Nutrient composition of different energy-restricted diets determines plasma endocannabinoid profiles and adipose tissue DAGL-α expression; a 12-week randomized controlled trial in subjects with abdominal obesity

The endocannabinoid system (ECS) is dysregulated during obesity and metabolic disorders. Weight loss favours the re-establishment of ECS homeostatic conditions, but also the fatty acid composition of the diet can modulate endocannabinoid profiles. However, the combined impact of nutrient quality and energy restriction on the ECS remains unclear. In this 12 weeks randomized controlled trial, men and women (40-70 years) with obesity (BMI: 31.3 ± 3.5 kg/ m2) followed either a low nutrient quality 25% energy-restricted (ER) diet (n=39) high in saturated fats and fructose, or a high nutrient quality ER diet (n=34) amongst others enriched in n-3 polyunsaturated fatty acids (PUFAs) or kept their habitual diet (controls). Profiles of plasma- and adipose N-acylethanolamines and mono-acyl glycerol esters were quantified using LC-MS/MS. Gene expression of ECS-related enzymes and receptors was determined in adipose tissue. Measurements were performed under fasting conditions before and after 12 weeks. Our results showed that plasma level of the DHA-derived compound docosahexaenoylethanolamide (DHEA) was decreased in the low nutrient quality ER diet (P<0.001) compared with the high nutrient quality ER diet, whereas anandamide (AEA) and arachidonoylglycerol (2-AG) levels were unaltered. However, adipose tissue gene expression of the 2-AG synthesizing enzyme diacylglycerol lipase alpha (DAGL-α) was increased following the low nutrient quality ER diet (P<.009) and differed upon intervention with both other diets. Concluding, nutrient quality of the diet affects N-acylethanolamine profiles and gene expression of ECS-related enzymes and receptors even under conditions of high energy restriction in abdominally obese humans. ClinicalTrials.gov NCT02194504.

Immunometabolic Signatures of Circulating Monocytes in Humans with Obesity and Insulin Resistance

Obesity is associated with chronic inflammation and metabolic complications, including insulin resistance (IR). Immune cells drive inflammation through the rewiring of intracellular metabolism. However, the impact of obesity-related IR on the metabolism and functionality of circulating immune cells, like monocytes, remains poorly understood. To increase insight into the inter-individual variation of immunometabolic signatures among individuals and their role in the development of IR, we assessed systemic and tissue-specific IR and circulating immune markers, and we characterized metabolic signatures and cytokine secretion of circulating monocytes from 194 individuals with a BMI≥25kg/m2. Monocyte metabolic signatures were defined using extracellular acidification rates (ECAR) to estimate glycolysis and oxygen consumption rates (OCR) for oxidative metabolism. Although monocyte metabolic signatures and function based on cytokine secretion varied greatly among subjects, they were strongly associated with each other. The ECAR/OCR ratio, representing the balance between glycolysis and oxidative metabolism, was negatively associated with fasting insulin, systemic IR, and liver-specific IR. These results indicate that monocytes from individuals with IR were relatively more dependent on oxidative metabolism, while monocytes from more insulinsensitive individuals were more dependent on glycolysis. Additionally, circulating CXCL11 was negatively associated with the degree of systemic IR and positively with the ECAR/OCR ratio in monocytes, suggesting that individuals with high IR and a monocyte metabolic dependence on oxidative metabolism also have lower levels of circulating CXCL11. Our findings suggest that monocyte metabolism is related to obesity-associated IR progression and deepen insights into the interplay between innate immune cell metabolism and IR development in humans.

Quantifying the effect of nutritional interventions on metabolic resilience using personalized computational models

The manifestation of metabolic deteriorations that accompany overweight and obesity can differ greatly between individuals, giving rise to a highly heterogeneous population. This inter-individual variation can impede both the provision and assessment of nutritional interventions as multiple aspects of metabolic health should be considered at once. Here, we apply the Mixed Meal Model, a physiology-based computational model, to characterize an individual's metabolic health in silico. A population of 342 personalized models were generated using data for individuals with overweight and obesity from three independent intervention studies, demonstrating a strong relationship between the model-derived metric of insulin resistance (ρ = 0.67, p < 0.05) and the gold-standard hyperinsulinemic-euglycemic clamp. The model is also shown to quantify liver fat accumulation and β-cell functionality. Moreover, we show that personalized Mixed Meal Models can be used to evaluate the impact of a dietary intervention on multiple aspects of metabolic health at the individual level.

Body composition and body fat distribution in tissue-specific insulin resistance and in response to a 12-week isocaloric dietary macronutrient intervention

BACKGROUND

Body composition and body fat distribution are important predictors of cardiometabolic diseases. The etiology of cardiometabolic diseases is heterogenous, and partly driven by inter-individual differences in tissue-specific insulin sensitivity.

OBJECTIVES

To investigate (1) the associations between body composition and whole-body, liver and muscle insulin sensitivity, and (2) changes in body composition and insulin sensitivity and their relationship after a 12-week isocaloric diet high in mono-unsaturated fatty acids (HMUFA) or a low-fat, high-protein, high-fiber (LFHP) diet.

METHODS

This subcohort analysis of the PERSON study includes 93 individuals (53% women, BMI 25-40 kg/m2, 40-75 years) who participated in this randomized intervention study. At baseline and after 12 weeks of following the LFHP, or HMUFA diet, we performed a 7-point oral glucose tolerance test to assess whole-body, liver, and muscle insulin sensitivity, and whole-body magnetic resonance imaging to determine body composition and body fat distribution. Both diets are within the guidelines of healthy nutrition.

RESULTS

At baseline, liver fat content was associated with worse liver insulin sensitivity (β [95%CI]; 0.12 [0.01; 0.22]). Only in women, thigh muscle fat content was inversely related to muscle insulin sensitivity (-0.27 [-0.48; -0.05]). Visceral adipose tissue (VAT) was inversely associated with whole-body, liver, and muscle insulin sensitivity. Both diets decreased VAT, abdominal subcutaneous adipose tissue (aSAT), and liver fat, but not whole-body and tissue-specific insulin sensitivity with no differences between diets. Waist circumference, however, decreased more following the LFHP diet as compared to the HMUFA diet (-3.0 vs. -0.5 cm, respectively). After the LFHP but not HMUFA diet, improvements in body composition were positively associated with improvements in whole-body and liver insulin sensitivity.

CONCLUSIONS

Liver and muscle insulin sensitivity are distinctly associated with liver and muscle fat accumulation. Although both LFHP and HMUFA diets improved in body fat, VAT, aSAT, and liver fat, only LFHP-induced improvements in body composition are associated with improved insulin sensitivity.

TRIAL REGISTRATION

NCT03708419 (clinicaltrials.gov).

Leveraging continuous glucose monitoring for personalized modeling of insulin-regulated glucose metabolism

Continuous glucose monitoring (CGM) is a promising, minimally invasive alternative to plasma glucose measurements for calibrating physiology-based mathematical models of insulin-regulated glucose metabolism, reducing the reliance on in-clinic measurements. However, the use of CGM glucose, particularly in combination with insulin measurements, to develop personalized models of glucose regulation remains unexplored. Here, we simultaneously measured interstitial glucose concentrations using CGM as well as plasma glucose and insulin concentrations during an oral glucose tolerance test (OGTT) in individuals with overweight or obesity to calibrate personalized models of glucose-insulin dynamics. We compared the use of interstitial glucose with plasma glucose in model calibration, and evaluated the effects on model fit, identifiability, and model parameters' association with clinically relevant metabolic indicators. Models calibrated on both plasma and interstitial glucose resulted in good model fit, and the parameter estimates associated with metabolic indicators such as insulin sensitivity measures in both cases. Moreover, practical identifiability of model parameters was improved in models estimated on CGM glucose compared to plasma glucose. Together these results suggest that CGM glucose may be considered as a minimally invasive alternative to plasma glucose measurements in model calibration to quantify the dynamics of glucose regulation.

Hepatic insulin resistance and muscle insulin resistance are characterized by distinct postprandial plasma metabolite profiles: a cross-sectional study

BACKGROUND

Tissue-specific insulin resistance (IR) predominantly in muscle (muscle IR) or liver (liver IR) has previously been linked to distinct fasting metabolite profiles, but postprandial metabolite profiles have not been investigated in tissue-specific IR yet. Given the importance of postprandial metabolic impairments in the pathophysiology of cardiometabolic diseases, we compared postprandial plasma metabolite profiles in response to a high-fat mixed meal between individuals with predominant muscle IR or liver IR.

METHODS

This cross-sectional study included data from 214 women and men with BMI 25-40 kg/m2, aged 40-75 years, and with predominant muscle IR or liver IR. Tissue-specific IR was assessed using the muscle insulin sensitivity index (MISI) and hepatic insulin resistance index (HIRI), which were calculated from the glucose and insulin responses during a 7-point oral glucose tolerance test. Plasma samples were collected before (T = 0) and after (T = 30, 60, 120, 240 min) consumption of a high-fat mixed meal and 247 metabolite measures, including lipoproteins, cholesterol, triacylglycerol (TAG), ketone bodies, and amino acids, were quantified using nuclear magnetic resonance spectroscopy. Differences in postprandial plasma metabolite iAUCs between muscle and liver IR were tested using ANCOVA with adjustment for age, sex, center, BMI, and waist-to-hip ratio. P-values were adjusted for a false discovery rate (FDR) of 0.05 using the Benjamini-Hochberg method.

RESULTS

Sixty-eight postprandial metabolite iAUCs were significantly different between liver and muscle IR. Liver IR was characterized by greater plasma iAUCs of large VLDL (p = 0.004), very large VLDL (p = 0.002), and medium-sized LDL particles (p = 0.026), and by greater iAUCs of TAG in small VLDL (p = 0.025), large VLDL (p = 0.003), very large VLDL (p = 0.002), all LDL subclasses (all p < 0.05), and small HDL particles (p = 0.011), compared to muscle IR. In liver IR, the postprandial plasma fatty acid (FA) profile consisted of a higher percentage of saturated FA (p = 0.013), and a lower percentage of polyunsaturated FA (p = 0.008), compared to muscle IR.

