in a random subsample of volunteers from the PREDIMED Study (Prevención con Dieta Mediterránea; n=296) after a 1-year intervention. We compared the effects of 2 TMDs, one enriched with virgin olive oil (TMD-VOO; n=100) and the other enriched with nuts (TMD-Nuts; n=100), with respect to a low-fat control diet (n=96). We assessed the effects of both TMDs on the role of HDL particles on reverse cholesterol transport (cholesterol efflux capacity, HDL ability to esterify cholesterol, and cholesteryl ester transfer protein activity), HDL antioxidant properties (paraoxonase-1 arylesterase activity and total HDL antioxidant capacity on low-density lipoproteins), and HDL vasodilatory capacity (HDL ability to induce the release of nitric oxide in endothelial cells). We also studied the effects of a TMD on several HDL quality-related characteristics (HDL particle oxidation, resistance against oxidative modification, main lipid and protein composition, and size distribution).

RESULTS

Both TMDs increased cholesterol efflux capacity relative to baseline (P=0.018 and P=0.013 for TMD-VOO and TMD-Nuts, respectively). The TMD-VOO intervention decreased cholesteryl ester transfer protein activity (relative to baseline, P=0.028) and increased HDL ability to esterify cholesterol, paraoxonase-1 arylesterase activity, and HDL vasodilatory capacity (relative to control, P=0.039, P=0.012, and P=0.026, respectively). Adherence to a TMD induced these beneficial changes by improving HDL oxidative status and composition. The 3 diets increased the percentage of large HDL particles (relative to baseline, P<0.001).

CONCLUSIONS

The TMD, especially when enriched with virgin olive oil, improved HDL atheroprotective functions in humans.

CLINICAL TRIAL REGISTRATION

URL: http://www.controlled-trials.com. Unique identifier: ISRCTN35739639.

Comprehensive metabolomics identified lipid peroxidation as a prominent feature in human plasma of patients with coronary heart diseases

Coronary heart disease (CHD) is a complex human disease associated with inflammation and oxidative stress. The underlying mechanisms and diagnostic biomarkers for the different types of CHD remain poorly defined. Metabolomics has been increasingly recognized as an enabling technique with the potential to identify key metabolomic features in an attempt to understand the pathophysiology and differentiate different stages of CHD. We performed comprehensive metabolomic analysis in human plasma from 28 human subjects with stable angina (SA), myocardial infarction (MI), and healthy control (HC). Subsequent analysis demonstrated a uniquely altered metabolic profile in these CHD: a total of 18, 37 and 36 differential metabolites were identified to distinguish SA from HC, MI from SA, and MI from HC groups respectively. Among these metabolites, glycerophospholipid (GPL) metabolism emerged as the most significantly disturbed pathway. Next, we used a targeted metabolomic approach to systematically analyze GPL, oxidized phospholipid (oxPL), and downstream metabolites derived from polyunsaturated fatty acids (PUFAs), such as arachidonic acid and linoleic acid. Surprisingly, lipids associated with lipid peroxidation (LPO) pathways including oxidized PL and isoprostanes, isomers of prostaglandins, were significantly elevated in plasma of MI patients comparing to HC and SA, consistent with the notion that oxidative stress-induced LPO is a prominent feature in CHD. Our studies using the state-of-the-art metabolomics help to understand the underlying biological mechanisms involved in the pathogenesis of CHD; LPO metabolites may serve as potential biomarkers to differentiation MI from SA and HC.

Mediterranean lifestyle and cardiovascular disease prevention

BACKGROUND

Adherence to a Mediterranean dietary pattern is a well-established protective factor against cardiovascular disease (CVD). However, diet quality is only one aspect of the overall healthy lifestyle adopted by Mediterranean populations. The latter has never been evaluated as a multi-factorial composite lifestyle. Thus, the aim of the present study was to provide a broader picture of the Mediterranean lifestyle and its effects on CVD risk, among elderly individuals.

METHODS

During 2005-2015, 2,749 older (aged 65-100 years) from 21 Mediterranean islands (MEDIS) and the rural Mani region (Peloponnesus) of Greece were voluntarily enrolled onto the study. Dietary habits, physical activity status, socio-demographic characteristics, lifestyle parameters (sleep, smoking habits, social life and educational status) and clinical profile aspects were derived through standard procedures.

RESULTS

The overall prevalence of the traditional CVD risk factors were 62.3% for hypertension, 22.3% for diabetes mellitus (type 2) and 47.7% for hypercholesterolemia. The presence of diabetes mellitus was positively predicted by the geriatric depression scale (GDS) [odds ratio (OR) =1.13, 95% confidence interval (CI): 1.02-1.25] and by an urban residential environment (OR =2.57, 95% CI: 1.10-6.06) after adjusting for several confounders. Presence of hypertension was predicted by increasing age (OR =1.07, 95% CI: 1.02-1.12), increasing body mass index (BMI) (OR =1.12, 95% CI: 1.04-1.21), the habit of midday sleep (OR =2.07, 95% CI: 1.07-4.02) and inversely predicted by the frequency of socializing with friends (OR =0.767, 95% CI: 0.616-0.955). The estimated score in the GDS was the only independent positive predictor for the presence of hypercholesterolemia (OR =1.10, 95% CI: 1.01-1.21).

