Analysis of the SYSDIET Healthy Nordic Diet randomized trial based on metabolic profiling reveal beneficial effects on glucose metabolism and blood lipids.

BACKGROUND & AIMS: Intake assessment in multicenter trials is challenging, yet important for accurate outcome evaluation. The present study aimed to characterize a multicenter randomized controlled trial with a healthy Nordic diet (HND) compared to a Control diet (CD) by plasma and urine metabolic profiles and to associate them with cardiometabolic markers. METHODS: During 18-24 weeks of intervention, 200 participants with metabolic syndrome were advised at six centres to eat either HND (e.g. whole-grain products, berries, rapeseed oil, fish and low-fat dairy) or CD while being weight stable. Of these 166/159 completers delivered blood/urine samples. Metabolic profiles of fasting plasma and 24 h pooled urine were analysed to identify characteristic diet-related patterns. Principal components analysis (PCA) scores (i.e. PC1 and PC2 scores) were used to test their combined effect on blood glucose response (primary endpoint), serum lipoproteins, triglycerides, and inflammatory markers. RESULTS: The profiles distinguished HND and CD with AUC of 0.96 ± 0.03 and 0.93 ± 0.02 for plasma and urine, respectively, with limited heterogeneity between centers, reflecting markers of key foods. Markers of fish, whole grain and polyunsaturated lipids characterized HND, while CD was reflected by lipids containing palmitoleic acid. The PC1 scores of plasma metabolites characterizing the intervention is associated with HDL (ß = 0.05; 95% CI: 0.02, 0.08; P = 0.001) and triglycerides (ß = -0.06; 95% CI: -0.09, -0.03; P < 0.001). PC2 scores were related with glucose metabolism (2 h Glucose, ß = 0.1; 95% CI: 0.05, 0.15; P < 0.001), LDL (ß = 0.06; 95% CI: 0.01, 0.1; P = 0.02) and triglycerides (ß = 0.11; 95% CI: 0.06, 0.15; P < 0.001). For urine, the scores were related with LDL cholesterol. CONCLUSIONS: Plasma and urine metabolite profiles from SYSDIET reflected good compliance with dietary recommendations across the region. The scores of metabolites characterizing the diets associated with outcomes related with cardio-metabolic risk. Our analysis therefore offers a novel way to approach a per protocol analysis with a balanced compliance assessment in larger multicentre dietary trials. The study was registered at clinicaltrials.gov with NCT00992641.

Grains - a major source of sustainable protein for health.

Cereal grains are the main dietary source of energy, carbohydrates, and plant proteins world-wide. Currently, only 41% of grains are used for human consumption, and up to 35% are used for animal feed. Cereals have been overlooked as a source of environmentally sustainable and healthy plant proteins and could play a major role in transitioning towards a more sustainable food system for healthy diets. Cereal plant proteins are of good nutritional quality, but lysine is often the limiting amino acid. When consumed as whole grains, cereals provide health-protecting components such as dietary fiber and phytochemicals. Shifting grain use from feed to traditional foods and conceptually new foods and ingredients could improve protein security and alleviate climate change. Rapid development of new grain-based food ingredients and use of grains in new food contexts, such as dairy replacements and meat analogues, could accelerate the transition. This review discusses recent developments and outlines future perspectives for cereal grain use.

An Isocaloric Nordic Diet Modulates RELA and TNFRSF1A Gene Expression in Peripheral Blood Mononuclear Cells in Individuals with Metabolic Syndrome-A SYSDIET Sub-Study.

