Identification of Plasma Lipid Metabolites Associated with Nut Consumption in US Men and Women

Dietary biomarkers-an update on their validity and applicability in epidemiological studies

The aim of this literature review was to identify and provide a summary update on the validity and applicability of the most promising dietary biomarkers reflecting the intake of important foods in the Western diet for application in epidemiological studies. Many dietary biomarker candidates, reflecting intake of common foods and their specific constituents, have been discovered from intervention and observational studies in humans, but few have been validated. The literature search was targeted for biomarker candidates previously reported to reflect intakes of specific food groups or components that are of major importance in health and disease. Their validity was evaluated according to 8 predefined validation criteria and adapted to epidemiological studies; we summarized the findings and listed the most promising food intake biomarkers based on the evaluation. Biomarker candidates for alcohol, cereals, coffee, dairy, fats and oils, fruits, legumes, meat, seafood, sugar, tea, and vegetables were identified. Top candidates for all categories are specific to certain foods, have defined parent compounds, and their concentrations are unaffected by nonfood determinants. The correlations of candidate dietary biomarkers with habitual food intake were moderate to strong and their reproducibility over time ranged from low to high. For many biomarker candidates, critical information regarding dose response, correlation with habitual food intake, and reproducibility over time is yet unknown. The nutritional epidemiology field will benefit from the development of novel methods to combine single biomarkers to generate biomarker panels in combination with self-reported data. The most promising dietary biomarker candidates that reflect commonly consumed foods and food components for application in epidemiological studies were identified, and research required for their full validation was summarized.

Nuts and Cardiovascular Disease Outcomes: A Review of the Evidence and Future Directions

Nuts are nutrient-rich foods that contain many bioactive compounds that are beneficial for cardiovascular health. Higher consumption of nuts has been associated with a reduced risk of several cardiovascular diseases (CVD) in prospective cohort studies, including a 19% and 25% lower risk of CVD incidence and mortality, respectively, and a 24% and 27% lower risk of coronary heart disease incidence and mortality, respectively. An 18% lower risk of stroke mortality, a 15% lower risk of atrial fibrillation, and a 19% lower risk of total mortality have also been observed. The role of nuts in stroke incidence, stroke subtypes, peripheral arterial disease and heart failure has been less consistent. This narrative review summarizes recommendations for nuts by clinical practice guidelines and governmental organizations, epidemiological evidence for nuts and CVD outcomes, nut-containing dietary patterns, potential mechanisms of nuts and CVD risk reduction, and future research directions, such as the use of biomarkers to help better assess nut intake. Although there are still some uncertainties around nuts and CVD prevention which require further research, as summarized in this review, there is a substantial amount of evidence that supports that consuming nuts will have a positive impact on primary and secondary prevention of CVD.

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.

Serum Levels of Plasmalogens and Fatty Acid Metabolites Associate with Retinal Microangiopathy in Participants from the Finnish Diabetes Prevention Study

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes, and retinal microaneurysms (MA) are one of the first detected abnormalities associated with DR. We recently showed elevated serum triglyceride levels to be associated with the development of MA in the Finnish Diabetes Prevention Study (DPS). The purpose of this metabolomics study was to assess whether serum fatty acid (FA) composition, plasmalogens, and low-grade inflammation may enhance or decrease the risk of MA. Originally, the DPS included 522 individuals (mean 55 years old, range 40-64 years) with impaired glucose tolerance who were randomized into an intervention (n = 265) or control group (n = 257). The intervention lasted for a median of four years (active period), after which annual follow-up visits were conducted. At least five years after stopping the intervention phase of DPS, participants classified as MA negative (n = 115) or MA positive (n = 51) were included in the current study. All these participants were free of diabetes at baseline (WHO 1985) and had high-sensitive C-reactive protein (hs-CRP), serum FA composition, and selected lipid metabolites measured during the active study period. Among the markers associated with MA, the serum plasmalogen dm16:0 (p = 0.006), the saturated odd-chain FA 15.0 (pentadecanoic acid; p = 0.015), and omega-3 very long-chain FAs (p < 0.05) were associated with a decreased occurrence of MA. These associations were independent of study group and other risk factors. The association of high serum triglycerides with the MA occurrence was attenuated when these MA-associated serum lipid markers were considered. Our findings suggest that, in addition to n-3 FAs, odd-chain FA 15:0 and plasmalogen dm16:0 may contribute to a lower risk of MA in individuals with impaired glucose tolerance. These putative novel lipid biomarkers have an association with MA independently of triglyceride levels.