CONCLUSION

People with muscle IR or liver IR have distinct postprandial plasma metabolite profiles, with more unfavorable postprandial metabolite responses in those with liver IR compared to muscle IR.

Intraintestinal fermentation of fructo- and galacto-oligosaccharides and the fate of short-chain fatty acids in humans

Consumption of fructo- (FOS) and galacto-oligosaccharides (GOS) has health benefits which have been linked in part to short-chain fatty acids (SCFA) production by the gut microbiota. However, detailed knowledge of this process in the human intestine is lacking. We aimed to determine the acute fermentation kinetics of a FOS:GOS mixture in healthy males using a naso-intestinal catheter for sampling directly in the ileum or colon. We studied the fate of SCFA as substrates for glucose and lipid metabolism by the host after infusion of 13C-SCFA. In the human distal ileum, no fermentation of FOS:GOS, nor SCFA production, or bacterial cross-feeding was observed. The relative composition of intestinal microbiota changed rapidly during the test day, which demonstrates the relevance of postprandial intestinal sampling to track acute responses of the microbial community toward interventions. SCFA were vividly taken up and metabolized by the host as shown by incorporation of 13C in various host metabolites.

Milk fat globule membrane modulates inflammatory pathways in human monocytes: A crossover human intervention study

BACKGROUND

Intake of high-fat foods raises postprandial plasma triglycerides and inflammatory markers, which may depend on the type of fat ingested. Dairy products are commonly consumed, but not much is known about the impact of milk fat and the milk fat globule membrane on postprandial inflammation. Here, we aimed to study the effect of milk fat with and without milk fat globule membrane and a vegetable fat blend on post-prandial inflammation, with a focus on blood monocyte gene expression.

METHODS

We performed a randomized, double-blind cross-over trial in 37 middle-aged healthy male and female volunteers (BMI 22-27 kg/m2). The participants consumed a meal shake containing 95.5 g of fat consisting of either a vegetable fat blend (VEGE), anhydrous milk fat (AMF, without milk fat globule membrane), or cream (CREAM, containing milk fat globule membrane). Blood monocytes were collected at 0 h and 6 h postprandially and used for bulk RNA sequencing and ex vivo stimulation with LPS.

RESULTS

Consumption of all three shakes significantly decreased the percentage of classical monocytes and increased the percentages of intermediate monocytes and non-classical monocytes. No differences in these measures were observed between shakes. Using a threshold of p < 0.01, 787 genes were differentially regulated postprandially between the three shakes. 89 genes were differentially regulated postprandially between AMF and VEGE, 373 genes between AMF and CREAM, and 667 genes between VEGE and CREAM, indicating that the effect of CREAM on monocyte gene expression was distinct from AMF and VEGE. Pathway analyses showed that VEGE significantly increased the expression of genes involved in inflammatory pathways, whereas this was less pronounced after AMF and not observed after CREAM. In addition, CREAM significantly down-regulated the expression of genes involved in energy metabolism-related pathways, such as glycolysis, TCA cycle, and oxidative phosphorylation, as well as HIF-1 signaling.

CONCLUSION

Compared to the consumption of an anhydrous milk fat without milk fat globule membrane and a vegetable fat blend, the consumption of cream with milk fat globule membrane downregulated inflammatory pathways in blood monocytes, thus suggesting a potential inflammation inhibitory effect of milk fat globule membrane.

Are postprandial glucose responses sufficiently person-specific to use in personalized dietary advice? Design of the RepEAT study: a fully controlled dietary intervention to determine the variation in glucose responses

Introduction

An elevated postprandial glucose response is associated with an increased risk of cardiometabolic diseases. Existing research suggests large heterogeneity in the postprandial glucose responses to identical meals and food products between individuals, but the effect of other consumed meals during the day and the order of meals during the day on the heterogeneity in postprandial glucose responses still needs to be investigated. In addition, the robustness of the glucose responses to meals or foods is still unknown.

Objectives

The overall aim of the project is to assess whether the glucose response to a meal is sufficiently person-specific to use in personalized dietary advice. We aim to answer the question: "How replicable are glucose responses to meals within individuals and how consistent is the variation in glucose responses between individuals?"

Methods

The question will be assessed under standardized conditions of a 9-week fully controlled dietary intervention in which all meals are the same between individuals and consumed in a fixed order at a fixed time. 63 apparently healthy men and women with a BMI of 25-40 kg/m2 and aged 45-75 years were enrolled in the RepEAT study (NCT05456815), of whom 53 participants completed the study. The RepEAT study comprised a fully controlled dietary intervention of nine weeks, consisting of three repetitive periods of three weeks. Within each three-week period, a variety of meals and food products were offered during breakfast, lunch, dinner and in between meal snacks. Throughout the dietary intervention, glucose was continuously monitored using Freestyle Libre Pro IQ monitors. Physical activity was monitored using the ActiGraph and ActivPAL. To measure the association between glucose responses and an individual's phenotype, various measurements were performed before the start of the dietary intervention including an oral glucose tolerance test, a high-fat mixed meal challenge, assessment of body fat distribution including liver fat (MRI/MRS), and cardiometabolic markers.

Discussion

The repetitive and fully controlled nature of the dietary study allows detailed assessment of the replicability of the glucose responses to meals and food products within individuals. Furthermore, the consistency of the variation between individuals independent of insulin resistance will be determined.

Diet-induced Weight Loss and Phenotypic Flexibility Among Healthy Overweight Adults: A Randomized Trial

BACKGROUND

The capacity of an individual to respond to changes in food intake so that postprandial metabolic perturbations are resolved, and metabolism returns to its pre-prandial state, is called phenotypic flexibility. This ability may be a more important indicator of current health status than metabolic markers in a fasting state.

AIM

In this parallel randomized controlled trial study, an energy-restricted healthy diet and 2 dietary challenges were used to assess the effect of weight loss on phenotypic flexibility.

METHODS

Seventy-two volunteers with overweight and obesity underwent a 12-wk dietary intervention. The participants were randomized to a weight loss group (WLG) with 20% less energy intake or a weight-maintenance group (WMG). At weeks 1 and 12, participants were assessed for body composition by MRI. Concurrently, markers of metabolism and insulin sensitivity were obtained from the analysis of plasma metabolome during 2 different dietary challenges-an oral glucose tolerance test (OGTT) and a mixed-meal tolerance test.

RESULTS

Intended weight loss was achieved in the WLG (-5.6 kg, P < 0.0001) and induced a significant reduction in total and regional adipose tissue as well as ectopic fat in the liver. Amino acid-based markers of insulin action and resistance such as leucine and glutamate were reduced in the postprandial phase of the OGTT in the WLG by 11.5% and 28%, respectively, after body weight reduction. Weight loss correlated with the magnitude of changes in metabolic responses to dietary challenges. Large interindividual variation in metabolic responses to weight loss was observed.

CONCLUSION

Application of dietary challenges increased sensitivity to detect metabolic response to weight loss intervention. Large interindividual variation was observed across a wide range of measurements allowing the identification of distinct responses to the weight loss intervention and mechanistic insight into the metabolic response to weight loss.

Physical activity and sedentary behavior show distinct associations with tissue-specific insulin sensitivity in adults with overweight

AIM

The aim of this study is to investigate associations between the physical activity (PA) spectrum (sedentary behavior to exercise) and tissue-specific insulin resistance (IR).

METHODS

We included 219 participants for analysis (median [IQR]: 61 [55; 67] years, BMI 29.6 [26.9; 32.0] kg/m² ; 60% female) with predominant muscle or liver IR, as determined using a 7-point oral glucose tolerance test (OGTT). PA and sedentary behavior were measured objectively (ActivPAL) across 7 days. Context-specific PA was assessed with the Baecke questionnaire. Multiple linear regression models (adjustments include age, sex, BMI, site, season, retirement, and dietary intake) were used to determine associations between the PA spectrum and hepatic insulin resistance index (HIRI), muscle insulin sensitivity index (MISI) and whole-body IR (HOMA-IR, Matsuda index).

RESULTS

In fully adjusted models, objectively measured total PA (standardized regression coefficient β = 0.17, p = 0.020), light-intensity PA (β = 0.15, p = 0.045) and moderate-to-vigorous intensity PA (β = 0.13, p = 0.048) were independently associated with Matsuda index, but not HOMA-IR (p > 0.05). A higher questionnaire-derived sport index and leisure index were associated with significantly lower whole-body IR (Matsuda, HOMA-IR) in men but not in women. Results varied across tissues: more time spent sedentary (β = -0.24, p = 0.045) and a higher leisure index (β = 0.14, p = 0.034) were respectively negatively and positively associated with MISI, but not HIRI. A higher sport index was associated with lower HIRI (β = -0.30, p = 0.007, in men only).

CONCLUSION

While we confirm a beneficial association between PA and whole-body IR, our findings indicate that associations between the PA spectrum and IR seem distinct depending on the primary site of insulin resistance (muscle or liver).

Circulating and adipose tissue immune cells in tissue-specific insulin resistance in humans with overweight and obesity

OBJECTIVE

A proinflammatory adipose tissue (AT) microenvironment and systemic low-grade inflammation may differentially affect tissue-specific insulin sensitivity. This study investigated the relationships of abdominal subcutaneous AT (aSAT) and circulating immune cells, aSAT gene expression, and circulating inflammatory markers with liver and skeletal muscle insulin sensitivity in people with overweight and obesity.

METHODS

Individuals with overweight and obesity from the PERSonalized Glucose Optimization Through Nutritional Intervention (PERSON) Study (n = 219) and the Maastricht Study (replication cohort; n = 1256) underwent a seven-point oral glucose tolerance test to assess liver and muscle insulin sensitivity, and circulating inflammatory markers were determined. In subgroups, flow cytometry was performed to identify circulating and aSAT immune cells, and aSAT gene expression was evaluated.