A healthy dietary pattern is associated with a lower risk of metabolic syndrome (MetS) and reduced inflammation. To explore this at the molecular level, we investigated the effect of a Nordic diet (ND) on changes in the gene expression profiles of inflammatory and lipid-related genes in peripheral blood mononuclear cells (PBMCs) of individuals with MetS. We hypothesized that the intake of an ND compared to a control diet (CD) would alter the expression of inflammatory genes and genes involved in lipid metabolism. The individuals with MetS underwent an 18/24-week randomized intervention to compare a ND with a CD. Eighty-eight participants (66% women) were included in this sub-study of the larger SYSDIET study. Fasting PBMCs were collected before and after the intervention and changes in gene expression levels were measured using TaqMan Array Micro Fluidic Cards. Forty-eight pre-determined inflammatory and lipid related gene transcripts were analyzed. The expression level of the gene tumor necrosis factor (TNF) receptor superfamily member 1A (TNFRSF1A) was down-regulated (p = 0.004), whereas the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) subunit, RELA proto-oncogene, was up-regulated (p = 0.016) in the ND group compared to the CD group. In conclusion, intake of an ND in individuals with the MetS may affect immune function.

Healthy Nordic Diet Modulates the Expression of Genes Related to Mitochondrial Function and Immune Response in Peripheral Blood Mononuclear Cells from Subjects with Metabolic Syndrome-A SYSDIET Sub-Study.

SCOPE: To explore the effect of a healthy Nordic diet on the global transcriptome profile in peripheral blood mononuclear cells (PBMCs) of subjects with metabolic syndrome. METHODS AND RESULTS: Subjects with metabolic syndrome undergo a 18/24 week randomized intervention study comparing an isocaloric healthy Nordic diet with an average habitual Nordic diet served as control (SYSDIET study). Altogether, 68 participants are included. PBMCs are obtained before and after intervention and total RNA is subjected to global transcriptome analysis. 1302 probe sets are differentially expressed between the diet groups (p-value < 0.05). Twenty-five of these are significantly regulated (FDR q-value < 0.25) and are mainly involved in mitochondrial function, cell growth, and cell adhesion. The list of 1302 regulated probe sets is subjected to functional analyses. Pathways and processes involved in the mitochondrial electron transport chain, immune response, and cell cycle are downregulated in the healthy Nordic diet group. In addition, gene transcripts with common motifs for 42 transcription factors, including NFR1, NFR2, and NF-κB, are downregulated in the healthy Nordic diet group. CONCLUSION: These results suggest that benefits of a healthy diet may be mediated by improved mitochondrial function and reduced inflammation.

Recommendations for characterization and reporting of dietary fibers in nutrition research.

Dietary fiber (DF) comprises a wide range of naturally occurring and modified materials with substantial variations in physical and chemical properties and potential physiologic effects. Although nutrition studies testing the effects of DF usually provide extensive detail on the physiologic responses, many still fail to adequately report the type and properties of the DF itself. This weakens the ability to directly replicate and compare studies and to establish structure-function relations. We outline the factors that affect DF functionality and provide 4 overarching recommendations for the characterization and reporting of DF preparations and DF-containing foods in nutrition research. These relate to 1) undertaking characterization methods that reflect the study hypothesis; 2) adequate reporting of DF source, quantity, and composition; 3) measurement of DF rheological properties; and 4) estimation of the DF fermentation rate and extent. Importantly, the food matrix of the test products should also be considered, because this can influence DF functionality and hence the apparent DF efficacy for health-relevant outcomes. Finally, we point out differences in DF functionality to be considered in acute and longer-term trials, the need to design the control treatment according to the research question, and the importance of reporting the amount and type of DF in the background diet.

A review of the characteristics of dietary fibers relevant to appetite and energy intake outcomes in human intervention trials.

