Search

Purpose: Oxysterols are cholesterol-oxygenated derivatives generated in the organism and also present in foods because of cholesterol oxidation during processing and storage. They are the natural ligands of liver X receptors (LXRs) and are generally recognized as hypocholesterolemic and anti-inflammatory molecules although this latter property is still controversial. Most oxysterol studies have been performed in macrophages, whereas the effects of oxysterols in neutrophils are poorly known. In this study, human neutrophils were exposed to two different oxysterols, 7-keto-cholesterol (7-k-chol) and 25-hydroxy-cholesterol (25-OH-chol), and their possible participation in inflammatory process was evaluated. Methods: Human neutrophils were incubated with 7-k-chol and 25-OH-chol, and ROS production, translocation of the NADPH oxidase cytosolic components, hemoxygenase-1 (HO-1) expression and lysozyme secretion were analyzed. Results: An increase in ROS production was observed within a short period of time (minutes) with both molecules. These oxysterols also stimulated the cellular membrane translocation of the NADPH oxidase cytosolic components, p47phox and p67phox. On the other hand, HO-1 expression, a cytoprotector enzyme, is inhibited in human neutrophils upon oxysterols treatment. Moreover, both oxysterols were associated with high lysozyme enzyme secretion at 5 and 18 h of incubation. Conclusions: The present paper describes for the first time that two oxysterols (7-k-chol and 25-OH-chol) enhance the ROS production within a short period of time in human neutrophils, stimulate the translocation of the cytosolic components of NADPH oxidase to the cellular membrane and increase lysozyme secretion. These data suggest that both oxysterols are able to activate pro-inflammatory effects in human neutrophils which contrasts with the role assigned to the oxysterols when they act through LXR at long time of incubation. [ABSTRACT FROM AUTHOR]

Purpose: Diabetes remission is a phenomenon described in the context of drastic weight loss due to bariatric surgery or low-calorie diets. Evidence suggests that increasing the intake of plant protein could reduce the risk of type 2 diabetes. We sought for association between changes in plant protein intake in the context of 2 healthy diets without weight loss nor glucose-lowering medication, and diabetes remission in coronary heart disease patients from the CORDIOPREV study. Methods: Newly diagnosed type 2 diabetes participants without glucose-lowering treatment were randomized to consume a Mediterranean or a low-fat diet. Type 2 diabetes remission was assessed with a median follow-up of 60 months according to the ADA recommendation. Information on patient's dietary intake was collected using food-frequency questionnaires. At first year of intervention, 177 patients were classified according to changes in plant protein consumption into those who increased or decreased its intake, in order to perform an observational analysis on the association between protein intake and diabetes remission. Results: Cox regression showed that patients increasing plant protein intake were more likely to remit from diabetes than those who decreased its intake (HR = 1.71(1.05–2.77)). The remission occurred mainly at first and second year of follow-up with diminished number of patients achieving remission in the third year onwards. The increase in plant protein was associated with lower intake of animal protein, cholesterol, saturated fatty acids, and fat, and with higher intake of whole grains, fibre, carbohydrates, legumes, and tree nuts. Conclusion: These results support the need to increase protein intake of vegetal origin as dietary therapy to reverse type 2 diabetes in the context of healthy diets without weight loss. [ABSTRACT FROM AUTHOR]

Purpose: Increased awareness of the importance of dietary fibre has led to increased interest in 'functional' fibre components like digestion-resistant maltodextrin (RMD). This randomized, placebo-controlled, double-blind study assessed the effects of RMD in the colonic transit time (CTT) and defecation characteristics (frequency, stool volume and consistency). Methods: Sixty-six healthy adult volunteers (32 men) who did not have a daily defecation habit had a 7-day run-in period before the 21-day intervention period with RMD or placebo. CTT and segmental CTT (SCTT) were assessed by a single abdominal X-ray film taken at the end of both periods after radiopaque marker ingestion. Defecation characteristics and intestinal functions were also assessed, which were self-reported by patients. Intragroup comparisons were evaluated by Student's paired t test, Bonferroni test and Chi-square test, while time comparisons by analysis of variance (ANOVA) and time-by-treatment interaction by repeated-measures ANOVA. Results: Fifty-seven subjects were assessed for CTT (placebo, n = 28; RMD, n = 29). In the RMD group, the total CTT, left SCTT and rectosigmoidal SCTT decreased significantly compared to baseline ( p < 0.01 each; −13.3, −4.7, −8.7 h, respectively). Significant differences between groups were observed in total CTT and left SCTT. Significant time-by-treatment interaction was observed in the RMD group for stool volume ( p = 0.014), increasing 56 % compared to baseline ( p < 0.01), while remained unchanged in the placebo group. Stool consistency was improved only in the RMD group ( p < 0.01). No adverse effects related to study products were observed. Conclusions: The results show that RMD improved CTT, stool volume, stool consistency and some intestinal functions in a healthy population. [ABSTRACT FROM AUTHOR]

