Plasma lipidome and risk of atrial fibrillation: results from the PREDIMED trial.

The potential role of the lipidome in atrial fibrillation (AF) development is still widely unknown. We aimed to assess the association between lipidome profiles of the Prevención con Dieta Mediterránea (PREDIMED) trial participants and incidence of AF. We conducted a nested case-control study (512 incident centrally adjudicated AF cases and 735 controls matched by age, sex, and center). Baseline plasma lipids were profiled using a Nexera X2 U-HPLC system coupled to an Exactive Plus orbitrap mass spectrometer. We estimated the association between 216 individual lipids and AF using multivariable conditional logistic regression and adjusted the p values for multiple testing. We also examined the joint association of lipid clusters with AF incidence. Hitherto, we estimated the lipidomics network, used machine learning to select important network-clusters and AF-predictive lipid patterns, and summarized the joint association of these lipid patterns weighted scores. Finally, we addressed the possible interaction by the randomized dietary intervention.Forty-one individual lipids were associated with AF at the nominal level (p < 0.05), but no longer after adjustment for multiple-testing. However, the network-based score identified with a robust data-driven lipid network showed a multivariable-adjusted ORper+1SD of 1.32 (95% confidence interval: 1.16-1.51; p < 0.001). The score included PC plasmalogens and PE plasmalogens, palmitoyl-EA, cholesterol, CE 16:0, PC 36:4;O, and TG 53:3. No interaction with the dietary intervention was found. A multilipid score, primarily made up of plasmalogens, was associated with an increased risk of AF. Future studies are needed to get further insights into the lipidome role on AF.Current Controlled Trials number, ISRCTN35739639.

Circulating vitamin D levels and colorectal cancer risk: A meta-analysis and systematic review of case-control and prospective cohort studies.

The associations between circulating vitamin D concentrations and total and site-specific colorectal cancer (CRC) incidence have been examined in several epidemiological studies with overall inconclusive findings. The aim of this systematic review and meta-analysis of both case-control and prospective cohort studies was to evaluate the association between CRC and circulating levels of vitamin D. The main exposure and outcome were circulating total 25(OH)D and CRC, respectively, in the overall population (i.e., all subjects). Two reviewers, working independently, screened all the literature available to identify studies that met the inclusion criteria (e.g., case-control or prospective cohort studies, published in English, and excluding non-original papers). Data were pooled by the generic inverse variance method using a random or fixed effect model, as approriate. Heterogeneity was identified using the Cochran's Q-test and quantified by the I2 statistic. Results were stratified by study design, sex, and metabolite of vitamin D. Sensitivity and subgroup analyses were also performed. A total of 28 original studies were included for the quantitative meta-analysis. Meta-analyses comparing the highest vs lowest categories, showed a 39% lower risk between levels of total 25(OH)D and CRC risk (OR (95% CI): 0.61 (0.52; 0.71); 11 studies) in case-control studies; whereas a 20% reduced CRC risk in prospective cohort studies (HR (95% CI): 0.80 (0.66; 0.97); 6 studies). Results in women mirrored main results, whereas results in men were non-significant in both analyses. Our findings support an inverse association between circulating vitamin D levels and CRC risk.

Plasma acylcarnitines and risk of incident heart failure and atrial fibrillation: the Prevención con dieta mediterránea study.

INTRODUCTION AND OBJECTIVES: Fatty acid metabolic dysregulation in mitochondria is a common mechanism involved in the development of heart failure (HF) and atrial fibrillation (AF). We evaluated the association between plasma acylcarnitine levels and the incidence of HF or AF, and whether the mediterranean diet (MedDiet) may attenuate the association between acylcarnitines and HF or AF risk. METHODS: Two case-control studies nested within the Prevención con dieta mediterránea (PREDIMED) trial. High cardiovascular risk participants were recruited in Spain: 326 incident HF and 509 AF cases individually matched to 1 to 3 controls. Plasma acylcarnitines were measured with high-throughput liquid chromatography-tandem mass spectrometry. Conditional logistic regression models were fitted to estimate multivariable OR and 95%CI. Additive and multiplicative interactions were assessed by intervention group, obesity (body mass index ≥ 30 kg/m2), and type 2 diabetes. RESULTS: Elevated levels of medium- and long-chain acylcarnitines were associated with increased HF risk (adjusted ORperDE, 1.28; 95%CI, 1.09-1.51 and adjusted ORperDE, 1.21; 95%CI, 1.04-1.42, respectively). A significant association was observed for AF risk with long-chain acylcarnitines: 1.20 (1.06-1.36). Additive interaction of the association between long-chain acylcarnitines and AF by the MediDiet supplemented with extra virgin olive oil (P for additive interaction=.036) and by obesity (P=.022) was observed in an inverse and direct manner, respectively. CONCLUSIONS: Among individuals at high cardiovascular risk, elevated long-chain acylcarnitines were associated with a higher risk of incident HF and AF. An intervention with MedDiet+extra-virgin olive oil may reduce AF risk associated with long-chain acylcarnitines. This trial was registered at controlled-trials.com (Identifier: ISRCTN35739639).