Nutritional Metabolomics and the Classification of Dietary Biomarker Candidates: A Critical Review

Recent advances in metabolomics allow for more objective assessment of contemporary food exposures, which have been proposed as an alternative or complement to self-reporting of food intake. However, the quality of evidence supporting the utility of dietary biomarkers as valid measures of habitual intake of foods or complex dietary patterns in diverse populations has not been systematically evaluated. We reviewed nutritional metabolomics studies reporting metabolites associated with specific foods or food groups; evaluated the interstudy repeatability of dietary biomarker candidates; and reported study design, metabolomic approach, analytical technique(s), and type of biofluid analyzed. A comprehensive literature search of 5 databases (PubMed, EMBASE, Web of Science, BIOSIS, and CINAHL) was conducted from inception through December 2020. This review included 244 studies, 169 (69%) of which were interventional studies (9 of these were replicated in free-living participants) and 151 (62%) of which measured the metabolomic profile of serum and/or plasma. Food-based metabolites identified in ≥1 study and/or biofluid were associated with 11 food-specific categories or dietary patterns: 1) fruits; 2) vegetables; 3) high-fiber foods (grain-rich); 4) meats; 5) seafood; 6) pulses, legumes, and nuts; 7) alcohol; 8) caffeinated beverages, teas, and cocoas; 9) dairy and soya; 10) sweet and sugary foods; and 11) complex dietary patterns and other foods. We conclude that 69 metabolites represent good candidate biomarkers of food intake. Quantitative measurement of these metabolites will advance our understanding of the relation between diet and chronic disease risk and support evidence-based dietary guidelines for global health.

Variability of the Plasma Lipidome and Subclinical Coronary Atherosclerosis

Supplemental Digital Content is available in the text.

Objective:

While the risk of acute coronary events has been associated with biological variability of circulating cholesterol, the association with variability of other atherogenic lipids remains less understood. We evaluated the longitudinal variability of 284 lipids and investigated their association with asymptomatic coronary atherosclerosis.

Approach and Results:

Circulating lipids were extracted from fasting blood samples of 83 community-sampled symptom-free participants (age 41–75 years), collected longitudinally over 6 months. Three types of coronary plaque volume (calcified, lipid-rich, and fibrotic) were quantified using computed tomography coronary angiogram. We first deconvoluted between-subject (CV_g) and within-subject (CV_w) lipid variabilities. We then tested whether the mean lipid abundance was different across groups categorized by Framingham risk score and plaques phenotypes (lipid-rich, fibrotic, and calcified). Finally, we investigated whether visit-to-visit variability of each lipid was associated with plaque burden. Most lipids (72.5%) exhibited higher CV_g than CV_w. Among the lipids (n=145) with 1.2-fold higher CV_g than CV_w, 26 species including glycerides and ceramides were significantly associated with Framingham risk score and the 3 plaque phenotypes (false discovery rate <0.05). In an exploratory analysis of person-specific visit-to-visit variability without multiple testing correction, high variability of 3 lysophospholipids (lysophosphatidylethanolamines 16:0, 18:0, and lysophosphatidylcholine O-18:1) was associated with lipid-rich and fibrotic (noncalcified) plaque volume while high variability of diacylglycerol 18:1_20:0, triacylglycerols 52:2, 52:3, and 52:4, ceramide d18:0/20:0, dihexosylceramide d18:1/16:0, and sphingomyelin 36:3 was associated with calcified plaque volume.

Conclusions:

High person-specific longitudinal variation of specific nonsterol lipids is associated with the burden of subclinical coronary atherosclerosis. Larger studies are needed to confirm these exploratory findings.

Dietary Patterns, Ceramide Ratios, and Risk of All-Cause and Cause-Specific Mortality: The Framingham Offspring Study

BACKGROUND

Prior evidence suggests that diet modifies the association of blood ceramides with the risk of incident cardiovascular disease (CVD). It remains unknown if diet quality modifies the association of very long-chain-to-long-chain ceramide ratios with mortality in the community.