Background: Many intervention studies have tested the effect of dietary fibers (DFs) on appetite-related outcomes, with inconsistent results. However, DFs comprise a wide range of compounds with diverse properties, and the specific contribution of these to appetite control is not well characterized.Objective: The influence of specific DF characteristics [i.e., viscosity, gel-forming capacity, fermentability, or molecular weight (MW)] on appetite-related outcomes was assessed in healthy humans.Design: Controlled human intervention trials that tested the effects of well-characterized DFs on appetite ratings or energy intake were identified from a systematic search of literature. Studies were included only if they reported 1) DF name and origin and 2) data on viscosity, gelling properties, fermentability, or MW of the DF materials or DF-containing matrixes.Results: A high proportion of the potentially relevant literature was excluded because of lack of adequate DF characterization. In total, 49 articles that met these criteria were identified, which reported 90 comparisons of various DFs in foods, beverages, or supplements in acute or sustained-exposure trials. In 51 of the 90 comparisons, the DF-containing material of interest was efficacious for ≥1 appetite-related outcome. Reported differences in material viscosity, MW, or fermentability did not clearly correspond to differences in efficacy, whereas gel-forming DF sources were consistently efficacious (but with very few comparisons).Conclusions: The overall inconsistent relations of DF properties with respect to efficacy may reflect variation in measurement methodology, nature of the DF preparation and matrix, and study designs. Methods of DF characterization, incorporation, and study design are too inconsistent to allow generalized conclusions about the effects of DF properties on appetite and preclude the development of reliable, predictive, structure-function relations. Improved standards for characterization and reporting of DF sources and DF-containing materials are strongly recommended for future studies on the effects of DF on human physiology. This trial was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42015015336.

Effects of a healthy Nordic diet on gene expression changes in peripheral blood mononuclear cells in response to an oral glucose tolerance test in subjects with metabolic syndrome: a SYSDIET sub-study.

BACKGROUND: Diet has a great impact on the risk of developing features of metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and cardiovascular diseases (CVD). We evaluated whether a long-term healthy Nordic diet (ND) can modify the expression of inflammation and lipid metabolism-related genes in peripheral blood mononuclear cells (PBMCs) during a 2-h oral glucose tolerance test (OGTT) in individuals with MetS. METHODS: A Nordic multicenter randomized dietary study included subjects (n = 213) with MetS, randomized to a ND group or a control diet (CD) group applying an isocaloric study protocol. In this sub-study, we included subjects (n = 89) from three Nordic centers: Kuopio (n = 26), Lund (n = 30), and Oulu (n = 33) with a maximum weight change of ±4 kg, high-sensitivity C-reactive protein concentration ≤10 mg L(-1), and baseline body mass index <39 kg m(-2). PBMCs were isolated, and the mRNA gene expression analysis was measured by quantitative real-time polymerase chain reaction (qPCR). We analyzed the mRNA expression changes of 44 genes before and after a 2hOGTT at the beginning and the end of the intervention. RESULTS: The healthy ND significantly down-regulated the expression of toll-like receptor 4 (TLR4), interleukin 18 (IL18), and thrombospondin receptor (CD36) mRNA transcripts and significantly up-regulated the expression of peroxisome proliferator-activated receptor delta (PPARD) mRNA transcript after the 2hOGTT compared to the CD. CONCLUSIONS: A healthy ND is able to modify the gene expression in PBMCs after a 2hOGTT. However, more studies are needed to clarify the biological and clinical relevance of these findings.

Fiber content of diet affects exhaled breath volatiles in fasting and postprandial state in a pilot crossover study.

Our pilot study examined the potential of exhaled breath analysis in studying the metabolic effects of dietary fiber (DF). We hypothesized that a high-fiber diet (HFD) containing whole grain rye changes volatile organic compound (VOC) levels in exhaled breath and that consuming a single meal affects these levels. Seven healthy men followed a week-long low-fiber diet (17 g/d) and HFD (44 g/d) in a randomized crossover design. A test meal containing 50 g of the available carbohydrates from wheat bread was served as breakfast after each week. Alveolar exhaled breath samples were analyzed at fasting state and 30, 60, and 120 minutes after this meal parallel to plasma glucose, insulin, and serum lipids. We used solid-phase microextraction and gas chromatography-mass spectrometry for detecting changes in 15 VOCs. These VOCs were acetone, ethanol, 1-propanol, 2-propanol, 1-butanol, acetic acid, propionic acid, butyric acid, valeric acid, isovaleric acid, 2-methylbutyric acid, hexanoic acid, acetoin, diacetyl, and phenol. Exhaled breath 2-methylbutyric acid in the fasting state and 1-propanol at 120 minutes decreased (P = .091 for both) after an HFD. Ingestion of the test meal increased ethanol, 1-propanol, acetoin, propionic acid, and butyric acid levels while reducing acetone, 1-butanol, diacetyl, and phenol levels. Both DF diet content and having a single meal affected breathVOCs. Exploring exhaled breath further could help to develop tools for monitoring the metabolic effects of DF.