RESULTS

The relative abundances of circulating T cells, nonclassical monocytes, and CD56dim CD16+ natural killer cells were inversely associated with liver, but not muscle, insulin sensitivity in the PERSON Study. The inverse association between circulating (classical) monocytes and liver insulin sensitivity was confirmed in the Maastricht Study. In aSAT, immune cell populations were not related to insulin sensitivity. Furthermore, aSAT gene expression of interleukin 6 and CD14 was positively associated with muscle, but not liver, insulin sensitivity.

CONCLUSIONS

The present findings demonstrate that circulating immune cell populations and inflammatory gene expression in aSAT show distinct associations with liver and muscle insulin sensitivity.

Cardiometabolic health improvements upon dietary intervention are driven by tissue-specific insulin resistance phenotype: A precision nutrition trial

Precision nutrition based on metabolic phenotype may increase the effectiveness of interventions. In this proof-of-concept study, we investigated the effect of modulating dietary macronutrient composition according to muscle insulin-resistant (MIR) or liver insulin-resistant (LIR) phenotypes on cardiometabolic health. Women and men with MIR or LIR (n = 242, body mass index [BMI] 25-40 kg/m², 40-75 years) were randomized to phenotype diet (PhenoDiet) group A or B and followed a 12-week high-monounsaturated fatty acid (HMUFA) diet or low-fat, high-protein, and high-fiber diet (LFHP) (PhenoDiet group A, MIR/HMUFA and LIR/LFHP; PhenoDiet group B, MIR/LFHP and LIR/HMUFA). PhenoDiet group B showed no significant improvements in the primary outcome disposition index, but greater improvements in insulin sensitivity, glucose homeostasis, serum triacylglycerol, and C-reactive protein compared with PhenoDiet group A were observed. We demonstrate that modulating macronutrient composition within the dietary guidelines based on tissue-specific insulin resistance (IR) phenotype enhances cardiometabolic health improvements. Clinicaltrials.gov registration: NCT03708419, CCMO registration NL63768.068.17.

Quantifying the contribution of triglycerides to metabolic resilience through the mixed meal model

Despite the pivotal role played by elevated circulating triglyceride levels in the pathophysiology of cardio-metabolic diseases many of the indices used to quantify metabolic health focus on deviations in glucose and insulin alone. We present the Mixed Meal Model, a computational model describing the systemic interplay between triglycerides, free fatty acids, glucose, and insulin. We show that the Mixed Meal Model can capture deviations in the post-meal excursions of plasma glucose, insulin, and triglyceride that are indicative of features of metabolic resilience; quantifying insulin resistance and liver fat; validated by comparison to gold-standard measures. We also demonstrate that the Mixed Meal Model is generalizable, applying it to meals with diverse macro-nutrient compositions. In this way, by coupling triglycerides to the glucose-insulin system the Mixed Meal Model provides a more holistic assessment of metabolic resilience from meal response data, quantifying pre-clinical metabolic deteriorations that drive disease development in overweight and obesity.

Diverging metabolic effects of 2 energy-restricted diets differing in nutrient quality: a 12-week randomized controlled trial in subjects with abdominal obesity

BACKGROUND

Despite the established relation between energy restriction (ER) and metabolic health, the most beneficial nutrient composition of a weight-loss diet is still a subject of debate.

OBJECTIVES

The aim of the study was to examine the additional effects of nutrient quality on top of ER.

METHODS

A parallel-designed, 12-week 25% ER dietary intervention study was conducted (clinicaltrials.gov: NCT02194504). Participants aged 40-70 years with abdominal obesity were randomized over 3 groups: a 25% ER high-nutrient-quality diet (n = 40); a 25% ER low-nutrient-quality diet (n = 40); or a habitual diet (n = 30). Both ER diets were nutritionally adequate, and the high-nutrient-quality ER diet was enriched in MUFAs, n-3 PUFAs, fiber, and plant protein and reduced in fructose. Before and after the intervention, intrahepatic lipids, body fat distribution, fasting and postprandial responses to a mixed-meal shake challenge test of cardiometabolic risk factors, lipoproteins, vascular measurements, and adipose tissue transcriptome were assessed.

RESULTS

The high-nutrient-quality ER diet (-8.4 ± 3.2) induced 2.1 kg more weight loss (P = 0.007) than the low-nutrient-quality ER diet (-6.3 ± 3.9), reduced fasting serum total cholesterol (P = 0.014) and plasma triglycerides (P < 0.001), promoted an antiatherogenic lipoprotein profile, and induced a more pronounced decrease in adipose tissue gene expression of energy metabolism pathways than the low-quality ER diet. Explorative analyses showed that the difference in weight loss between the two ER diets was specifically present in insulin-sensitive subjects (HOMA-IR ≤ 2.5), in whom the high-nutrient-quality diet induced 3.9 kg more weight loss than the low-nutrient-quality diet.

CONCLUSIONS

A high-nutrient-quality 25% ER diet is more beneficial for cardiometabolic health than a low-nutrient-quality 25% ER diet. Overweight, insulin-sensitive subjects may benefit more from a high- than a low-nutrient-quality ER diet with respect to weight loss, due to potential attenuation of glucose-induced lipid synthesis in adipose tissue.

Effects of a 12-week whole-grain or refined wheat intervention on plasma acylcarnitines, bile acids and signaling lipids, and association with liver fat: A post-hoc metabolomics study of a randomized controlled trial

BACKGROUND

We previously showed that whole-grain wheat (WGW) consumption had beneficial effects on liver fat accumulation, as compared to refined wheat (RW). The mechanisms underlying these effects remain unclear.

OBJECTIVE

In this study, we investigated the effects of WGW vs. RW consumption on plasma metabolite levels to explore potential underlying mechanisms of the preventive effect of WGW consumption on liver fat accumulation.

METHODS

Targeted metabolomics of plasma obtained from a concluded 12-week double-blind, randomized controlled trial was performed. Fifty overweight or obese men and women aged 45-70 years with mildly elevated levels of plasma cholesterol were randomized to either 98 g/d of WGW or RW products. Before and after the intervention, a total of 89 fasting plasma metabolite concentrations including acylcarnitines, trimethylamine-N-oxide (TMAO), choline, betaine, bile acids, and signaling lipids were quantified by UPLC-MS/MS. Intrahepatic triglycerides (IHTG) were quantified by ¹H-MRS, and multiple liver markers, including circulating levels of β-hydroxybutyrate, alanine transaminase (ALT), aspartate transaminase (AST), γ-glutamyltransferase (γ-GT), serum amyloid A (SAA), and C-reactive protein, were assessed.

RESULTS

The WGW intervention increased plasma concentrations of four out of 52 signaling lipids-lysophosphatidic acid C18:2, lysophosphatidylethanolamine C18:1 and C18:2, and platelet-activating factor C18:2-and decreased concentrations of the signaling lipid lysophosphatidylglycerol C20:3 as compared to RW intervention, although these results were no longer statistically significant after false discovery rate (FDR) correction. Plasma concentrations of the other metabolites that we quantified were not affected by WGW or RW intervention. Changes in the above-mentioned metabolites were not correlated to change in IHTG upon the intervention.

CONCLUSION

Plasma acylcarnitines, bile acids, and signaling lipids were not robustly affected by the WGW or RW interventions, which makes them less likely candidates to be directly involved in the mechanisms that underlie the protective effect of WGW consumption or detrimental effect of RW consumption on liver fat accumulation.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [NCT02385149].

Comparative Analysis of the Effects of Fish Oil and Fenofibrate on Plasma Metabolomic Profiles in Overweight and Obese Individuals

SCOPE

The drug fenofibrate and dietary fish oils can effectively lower circulating triglyceride (TG) concentrations. However, a detailed comparative analysis of the effects on the plasma metabolome is missing.

METHODS AND RESULTS

Twenty overweight and obese subjects participate in a double-blind, cross-over intervention trial and receive in a random order 3.7 g day-1 n-3 fatty acids, 200 mg fenofibrate, or placebo treatment for 6 weeks. Four hundred twenty plasma metabolites are measured via gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). Among the treatments, 237 metabolites are significantly different, of which 22 metabolites change in the same direction by fish oil and fenofibrate, including a decrease in several saturated TG-species. Fenofibrate additionally changes 33 metabolites, including a decrease in total cholesterol, and total lysophosphatidylcholine (LPC), whereas 54 metabolites are changed by fish oil, including an increase in unsaturated TG-, LPC-, phosphatidylcholine-, and cholesterol ester-species. All q < 0.05.

CONCLUSION

Fenofibrate and fish oil reduce several saturated TG-species markedly. These reductions have been associated with a decreased risk for developing cardiovascular disease (CVD). Interestingly, fish oil consumption increases several unsaturated lipid species, which have also been associated with a reduced CVD risk. Altogether, this points towards the power of fish oil to change the plasma lipid metabolome in a potentially beneficial way.

Health Effects of Increasing Protein Intake Above the Current Population Reference Intake in Older Adults: A Systematic Review of the Health Council of the Netherlands

Whether older adults need more protein than younger adults is debated. The population reference intake for adults set by the European Food Safety Authority is 0.83 g/kg body weight (BW)/d based primarily on nitrogen balance studies, but the underlying data on health outcomes are outdated. An expert committee of the Health Council of the Netherlands conducted a systematic review (SR) of randomized controlled trials (RCTs) examining the effect of increased protein intake on health outcomes in older adults from the general population with an average habitual protein intake ≥0.8 g/(kg BW · d). Exposures were the following: 1) extra protein compared with no protein and 2) extra protein and physical exercise compared with physical exercise. Outcomes included lean body mass, muscle strength, physical performance, bone health, blood pressure, serum glucose and insulin, serum lipids, kidney function, and cognition. Data of >1300 subjects from 18 RCTs were used. Risk of bias was judged as high (n = 9) or "some concerns" (n = 9). In 7 of 18 RCTs, increased protein intake beneficially affected ≥1 of the tested outcome measures of lean body mass. For muscle strength, this applied to 3 of 8 RCTs in the context of physical exercise and in 1 of 7 RCTs without physical exercise. For the other outcomes, <30% (0-29%) of RCTs showed a statistically significant effect. The committee concluded that increased protein intake has a possible beneficial effect on lean body mass and, when combined with physical exercise, muscle strength; likely no effect on muscle strength when not combined with physical exercise, or on physical performance and bone health; an ambiguous effect on serum lipids; and that too few RCTs were available to allow for conclusions on the other outcomes. This SR provides insufficiently convincing data that increasing protein in older adults with a protein intake ≥0.8 g/(kg BW · d) elicits health benefits.

