Weight-Reducing Dietary Intervention Increases the Ability of Hyperinsulinemia to Suppress Serum Ghrelin Concentration in Individuals with Obesity.

BACKGROUND: Ghrelin is an orexigenic peptide secreted mainly by the stomach. Serum ghrelin concentrations are suppressed after a meal, probably due to insulin release. Individuals with obesity are characterized by a lower fasting serum ghrelin and a lower ghrelin decrease after a meal. The effect of weight loss on the ability of insulin to suppress serum ghrelin concentration remains unknown. OBJECTIVE: The aim of the present study was to analyze the effect of weight-reducing dietary intervention on the ability of hyperinsulinemia to suppress serum ghrelin concentration in young individuals with uncomplicated obesity. METHODS: We examined 38 individuals with marked overweight or obesity, who underwent a 12-wk dietary intervention program. Serum ghrelin concentration was measured before and after a 2-h hyperinsulinemic-euglycemic clamp, both pre- and post-intervention. Twenty normal-weight individuals served as a control group and were examined at baseline only. RESULTS: Individuals with overweight/obesity were characterized by a lower fasting serum ghrelin concentration than normal-weight individuals (P = 0.006). Insulin decreased serum ghrelin concentration in both groups (P < 0.001); however, this decrease was markedly lower in individuals with overweight/obesity than in normal-weight individuals (99.70 ± 136.37 vs. 215.45 ± 250.28 pg/mL; P = 0.026). Fasting serum ghrelin concentration increased after the intervention. After weight-reducing dietary intervention, the decrease in serum ghrelin concentration after the clamp was significantly greater than the pre-intervention value (99.70 ± 136.37 vs. 221.82 ± 228.75 pg/mL; P = 0.002). CONCLUSIONS: Weight-reducing dietary intervention restores the ability of hyperinsulinemia to suppress serum ghrelin concentration. It may suggest an enhanced feeling of satiety after moderate weight loss in individuals with overweight/obesity.

Time-Restricted Feeding Restored Insulin-Growth Hormone Balance and Improved Substrate and Energy Metabolism in MC4RKO Obese Mice.

BACKGROUND: Dysregulation of metabolic regulatory hormones often occurs during the progress of obesity. Key regulatory hormone insulin-growth hormone (GH) balance has recently been proposed to maintain metabolism profiles. Time-restricted feeding (TRF) is an effective strategy against obesity without detailed research on pulsatile GH releasing patterns. METHODS: TRF was performed in an over-eating melanocortin 4 receptor-knockout (MC4RKO) obese mouse model using normal food. Body weight and food intake were measured. Series of blood samples were collected for 6-h pulsatile GH profile, glucose tolerance test, and insulin tolerance test at 5, 8, and 9 weeks of TRF, respectively. Indirect calorimetric recordings were performed by the Phenomaster system at 6 weeks for 1 week, and body composition was measured by nuclear magnetic resonance spectroscopy (NMR). Substrate- and energy metabolism-related gene expressions were measured in terminal liver and subcutaneous white adipose tissues. RESULTS: TRF increased pulsatile GH secretion in dark phase and suppressed hyperinsulinemia in MC4RKO obese mice to reach a reduced insulin/GH ratio. This was accompanied by the improvement in insulin sensitivity, metabolic flexibility, glucose tolerance, and decreased glucose fluctuation, together with appropriate modification of gene expression involved in substrate metabolism and adipose tissue browning. NMR measurement showed that TRF decreased fat mass but increased lean mass. Indirect calorimeter recording indicated that TRF decreased the respiratory exchange ratio (RER) reflecting consumption of more fatty acid in energy production in light phase and increased the oxygen consumption during activities in dark phase. CONCLUSIONS: TRF effectively decreases hyperinsulinemia and restores pulsatile GH secretion in the overeating obese mice with significant improvement in substrate and energy metabolism and body composition without reducing total caloric intake.

Dietary substitution of SFA with MUFA within high-fat diets attenuates hyperinsulinaemia and pancreatic islet dysfunction.