Purpose: Fructooligosaccharides (FOS) are used as functional foods due to their prebiotic effects. Intestinal anti-inflammatory activity has been established in most, but not all, studies in animal models of colitis, using mainly chemically induced inflammation. Our goal was to test the effect of FOS (degree of polymerization 2-8) in the chronic, lymphocyte-driven CD4+ CD62L+ T cell transfer model of colitis. Methods: Colitis was induced by transfer of CD4+ CD62L+ T cells to C57BL/6J Rag1 mice. FOS (75 mg day) was administered by gavage as a post-treatment. Three groups were established: non-colitic (NC), colitic control (C, CD4+ CD62L+ transferred mice treated with vehicle) and colitic+FOS (C+FOS, similar but treated with FOS). Mice were killed after 13 days. Results: Treatment of mice with FOS ameliorated colitis, as evidenced by an increase in body weight, a lesser myeloperoxidase and alkaline phosphatase activities, a lower secretion of proinflammatory cytokines by mesenteric lymph node cells ex vivo (IFN-γ, IL-17, and TNF-α), and a higher colonic expression of occludin (C+FOS vs. C, p < 0.05). Increased relative abundance of lactic acid bacteria was observed in FOS-treated mice ( p < 0.05). Conclusions: FOS exert intestinal anti-inflammatory activity in T lymphocyte-dependent colitis, suggesting it may be useful in the management of inflammatory bowel disease in appropriate conditions. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of two extracts obtained from Agaricus bisporus on the mRNA expression of cholesterol-related genes. One of the extracts contained ergosterol and other fungal sterols (SFE) and the other contained β-glucans and fungal sterols (EβG). Methods: Firstly, the dietary mixed micelles (DMMs) generated after in vitro digestion of standards and SFE were applied to Caco2 cells. Then, the lower compartment after a Caco2-transport experiment was applied to HepG2 cells. The mRNA expression was assessed in both cell lines by low-density arrays (LDA). Mice received the extracts, ergosterol or control drugs after 4 weeks of a high-cholesterol diet. The lipid profile of plasma, liver and feces was determined. LDA assays were performed in liver and intestines. Results: The DMM fraction of SFE up-regulated the LDLR mRNA expression in Caco2 cells. The lower compartment after Caco2-transport experiments up-regulated LDLR and modulated several other lipid-related genes in HepG2 cells. In mice, SFE decreased TC/HDL ratio and reduced hepatic triglycerides paralleled with down-regulation of Dgat1 expression, while EβG did it without transcriptional changes. Addition of SFE or ergosterol induced in jejunum a similar transcriptional response to simvastatin and ezetimibe; they all down-regulated Srebf2 and Nr1h4 (FXR) genes. Conclusion: Ergosterol-containing extracts from A. bisporus lowered hepatic triglyceride and modify the mRNA expression of cholesterol-related genes although the transcriptional regulation was unrelated to changes in plasma lipid profile. These extracts may be useful limiting hepatic steatosis and as bioactive ingredients to design novel functional foods preventing lifestyle-related diseases such as non-alcoholic fatty liver disease. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of the consumption of Maillard reaction products (MRPs) from bread crust (BC) on iron, copper and zinc body retention and tissue distribution, determining whether these effects are related to the molecular weight of browning products. Methods: During an 88-day study period, rats were fed a Control diet or diets containing BC as source of MRPs, its soluble high or low molecular weight fractions (BC, LMW or HMW diets). A mineral balance was conducted throughout the experiment to determine iron, copper and zinc retention. At day 88, animals were killed, blood was drawn for haemoglobin determination and some organs removed to analyse minerals. Results: Copper and zinc balances were unchanged, and scant modification detected in their body delivery. However, the Fe retention rate from the diet increased (13, 22 and 32 % for BC, LMW and HMW diets), and a parallel higher Fe body concentration was observed (13-18 % higher than the Control group). Incoming iron accumulated particularly in the liver, femur and small intestine, but functional iron tended to decrease, as reflected by haemoglobin levels. Conclusions: The long-term intake of BC or derivatives did not produce a notable effect on copper or zinc balances, although slightly increased iron retention rate and the body concentration of this mineral were observed. Iron accumulated in some organs, but the production of haemoglobin was not improved. In view of the differences observed between the effects of BC and its derivatives, our results underline the importance of working with real food matrices, where the joint presence of different components modulates the in vivo final effects. [ABSTRACT FROM AUTHOR]