Abdominal adipose tissue radiodensity is associated with survival after colorectal cancer

BACKGROUND

Adipose tissue radiodensity may have prognostic importance for colorectal cancer (CRC) survival. Lower radiodensity is indicative of larger adipocytes, while higher radiodensity may represent adipocyte atrophy, inflammation, or edema.

OBJECTIVES

We investigated associations of adipose tissue radiodensity and longitudinal changes in adipose tissue radiodensity with mortality among patients with nonmetastatic CRC.

METHODS

In 3023 patients with stage I-III CRC, radiodensities of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were quantified from diagnostic computed tomography (CT) images. There were 1775 patients with follow-up images available. Cox proportional hazards models and restricted cubic splines were used to examine associations of at-diagnosis values and of longitudinal changes in VAT and SAT radiodensities with risks of death after adjusting for potential confounders, including body size and comorbidities.

RESULTS

VAT and SAT radiodensities were linearly associated with all-cause mortality: the HRs for death per SD increase were 1.21 (95% CI, 1.11-1.32) for VAT radiodensity and 1.18 (95% CI, 1.11-1.26) for SAT radiodensity. Changes in adipose tissue radiodensity had curvilinear associations with risks of death. The HR for an increase in VAT radiodensity of at least 1 SD was 1.53 (95% CI, 1.23-1.90), while the HR for a decrease of at least 1 SD was nonsignificant at 1.11 (95% CI, 0.84-1.47) compared with maintaining radiodensity within 1 SD of baseline. Similarly, increases (HR, 1.88; 95% CI, 1.48-2.40) but not decreases (HR, 1.20; 95% CI, 0.94-1.54) in SAT radiodensity significantly increased the risk of death compared with no change in radiodensity.

CONCLUSIONS

In patients with nonmetastatic CRC, adipose tissue radiodensity is a novel risk factor for total mortality that is independent of BMI and changes in body weight.

The PERSonalized Glucose Optimization Through Nutritional Intervention (PERSON) Study: Rationale, Design and Preliminary Screening Results

Background: It is well-established that the etiology of type 2 diabetes differs between individuals. Insulin resistance (IR) may develop in different tissues, but the severity of IR may differ in key metabolic organs such as the liver and skeletal muscle. Recent evidence suggests that these distinct tissue-specific IR phenotypes may also respond differentially to dietary macronutrient composition with respect to improvements in glucose metabolism.

Objective: The main objective of the PERSON study is to investigate the effects of an optimal vs. suboptimal dietary macronutrient intervention according to tissue-specific IR phenotype on glucose metabolism and other health outcomes.

Methods: In total, 240 overweight/obese (BMI 25 – 40 kg/m²) men and women (age 40 – 75 years) with either skeletal muscle insulin resistance (MIR) or liver insulin resistance (LIR) will participate in a two-center, randomized, double-blind, parallel, 12-week dietary intervention study. At screening, participants undergo a 7-point oral glucose tolerance test (OGTT) to determine the hepatic insulin resistance index (HIRI) and muscle insulin sensitivity index (MISI), classifying each participant as either “No MIR/LIR,” “MIR,” “LIR,” or “combined MIR/LIR.” Individuals with MIR or LIR are randomized to follow one of two isocaloric diets varying in macronutrient content and quality, that is hypothesized to be either an optimal or suboptimal diet, depending on their tissue-specific IR phenotype (MIR/LIR). Extensive measurements in a controlled laboratory setting as well as phenotyping in daily life are performed before and after the intervention. The primary study outcome is the difference in change in disposition index, which is the product of insulin sensitivity and first-phase insulin secretion, between participants who received their hypothesized optimal or suboptimal diet.

Discussion: The PERSON study is one of the first randomized clinical trials in the field of precision nutrition to test effects of a more personalized dietary intervention based on IR phenotype. The results of the PERSON study will contribute knowledge on the effectiveness of targeted nutritional strategies to the emerging field of precision nutrition, and improve our understanding of the complex pathophysiology of whole body and tissue-specific IR.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03708419, clinicaltrials.gov as NCT03708419.

Minor Changes in the Composition and Function of the Gut Microbiota During a 12-Week Whole Grain Wheat or Refined Wheat Intervention Correlate with Liver Fat in Overweight and Obese Adults

BACKGROUND

Whole grain wheat (WGW) products are advocated as a healthy choice when compared with refined wheat (RW). One proposed mechanism for these health benefits is via the microbiota, because WGW contains multiple fibers. WGW consumption has been proposed to ameliorate nonalcoholic fatty liver disease, in which microbiota might play a role.

OBJECTIVES

We investigated the effect of WGW compared with RW intervention on the fecal microbiota composition and functionality, and correlated intervention-induced changes in bacteria with changes in liver health parameters in adults with overweight or obesity.

METHODS

We used data of a 12-wk double-blind, randomized, controlled, parallel trial to examine the effects of a WGW (98 g/d) or RW (98 g/d) intervention on the secondary outcomes fecal microbiota composition, predicted microbiota functionality, and stool consistency in 37 women and men (aged 45-70 y, BMI 25-35 kg/m2). The changes in microbiota composition, measured using 16S ribosomal RNA gene sequencing, after a 12-wk intervention were analyzed with nonparametric tests, and correlated with changes in liver fat and circulating concentrations of liver enzymes including alanine transaminase, aspartate transaminase, γ-glutamyltransferase, and serum amyloid A.

RESULTS

The WGW intervention increased the mean (± SD) relative abundances of Ruminococcaceae_UCG-014 (baseline: 2.2 ± 4.6%, differential change over time (Δ) 0.51 ± 4.2%), Ruminiclostridium_9 (baseline: 0.065 ± 0.11%, Δ 0.054 ± 0.14%), and Ruminococcaceae_NK4A214_group (baseline: 0.37 ± 0.56%, Δ 0.17 ± 0.83%), and also the predicted pathway acetyl-CoA fermentation to butyrate II (baseline: 0.23 ± 0.062%, Δ 0.035 ± 0.059%), compared with the RW intervention (P values <0.05). A change in Ruminococcaceae_NK4A214_group was positively correlated with the change in liver fat, in both the WGW (ρ = 0.54; P = 0.026) and RW (ρ = 0.67; P = 0.024) groups.

CONCLUSIONS

In middle-aged overweight and obese adults, a 12-wk WGW intervention increased the relative abundance of a number of bacterial taxa from the family Ruminococcaceae and increased predicted fermentation pathways when compared with an RW intervention. Potential protective health effects of replacement of RW by WGW on metabolic organs, such as the liver, via modulation of the microbiota, deserve further investigation.This trial was registered at clinicaltrials.gov as NCT02385149.

Ayurvedic Herbal Preparation Supplementation Does Not Improve Metabolic Health in Impaired Glucose Tolerance Subjects; Observations from a Randomised Placebo Controlled Trial

The increased usage of alternative Ayurvedic treatments as potential health-beneficial therapies emphasizes the importance of studying its efficacy in sound placebo-controlled intervention trials. An example of such a traditional Ayurvedic herbal preparation is Mohana Choorna, a mixture composed of 20 different herbs and used to prevent and treat type 2-diabetes (T2D). We studied the efficacy of “Mohana Choorna” on T2D-related parameters in subjects with impaired glucose tolerance. In a double blind, placebo-controlled cross-over trial, 19 overweight (BMI > 27 kg/m²) subjects aged 50–70 years with an impaired glucose tolerance received two four-week interventions, i.e., herbal or placebo with a four-week wash-out between interventions. HbA1c, glucose, insulin, triglycerides, cholesterol, blood pressure and augmentation index were measured before and after both interventions at fasting and during a glucose tolerance test. After both interventions, urine was collected to measure treatment exposure using LCMS-based metabolomics and whole genome gene-expression in adipose tissue of 13 subjects. The herbal intervention did not affect plasma glucose triglycerides, cholesterol, blood pressure or the augmentation index but showed a trend towards an increased insulin, HOMA-IR and postprandial insulin levels (p = 0.054, p = 0.056 and p = 0.095 respectively). An increase in expression of inflammation-related gene sets in adipose tissue was observed after the herbal intervention compared to placebo. Urine metabolomic analysis did not reveal a correlation of the presence of specific plant metabolites with “health markers”. Our findings suggest that there is no substantiating evidence to claim that four weeks’ use of the Ayurvedic herbal supplement Mohana Choorna beneficially affects glucose homeostasis.

Discriminating Dietary Responses by Combining Transcriptomics and Metabolomics Data in Nutrition Intervention Studies

Scope

Combining different “omics” data types in a single, integrated analysis may better characterize the effects of diet on human health.

Methods and results

The performance of two data integration tools, similarity network fusion tool (SNFtool) and Data Integration Analysis for Biomarker discovery using Latent variable approaches for “Omics” (DIABLO; MixOmics), in discriminating responses to diet and metabolic phenotypes is investigated by combining transcriptomics and metabolomics datasets from three human intervention studies: a postprandial crossover study testing dairy foods (n = 7; study 1), a postprandial challenge study comparing obese and non‐obese subjects (n = 13; study 2); and an 8‐week parallel intervention study that assessed three diets with variable lipid content on fasting parameters (n = 39; study 3). In study 1, combining datasets using SNF or DIABLO significantly improve sample classification. For studies 2 and 3, the value of SNF integration depends on the dietary groups being compared, while DIABLO discriminates samples well but does not perform better than transcriptomic data alone.