Preliminary evidence has suggested that high-fat diets (HFD) enriched with SFA, but not MUFA, promote hyperinsulinaemia and pancreatic hypertrophy with insulin resistance. The objective of this study was to determine whether the substitution of dietary MUFA within a HFD could attenuate the progression of pancreatic islet dysfunction seen with prolonged SFA-HFD. For 32 weeks, C57BL/6J mice were fed either: (1) low-fat diet, (2) SFA-HFD or (3) SFA-HFD for 16 weeks, then switched to MUFA-HFD for 16 weeks (SFA-to-MUFA-HFD). Fasting insulin was assessed throughout the study; islets were isolated following the intervention. Substituting SFA with MUFA-HFD prevented the progression of hyperinsulinaemia observed in SFA-HFD mice (P < 0·001). Glucose-stimulated insulin secretion from isolated islets was reduced by SFA-HFD, yet not fully affected by SFA-to-MUFA-HFD. Markers of ß-cell identity (Ins2, Nkx6.1, Ngn3, Rfx6, Pdx1 and Pax6) were reduced, and islet inflammation was increased (IL-1ß, 3·0-fold, P = 0·007; CD68, 2·9-fold, P = 0·001; Il-6, 1·1-fold, P = 0·437) in SFA-HFD - effects not seen with SFA-to-MUFA-HFD. Switching to MUFA-HFD can partly attenuate the progression of SFA-HFD-induced hyperinsulinaemia, pancreatic inflammation and impairments in ß-cell function. While further work is required from a mechanistic perspective, dietary fat may mediate its effect in an IL-1ß-AMP-activated protein kinase α1-dependent fashion. Future work should assess the potential translation of the modulation of metabolic inflammation in man.

Low-carbohydrate diets for the treatment of obesity and type 2 diabetes.

PURPOSE OF REVIEW: Summarize the physiological effects of low-carbohydrate diets as they relate to weight loss, glycemic control, and metabolic health. RECENT FINDINGS: Low-carbohydrate diets are at least as effective for weight loss as other diets, but claims about increased energy expenditure and preferential loss of body fat are unsubstantiated. Glycemic control and hyperinsulinemia are improved by low-carbohydrate diets, but insulin sensitivity and glucose-stimulated insulin secretion may be impaired, especially in the absence of weight loss. Fasting lipid parameters are generally improved, but such improvements may depend on the quality of dietary fat and the carbohydrates they replaced. Postprandial hyperlipemia is a potential concern given the high fat content typical of low-carbohydrate diets. SUMMARY: Low-carbohydrate diets have several potential benefits for treatment of obesity and type 2 diabetes, but more research is required to better understand their long-term consequences as well as the variable effects on the endocrine control of glucose, lipids, and metabolism.

Intermittent v. continuous energy restriction: differential effects on postprandial glucose and lipid metabolism following matched weight loss in overweight/obese participants.

The intermittent energy restriction (IER) approach to weight loss involves short periods of substantial (>70 %) energy restriction (ER) interspersed with normal eating. Studies to date comparing IER to continuous energy restriction (CER) have predominantly measured fasting indices of cardiometabolic risk. This study aimed to compare the effects of IER and CER on postprandial glucose and lipid metabolism following matched weight loss. In all, twenty-seven (thirteen male) overweight/obese participants (46 (sem 3) years, 30·1 (sem 1·0) kg/m2) who were randomised to either an IER intervention (2638 kJ for 2 d/week with an overall ER of 22 (sem 0·3) %, n 15) or a CER intervention (2510 kJ below requirements with overall ER of 23 (sem 0·8) %) completed the study. Postprandial responses to a test meal (over 360 min) and changes in anthropometry (fat mass, fat-free mass, circumferences) were assessed at baseline and upon attainment of 5 % weight loss, following a 7-d period of weight stabilisation. The study found no statistically significant difference in the time to attain a 5 % weight loss between groups (median 59 d (interquartile range (IQR) 41-80) and 73 d (IQR 48-128), respectively, P=0·246), or in body composition (P≥0·437). For postprandial measures, neither diet significantly altered glycaemia (P=0·266), whereas insulinaemia was reduced comparatively (P=0·903). The reduction in C-peptide tended (P=0·057) to be greater following IER (309 128 (sem23 268) to 247781 (sem20 709) pmol×360 min/l) v. CER (297 204 (sem25 112) to 301 655 (sem32 714) pmol×360 min/l). The relative reduction in TAG responses was greater (P=0·045) following IER (106 (sem30) to 68 (sem 15) mmol×360 min/l) compared with CER (117 (sem 43) to 130 (sem 31) mmol×360 min/l). In conclusion, these preliminary findings highlight underlying differences between IER and CER, including a superiority of IER in reducing postprandial lipaemia, which now warrant targeted mechanistic evaluation within larger study cohorts.