Purpose: To examine the association between dietary glycaemic index (GI) and dietary glycaemic load (GL) with cardiovascular disease (CVD) risk factors in a rural elderly population. Methods: A cross-sectional study was conducted in 343 subjects (60-74 years) residing in a Spanish rural area (Priego de Córdoba). Subjects were selected using stratified random sampling. Food intake was assessed using a validated food frequency questionnaire (FFQ). We assigned GI values to each item of the FFQ to estimate dietary GI and GL. Multivariate linear regression models were fitted to assess the association between GI/GL with CVD risk factors (blood glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, apolipoprotein A1, body mass index, waist circumference and blood pressure). The potential modifying effect of sex, smoking status, diabetes and medication has been explored. Results: A statistically significant inverse association between dietary GI and blood glucose was found in the multivariate model ( p = 0.029): for every 10 unit increment of GI, serum glucose levels decreased by 0.2 units. However, statistical significance was lost after controlling for diabetes or hypoglycaemic medication. In the crude model, dietary GL was associated with triglycerides ( ß for every 10 GL units increase = 0.70, p = 0.005), but statistical significance was lost in the multivariate model ( p = 0.508). No associations were found between dietary GI/GL and the rest of the variables studied. Conclusions: Neither dietary GI nor GL were associated with CVD risk factors in the study population of Priego de Córdoba. Results obtained suggest the necessity to consider the diagnosis of diabetes in these studies. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of modified frankfurters and pâtés: (a) reduced-fat products (RF) (15.3 and 15.2 % fat, respectively); (b) n-3-enriched reduced-fat products (n-3 RF) (15.1 and 15.5 % fat, respectively); and (c) normal-fat products (NF) (18 and 30.8 % fat, respectively) on lipids, lipoproteins, atherogenic ratios, oxidized LDL, and blood pressure of volunteers at high CVD risk. Methods: Twenty-two volunteers were enrolled in a sequential study of 3 consecutive 4-week periods separated by 4-week washout periods. Results: LDL-cholesterol ( p < 0.01), oxidized LDL, LDL-cholesterol/HDL-cholesterol (both p < 0.05) were significantly affected by the overall intervention. Compared to baseline, LDL-cholesterol decreased significantly ( p = 0.012) during the RF period; the LDL-cholesterol/HDL-cholesterol ratio ( p = 0.08) and the diastolic blood pressure ( p = 0.06) also decreased, although non-significantly, after RF consumption. LDL-cholesterol ( p = 0.040) and oxidized LDL ( p = 0.016) increased significantly after NF product consumption; systolic blood pressure did not show significant variations after this period. No significant differences, in absolute or relative changes, were observed between RF and n-3 RF consumption for any parameter tested. However, LDL-cholesterol, oxidized LDL, and the LDL-cholesterol/HDL-cholesterol ratio were lower (12, 15 and 10 %, respectively) after n-3 RF versus NF product consumption. Oxidized LDL was approximately 15 % lower after RF versus NF product consumption. Conclusions: The regular consumption of RF meat products, enriched in n-3 fatty acids or not, positively affects the lipoprotein profile of volunteers, decreasing LDL-cholesterol and oxidized LDL levels and, thus, future risk of cardiovascular accident. On comparison with the effects of NF product intake, the responses to n-3 RF and RF products differ, and while n-3 RF intake induces a reduction in LDL-cholesterol, oxidized LDL-cholesterol, and LDL-cholesterol/HDL-cholesterol ratio, the intake of RF products modifies only the oxidized LDL level. [ABSTRACT FROM AUTHOR]