Cross-linking of sodium caseinate-structured emulsion with transglutaminase alters postprandial metabolic and appetite responses in healthy young individuals.

The physico-chemical and interfacial properties of fat emulsions influence lipid digestion and may affect postprandial responses. The aim of the present study was to determine the effects of the modification of the interfacial layer of a fat emulsion by cross-linking on postprandial metabolic and appetite responses. A total of fifteen healthy individuals (26.5 (sem 6.9) years and BMI 21.9 (sem 2.0) kg/m2) participated in a cross-over design experiment in which they consumed two isoenergetic (1924 kJ (460 kcal)) and isovolumic (250 g) emulsions stabilised with either sodium caseinate (Cas) or transglutaminase-cross-linked sodium caseinate (Cas-TG) in a randomised order. Blood samples were collected from the individuals at baseline and for 6 h postprandially for the determination of serum TAG and plasma NEFA, cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), glucose and insulin responses. Appetite was assessed using visual analogue scales. Postprandial TAG and NEFA responses and gastric emptying (GE) rates were comparable between the emulsions. CCK increased more after the ingestion of Cas-TG than after the ingestion of Cas (P< 0.05), while GLP-1 responses did not differ between the two test emulsions. Glucose and insulin profiles were lower after consuming Cas-TG than after consuming Cas (P< 0.05). The overall insulin, glucose and CCK responses, expressed as areas above/under the curve, did not differ significantly between the Cas and Cas-TG meal conditions. Satiety ratings were reduced and hunger, desire to eat and thirst ratings increased more after the ingestion of Cas-TG than after the ingestion of Cas (P< 0.05). The present results suggest that even a subtle structural modification of the interfacial layer of a fat emulsion can alter the early postprandial profiles of glucose, insulin, CCK, appetite and satiety through decreased protein digestion without affecting significantly on GE or overall lipid digestion.

Healthy Nordic diet downregulates the expression of genes involved in inflammation in subcutaneous adipose tissue in individuals with features of the metabolic syndrome.

BACKGROUND: Previously, a healthy Nordic diet (ND) has been shown to have beneficial health effects close to those of Mediterranean diets. OBJECTIVE: The objective was to explore whether the ND has an impact on gene expression in abdominal subcutaneous adipose tissue (SAT) and whether changes in gene expression are associated with clinical and biochemical effects. DESIGN: Obese adults with features of the metabolic syndrome underwent an 18- to 24-wk randomized intervention study comparing the ND with the control diet (CD) (the SYSDIET study, carried out within Nordic Centre of Excellence of the Systems Biology in Controlled Dietary Interventions and Cohort Studies). The present study included participants from 3 Nordic SYSDIET centers [Kuopio (n = 20), Lund (n = 18), and Oulu (n = 18)] with a maximum weight change of ±4 kg, highly sensitive C-reactive protein concentration <10 mg/L at the beginning and the end of the intervention, and baseline body mass index (in kg/m²) <38. SAT biopsy specimens were obtained before and after the intervention and subjected to global transcriptome analysis with Gene 1.1 ST Arrays (Affymetrix). RESULTS: Altogether, 128 genes were differentially expressed in SAT between the ND and CD (nominal P < 0.01; false discovery rate, 25%). These genes were overrepresented in pathways related to immune response (adjusted P = 0.0076), resulting mainly from slightly decreased expression in the ND and increased expression in the CD. Immune-related pathways included leukocyte trafficking and macrophage recruitment (e.g., interferon regulatory factor 1, CD97), adaptive immune response (interleukin32, interleukin 6 receptor), and reactive oxygen species (neutrophil cytosolic factor 1). Interestingly, the regulatory region of the 128 genes was overrepresented for binding sites for the nuclear transcription factor κB. CONCLUSION: A healthy Nordic diet reduces inflammatory gene expression in SAT compared with a control diet independently of body weight change in individuals with features of the metabolic syndrome.