Modulation of Telomere Length by Mediterranean Diet, Caloric Restriction, and Exercise: Results from PREDIMED-Plus Study.

Telomere length (TL) has been associated with aging and is determined by lifestyle. However, the mechanisms by which a dietary pattern such as the Mediterranean diet (MedDiet) affects TL homeostasis are still unknown. Our aim was to analyse the effect of an energy-restricted MedDiet with physical activity promotion (intervention group) versus an unrestricted-caloric MedDiet with no weight-loss advice (control group) on TL and 8-hydroxydeoxyguanosine (8-OHdG) plasma levels. In total, 80 non-diabetic participants with metabolic syndrome were randomly selected from the PREDIMED (PREvención con DIeta MEDiterránea)-Plus-Reus study. TL was measured by a hybridisation method and 8-OHdG levels by ELISA at baseline and after one year of intervention. Linear mixed models (LMM)-raw and after adjusting for potential confounders-were used to examine the associations between TL or 8-OHdG plasma levels by intervention group and/or time. A total of 69 subjects with available DNA samples were included in the analyses. A significant ß-coefficient was found for time towards increasing values through the year of follow-up for TL (unadjusted ß of 0.740 (95% CI: 0.529 to 0.951), and multivariable model ß of 0.700 (95% CI: 0.477 to 0.922)). No significant ßs were found, neither for the intervention group nor for the interaction between the intervention group and time. Regarding 8-OHdG plasma levels, no significant ßs were found for the intervention group, time, and its interaction. Our results suggest that MedDiet could have an important role in preventing telomere shortening, but calorie restriction and exercise promotion did not provide an additional advantage concerning telomere length after one year of MedDiet intervention.

Physical activity and metabolic syndrome severity among older adults at cardiovascular risk: 1-Year trends.

BACKGROUND AND AIMS: Modifiable lifestyle factors, such as physical activity (PA) and Mediterranean diet (MD), decrease metabolic syndrome (MetS). The aim was to assess 1-year changes of leisure-time physical activity (LTPA), sedentary behavior, and diet quality according to MetS severity in older population at high cardiovascular risk. METHODS AND RESULTS: Prospective analysis of 55-75-year-old 4359 overweight/obese participants with MetS (PREDIMED-Plus trial) categorized in tertiles according to 1-year changes of a validated MetS severity score (MetSSS). Anthropometrics, visceral adiposity index, triglycerides and glucose index, dietary nutrient intake, biochemical marker levels, dietary inflammatory index, and depression symptoms were measured. Diet quality was assessed by 17-item MD questionnaire. PAs were self-reported using the Minnesota-REGICOR Short Physical Activity Questionnaire and 30-s chair stand test. Sedentary behaviors were measured using the Spanish version of the Nurses' Health Study questionnaire. After 1-year follow-up, decreasing MetSSS was associated with an anti-inflammatory dietary pattern, high intake of vegetables, fruits, legumes, nuts, whole grain cereals, white fish, and bluefish and low intake of refined cereals, red and processed meat, cookies/sweets, and snacks/ready-to-eat-meals. It resulted in high intake of polyunsaturated fatty acids, omega-3 fatty acids, protein, fiber, vitamins B1, B6, B9, C, D, potassium, magnesium, and phosphorus and low glycemic index and saturated fatty acid, trans fatty acid, and carbohydrates intake. Regarding PA and sedentary behavior, decreasing MetSSS was associated with increased moderate-to-vigorous LTPA, chair stand test, and decreased sedentary and TV-viewing time. CONCLUSION: Decreasing MetSSS was associated with an anti-inflammatory dietary pattern, high LTPA, high MD adherence, low sedentary time, and low depression risk.

Metabolomics of the tryptophan-kynurenine degradation pathway and risk of atrial fibrillation and heart failure: potential modification effect of Mediterranean diet.