Background: Reducing the dietary glycaemic response has been proposed as a means of reducing the risk of diabetes. Aim: To evaluate the effects of a new diabetes-specific formula (DSF) enriched with resistant starch type IV and fructose-free on postprandial glycaemia, insulinaemia and gastrointestinal hormones in healthy volunteers and in outpatient type 2 diabetics. Methods: (1) Twenty-four healthy volunteers were divided into two groups: Group 1 ( n = 10) was provided 50 g of the carbohydrate (CHO) constituent of the new product and 50 g of glucose separated by 1 week; Group 2 ( n = 14) was provided 400 ml of the new DSF (T-Diet Plus Diabet NP) and 400 ml of a control product separated by 1 week. (2) Ten type 2 diabetic patients received 400 ml of the new DSF and two other commercially available DSF (Glucerna SR and Novasource Diabet) on three occasions separated by 1 week. Venous blood samples were drawn at time 0 and at different times until 120 min. Glucose, insulin and gastrointestinal hormones were determined. Glycaemic and insulinaemic indices and glycaemic load were calculated. Results: The CHO constituent and the new DSF showed low glycaemic index and glycaemic load. In healthy subjects, insulin and C-peptide release were lower after administration of the CHO constituent as well as after the new DSF ( P < 0.001). Ghrelin, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) production were lower after intake of the CHO constituent ( P ranging from <0.001 to 0.019) compared with glucose, and GIP was lower after ingestion of the new DSF ( P = 0.002) than after the control product. In type 2 diabetic patients, glucose AUC was lower after the administration of the new DSF ( P = 0.037) compared with the others. Conclusions: Our results indicate that this new product could be beneficial for diabetic patients. [ABSTRACT FROM AUTHOR]

Background: Maillard reaction products (MRP) improve food palatability and are linked to some positive biological actions. However, diverse negative consequences, some related to protein damage and mineral availability, have been established. Aim of study: We investigated the effects of MRP, from a bread crust diet, on phosphorus bioavailability and tissue distribution in rats to determine whether these effects are related to the molecular weight of browning products. Methods: During a study period of 88 days, rats were fed either a control diet or one of the following: with bread crust as a source of MRP, or one with its soluble high molecular weight, soluble low molecular weight or insoluble fraction (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a phosphorus balance was performed, after which the animals were sacrificed and some organs removed to analyse phosphorus content. A second balance was carried out throughout the experimental period to calculate phosphorus retention. Results: Phosphorus balance in the last week was unchanged. However, considering the whole experimental period, a trend towards improved bioavailability, significant in the HMW group, was observed. Higher phosphorus concentrations were measured in the small intestine and bone. Conclusions: The consumption of MRP derived from bread did not alter phosphorus retention, due to increased bioavailability, especially concerning HMW compounds. The overall phosphorus body content remained unchanged and there were no changes in the bone, its principal metabolic destination. However, MRP consumption markedly raised phosphorus levels at the digestive level, especially when consumed as isolate fractions. The slower rate of stomach emptying is assumed to be related to this effect. [ABSTRACT FROM AUTHOR]

Purpose: To study the gluten metabolism in healthy individuals and its effect over the intestinal microbial activity. Methods: The faeces of eleven healthy subjects were analysed under 4 diet regimens: their normal gluten diet, a strict gluten-free diet (GFD), a GFD with a supplemental intake of 9 g gluten/day and a GFD with a supplemental intake of 30 g gluten/day. Gluten content, faecal tryptic activity (FTA), short-chain fatty acids (SCFAs) and faecal glutenasic activity (FGA) were analysed in faecal samples. Results: Faecal gluten contents, FTA, SCFAs and FGA varied significantly with different levels of gluten intake in the diet. When high gluten doses (30 g/day) were administered in the diet, SCFA concentrations (70.5 mmoles/kg faeces) were significantly different from those from the GFD period (33.8 mmoles/kg faeces) of the experiment. However, the FTA showed significant differences between the GFD (34 units) and the normal gluten-containing diet (60 units) and also between the GFD and the GFD + 30 g of gluten/day (67 units). When gluten was present in the diet, gluten was detected in the faeces, showing that at least a portion of the gluten ingested is eliminated in the large intestine, providing a substrate for intestinal microbial proteases. We have also shown the presence of faecal glutenasic activity that increased proportionally with the gluten intake in the diet, showing an enzymatic activity of 993 units in DSG, 2,063 units in DSG + 9 g and 6,090 units in DSG + 30 g. Conclusions: The activity of the intestinal microbiota is modified by gluten intake in the diet. The incorporation of gluten in the diet increases the activity of a gluten proteolytic activity in the faeces. [ABSTRACT FROM AUTHOR]