Conclusion

The integration of associated “omics” datasets can help clarify the subtle signals observed in nutritional interventions. The performance of each integration tool is differently influenced by study design, size of the datasets, and sample size.

Transcriptomic signature of fasting in human adipose tissue

Little is known about gene regulation by fasting in human adipose tissue. Accordingly, the objective of this study was to investigate the effects of fasting on adipose tissue gene expression in humans. To that end, subcutaneous adipose tissue biopsies were collected from 11 volunteers 2 and 26 h after consumption of a standardized meal. For comparison, epididymal adipose tissue was collected from C57Bl/6J mice in the ab libitum-fed state and after a 16 h fast. The timing of sampling adipose tissue roughly corresponds with the near depletion of liver glycogen. Transcriptome analysis was carried out using Affymetrix microarrays. We found that, 1) fasting downregulated numerous metabolic pathways in human adipose tissue, including triglyceride and fatty acid synthesis, glycolysis and glycogen synthesis, TCA cycle, oxidative phosphorylation, mitochondrial translation, and insulin signaling; 2) fasting downregulated genes involved in proteasomal degradation in human adipose tissue; 3) fasting had much less pronounced effects on the adipose tissue transcriptome in humans than mice; 4) although major overlap in fasting-induced gene regulation was observed between human and mouse adipose tissue, many genes were differentially regulated in the two species, including genes involved in insulin signaling (PRKAG2, PFKFB3), PPAR signaling (PPARG, ACSL1, HMGCS2, SLC22A5, ACOT1), glycogen metabolism (PCK1, PYGB), and lipid droplets (PLIN1, PNPLA2, CIDEA, CIDEC). In conclusion, although numerous genes and pathways are regulated similarly by fasting in human and mouse adipose tissue, many genes show very distinct responses to fasting in humans and mice. Our data provide a useful resource to study adipose tissue function during fasting.

Fasting induces ANGPTL4 and reduces LPL activity in human adipose tissue

Objective

Studies in mice have shown that the decrease in lipoprotein lipase (LPL) activity in adipose tissue upon fasting is mediated by induction of the inhibitor ANGPTL4. Here, we aimed to validate this concept in humans by determining the effect of a prolonged fast on ANGPTL4 and LPL gene and protein expression in human subcutaneous adipose tissue.

Methods

Twenty-three volunteers ate a standardized meal at 18.00 h and fasted until 20.00 h the next day. Blood was drawn and periumbilical adipose tissue biopsies were collected 2 h and 26 h after the meal.

Results

Consistent with previous mouse data, LPL activity in human adipose tissue was significantly decreased by fasting (−60%), concurrent with increased ANGPTL4 mRNA (+90%) and decreased ANGPTL8 mRNA (−94%). ANGPTL4 protein levels in adipose tissue were also significantly increased by fasting (+46%), whereas LPL mRNA and protein levels remained unchanged. In agreement with the adipose tissue data, plasma ANGPTL4 levels increased upon fasting (+100%), whereas plasma ANGPTL8 decreased (−79%). Insulin, levels of which significantly decreased upon fasting, downregulated ANGPTL4 mRNA and protein in primary human adipocytes. By contrast, cortisol, levels of which significantly increased upon fasting, upregulated ANGPTL4 mRNA and protein in primary human adipocytes as did fatty acids.

Conclusion

ANGPTL4 levels in human adipose tissue are increased by fasting, likely via increased plasma cortisol and free fatty acids and decreased plasma insulin, resulting in decreased LPL activity.

This clinical trial was registered with identifier NCT03757767.

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24-h fast in humans reduces LPL activity in subcutaneous adipose tissue.

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24-h fast in humans increases adipose ANGPTL4 mRNA, protein, and plasma ANGPTL4 levels.

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Cortisol, fatty acids, and insulin regulate ANGPTL4 in vitro.

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ANGPTL4 mediates the reduction in adipose LPL activity during fasting.

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24-h fast in humans decreases adipose ANGPTL8 mRNA and plasma ANGPTL8 levels.

Whole Grain Wheat Consumption Affects Postprandial Inflammatory Response in a Randomized Controlled Trial in Overweight and Obese Adults with Mild Hypercholesterolemia in the Graandioos Study

BACKGROUND

Whole grain wheat (WGW) consumption is associated with health benefits in observational studies. However, WGW randomized controlled trial (RCT) studies show mixed effects.

OBJECTIVES

The health impact of WGW consumption was investigated by quantification of the body's resilience, which was defined as the "ability to adapt to a standardized challenge."

METHODS

A double-blind RCT was performed with overweight and obese (BMI: 25-35 kg/m2) men (n = 19) and postmenopausal women (n = 31) aged 45-70 y, with mildly elevated plasma total cholesterol (>5 mmol/L), who were randomly assigned to either 12-wk WGW (98 g/d) or refined wheat (RW). Before and after the intervention a standardized mixed-meal challenge was performed. Plasma samples were taken after overnight fasting and postprandially (30, 60, 120, and 240 min). Thirty-one biomarkers were quantified focusing on metabolism, liver, cardiovascular health, and inflammation. Linear mixed-models evaluated fasting compared with postprandial intervention effects. Health space models were used to evaluate intervention effects as composite markers representing resilience of inflammation, liver, and metabolism.

RESULTS

Postprandial biomarker changes related to liver showed decreased alanine aminotransferase by WGW (P = 0.03) and increased β-hydroxybutyrate (P = 0.001) response in RW. Postprandial changes related to inflammation showed increased C-reactive protein (P = 0.001), IL-6 (P = 0.02), IL-8 (P = 0.007), and decreased IL-1B (P = 0.0002) in RW and decreased C-reactive protein (P < 0.0001), serum amyloid A (P < 0.0001), IL-8 (P = 0.02), and IL-10 (P < 0.0001) in WGW. Health space visualization demonstrated diminished inflammatory (P < 0.01) and liver resilience (P < 0.01) by RW, whereas liver resilience was rejuvenated by WGW (P < 0.05).

CONCLUSIONS

Twelve-week 98 g/d WGW consumption can promote liver and inflammatory resilience in overweight and obese subjects with mildly elevated plasma cholesterol. The health space approach appeared appropriate to evaluate intervention effects as composite markers. This trial was registered at www.clinicaltrials.gov as NCT02385149.

Integrated Analys of High-Fat Challenge-Induced Changes in Blood Cell Whole-Genome Gene Expression

SCOPE

Several studies have examined the whole-genome gene expression response in blood cells to high-fat challenges with differing results. The study aims to identify consistently up- or downregulated genes and pathways in response to a high-fat challenge using several integration methods.

METHODS AND RESULTS

Three studies measuring the gene expression response to a high-fat challenge in white blood cells are evaluated for common trends using several integration methods. Overlap in differentially expressed genes between separate studies is examined, p-values of each separate study are combined, and data are analyzed as one merged dataset. Differentially expressed genes and pathways are compared between these methods. Selecting genes differentially expressed in the three separate studies result in 67 differentially expressed genes, primarily involved in circadian pathways. Using the Fishers p-value method and a merged dataset analysis, changes in 1097 and 1182 genes, respectively, are observed. The upregulated genes upon a high-fat challenge are related to inflammation, whereas downregulated genes are related to unfolded protein response, protein processing, cholesterol biosynthesis, and translation.

CONCLUSION

A general gene expression response to a high-fat challenge is identified. Compared to separate analyses, integrated analysis provides added value for the discovery of a consistent gene expression response.

Measuring phenotypic flexibility by transcriptome time-course analyses during challenge tests before and after energy restriction

Metabolic challenge tests may be a valuable tool to magnify the effects of diet on health. The use of transcriptomics enables a more extensive characterization of the effects of diet. The question remains whether transcriptome time-course analyses during challenge tests will deliver more information on the effect of diet than a static fasting measurement. A dietary intervention known to improve health is energy restriction (ER). Seventy-two healthy, overweight men and women aged 50-65 were subjected to an oral glucose tolerance test (OGTT) and a mixed-meal test (MMT) before and after 12 wk of a 20% ER diet or control diet. Whole-genome gene expression of peripheral blood mononuclear cells was performed before and after the intervention. This was done during fasting, during the OGTT at 30, 60, and 120 min, and during the MMT at 60, 120, 240, and 360 min. Upon ER, the OGTT resulted in a faster and more pronounced down-regulation in gene expression of oxidative phosphorylation, cell adhesion, and DNA replication compared with the control. The MMT showed less-consistent effects. The OGTT combined with transcriptomics can be used to measure dynamic cellular adaptation upon an intervention that cannot be determined with a static fasting measurement.-Van Bussel, I. P. G., Fazelzadeh, P., Frost, G. S., Rundle, M., Afman, L. A. Measuring phenotypic flexibility by transcriptome time-course analyses during challenge tests before and after energy restriction.

Disentangling the Effects of Monounsaturated Fatty Acids from Other Components of a Mediterranean Diet on Serum Metabolite Profiles: A Randomized Fully Controlled Dietary Intervention in Healthy Subjects at Risk of the Metabolic Syndrome

Scope

The Mediterranean (MED) diet has been associated with a decreased risk of cardiovascular diseases. It is unclear whether this health effect can be mainly contributed to high intakes of monounsaturated fatty acids (MUFA), characteristic for the MED diet, or whether other components of a MED diet also play an important role.