BACKGROUND: The tryptophan-kynurenine pathway is linked to inflammation. We hypothesize that metabolites implicated in this pathway may be associated with the risk of heart failure (HF) or atrial fibrillation (AF) in a population at high risk of cardiovascular disease. OBJECTIVES: We aimed to prospectively analyze the associations of kynurenine-related metabolites with the risk of HF and AF and to analyze a potential effect modification by the randomized interventions of the PREDIMED (Prevención con Dieta Mediterránea) trial with Mediterranean diet (MedDiet). METHODS: Two case-control studies nested within the PREDIMED trial were designed. We selected 324 incident HF cases and 502 incident AF cases individually matched with ≤3 controls. Conditional logistic regression models were fitted. Interactions with the intervention were tested for each of the baseline plasma metabolites measured by LC-tandem MS. RESULTS: Higher baseline kynurenine:tryptophan ratio (OR for 1 SD: 1.20; 95% CI: 1.01, 1.43) and higher levels of kynurenic acid (OR: 1.19; 95% CI: 1.01, 1.40) were associated with HF. Quinolinic acid was associated with AF (OR: 1.15; 95% CI: 1.01, 1.32) and HF (OR: 1.25; 95% CI: 1.04, 1.49). The MedDiet intervention modified the positive associations of kynurenine (Pinteraction = 0.006), kynurenic acid (Pinteraction = 0.008), and quinolinic acid (Pinteraction = 0.033) with HF and the association between kynurenic acid and AF (Pinteraction = 0.02). CONCLUSIONS: We found that tryptophan-kynurenine pathway metabolites were prospectively associated with higher HF risk and to a lesser extent with AF risk. Moreover, an effect modification by MedDiet was observed for the association between plasma baseline kynurenine-related metabolites and the risk of HF, showing that the positive association of increased levels of these metabolites and HF was restricted to the control group.

An Epigenetic Signature is Associated with Serum 25-Hydroxyvitamin D in Colorectal Cancer Tumors.

INTRODUCTION: Vitamin D has been widely associated with colorectal cancer (CRC) through different insights. This study aims to explore the association between serum 25-hydroxyvitamin D (25(OH)D) and the global DNA methylation in tumor from CRC patients. METHODS AND RESULTS: A genome-wide DNA methylation analysis is conducted in 20 CRC patients under categorical (10 patients have 25(OH)D <30 ng mL-1 ; 10 patients with 25(OH)D ≥30 ng mL-1 ) and continuous models of 25(OH)D. A total of 95 differentially methylated CpGs (DMCpGs) are detected under the categorical model (false discovery rate (FDR) < 0.05), while 16 DMCpGs are found under the continuous model. Regional analysis showed eight vitamin D-associated differentially methylated regions (DMR). Between them, a DMR is the most significant at cAMP-Dependent Protein Kinase Inhibitor Alpha (PKIA) locus. Furthermore, seven genes, including PKIA gene, have more or equal than two significant DMCpGs. The protein networking analysis found pathways implicated in cell adhesion and extracellular matrix, as well as signaling transduction. CONCLUSIONS: This study identifies novel epigenetic loci associated with serum 25(OH)D status. Interestingly, also, a positive association between vitamin D and DNA methylation in the CRC context is found, suggesting a role in CRC. Further studies are warranted to clarify and replicate these results.

Vitamin D Intake and the Risk of Colorectal Cancer: An Updated Meta-Analysis and Systematic Review of Case-Control and Prospective Cohort Studies.

Obesity, a sedentary lifestyle, high red meat consumption and alcohol, and tobacco are considered the driving factors behind colorectal cancer (CRC) worldwide. Both diet and lifestyle are recognized to play an important role in the prevention of CRC. Forty years later, the vitamin D-cancer hypothesis is considered consistent. However, the relationship between low vitamin D intake and CRC is still controversial. The aim of this meta-analysis is to determine the associations between Vitamin D intake and CRC. MEDLINE-PubMed and Cochrane databases were searched up to May 2020 for studies evaluating the association between vitamin D intake (from foods and supplements) and CRC. Two reviewers, working independently, screened all titles and abstracts to identify the studies that met the inclusion criteria (case-control or prospective cohort (PC) studies published in English). Data were pooled by the generic inverse variance method using a random or fixed effect model. Heterogeneity was identified using the Cochran Q-test and quantified by the I2 statistic. A total of 31 original studies were included for the quantitative meta-analysis, comprising a total 47.540 cases and 70.567 controls in case-control studies, and a total of 14.676 CRC-incident cases (out of 808.130 subjects in PC studies) from 17 countries. A significant 25% lower risk was reported comparing the highest vs. the lowest dietary vitamin D consumption and CRC risk (odds ratio (95% confidence interval): 0.75 (0.67; 0.85)) in case-control studies, whereas a non-significant association was reported in case of prospective studies (hazard ratio (95% confidence interval): 0.94 (0.79; 1.11). The present meta-analysis demonstrates that high dietary vitamin D is associated to CRC prevention. However, larger and high-quality prospective studies and clinical trials are warranted to confirm this association.