Taurine supplementation regulates Iκ-Bα protein expression in adipose tissue and serum IL-4 and TNF-α concentrations in MSG obesity.

PURPOSE: Obesity is usually associated with low-grade inflammation, which impairs insulin action. The amino acid, taurine (TAU), regulates glucose homeostasis and lipid metabolism and presents anti-inflammatory actions. Here, we evaluated whether inflammatory markers are altered in the serum and retroperitoneal adipose tissue of monosodium glutamate (MSG) obese rats, supplemented or not with TAU. METHODS: Male Wistar rats received subcutaneous injections of MSG (4 mg/kg body weight/day, MSG group) or hypertonic saline (CTL) during the first 5 days of life. From 21 to 120 days of age, half of each of the MSG and CTL groups received 2.5 % TAU in their drinking water (CTAU and MTAU). RESULTS: At 120 days of age, MSG rats were obese and hyperinsulinemic. TAU supplementation reduced fat deposition without affecting insulinemia in MTAU rats. MSG rats presented increased pIκ-Bα/Iκ-Bα protein expression in the retroperitoneal adipose tissue. TAU supplementation decreased the ratio of pIκ-Bα/Iκ-Bα protein, possibly contributing to the increased Iκ-Bα content in MTAU adipose tissue. Furthermore, MSG obesity or supplementation did not alter TNF-α, IL-1ß or IL-6 content in adipose tissue. In contrast, MSG rats presented lower serum TNF-α, IL-4 and IL-10 concentrations, and these alterations were prevented by TAU treatment. CONCLUSION: MSG obesity in rats was not associated with alterations in pro-inflammatory markers in retroperitoneal fat stores; however, reductions in the serum concentrations of anti-inflammatory cytokines and of TNF-α were observed. TAU treatment decreased adiposity, and this effect was associated with the normalization of circulating TNF-α and IL-4 concentrations in MTAU rats.

Substituting poly- and mono-unsaturated fat for dietary carbohydrate reduces hyperinsulinemia in women with polycystic ovary syndrome.

OBJECTIVE: Hyperinsulinemia is a prevalent feature of polycystic ovary syndrome (PCOS), contributing to metabolic and reproductive manifestations of the syndrome. Weight loss reduces hyperinsulinemia but weight regain is the norm, thus preventing long-term benefits. In the absence of weight loss, replacement of dietary carbohydrate (CHO) with mono/polyunsaturated fat reduces ambient insulin concentrations in non-PCOS subjects. The current study evaluated whether this dietary intervention could ameliorate hyperinsulinemia in women with PCOS. DESIGN/SETTING/PATIENTS: Obese women with PCOS (BMI 39 ± 7 kg/m2) and insulin resistance completed a crossover study (Stanford University Clinical Research Center) comparing two isocaloric diets, prepared by research dietitians, containing 60% CHO/25% fat versus 40% CHO/45% fat (both 15% protein and ≤7% saturated fat). After 3 weeks on each diet, daylong glucose, insulin, and fasting lipid/lipoproteins were measured. RESULTS: Daylong glucose did not differ according to diet. Daylong insulin concentrations were substantially (30%) and significantly lower on the low CHO/higher fat diet. Beneficial changes in lipid profile were also observed. CONCLUSIONS: Replacement of dietary CHO with mono/polyunsaturated fat yields clinically important reductions in daylong insulin concentrations, without adversely affecting lipid profile in obese, insulin-resistant women with PCOS. This simple and safe dietary intervention may constitute an important treatment for PCOS. ClinicalTrials.gov Identifier: NCT00186459.