OBJECTIVES

Our objectives were to determine how healthy dietary patterns associate with blood ceramide concentrations and to examine if healthy dietary patterns modify associations of ceramide ratios (C22:0/C16:0 and C24:0/C16:0) with all-cause and cause-specific mortality.

METHODS

We examined 2157 participants of the Framingham Offspring Study (mean age = 66 y, 55% women). Blood ceramides were quantified using a validated assay. We evaluated prospective associations of the Dietary Guidelines Adherence Index (DGAI) and Mediterranean-style Diet Score (MDS) with incidence of all-cause and cause-specific mortality using Cox proportional hazards models. Cross-sectional associations of the DGAI and MDS with ceramides were evaluated using multivariable linear regression models.

RESULTS

The C22:0/C16:0 and C24:0/C16:0 ceramide ratios were inversely associated with all-cause, CVD, and cancer mortality; multivariable-adjusted HRs (95% CIs) were 0.73 (0.67, 0.80) and 0.70 (0.63, 0.77) for all-cause mortality, 0.74 (0.60, 0.90) and 0.69 (0.55, 0.86) for CVD mortality, and 0.75 (0.65, 0.87) and 0.75 (0.64, 0.88) for cancer mortality, respectively. Inverse associations of the C22:0/C16:0 and C24:0/C16:0 ceramide ratios with cancer mortality were attenuated among individuals with a higher diet quality (DGAI or MDS above the median, all P-interaction ≤0.1). The DGAI and MDS had distinct associations with ceramide ratios (DGAI: lower C22:0/C16:0 across quartiles; MDS: higher C24:0/C16:0 across quartiles; all P-trend ≤0.01).

CONCLUSION

In our community-based sample, ceramide ratios (C22:0/C16:0 and C24:0/C16:0) were associated with a lower risk of all-cause and cause-specific mortality. Further, we observed that a higher overall diet quality attenuates the association between blood ceramide ratios and cancer mortality and that dietary patterns have distinct relations with ceramide ratios.

Computational approaches to understanding nutrient metabolism and metabolic disorders

Computational methods are becoming more and more essential to elucidate biological systems. Many different approaches exist with pros and cons. This paper reviews the most useful technologies focusing on nutrient metabolism and metabolic disorders. Space limitation prevents from exploring the examples in details, but pointers to the relevant papers are reported.

Plasma lipidomic analysis of sphingolipids in patients with large artery atherosclerosis cerebrovascular disease and cerebral small vessel disease

BACKGROUND

Sphingolipids mainly consist of ceramides (Cer), sphingomyelins (SM) and glycosphingolipids. Sphingolipids are related with coronary heart disease and metabolic disease, but there're few studies about cerebrovascular disease. The purpose was to detect sphingolipids in plasma of patients with large artery atherosclerosis (LAA) cerebrovascular disease and cerebral small vessel disease (CSVD) to explore the similarities and differences of pathogenesis of the two subtypes.

METHODS

20 patients with LAA cerebrovascular disease, 20 patients with age-related CSVD, 10 patients with Fabry disease and 14 controls were enrolled from October 2017 to January 2019. Ultra-high performance liquid chromatography-quadruple-time-of-flight mass spectrometry/mass spectrometry was used to determine sphingolipids. Univariate combined with multivariate analysis was used for comparison. Receiver operating characteristic curves were used to determine sensitivities and specificities.

RESULTS

276 sphingolipids were detected, including 39 Cer, 3 ceramide phosphates, 72 glycosphingolipids and 162 SM. (1) Cer (d36:3), Cer (d34:2), Cer (d38:6), Cer (d36:4) and Cer (d16:0/18:1) were increased in LAA; SM (d34:1), Cer (d34:2), Cer (d36:4), Cer (d16:0/18:1), Cer (d38:6), Cer (d36:3) and Cer (d32:0) were increased in age-related CSVD. (2) Cer (d36:4) and SM (d34:1) were increased in age-related CSVD compared with LAA. (3) Total trihexosyl ceramides were increased in Fabry group compared with control (P<0.05); SM (d34:1) was increased in Fabry group.

CONCLUSIONS

Ceramides are increased in both LAA and age-related CSVD, which may be related to similar risk factors and pathophysiological process of arteriosclerosis; SM is increased in both age-related CSVD and Fabry disease, suggesting that increased SM may be associated with CSVD. Glycosphingolipids, trihexosylceramides in particular, are increased in Fabry disease.

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.