Glycolysis Metabolites and Risk of Atrial Fibrillation and Heart Failure in the PREDIMED Trial.

The increased prevalence of atrial fibrillation (AF) and heart failure (HF) highlights the need to better understand the mechanisms underlying these cardiovascular diseases (CVDs). In the present study, we aimed to evaluate the association between glycolysis-related metabolites and the risk of AF and HF in a Mediterranean population at high risk of CVD. We used two case-control studies nested within the PREDIMED trial. A total of 512 incident AF cases matched to 734 controls, and 334 incident HF cases matched to 508 controls, were included. Plasma metabolites were quantified by using hydrophilic interaction liquid chromatography coupled with high-resolution negative ion mode MS detection. Conditional logistic regression analyses were performed. The results showed no association between baseline plasma glycolysis intermediates and other related metabolites with AF. Only phosphoglycerate was associated with a higher risk of HF (OR for 1 SD increase: 1.28; 95% CI: 1.06, 1.53). The present findings do not support a role of the glycolysis pathway in the pathogenesis of AF. However, the increased risk of HF associated with phosphoglycerate requires further studies.

Dietary vitamin D intake and colorectal cancer risk: a longitudinal approach within the PREDIMED study.

PURPOSE: We evaluated whether the intake of dietary vitamin D is associated with the incidence of both colorectal cancer (CRC) and colon cancer in the framework of the PREDIMED cohort of older adults at high cardiovascular risk. METHODS: We analyzed data from 7216 men and women (55-80 years) without CRC at baseline from the PREvención con DIeta MEDiterránea study. Baseline consumption of vitamin D was assessed using a validated 137-item food frequency questionnaire. Cox proportional hazards ratios (HRs) of CRC and colon cancer incidence were estimated for quartiles and per 1-SD of baseline vitamin D intake. RESULTS: During a median follow-up of 6 years, we documented 97 incident CRC cases after the exclusion of subjects with no baseline dietary data and/or outliers of energy intake. A non-significant HRs and 95% confidence intervals (CIs) of CRC for the comparison of extreme quartiles (4th vs 1st) of vitamin D intake were observed [0.55 (0.30-1.00), P for trend = 0.072], whereas it was significant for colon cancer incidence alone [0.44 (0.22-0.90), P for trend = 0.032]. However, this association became significant in CRC and colon cancer incidence, after excluding 391 subjects consuming baseline vitamin D and/or calcium medication or prescribed supplements [0.52 (0.28-0.96) and 0.41 (0.12-0.85), respectively]. CONCLUSION: A higher dietary intake of vitamin D was significantly associated with a reduced CRC risk in individuals at high cardiovascular risk.

Longitudinal changes in adherence to the portfolio and DASH dietary patterns and cardiometabolic risk factors in the PREDIMED-Plus study.

BACKGROUND & AIMS: The Portfolio and Dietary Approaches to Stop Hypertension (DASH) diets have been shown to lower cardiometabolic risk factors in randomized controlled trials (RCTs). However, the Portfolio diet has only been assessed in RCTs of hyperlipidemic patients. Therefore, to assess the Portfolio diet in a population with metabolic syndrome (MetS), we conducted a longitudinal analysis of one-year data of changes in the Portfolio and DASH diet scores and their association with cardiometabolic risk factors in Prevención con Dieta Mediterránea (PREDIMED)-Plus trial. METHODS: PREDIMED-Plus is an ongoing clinical trial (Trial registration: ISRCTN89898) conducted in Spain that includes 6874 older participants (mean age 65 y, 48% women) with overweight/obesity fulfilling at least three criteria for MetS. Data for this analysis were collected at baseline, six months and one year. Adherence to the Portfolio and DASH diet scores were derived from a validated 143-item food frequency questionnaire. We used linear mixed models to examine the associations of 1-SD increase and quartile changes in the diet scores with concomitant changes in cardiometabolic risk factors. RESULTS: After adjusting for several potential confounders, a 1-SD increase in the Portfolio diet score was significantly associated with lower HbA1c (ß [95% CI]: -0.02% [-0.02, -0.01], P < 0.001), fasting glucose (-0.47 mg/dL [-0.83, -0.11], P = 0.01), triglycerides (-1.29 mg/dL [-2.31, -0.28], P = 0.01), waist circumference (WC) (-0.51 cm [-0.59, -0.43], P < 0.001), and body mass index (BMI) (-0.17 kg/m2 [-0.19, -0.15], P < 0.001). A 1-SD increase in the DASH diet score was significantly associated with lower HbA1c (-0.03% [-0.04, -0.02], P < 0.001), glucose (-0.84 mg/dL [-1.18, -0.51], P < 0.001), triglycerides (-3.38 mg/dL [-4.37, -2.38], P < 0.001), non-HDL-cholesterol (-0.47 mg/dL [-0.91, -0.04], P = 0.03), WC (-0.69 cm [-0.76, -0.60 cm], P < 0.001), BMI (-0.25 kg/m2 [-0.28, -0.26 kg/m2], P < 0.001), systolic blood pressure (-0.57 mmHg [-0.81, -0.32 mmHg], P < 0.001), diastolic blood pressure (-0.15 mmHg [-0.29, -0.01 mmHg], P = 0.03), and with higher HDL-cholesterol (0.21 mg/dL [0.09, 0.34 mg/dL, P = 0.001]). Similar associations were seen when both diet scores were assessed as quartiles, comparing extreme categories of adherence. CONCLUSIONS: Among older adults at high cardiovascular risk with MetS, greater adherence to the Portfolio and DASH diets showed significant favourable prospective associations with several clinically relevant cardiometabolic risk factors. Both diets are likely beneficial for cardiometabolic risk reduction.