Reduction in peripheral vascular resistance predicts improvement in insulin clearance following weight loss.

BACKGROUND: The hyperinsulinemia of obesity is a function of both increased pancreatic insulin secretion and decreased insulin clearance, and contributes to cardiovascular risk. Whilst weight loss is known to enhance insulin clearance, there is a paucity of data concerning the underlying mechanisms. This study was conducted to examine the inter-relationships between changes in sympathetic nervous system (SNS) activity, vascular function and insulin clearance during a weight loss program. METHODS: Seventeen non-smoking, un-medicated individuals aged 55 ± 1 years (mean ± SEM), body mass index (BMI) 33.9 ± 1.7 kg/m(2), underwent a 4-month hypocaloric diet (HCD), using a modified Dietary Approaches to Stop Hypertension diet, whilst seventeen age- and BMI-matched subjects acted as controls. Insulin sensitivity and insulin clearance were assessed via euglycemic hyperinsulinemic clamp (exogenous insulin clearance); hepatic insulin extraction was calculated as fasting C-peptide to insulin ratio (endogenous insulin clearance); SNS activity was quantified by microneurographic nerve recordings of muscle sympathetic nerve activity (MSNA) and whole-body norepinephrine kinetics; and vascular function by calf venous occlusion plethysmography and finger arterial tonometry. RESULTS: Weight loss averaged -8.3 ± 0.6% of body weight in the HCD group and was accompanied by increased clamp-derived glucose utilization (by 20 ± 9%, P = 0.04) and exogenous insulin clearance (by 12 ± 5%, P = 0.02). Hepatic insulin extraction increased from 6.3 ± 0.8 to 7.1 ± 0.9 (P = 0.09). Arterial norepinephrine concentration decreased by -12 ± 5%, whole-body norepinephrine spillover rate by -14 ± 8%, and MSNA by -9 ± 5 bursts per 100 heartbeats in the HCD group (P all >0.05 versus control group). Step-wise regression analysis revealed a bidirectional relationship between enhanced exogenous insulin clearance post weight loss and reduction in calf vascular resistance (r = -0.63, P = 0.01) which explained 40% of the variance. Increase in hepatic insulin extraction was predicted by enhanced finger reactive hyperaemic response (P = 0.006) and improvement in oral glucose tolerance (P = 0.002) which together explained 64% of the variance. CONCLUSIONS: Insulin clearance is independently and reciprocally associated with changes in vascular function during weight loss intervention. Trial registration ClinicalTrials.gov: NCT01771042 and NCT00408850.

Dietary phytochemical index and the risk of insulin resistance and ß-cell dysfunction: a prospective approach in Tehran lipid and glucose study.

BACKGROUND: In this study, we aimed to investigate the association of dietary phytochemical index (DPI) with insulin resistance, ß-cell dysfunction, and insulin sensitivity. METHODS: This longitudinal study was conducted on 1141 participants of the Tehran Lipid and Glucose Study. Dietary data were collected using a validated semi-quantitative FFQ with 168 food items at baseline and DPI was calculated. Fasting serum insulin and glucose were measured at baseline and again after a 3-year of follow-up. RESULTS: After 3-years of follow-up, the risk of hyperinsulinemia significantly decreased by 65 (OR = 0.35, 95% CI = 0.21-0.60) and 86% (OR = 0.14, 0.07-0.29), in the third and fourth quartile categories of DPI, respectively. The occurrence of insulin resistance and insulin insensitivity in participants with higher DPI was significantly lower than the others (OR = 0.48, 95% CI = 0.25-0.93 and OR = 0.11, 95% CI = 0.05-0.24, respectively). CONCLUSION: Higher consumption of phytochemical-rich foods may have protective effects against development of insulin resistance.

Metabolic Correction as a tool to improve diabetes type 2 management.