A dietary biomarker approach captures compliance and cardiometabolic effects of a healthy Nordic diet in individuals with metabolic syndrome.

Assessment of compliance with dietary interventions is necessary to understand the observed magnitude of the health effects of the diet per se. To avoid reporting bias, different dietary biomarkers (DBs) could be used instead of self-reported data. However, few studies investigated a combination of DBs to assess compliance and its influence on cardiometabolic risk factors. The objectives of this study were to use a combination of DBs to assess compliance and to investigate how a healthy Nordic diet (ND) influences cardiometabolic risk factors in participants with high apparent compliance compared with the whole study population. From a recently conducted isocaloric randomized trial, SYSDIET (Systems Biology in Controlled Dietary Interventions and Cohort Studies), in 166 individuals with metabolic syndrome, several DBs were assessed to reflect different key components of the ND: canola oil (serum phospholipid α-linolenic acid), fatty fish [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)], vegetables (plasma ß-carotene), and whole grains (plasma alkylresorcinols). High-fat dairy intake (expectedly low in the ND) was reflected by serum pentadecanoic acid. All participants with biomarker data (n = 154) were included in the analyses. Biomarkers were combined by using a biomarker rank score (DB score) and principal component analysis (PCA). The DB score was then used to assess compliance. During the intervention, median concentrations of alkylresorcinols, α-linolenic acid, EPA, and DHA were >25% higher in the ND individuals than in the controls (P < 0.05), whereas median concentrations of pentadecanoic acid were 14% higher in controls (P < 0.05). Median DB score was 57% higher in the ND than in controls (P < 0.001) during the intervention, and participants were ranked similarly by DB score and PCA score. Overall, estimates of group difference in cardiometabolic effects generally appeared to be greater among compliant participants than in the whole study population (e.g., estimates of treatment effects on blood pressure and lipoproteins were ∼1.5- to 2-fold greater in the most compliant participants), suggesting that poor compliance attenuated the dietary effects. With adequate consideration of their limitations, DB combinations (e.g., DB score) could be useful for assessing compliance in intervention studies investigating cardiometabolic effects of healthy dietary patterns. The study was registered at clinicaltrials.gov as NCT00992641.

Effects of a healthy Nordic diet on plasma 25-hydroxyvitamin D concentration in subjects with metabolic syndrome: a randomized, [corrected] controlled trial (SYSDIET).

PURPOSE: At northern latitudes, vitamin D is not synthesized endogenously during winter, causing low plasma 25-hydroxyvitamin D (25(OH)D) concentrations. Therefore, we evaluated the effects of a healthy Nordic diet based on Nordic nutrition recommendations (NNR) on plasma 25(OH)D and explored its dietary predictors. METHODS: In a Nordic multi-centre trial, subjects (n = 213) with metabolic syndrome were randomized to a control or a healthy Nordic diet favouring fish (≥300 g/week, including ≥200 g/week fatty fish), whole-grain products, berries, fruits, vegetables, rapeseed oil and low-fat dairy products. Plasma 25(OH)D and parathyroid hormone were analysed before and after 18- to 24-week intervention. RESULTS: At baseline, 45 % had vitamin D inadequacy (<50 nmol/l), whereas 8 % had deficiency (<25 nmol/l). Dietary vitamin D intake was increased by the healthy Nordic diet (P < 0.001). The healthy Nordic and the control diet reduced the prevalence of vitamin D inadequacy by 42 % (P < 0.001) and 19 % (P = 0.002), respectively, without between-group difference (P = 0.142). Compared with control, plasma 25(OH)D (P = 0.208) and parathyroid hormone (P = 0.207) were not altered by the healthy Nordic diet. Predictors for 25(OH)D were intake of vitamin D, eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), vitamin D supplement, plasma EPA and plasma DHA. Nevertheless, only vitamin D intake and season predicted the 25(OH)D changes. CONCLUSION: Consuming a healthy Nordic diet based on NNR increased vitamin D intake but not plasma 25(OH)D concentration. The reason why fish consumption did not improve vitamin D status might be that many fish are farmed and might contain little vitamin D or that frying fish may result in vitamin D extraction. Additional ways to improve vitamin D status in Nordic countries may be needed.