Assessment of price and nutritional quality of gluten-free products versus their analogues with gluten through the algorithm of the nutri-score front-of-package labeling system.

Evidence has shown that the nutritional quality of gluten-free products (GFPs) is lower than that of non-GFPs. Our main objective was to compare the nutritional quality through nutritional profiles of foods underlying the Nutri-Score front-of-pack and the price of GFPs with respect to non-GFPs, and to evaluate whether there is a correlation between both parameters. Nutritional information of all products was obtained from the CELIACBASE database and the price through Spanish supermarkets websites. Global quality using the Nutri-Score algorithm and the price were compared between both types of products. GFPs do not always have poorer quality than their counterparts. A better quality of gluten-free pasta was correlated with the higher price but also a worse quality of gluten-free muesli was correlated with the higher price. The price of GFPs compared to non-GFPs was higher up to 391.5%. However, for ham and cheese pizza, ham pizza, Marie biscuits, and baby biscuits, the difference was not statistically significant. Generally, the price of GFPs did not correlate with better nutritional quality. Nutri-Score would ease the nutritional quality identification, empowering consumers and could also influence manufacturers to improve the nutritional quality of GFPs. Nowadays, given that many GFPs have poor nutritional quality, they should be included only occasionally in a balanced gluten-free diet.

Dairy consumption, plasma metabolites, and risk of type 2 diabetes.

BACKGROUND: Epidemiologic studies have reported a modest inverse association between dairy consumption and the risk of type 2 diabetes (T2D). Whether plasma metabolite profiles associated with dairy consumption reflect this relationship remains unknown. OBJECTIVES: We aimed to identify the plasma metabolites associated with total and specific dairy consumption, and to evaluate the association between the identified multi-metabolite profiles and T2D. METHODS: The discovery population included 1833 participants from the Prevención con Dieta Mediterránea (PREDIMED) trial. The confirmatory cohorts included 1522 PREDIMED participants at year 1 of the trial and 4932 participants from the Nurses' Health Studies (NHS), Nurses' Health Study II (NHSII), and Health Professionals Follow-Up Study US-based cohorts. Dairy consumption was assessed using validated FFQs. Plasma metabolites (n = 385) were profiled using LC-MS. We identified the dairy-related metabolite profiles using elastic net regularized regressions with a 10-fold cross-validation procedure. We evaluated the associations between the metabolite profiles and incident T2D in the discovery and the confirmatory cohorts. RESULTS: Total dairy intake was associated with 38 metabolites. C14:0 sphingomyelin (positive coefficient), C34:0 phosphatidylethanolamine (positive coefficient), and γ-butyrobetaine (negative coefficient) were associated in a directionally similar fashion with total and specific (milk, yogurt, cheese) dairy consumption. The Pearson correlation coefficients between self-reported total dairy intake and predicted total dairy intake based on the corresponding multi-metabolite profile were 0.37 (95% CI, 0.33-0.40) in the discovery cohort and 0.16 (95% CI, 0.13-0.19) in the US confirmatory cohort. After adjusting for T2D risk factors, a higher total dairy intake-related metabolite profile score was associated with a lower T2D risk [HR per 1 SD; discovery cohort: 0.76 (95% CI, 0.63-0.90); US confirmatory cohort: 0.88 (95% CI, 0.78-0.99)]. CONCLUSIONS: Total dairy intake was associated with 38 metabolites, including 3 consistently associated with dairy subtypes (C14:0 sphingomyelin, C34:0 phosphatidylethanolamine, γ-butyrobetaine). A score based on the 38 identified metabolites showed an inverse association with T2D risk in Spanish and US populations.