Methods and Results

A randomized fully controlled parallel trial is performed to examine the effects of the consumption of a saturated fatty acid rich diet, a MUFA‐rich diet, or a MED diet for 8 weeks on metabolite profiles, in 47 subjects at risk of the metabolic syndrome. A total of 162 serum metabolites are assessed before and after the intervention by using a targeted NMR platform. Fifty‐two metabolites are changed during the intervention (false discovery rate [FDR] p < 0.05). Both the MUFA and MED diet decrease exactly the same fractions of LDL, including particle number, lipid, phospholipid, and free cholesterol fraction (FDR p < 0.05). The MED diet additionally decreases the larger subclasses of very‐low‐density lipoprotein (VLDL), related VLDL fractions, VLDL‐triglycerides, and serum‐triglycerides (FDR p < 0.05).

Conclusion

The findings clearly demonstrate that the MUFA component is responsible for reducing LDL subclasses and fractions, and therefore causes an antiatherogenic lipid profile. Interestingly, consumption of the other components in the MED diet show additional health effects.

A 12-wk whole-grain wheat intervention protects against hepatic fat: the Graandioos study, a randomized trial in overweight subjects

Background

Whole-grain wheat (WGW) is described as nutritionally superior to refined wheat (RW) and thus advocated as the healthy choice, although evidence from intervention studies is often inconsistent. The liver, as the central organ in energy metabolism, might be an important target organ for WGW interventions.

Objective

The aim of this study was to investigate the potential benefits of WGW consumption compared with RW consumption on liver health and associated parameters.

Design

We performed a double-blind, parallel trial in which 50 overweight 45- to 70-y-old men and postmenopausal women were randomly allocated to a 12-wk intervention with either WGW (98 g/d) or RW (98 g/d) products. Before and after the intervention we assessed intrahepatic triglycerides (IHTGs) and fat distribution by proton magnetic resonance spectroscopy/magnetic resonance imaging, fecal microbiota composition, adipose tissue gene expression, and several fasting plasma parameters, as well as postprandial plasma lipids after a mixed meal.

Results

Fasting plasma cholesterol, triglycerides, nonesterified fatty acids, and insulin were not affected by RW or WGW intervention. We observed a substantial increase of 49.1% in IHTGs in the RW when compared with the WGW group (P = 0.033). Baseline microbiota composition could not predict the increase in IHTGs after RW, but gut microbiota diversity decreased in the RW group when compared with the WGW group (P = 0.010). In the WGW group, we observed increased postprandial triglyceride levels compared with the RW group (P = 0.020). In addition, the WGW intervention resulted in a trend towards lower fasting levels of the liver acute-phase proteins serum amyloid A (P = 0.057) and C-reactive protein (P = 0.064) when compared to the RW intervention.

Conclusions

A 12-wk RW intervention increases liver fat and might contribute to the development of nonalcoholic fatty liver disease, whereas a 12-wk 98-g/d WGW intervention prevents a substantial increase in liver fat. Our results show that incorporating feasible doses of WGW in the diet at the expense of RW maintains liver health. The study was registered at clinicaltrials.gov as NCT02385149.

Quercetin, but Not Epicatechin, Decreases Plasma Concentrations of Methylglyoxal in Adults in a Randomized, Double-Blind, Placebo-Controlled, Crossover Trial with Pure Flavonoids

Background

Methylglyoxal (MGO) is the most potent precursor of advanced glycation end products (AGEs). MGO and AGEs have been associated with diabetes, its complications, and other age-related diseases. Experimental studies have shown that the flavonoids quercetin and epicatechin are able to scavenge MGO and lower AGE formation.

Objective

Data on the effects of these flavonoids on MGO and AGE concentrations in humans are not yet available. We therefore investigated the effect of quercetin and epicatechin on the concentrations of MGO and AGEs in a post hoc analysis.

Methods

Thirty-seven apparently healthy, nonsmoking adults with a systolic blood pressure between 125 and 160 mm Hg at screening were included in a randomized, double-blind, placebo-controlled crossover trial. Participants ingested (-)-epicatechin (100 mg/d), quercetin 3-glucoside (160 mg/d), or placebo capsules for periods of 4 wk separated by 4-wk washout periods. Fasting blood samples were collected at the start and end of each intervention period. Liquid chromatography-tandem mass spectrometry was used to determine plasma concentrations of the dicarbonyl compounds MGO, glyoxal (GO), and 3-deoxyglucosone (3-DG) and free and protein-bound AGEs. Gene expression of glyoxalase 1 (GLO1), the enzyme involved in the degradation of MGO, was determined by either microarray or quantitative reverse transcriptase-polymerase chain reaction.

Results

The treatment effect (Δtreatment - Δplacebo) of quercetin on MGO was -40.2 nmol/L (95% CI: -73.6, -6.8 nmol/L; P = 0.019), a decrease of 11% from baseline values, whereas GO, 3-DG, and free and protein-bound AGEs did not change significantly. Epicatechin did not affect the concentrations of dicarbonyls and free and protein-bound AGEs. We did not find a significant change in expression of GLO1.

Conclusions

In apparently healthy (pre)hypertensive men and women, quercetin but not epicatechin decreased plasma MGO concentrations. Quercetin may potentially form a new treatment strategy for diseases in which MGO plays a pivotal role. This study was registered at clinicaltrials.gov as NCT01691404.

Biomarkers of food intake for cocoa and liquorice (products): a systematic review

Background

To unravel true links between diet and health, it is important that dietary exposure is accurately measured. Currently, mainly self-reporting methods (e.g. food frequency questionnaires and 24-h recalls) are used to assess food intake in epidemiological studies. However, these traditional instruments are subjective measures and contain well-known biases. Especially, estimating the intake of the group of confectionary products, such as products containing cocoa and liquorice, remains a challenge. The use biomarkers of food intake (BFIs) may provide a more objective measurement. However, an overview of current candidate biomarkers and their validity is missing for both cocoa- and liquorice-containing foods.

Objective

The purpose of the current study was to (1) identify currently described candidate BFIs for cocoa (products) and liquorice, (2) to evaluate the validity of these identified candidate BFIs and (3) to address further validation and/or identification work to be done.

Methods

This systematic review was based on a comprehensive literature search of three databases (PubMed, Scopus and ISI web of Science), to identify candidate BFIs. Via a second search step in the Human Metabolome Database (HMDB), the Food Database (FooDB) and Phenol-Explorer, the specificity of the candidate BFIs was evaluated, followed by an evaluation of the validity of the specific candidate BFIs, via pre-defined criteria.

Results

In total, 37 papers were included for cocoa and 8 papers for liquorice. For cocoa, 164 unique candidate BFIs were obtained, and for liquorice, four were identified in total. Despite the high number of identified BFIs for cocoa, none of the metabolites was specific. Therefore, the validity of these compounds was not further examined. For liquorice intake, 18-glycyrrhetinic acid (18-GA) was found to have the highest assumed validity.

Conclusions

For cocoa, specific BFIs were missing, mainly because the individual BFIs were also found in foods having a similar composition, such as tea (polyphenols) or coffee (caffeine). However, a combination of individual BFIs might lead to discriminating profiles between cocoa (products) and foods with a similar composition. Therefore, studies directly comparing the consumption of cocoa to these similar products are needed, enabling efforts to find a unique profile per product. For liquorice, we identified 18-GA as a promising BFI; however, important information on its validity is missing; thus, more research is necessary. Our findings indicate a need for more studies to determine acceptable BFIs for both cocoa and liquorice.

Pure flavonoid epicatechin and whole genome gene expression profiles in circulating immune cells in adults with elevated blood pressure: A randomised double-blind, placebo-controlled, crossover trial

Cocoa consumption has beneficial cardiometabolic effects, but underlying mechanisms remain unclear. Epicatechin, the cocoa major monomeric flavan-3-ol, is considered to contribute to these cardio-protective effects. We investigated effects of pure epicatechin supplementation on gene expression profiles of immune cells in humans. In a double blind, placebo-controlled cross-over trial, 32 (pre)hypertensive subjects aged 30 to 80, received two 4-week interventions, i.e. epicatechin (100mg/day) or placebo with a 4-week wash-out between interventions. Gene expression profiles of peripheral blood mononuclear cells were determined before and after both interventions. Epicatechin regulated 1180 genes, of which 234 differed from placebo. Epicatechin upregulated gene sets involved in transcription and tubulin folding and downregulated gene sets involved in inflammation, PPAR signalling and adipogenesis. Several negatively enriched genes within these gene sets were involved in insulin signalling. Most inhibited upstream regulators within the epicatechin intervention were cytokines or involved in inflammation. No upstream regulators were identified compared to placebo. Epicatechin, a cocoa flavan-3-ol, reduces gene expression involved in inflammation, PPAR-signalling and adipogenesis in immune cells. Effects were mild but our findings increase our understanding and provide new leads on how epicatechin rich products like cocoa may affect immune cells and exert cardiometabolic protective effects.

A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate

In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 μg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate.

Guidelines for Biomarker of Food Intake Reviews (BFIRev): how to conduct an extensive literature search for biomarker of food intake discovery

Identification of new biomarkers of food and nutrient intake has developed fast over the past two decades and could potentially provide important new tools for compliance monitoring and dietary intake assessment in nutrition and health science. In recent years, metabolomics has played an important role in identifying a large number of putative biomarkers of food intake (BFIs). However, the large body of scientific literature on potential BFIs outside the metabolomics area should also be taken into account. In particular, we believe that extensive literature reviews should be conducted and that the quality of all suggested biomarkers should be systematically evaluated. In order to cover the literature on BFIs in the most appropriate and consistent manner, there is a need for appropriate guidelines on this topic. These guidelines should build upon guidelines in related areas of science while targeting the special needs of biomarker methodology. This document provides a guideline for conducting an extensive literature search on BFIs, which will provide the basis to systematically validate BFIs. This procedure will help to prioritize future work on the identification of new potential biomarkers and on validating these as well as other biomarker candidates, thereby providing better tools for future studies in nutrition and health.