Crosslinking with transglutaminase does not change metabolic effects of sodium caseinate in model beverage in healthy young individuals.

BACKGROUND: Postprandial metabolic and appetitive responses of proteins are dependent on protein source and processing technique prior to ingestion. Studies on the postprandial effects of enzymatic crosslinking of milk proteins are sparse. Our aim was to study the effect of transglutaminase (TG)-induced crosslinking of sodium caseinate on postprandial metabolic and appetite responses. Whey protein was included as reference protein. METHODS: Thirteen healthy individuals (23.3 ± 1.1 y, BMI 21.7 ± 0.4 kg/m2) participated in a single-blind crossover design experiment in which the subjects consumed three different isovolumic (500 g) pourable beverages containing either sodium caseinate (Cas, 29 g), TG-treated sodium caseinate (Cas-TG, 29 g) or whey protein (Wh, 30 g) in a randomized order. Blood samples were collected at baseline and for 4 h postprandially for the determination of plasma glucose, insulin and amino acid (AA) concentrations. Gastric emptying (GE) was measured using the 13 C-breath test method. Appetite was assessed using visual analogue scales. RESULTS: All examined postprandial responses were comparable with Cas and Cas-TG. The protein type used in the beverages was reflected as differences in plasma AA concentrations between Wh and Cas, but there were no differences in plasma glucose or insulin responses. A tendency for faster GE rate after Wh was detected. Appetite ratings or subsequent energy intake did not differ among the protein beverages. CONCLUSIONS: Our results indicate that the metabolic responses of enzymatically crosslinked and native sodium caseinate in a liquid matrix are comparable, suggesting similar digestion and absorption rates and first pass metabolism despite the structural modification of Cas-TG.

Structure modification of a milk protein-based model food affects postprandial intestinal peptide release and fullness in healthy young men.

Physico-chemical and textural properties of foods in addition to their chemical composition modify postprandial metabolism and signals from the gastrointestinal tract. Enzymatic cross-linking of protein is a tool to modify food texture and structure without changing nutritional composition. We investigated the effects of structure modification of a milk protein-based model food and the type of milk protein used on postprandial hormonal, metabolic and appetitive responses. Healthy males (n 8) consumed an isoenergetic and isovolumic test product containing either whey protein (Wh, low-viscous liquid), casein (Cas, high-viscous liquid) or Cas protein cross-linked with transglutaminase (Cas-TG, rigid gel) in a randomised order. Blood samples were drawn for plasma glucose, insulin, cholecystokinin (CCK), glucagon-like peptide 1 and peptide YY analysis for 4 h. Appetite was assessed at concomitant time points. Cas and Wh were more potent in lowering postprandial glucose than Cas-TG during the first hour. Insulin concentrations peaked at 30 min, but the peaks were more pronounced for Cas and Wh than for Cas-TG. The increase in CCK was similar for Cas and Wh in the first 15 min, whereas for Cas-TG, the CCK release was significantly lower, but more sustained. The feeling of fullness was stronger after the consumption of Cas-TG than after the consumption of Cas and Wh. The present results suggest that food structure is more effective in modulating the postprandial responses than the type of dairy protein used. Modification of protein-based food structure could thus offer a possible tool for lowering postprandial glucose and insulin concentrations and enhancing postprandial fullness.

A psyllium fiber-enriched meal strongly attenuates postprandial gastrointestinal peptide release in healthy young adults.