Nut consumption and type 2 diabetes risk: a systematic review and meta-analysis of observational studies.

BACKGROUND: Previous meta-analyses, with some methodological controversies, have assessed the relation between nut consumption and type 2 diabetes (T2D) risk and pointed to contradictory results, making desirable the performance of an updated meta-analysis. OBJECTIVES: We aimed to systematically review and meta-analyze all the published studies investigating the relations of total nuts and different types of nuts-i.e., walnuts, peanuts, peanut butter, and total tree nuts-with the prevalence and incidence of T2D. METHODS: A systematic search was conducted in the PubMed and Cochrane databases through 12 August, 2020. The inverse variance method with fixed-effect models was used to pool data across studies, expressed as risk ratios (RRs) or ORs and 95% CIs for prospective cohort and cross-sectional studies, respectively. The Cochran Q test and I2 statistics were used to test and quantify heterogeneity, respectively. Dose-response meta-analysis was also conducted. RESULTS: Eight studies (5 prospective and 3 cross-sectional) were included in the quantitative synthesis. Meta-analyses of cross-sectional studies and prospective cohort studies, comparing the highest with the lowest categories, revealed a nonsignificant association between total nut consumption and T2D. Meta-analyses of prospective cohort studies showed an inverse association between peanut butter consumption and T2D incidence (RR: 0.87; 95% CI: 0.77, 0.98; I2 = 50.6%; Pheterogeneity = 0.16), whereas no association was observed between peanuts or tree nuts and T2D. There was no evidence of a linear dose-response or nonlinear dose-response gradient for total nut and peanut consumption in prospective cohort studies. The certainty of the evidence using NutriGrade was very low for all the exposures. CONCLUSIONS: Current results do not demonstrate an association of total nut, peanut, or tree nut consumption with T2D. Peanut butter consumption may be inversely associated with this disease.This review protocol was registered at www.crd.york.ac.uk/prospero/ as CRD42020149756.

Walnut Consumption, Plasma Metabolomics, and Risk of Type 2 Diabetes and Cardiovascular Disease.

BACKGROUND: Walnut consumption is associated with lower risk of type 2 diabetes (T2D) and cardiovascular disease (CVD). However, it is unknown whether plasma metabolites related to walnut consumption are also associated with lower risk of cardiometabolic diseases. OBJECTIVES: The study aimed to identify plasma metabolites associated with walnut consumption and evaluate the prospective associations between the identified profile and risk of T2D and CVD. METHODS: The discovery population included 1833 participants at high cardiovascular risk from the PREvención con DIeta MEDiterránea (PREDIMED) study with available metabolomics data at baseline. The study population included 57% women (baseline mean BMI (in kg/m2): 29.9; mean age: 67 y). A total of 1522 participants also had available metabolomics data at year 1 and were used as the internal validation population. Plasma metabolomics analyses were performed using LC-MS. Cross-sectional associations between 385 known metabolites and walnut consumption were assessed using elastic net continuous regression analysis. A 10-cross-validation (CV) procedure was used, and Pearson correlation coefficients were assessed between metabolite weighted models and self-reported walnut consumption in each pair of training-validation data sets within the discovery population. We further estimated the prospective associations between the identified metabolite profile and incident T2D and CVD using multivariable Cox regression models. RESULTS: A total of 19 metabolites were significantly associated with walnut consumption, including lipids, purines, acylcarnitines, and amino acids. Ten-CV Pearson correlation coefficients between self-reported walnut consumption and the plasma metabolite profile were 0.16 (95% CI: 0.11, 0.20) in the discovery population and 0.15 (95% CI: 0.10, 0.20) in the validation population. The metabolite profile was inversely associated with T2D incidence (HR per 1 SD: 0.83; 95% CI: 0.71, 0.97; P = 0.02). For CVD incidence, the HR per 1-SD was 0.71 (95% CI: 0.60, 0.85; P < 0.001). CONCLUSIONS: A metabolite profile including 19 metabolites was associated with walnut consumption and with a lower risk of incident T2D and CVD in a Mediterranean population at high cardiovascular risk.

Choline Metabolism and Risk of Atrial Fibrillation and Heart Failure in the PREDIMED Study.