CONCLUSIONS

Lifestyle parameters such as social life, midday sleep (siesta) and residential environment are strongly associated with the presence of CVD risk factors in elderly and should be part of broader CVD prevention strategies to reduce the burden of the disease.

Nutrigenomics of extra-virgin olive oil: A review

Nutrigenomics data on the functional components of olive oil are still sparse, but rapidly increasing. Olive oil is the main source of fat and health-promoting component of the Mediterranean diet. Positive effects have been observed on genes involved in the pathobiology of most prevalent age- and lifestyle-related human conditions, such as cancer, cardiovascular disease and neurodegeneration. Other effects on health-promoting genes have been identified for bioactive components of olives and olive leafs. Omics technologies are offering unique opportunities to identify nutritional and health biomarkers associated with these gene responses, the use of which in personalized and even predictive protocols of investigation, is a main breakthrough in modern medicine and nutrition. Gene regulation properties of the functional components of olive oil, such as oleic acid, biophenols and vitamin E, point to a role for these molecules as natural homeostatic and even hormetic factors with applications as prevention agents in conditions of premature and pathologic aging. Therapeutic applications can be foreseen in conditions of chronic inflammation, and particularly in cancer, which will be discussed in detail in this review paper as major clinical target of nutritional interventions with olive oil and its functional components. © 2016 BioFactors, 43(1):17-41, 2017.

Mediterranean diet and life expectancy; beyond olive oil, fruits, and vegetables

PURPOSE OF REVIEW

The recent relevant evidence of the effects of the Mediterranean diet (MedDiet) and lifestyle on health (2015 and first months of 2016).

RECENT FINDINGS

Large observational prospective epidemiological studies with adequate control of confounding and two large randomized trials support the benefits of the Mediterranean dietary pattern to increase life expectancy, reduce the risk of major chronic disease, and improve quality of life and well-being. Recently, 19 new studies from large prospective studies showed - with nearly perfect consistency - strong benefits of the MedDiet to reduce the risk of myocardial infarction, stroke, total mortality, heart failure, and disability. Interestingly, two large and well conducted cohorts reported significant cardiovascular benefits after using repeated measurements of diet during a long follow-up period. In addition, Prevención con Dieta Mediterránea, the largest randomized trial with MedDiet, recently reported benefits of this dietary pattern to prevent cognitive decline and breast cancer.

SUMMARY

In the era of evidence-based medicine, the MedDiet represents the gold standard in preventive medicine, probably because of the harmonic combination of many elements with antioxidant and anti-inflammatory properties, which overwhelm any single nutrient or food item. The whole seems more important than the sum of its parts.

Metabolites of Glutamate Metabolism Are Associated With Incident Cardiovascular Events in the PREDIMED PREvención con DIeta MEDiterránea (PREDIMED) Trial

BACKGROUND

Glutamate metabolism may play a role in the pathophysiology of cardiometabolic disorders. However, there is limited evidence of an association between glutamate-related metabolites and, moreover, changes in these metabolites, and risk of cardiovascular disease (CVD).

METHODS AND RESULTS

Plasma levels of glutamate and glutamine were measured at baseline and 1-year follow-up in a case-cohort study including 980 participants (mean age 68 years; 46% male) from the PREvención con DIeta MEDiterránea (PREDIMED) randomized trial, which assessed a Mediterranean diet intervention in the primary prevention of CVD. During median 4.8 years of follow-up, there were 229 incident CVD events (nonfatal stroke, nonfatal myocardial infarction, or CVD death). In fully adjusted models, per 1-SD, baseline glutamate was associated with 43% (95% CI: 16% to 76%) and 81% (39% to 137%) increased risk of composite CVD and stroke alone, respectively, and baseline glutamine-to-glutamate ratio with 25% (6% to 40%) and 44% (25% to 58%) decreased risk of composite CVD and stroke alone, respectively. Associations appeared linear for stroke (both Plinear trend≤0.005). Among participants with high baseline glutamate, the interventions lowered CVD risk by 37% compared to the control diet; the intervention effects were not significant when baseline glutamate was low (Pinteraction=0.02). No significant effect of the intervention on year-1 changes in metabolites was observed, and no effect of changes themselves on CVD risk was apparent.

CONCLUSIONS

Baseline glutamate was associated with increased CVD risk, particularly stroke, and glutamine-to-glutamate ratio was associated with decreased risk. Participants with high glutamate levels may obtain greater benefits from the Mediterranean diet than those with low levels.

CLINICAL TRIAL REGISTRATION

URL: www.controlled-trials.com. Unique identifier: ISRCTN 35739639.