Dietary fiber (DF) and protein are essential constituents of a healthy diet and are well known for their high satiety impact. However, little is known about their influence on postprandial gastrointestinal (GI) peptide release. Our aim in this single-blind, randomized, cross-over study was to investigate the effects of DF and/or protein enrichments on satiety-related metabolic and hormonal responses. Sixteen healthy, nonobese volunteers participated in the study and ingested 1 of 5 isoenergetic test meals in a randomized order on separate days. The test meals were as follows: 1) low in protein (2.8 g) and fiber (7.6 g); 2) low in protein (2.6 g) and high in soluble fiber (psyllium, 23.0 g); 3) high in protein (soy, 19.7 g) and low in fiber (6.2 g); 4) high in protein (18.4 g) and fiber (23.0 g); and 5) white wheat bread. Serum insulin and plasma glucose, ghrelin, glucagon-like peptide 1 (GLP-1), and peptide YY (PYY) concentrations were determined for 2 h following the meals. In addition, hunger and satiety ratings were collected. Postprandial glucose, insulin, ghrelin, GLP-1, and PYY responses all differed among the meals (P

[Regulation of food intake by gastrointestinal peptides]. / Ruoansulatuskanavan peptidit kylläisyyden säätelyssä--miten ravinto vaikuttaa?

Short-term regulation of food intake controls what, when and how much we eat during a single day or a meal, and is regulated by mechanical stimulation and release of peptides in the gastrointestinal (GI) tract. Both composition and structure of food affect peptide release. Many of these peptides inhibit also GI motility. Macronutrients stimulate GI peptides in different ways. Of special interest are the peptides ghrelin, cholecystokinin, glucagon-like peptide 1 and peptide YY. The amount of existing literature is, however, limited, and the results somewhat contradictory, which makes it challenging to make conclusions about the exact role of different macronutrients.

Viscosity of oat bran-enriched beverages influences gastrointestinal hormonal responses in healthy humans.

Viscous fibers, including beta-glucan in oat bran, favorably affect satiety as well as postprandial carbohydrate and lipid metabolism. However, effects of fiber viscosity on modulation of satiety-related gut hormone responses are largely unknown. We examined the effects of modified oat bran, with or without its natural viscosity, on sensations of appetite and satiety-related gastrointestinal (GI) hormone responses to establish the relevance of viscosity of beta-glucan in oat bran. Twenty healthy, normal-weight participants (16 female, 4 male, aged 22.6 +/- 0.7 y) ingested 2 isocaloric (1250 kJ) 300-mL oat bran beverages with low or high viscosity (carbohydrates, 57.9 g; protein, 7.8 g; fat, 3.3 g; fiber, 10.2 g) after a 12-h fast in randomized order. Viscosity of the low-viscosity oat bran beverage was reduced by beta-glucanase treatment. Blood samples were drawn before and 15, 30, 45, 60, 90, 120, and 180 min after beverage consumption. The oat bran beverage with low viscosity induced a greater postprandial increase in satiety (P = 0.048) and plasma glucose (P < 0.001), insulin (P = 0.008), cholecystokinin (P = 0.035), glucagon-like peptide 1 (P = 0.037), and peptide YY (P = 0.051) and a greater decrease in postprandial ghrelin (P = 0.009) than the beverage with high-viscosity oat bran. Gastric emptying as measured by paracetamol absorption was also faster (P = 0.034) after low-viscosity oat bran beverage consumption. In conclusion, viscosity differences in oat beta-glucan in a liquid meal with identical chemical composition strongly influenced not only glucose and insulin responses, but also short-term gut hormone responses, implying the importance of food structure in the modulation of postprandial satiety-related physiology.

Characterization and fate of black currant and bilberry flavonols in enzyme-aided processing.

The fate of black currant ( Ribes nigrum L.) and bilberry ( Vaccinium myrtillus L.) flavonols in enzyme-aided processing was studied. The flavonols were quantified and characterized by high-performance liquid chromatography equipped with a diode array detector and an electrospray ionization mass spectrometer. A tentative identification for 14 black currant and 19 bilberry flavonols is presented representing 11 previously unpublished conjugates. For the first time in any berry, the presence of laricitrin conjugates is reported. The enzyme-aided processing affected the flavonol extractability, elevating the yield in juices and decreasing that in press residues. Importantly, no significant loss of the berry flavonols was observed during the experiments, although some hydrolysis of flavonol conjugates was recorded. To maximize the effect on flavonol extractability, higher enzyme dosages were needed for black currants than for bilberries. The data show that the flavonol extractability and hydrolysis are dependent on the texture of raw material, the glycosylation pattern of the conjugates, and the activity profile of the enzyme preparation.