A scheme for a flexible classification of dietary and health biomarkers

Biomarkers are an efficient means to examine intakes or exposures and their biological effects and to assess system susceptibility. Aided by novel profiling technologies, the biomarker research field is undergoing rapid development and new putative biomarkers are continuously emerging in the scientific literature. However, the existing concepts for classification of biomarkers in the dietary and health area may be ambiguous, leading to uncertainty about their application. In order to better understand the potential of biomarkers and to communicate their use and application, it is imperative to have a solid scheme for biomarker classification that will provide a well-defined ontology for the field. In this manuscript, we provide an improved scheme for biomarker classification based on their intended use rather than the technology or outcomes (six subclasses are suggested: food compound intake biomarkers (FCIBs), food or food component intake biomarkers (FIBs), dietary pattern biomarkers (DPBs), food compound status biomarkers (FCSBs), effect biomarkers, physiological or health state biomarkers). The application of this scheme is described in detail for the dietary and health area and is compared with previous biomarker classification for this field of research.

Effect of energy restriction and physical exercise intervention on phenotypic flexibility as examined by transcriptomics analyses of mRNA from adipose tissue and whole body magnetic resonance imaging

Overweight and obesity lead to changes in adipose tissue such as inflammation and reduced insulin sensitivity. The aim of this study was to assess how altered energy balance by reduced food intake or enhanced physical activity affect these processes. We studied sedentary subjects with overweight/obesity in two intervention studies, each lasting 12 weeks affecting energy balance either by energy restriction (~20% reduced intake of energy from food) in one group, or by enhanced energy expenditure due to physical exercise (combined endurance‐ and strength‐training) in the other group. We monitored mRNA expression by microarray and mRNA sequencing from adipose tissue biopsies. We also measured several plasma parameters as well as fat distribution with magnetic resonance imaging and spectroscopy. Comparison of microarray and mRNA sequencing showed strong correlations, which were also confirmed using RT‐PCR. In the energy restricted subjects (body weight reduced by 5% during a 12 weeks intervention), there were clear signs of enhanced lipolysis as monitored by mRNA in adipose tissue as well as plasma concentration of free‐fatty acids. This increase was strongly related to increased expression of markers for M1‐like macrophages in adipose tissue. In the exercising subjects (glucose infusion rate increased by 29% during a 12‐week intervention), there was a marked reduction in the expression of markers of M2‐like macrophages and T cells, suggesting that physical exercise was especially important for reducing inflammation in adipose tissue with insignificant reduction in total body weight. Our data indicate that energy restriction and physical exercise affect energy‐related pathways as well as inflammatory processes in different ways, probably related to macrophages in adipose tissue.

A risk assessment-driven quantitative comparison of gene expression profiles in PBMCs and white adipose tissue of humans and rats after isoflavone supplementation

Quantitative insight into species differences in risk assessment is expected to reduce uncertainty and variability related to extrapolation from animals to humans. This paper explores quantification and comparison of gene expression data between tissues and species from intervention studies with isoflavones. Gene expression data from peripheral blood mononuclear cells (PBMCs) and white adipose tissue (WAT) after 8wk isoflavone interventions in postmenopausal women and ovariectomized F344 rats were used. A multivariate model was applied to quantify gene expression effects, which showed 3-5-fold larger effect sizes in rats compared to humans. For estrogen responsive genes, a 5-fold greater effect size was found in rats than in humans. For these genes, intertissue correlations (r = 0.23 in humans, r = 0.22 in rats) and interspecies correlation in WAT (r = 0.31) were statistically significant. Effect sizes, intertissue and interspecies correlations for some groups of genes within energy metabolism, inflammation and cell cycle processes were significant, but weak. Quantification of gene expression data reveals differences between rats and women in effect magnitude after isoflavone supplementation. For risk assessment, quantification of gene expression data and subsequent calculation of intertissue and interspecies correlations within biological pathways will further strengthen knowledge on comparability between tissues and species.

Differences in genome-wide gene expression response in peripheral blood mononuclear cells between young and old men upon caloric restriction

Background

Caloric restriction (CR) is considered to increase lifespan and to prevent various age-related diseases in different nonhuman organisms. Only a limited number of CR studies have been performed on humans, and results put CR as a beneficial tool to decrease risk factors in several age-related diseases. The question remains at what age CR should be implemented to be most effective with respect to healthy aging. The aim of our study was to elucidate the role of age in the transcriptional response to a completely controlled 30 % CR diet on immune cells, as immune response is affected during aging. Ten healthy young men, aged 20–28, and nine healthy old men, aged 64–85, were subjected to a 2-week weight maintenance diet, followed by 3 weeks of 30 % CR. Before and after 30 % CR, the whole genome gene expression in peripheral blood mononuclear cells (PBMCs) was assessed.

Results

Expression of 554 genes showed a different response between young and old men upon CR. Gene set enrichment analysis revealed a downregulation of gene sets involved in the immune response in young but not in old men. At baseline, immune response-related genes were higher expressed in old compared to young men. Upstream regulator analyses revealed that most potential regulators were controlling the immune response.

Conclusions

Based on the gene expression data, we theorise that a short period of CR is not effective in old men regarding immune-related pathways while it is effective in young men.

Trial registration

ClinicalTrials.gov, NCT00561145

Electronic supplementary material

The online version of this article (doi:10.1186/s12263-016-0528-0) contains supplementary material, which is available to authorized users.

Apolipoprotein E genotype status affects habitual human blood mononuclear cell gene expression and its response to fish oil intervention

SCOPE

People who carry the apolipoprotein E4 (APOE4) single nucleotide polymorphism have an increased risk of cardiovascular disease (CVD). Fish-oil supplementation may help in the prevention of CVD, though interindividual differences in the response to n-3 PUFAs have been observed. We aimed to assess the impact of APOE genotype on peripheral blood mononuclear cell whole genome gene expression at baseline and following a fish-oil intervention.

METHODS AND RESULTS

Participants received 6 months of fish-oil supplementation containing 1800 mg of eicosapentaenoic acid and docosahexaenoic acid per day. APOE genotype and peripheral blood mononuclear cell whole genome gene expression before and after supplementation were measured. We characterized the differences in gene expression profiles in carriers of APOE4 (N = 8) compared to noncarriers (N = 15). At baseline, 1320 genes were differentially expressed and the fish-oil supplementation differentially regulated 866 genes between APOE4 carriers and noncarriers. Gene set enrichment analysis showed that carriers had a higher gene expression of cholesterol biosynthesis and IFN signaling pathways. Fish-oil supplementation reduced expression of IFN-related genes in carriers only.

CONCLUSION

The increased expression of IFN signaling and cholesterol biosynthesis pathways might explain part of the association between APOE4 and CVD. Fish-oil supplementation may particularly benefit APOE4 carriers by decreasing expression of IFN-related genes.

High fat challenges with different fatty acids affect distinct atherogenic gene expression pathways in immune cells from lean and obese subjects

SCOPE

Early perturbations in vascular health can be detected by imposing subjects to a high fat (HF) challenge and measure response capacity. Subtle responses can be determined by assessment of whole-genome transcriptional changes. We aimed to magnify differences in health by comparing gene-expression changes in peripheral blood mononuclear cells toward a high MUFA or saturated fatty acids (SFA) challenge between subjects with different cardiovascular disease risk profiles and to identify fatty acid specific gene-expression pathways.

METHODS AND RESULTS

In a cross-over study, 17 lean and 15 obese men (50-70 years) received two 95 g fat shakes, high in SFAs or MUFAs. Peripheral blood mononuclear cell gene-expression profiles were assessed fasted and 4-h postprandially. Comparisons were made between groups and shakes. During fasting, 294 genes were significantly differently expressed between lean and obese. The challenge increased differences to 607 genes after SFA and 2516 genes after MUFA. In both groups, SFA decreased expression of cholesterol biosynthesis and uptake genes and increased cholesterol efflux genes. MUFA increased inflammatory genes and PPAR-α targets involved in β-oxidation.

CONCLUSION

Based upon gene-expression changes, we conclude that an HF challenge magnifies differences in health, especially after MUFA. Our findings also demonstrate how SFAs and MUFAs exert distinct effects on lipid handling pathways in immune cells.

Changes in gene expression in PBMCs profiles of PPARα target genes in obese and non-obese individuals during fasting

BACKGROUND

The prevalence of obesity has risen dramatically and the World Health Organization estimates that 700 million people will be obese worldwide by 2015. Approximately, 50% of the Brazilian population above 20 years of age is overweight, and 16% is obese.

AIM

This study aimed to evaluate the differences in the expression of PPARα target genes in human peripheral blood mononuclear cells (PBMCs) and free fatty acids (FFA) in obese and non-obese individuals after 24 h of fasting. We first presented evidence that Brazilian people exhibit expression changes in PPARα target genes in PBMCs under fasting conditions.

METHODS

Q-PCR was utilized to assess the mRNA expression levels of target genes.

RESULTS

In both groups, the FFA concentrations increased significantly after 24 h of fasting. The basal FFA mean concentration was two-fold higher in the obese group compared with the non-obese group. After fasting, all genes evaluated in this study showed increased expression levels compared with basal expression in both groups.

CONCLUSION

However, our results reveal no differences in gene expression between the obese and non-obese, more studies are necessary to precisely delineate the associated mechanisms, particularly those that include groups with different degrees of obesity and patients with diabetes mellitus type 2 because the expression of the main genes that are involved in β-oxidation and glucose level maintenance are affected by these factors.

Isoflavone supplement composition and equol producer status affect gene expression in adipose tissue: a double-blind, randomized, placebo-controlled crossover trial in postmenopausal women

BACKGROUND

Isoflavone supplements, consumed by women experiencing menopausal symptoms, are suggested to have positive effects on menopause-related adiposity and cardiovascular disease risk profile, but discussions about their safety are still ongoing.

OBJECTIVE

The objective was to study the effects of an 8-wk consumption of 2 different isoflavone supplements compared with placebo on whole-genome gene expression in the adipose tissue of postmenopausal women.