BACKGROUND: Few studies have examined the associations of trimethylamine-N-oxide (TMAO) and its precursors (choline, betaine, dimethylglycine, and L-carnitine) with the risk of atrial fibrillation (AF) and heart failure (HF). This study sought to investigate these associations. METHODS: Prospective associations of these metabolites with incident AF and HF were examined among participants at high cardiovascular risk in the PREDIMED study (PREvención con DIeta MEDiterránea) after follow-up for about 10 years. Two nested case-control studies were conducted, including 509 AF incident cases matched to 618 controls and 326 HF incident cases matched to 426 controls. Plasma levels of TMAO and its precursors were semi-quantitatively profiled with liquid chromatography tandem mass spectrometry. Odds ratios were estimated with multivariable conditional logistic regression models. RESULTS: After adjustment for classical risk factors and accounting for multiple testing, participants in the highest quartile vs. the lowest quartile of baseline choline and betaine levels had a higher risk of AF [OR (95% CI): 1.85 (1.30-2.63) and 1.57 (1.09-2.24), respectively]. The corresponding OR for AF for extreme quartiles of dimethylglycine was 1.39 (0.99-1.96). One SD increase in log-transformed dimethylglycine was positively associated with AF risk (OR, 1.17; 1.03-1.33). The corresponding ORs for HF for extreme quartiles of choline, betaine, and dimethylglycine were 2.51 (1.57-4.03), 1.65 (1.00-2.71) and 1.65 (1.04-2.61), respectively. TMAO and L-carnitine levels were not associated with AF or HF. CONCLUSIONS: Our findings support the role of the choline metabolic pathway in the pathogenesis of AF and HF.

Plasma Metabolomic Profiles of Glycemic Index, Glycemic Load, and Carbohydrate Quality Index in the PREDIMED Study.

BACKGROUND: The quality of carbohydrate consumed, assessed by the glycemic index (GI), glycemic load (GL), or carbohydrate quality index (CQI), affects the postprandial glycemic and insulinemic responses, which have been implicated in the etiology of several chronic diseases. However, it is unclear whether plasma metabolites involved in different biological pathways could provide functional insights into the role of carbohydrate quality indices in health. OBJECTIVES: We aimed to identify plasma metabolomic profiles associated with dietary GI, GL, and CQI. METHODS: The present study is a cross-sectional analysis of 1833 participants with overweight/obesity (mean age = 67 y) from 2 case-cohort studies nested within the PREDIMED (Prevención con Dieta Mediterránea) trial. Data extracted from validated FFQs were used to estimate the GI, GL, and CQI. Plasma concentrations of 385 metabolites were profiled with LC coupled to MS and associations of these metabolites with those indices were assessed with elastic net regression analyses. RESULTS: A total of 58, 18, and 57 metabolites were selected for GI, GL, and CQI, respectively. Choline, cotinine, γ-butyrobetaine, and 36:3 phosphatidylserine plasmalogen were positively associated with GI and GL, whereas they were negatively associated with CQI. Fructose-glucose-galactose was negatively and positively associated with GI/GL and CQI, respectively. Consistent associations of 21 metabolites with both GI and CQI were found but in opposite directions. Negative associations of kynurenic acid, 22:1 sphingomyelin, and 38:6 phosphatidylethanolamine, as well as positive associations of 32:1 phosphatidylcholine with GI and GL were also observed. Pearson correlation coefficients between GI, GL, and CQI and the metabolomic profiles were 0.30, 0.22, and 0.27, respectively. CONCLUSIONS: The GI, GL, and CQI were associated with specific metabolomic profiles in a Mediterranean population at high cardiovascular disease risk. Our findings may help in understanding the role of dietary carbohydrate indices in the development of cardiometabolic disorders. This trial was registered at isrctn.com as ISRCTN35739639.

Metabolic Syndrome Features and Excess Weight Were Inversely Associated with Nut Consumption after 1-Year Follow-Up in the PREDIMED-Plus Study.