Dietary carbohydrate modification induces alterations in gene expression in abdominal subcutaneous adipose tissue in persons with the metabolic syndrome: the FUNGENUT Study.

BACKGROUND: Diets rich in whole-grain cereals and foods with a low glycemic index may protect against type 2 diabetes, but the underlying molecular mechanisms are unknown. OBJECTIVE: The main objective was to test whether 2 different carbohydrate modifications--a rye-pasta diet characterized by a low postprandial insulin response and an oat-wheat-potato diet characterized by a high postprandial insulin response--affect gene expression in subcutaneous adipose tissue (SAT) in persons with the metabolic syndrome. DESIGN: We assessed the effect of carbohydrate modification on SAT gene expression in 47 subjects [24 men and 23 women with a mean (+/-SD) age of 55 +/- 6 y] with the features of the metabolic syndrome in a parallel study design. The subjects had a mean (+/-SD) body mass index (kg/m(2)) of 32.1 +/- 3.8 and a 2-h plasma glucose concentration of 8.0 +/- 2.3 mmol/L. Adipose tissue biopsies were performed, and oral-glucose-tolerance tests and other biochemical measurements were conducted before and after the intervention. RESULTS: We detected 71 down-regulated genes in the rye-pasta group, including genes linked to insulin signaling and apoptosis. In contrast, the 12-wk oat-wheat-potato diet up-regulated 62 genes related to stress, cytokine-chemokine-mediated immunity, and the interleukin pathway. The insulinogenic index improved after the rye-pasta diet (P=0.004) but not after the oat-wheat-potato diet. Body weight was unchanged in both groups. CONCLUSIONS: Dietary carbohydrate modification with rye and pasta or oat, wheat, and potato differentially modulates the gene expression profile in abdominal subcutaneous adipose tissue, even in the absence of weight loss.

Interaction between cholesterol and glucose metabolism during dietary carbohydrate modification in subjects with the metabolic syndrome.

BACKGROUND: Carbohydrate modification based on rye bread and pasta enhances early insulin secretion in subjects with the metabolic syndrome. OBJECTIVE: Because the actions of insulin and cholesterol metabolism are interrelated, the question is raised of whether it is possible to alter cholesterol metabolism by means of dietary carbohydrate modification. DESIGN: We investigated the 12-wk effects of dietary carbohydrate modification on cholesterol synthesis and absorption by measuring the ratios of surrogate markers of precursor (cholestenol, desmosterol, and lathosterol) and absorption (cholestanol and plant sterols) sterols to cholesterol and their association to glucose metabolism in 74 subjects with the metabolic syndrome. The subjects were randomly assigned to diets with rye bread and pasta (RPa) or oat, wheat bread, and potato (OWPo) as the main carbohydrate source (34% and 37% of energy intake, respectively). RESULTS: During the study, serum cholesterol concentrations remained unchanged. Cholesterol synthesis was lower (6-10% for cholestenol and lathosterol; P < 0.05) and absorption higher (9%; P < 0.05 for sitosterol) with the OWPo diet than at baseline. With the RPa diet, cholesterol absorption was lower and synthesis higher than with the OWPo diet. The increment in the glucose area under the curve with the RPa diet was positively related to baseline cholesterol synthesis (eg, lathosterol; r = 0.480, P < 0.05) and negatively to absorption (for cholestanol; r = -0.520, P < 0.05). In the combined group, the changes in the cholestanol ratio and the insulinogenic index were interrelated (r = -0.464, P < 0.001). CONCLUSIONS: Carbohydrate modifications had dissimilar effects on cholesterol metabolism. Consumption of RPa, as compared with OWPo, may be clinically more favorable because it seems to inhibit the absorption of cholesterol, a factor crucial in the development of arterial atherosclerosis.