DESIGN

This double-blind, randomized, placebo-controlled crossover intervention consisted of 2 substudies, one with a low-genistein (LG) supplement (56% daidzein + daidzin, 16% genistein + genistin, and 28% glycitein + glycitin) and the other with a high-genistein (HG) supplement (49% daidzein + daidzin, 41% genistein + genistin, and 10% glycitein + glycitin). Both supplements provided ∼ 100 mg isoflavones/d (aglycone equivalents). After the 8-wk isoflavone and placebo period, whole-genome arrays were performed in subcutaneous adipose tissue of postmenopausal women (n = 26 after LG, n = 31 after HG). Participants were randomized by equol-producing phenotype, and data analysis was performed per substudy for equol producers and nonproducers separately.

RESULTS

Gene set enrichment analysis showed downregulation of expression of energy metabolism-related genes after LG supplementation (n = 24) in both equol-producing phenotypes and oppositely regulated expression for equol producers (down) and nonproducers (up) after HG supplementation (n = 31). Expression of inflammation-related genes was upregulated in equol producers but downregulated in nonproducers, independent of supplement type. Only 4.4-7.0% of the genes with significantly changed expression were estrogen responsive. Body weight, adipocyte size, and plasma lipid profile were not affected by isoflavone supplementation.

CONCLUSIONS

Effects of isoflavones on adipose tissue gene expression were influenced by supplement composition and equol-producing phenotype, whereas estrogen-responsive effects were lacking. LG isoflavone supplementation resulted in a caloric restriction-like gene expression profile for both producer phenotypes and pointed toward a potential beneficial effect, whereas both supplements induced anti-inflammatory gene expression in equol producers. The study was registered at clinicaltrials.gov as NCT01556737.

Increasing protein intake modulates lipid metabolism in healthy young men and women consuming a high-fat hypercaloric diet

The objective of this study was to evaluate the effect of increasing protein intake, at the expense of carbohydrates, on intrahepatic lipids (IHLs), circulating triglycerides (TGs), and body composition in healthy humans consuming a high-fat, hypercaloric diet. A crossover randomized trial with a parallel control group was performed. After a 2-wk run-in period, participants were assigned to either the control diet [n = 10; 27.8 energy percent (en%) fat, 16.9 en% protein, 55.3 en% carbohydrates] for 4 wk or a high-fat, hypercaloric diet (n = 17; >2 MJ/d) crossover trial with 2 periods of 2 wk, with either high-protein (HP) (37.7 en% fat, 25.7 en% protein, 36.6 en% carbohydrates) or normal-protein (NP) (39.4 en% fat, 15.4 en% protein, 45.2 en% carbohydrates) content. Measurements were performed after 2 wk of run-in (baseline), 2 wk of intervention (period 1), and 4 wk of intervention (period 2). A trend toward lower IHL and plasma TG concentrations during the HP condition compared with the NP condition was observed (IHL: 0.35 ± 0.04% vs. 0.51 ± 0.08%, P = 0.08; TG: 0.65 ± 0.03 vs. 0.77 ± 0.05 mmol/L, P = 0.07, for HP and NP, respectively). Fat mass was significantly lower (10.6 ± 1.72 vs. 10.9 ± 1.73 kg; P = 0.02) with the HP diet than with the NP diet, whereas fat-free mass was higher (55.7 ± 2.79 vs. 55.2 ± 2.80 kg; P = 0.003). This study indicated that an HP, high-fat, hypercaloric diet affects lipid metabolism. It tends to lower the IHL and circulating TG concentrations and significantly lowers fat mass and increases fat-free mass compared with an NP, high-fat, hypercaloric diet. This trail was registered at www.clinicaltrials.gov as NCT01354626.

Postprandial fatty acid specific changes in circulating oxylipins in lean and obese men after high-fat challenge tests

SCOPE

Circulating oxylipins may affect peripheral tissues and are assumed to play an important role in endothelial function. They are esterified in triglyceride-rich lipoproteins that are increased after a high-fat (HF) meal, depending on BMI and fatty acid (FA) type. Yet, it is unclear which oxylipins appear in circulation after HF meals differing in FA composition.

METHODS AND RESULTS

In a double-blind randomized crossover challenge study, we characterized the postprandial oxylipin response after different HF challenges in lean and obese men receiving HF milkshakes, either high in saturated FAs (SFA), monounsaturated FAs (MUFA), or omega 3 (n-3) polyunsaturated FAs (PUFA). Plasma oxylipin profiles were significantly altered at 2 and 4 h after shake consumption when compared to baseline. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived oxylipins increased after n-3 PUFA shake consumption. MUFA shake consumption increased levels of cytochrome P450 mediated oxylipins. SFA shake consumption led to strong increases in linoleic acid (LA) derived HODEs. No differences were observed between lean and obese individuals at baseline and after any shake consumption.

CONCLUSION

We are the first demonstrating acute effects on circulating oxylipins after HF meal challenges. These changes were strongly influenced by different dietary FAs and may affect endothelial function.

Estrogen receptor-mediated effects of isoflavone supplementation were not observed in whole-genome gene expression profiles of peripheral blood mononuclear cells in postmenopausal, equol-producing women

Isoflavones (genistein, daidzein, and glycitein) are suggested to have benefits as well as risks for human health. Approximately one-third of the Western population is able to metabolize daidzein into the more potent metabolite equol. Having little endogenous estradiol, equol-producing postmenopausal women who use isoflavone supplements to relieve their menopausal symptoms could potentially be at high risk of adverse effects of isoflavone supplementation. The current trial aimed to study the effects of intake of an isoflavone supplement rich in daidzein compared with placebo on whole-genome gene expression profiles of peripheral blood mononuclear cells (PBMCs) in equol-producing, postmenopausal women. Thirty participants received an isoflavone supplement or a placebo for 8 wk each in a double-blind, randomized cross-over design. The isoflavone supplement was rich in daidzein (60%) and provided 94 mg isoflavones (aglycone equivalents) daily. Gene expression in PBMCs was significantly changed (P < 0.05) in 357 genes after the isoflavone intervention compared with placebo. Gene set enrichment analysis revealed downregulated clusters of gene sets involved in inflammation, oxidative phosphorylation, and cell cycle. The expression of estrogen receptor (ER) target genes and gene sets related to ER signaling were not significantly altered, which may be explained by the low ERα and ERβ expression in PBMCs. The observed downregulated gene sets point toward potential beneficial effects of isoflavone supplementation with respect to prevention of cancer and cardiovascular disease. However, whether ER-related effects of isoflavones are beneficial or harmful should be studied in tissues that express ERs.

A high-fat SFA, MUFA, or n3 PUFA challenge affects the vascular response and initiates an activated state of cellular adherence in lean and obese middle-aged men

BMI and fatty acid type affect postprandial metabolic TG responses, but whether these factors also affect vascular, inflammatory, and leukocyte adherence responses remains unclear. We therefore compared those postprandial responses between lean and obese men after 3 high-fat challenges differing in fatty acid composition. In a crossover double-blind study, 18 lean (BMI: 18-25 kg/m(2)) and 18 obese (BMI >29 kg/m(2)) middle-aged men received 3 isocaloric high-fat milkshakes containing 95 g fat (88% of energy), either high in SFAs (54% of energy/total fat), MUFAs (83% of energy/total fat), or n3 (omega-3) PUFAs (40% of energy/total fat). Hemodynamics, augmentation index (AIX), leukocyte cell surface adhesion markers, and plasma cytokines involved in vascular adherence, coagulation, and inflammation were measured before and after consumption of the milkshakes. In both groups and after all shakes were consumed, AIX decreased; plasma soluble intercellular adhesion molecule (sICAM) 1, sICAM3, soluble vascular cell adhesion molecule (sVCAM) 1, and interleukin-8 increased; monocyte CD11a, CD11b, and CD621 expression increased; neutrophil CD11a, CD11b, and CD621 expression increased; and lymphocyte CD62l expression increased (P < 0.05). Lymphocyte CD11a and CD11b expression decreased in lean participants after consumption of all shakes but did not change in obese participants (P < 0.05). Obese participants had a less pronounced decrease in heart rate after the consumption of all shakes (P < 0.05). MUFA consumption induced a more pronounced decrease in blood pressure and AIX compared with the other milkshakes in both lean and obese participants (P < 0.05). High-fat consumption initiates an activated state of cellular adherence and an atherogenic milieu. This response was independent of fatty acid type consumed or of being lean or obese, despite the clear differences in postprandial TG responses between the groups and different milkshakes. These findings suggest that in addition to increased TGs, other mechanisms are involved in the high-fat consumption-induced activated state of cellular adherence.

Vascular and inflammatory high fat meal responses in young healthy men; a discriminative role of IL-8 observed in a randomized trial

Background

High fat meal challenges are known to induce postprandial low-grade inflammation and endothelial dysfunction. This assumption is largely based on studies performed in older populations or in populations with a progressed disease state and an appropriate control meal is often lacking. Young healthy individuals might be more resilient to such challenges. We therefore aimed to characterize the vascular and inflammatory response after a high fat meal in young healthy individuals.

Methods

In a double-blind randomized cross-over intervention study, we used a comprehensive phenotyping approach to determine the vascular and inflammatory response after consumption of a high fat shake and after an average breakfast shake in 20 young healthy subjects. Both interventions were performed three times.

Results

Many features of the vascular postprandial response, such as FMD, arterial stiffness and micro-vascular skin blood flow were not different between shakes. High fat/high energy shake consumption was associated with a more pronounced increase in blood pressure, heart rate, plasma concentrations of IL-8 and PBMCs gene expression of IL-8 and CD54 (ICAM-1), whereas plasma concentrations of sVCAM1 were decreased compared to an average breakfast.

Conclusion

Whereas no difference in postprandial response were observed on classical markers of endothelial function, we did observe differences between consumption of a HF/HE and an average breakfast meal on blood pressure and IL-8 in young healthy volunteers. IL-8 might play an important role in dealing with high fat challenges and might be an early marker for endothelial stress, a stage preceding endothelial dysfunction.

Trial Registration

ClinicalTrials.gov NCT00766623