BACKGROUND: High nut consumption has been previously associated with decreased prevalence of metabolic syndrome (MetS) regardless of race and dietary patterns. OBJECTIVES: The aim of this study was to assess whether changes in nut consumption over a 1-y follow-up are associated with changes in features of MetS in a middle-aged and older Spanish population at high cardiovascular disease risk. METHODS: This prospective 1-y follow-up cohort study, conducted in the framework of the PREvención con DIeta MEDiterránea (PREDIMED)-Plus randomized trial, included 5800 men and women (55-75 y old) with overweight/obesity [BMI (in kg/m2) ≥27 and <40] and MetS. Nut consumption (almonds, pistachios, walnuts, and other nuts) was assessed using data from a validated FFQ. The primary outcome was the change from baseline to 1 y in features of MetS [waist circumference (WC), glycemia, HDL cholesterol, triglyceride (TG), and systolic and diastolic blood pressure] and excess weight (body weight and BMI) according to tertiles of change in nut consumption. Secondary outcomes included changes in dietary and lifestyle characteristics. A generalized linear model was used to compare 1-y changes in features of MetS, weight, dietary intakes, and lifestyle characteristics across tertiles of change in nut consumption. RESULTS: As nut consumption increased, between each tertile there was a significant decrease in WC, TG, systolic blood pressure, weight, and BMI (P < 0.05), and a significant increase in HDL cholesterol (only in women, P = 0.044). The interaction effect between time and group was significant for total energy intake (P < 0.001), adherence to the Mediterranean diet (MedDiet) (P < 0.001), and nut consumption (P < 0.001). Across tertiles of increasing nut consumption there was a significant increase in extra virgin olive oil intake and adherence to the MedDiet; change in energy intake, on the other hand, was inversely related to consumption of nuts. CONCLUSIONS: Features of MetS and excess weight were inversely associated with nut consumption after a 1-y follow-up in the PREDIMED-Plus study cohort. This trial was registered at isrctn.com as ISRCTN89898870.

Relationship between olive oil consumption and ankle-brachial pressure index in a population at high cardiovascular risk.

BACKGROUND AND AIMS: The aim of this study was to ascertain the association between the consumption of different categories of edible olive oils (virgin olive oils and olive oil) and olive pomace oil and ankle-brachial pressure index (ABI) in participants in the PREDIMED-Plus study, a trial of lifestyle modification for weight and cardiovascular event reduction in individuals with overweight/obesity harboring the metabolic syndrome. METHODS: We performed a cross-sectional analysis of the PREDIMED-Plus trial. Consumption of any category of olive oil and olive pomace oil was assessed through a validated food-frequency questionnaire. Multivariable linear regression models were fitted to assess associations between olive oil consumption and ABI. Additionally, ABI ≤1 was considered as the outcome in logistic models with different categories of olive oil and olive pomace oil as exposure. RESULTS: Among 4330 participants, the highest quintile of total olive oil consumption (sum of all categories of olive oil and olive pomace oil) was associated with higher mean values of ABI (beta coefficient: 0.014, 95% confidence interval [CI]: 0.002, 0.027) (p for trend = 0.010). Logistic models comparing the consumption of different categories of olive oils, olive pomace oil and ABI ≤1 values revealed an inverse association between virgin olive oils consumption and the likelihood of a low ABI (odds ratio [OR] 0.73, 95% CI [0.56, 0.97]), while consumption of olive pomace oil was positively associated with a low ABI (OR 1.22 95% CI [1.00, 1.48]). CONCLUSIONS: In a Mediterranean population at high cardiovascular risk, total olive oil consumption was associated with a higher mean ABI. These results suggest that olive oil consumption may be beneficial for peripheral artery disease prevention, but longitudinal studies are needed.

Association between Serum Vitamin B12 and Global DNA Methylation in Colorectal Cancer Patients.

Vitamin B12 has been widely related to methionine metabolism, which is an essential component for biological methylation reactions, including DNA methylation. However, the relationship between vitamin B12 and DNA methylation is still controversial. In addition, there is increasing evidence for the association between vitamin B12 and the risk of colorectal cancer (CRC), although results of this association need to be assessed with caution. For this purpose, we hypothesized that serum vitamin B12 could be associated with global DNA methylation in the CRC context. To test this hypothesis, we studied the association between global DNA methylation through long interspersed nuclear element-1 (LINE1) in CRC patients under the 25th percentile of serum vitamin B12. We found that the high vitamin B12 group had low LINE1 methylation in both tumor area and peripheral blood mononuclear cells (PBMCs) than the low serum vitamin B12 group. LINE1 methylation levels were significantly lower in tumor area compared to the adjacent tumor-free area, only in the high vitamin B12 group. LINE1 methylation in visceral adipose tissue (VAT) and PBMCs were correlated with tumoral, inflammatory, and insulin metabolism markers. However, the interaction between LINE1 methylation and vitamin B12 levels was associated with neoadjuvant therapy in the regression analysis only in men, suggesting a beneficial relationship. In conclusion, our results reported an inverse association between DNA methylation and vitamin B12 in the CRC context, which suggests that vitamin B12 may be implicated in an epigenetic state or mediation in CRC.