Diabetes Mellitus type 2 (DM2) is a metabolic disease that develops by a decrease in sensitivity of insulin receptors as an effect of the disruption certain metabolic functions in the processing of glucose. DM2 patients have, uncontrolled glucose levels, and commonly have problems with obesity and cardiovascular disease. Patients are treated with standard diet, insulin, diabetic oral agents and antihypertensive drugs, but this approach does not completely stops tissue deterioration since it does not address the metabolic root of the disease. Metabolic correction is proposed as a suitable adjunct treatment to improve clinical outcomes. Metabolic correction is based on diet modification, proper hydration and scientific supplementation directed to improve cellular biochemistry and metabolic efficiency. In addition, other possible benefits may include reduction in medication use, disease complications and medical costs. To test the results of a metabolic correction program, 25 patients with DM2 participated in an education program about adequate food consumption that promoted control of blood glucose levels. Anthropometric measurements and blood tests were performed during a 13 week program based on a low carbohydrate diet, proper hydration and magnesium supplementation. The metabolic correction program implemented by a proprietary educational system resulted in significant reductions in glucose, triglycerides, cholesterol, weight and waist circumference. Improvements in these values could represent an important reduction of coronary heart disease risk factors as well as other chronic degenerative diseases. In addition there was medication dosage reduction in one or more medications in 21 of the 25 participating patients, which suggest that the program has the potential to improve health outcomes and reduce health care costs.

Probiotic Lactobacillus casei Zhang ameliorates high-fructose-induced impaired glucose tolerance in hyperinsulinemia rats.

AIM: To evaluate the preventive and therapeutic effects of Lactobacilluscasei Zhang on impaired glucose tolerance (IGT) by using fructose-induced hyperinsulinemia rats. METHODS: Rats were fed 25 % fructose solution for hyperinsulinemia with L.casei Zhang for prevention or therapy. Serum levels of insulin, glucagon-like peptide-2 (GLP-2), osteocalcin, malondialdehyde (MDA), total intestinal bile acids and hepatic glycogen contents were determined by assay kits. The major bacteria from feces and liver expression of adiponectin receptor 2 (AdipoR2), liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor gamma (PPAR-γ) and vitamin K epoxide reductase complex subunit 1 mRNA were assessed by RT-PCR. Pancreas injury was evaluated by histological analysis. RESULTS: Lactobacilluscasei Zhang significantly increased numbers of Lactobacillus and Bifidobacterium and decreased Clostridium in the intestine (p < 0.01). Meanwhile, liver glycogen contents were significantly decreased (p < 0.05). In preventive group, accompanied by significantly lower insulin and GLP-2 levels (p < 0.05), L.casei Zhang prevented rats from an increase in oral glucose tolerance area under curve (AUC) which was significant in hyperinsulinemia group (p < 0.05). In therapeutic group, L.casei Zhang administration possessed improved glucose tolerance (p < 0.05), which were associated with increased osteocalcin level (p < 0.01), improved intestinal bile acids secretion (p = 0.060), decreased serum MDA levels (p < 0.05) and upregulation of LXR-α, PPAR-γ and AdipoR2 gene expression, as well as an increase in Bacteroides fragilis (p < 0.05). CONCLUSIONS: Lactobacilluscasei Zhang administration exert both preventive and ameliorative effect on oral glucose tolerance AUC in IGT rats but may be via different mechanisms. L.casei Zhang could prevent rats from increased AUC through GLP-2 lowering, while the ameliorative effect in high-fructose-fed post-adolescent rats may be via B. fragilis enriched vitamin K2-dependent osteocalcin mechanism in which AdipoR2, LXR-α and PPAR-γ signaling were involved.

Microvascular disorders in obese Zucker rats are restored by a rice bran diet.

BACKGROUND AND AIM: Nutritional-based approaches aimed to prevent microvascular dysfunction associated to obesity present potential advantages over pharmacological strategies. Our aim was to test whether a rice bran enzymatic extract (RBEE)-supplemented diet could attenuate microvascular alterations in obese rats. METHODS AND RESULTS: Lean and obese Zucker rats were fed standard diet supplemented or not with 1% and 5% RBEE for 20 weeks. Functional studies were performed in small mesenteric arteries in isometric myograph. Immunoblotting and fluorescence studies were made in arterial homogenates and arterial sections, respectively. RBEE-supplementation restored microvascular function in obese rats through a marked increase in NO and endothelial-derived hyperpolarizing factor contribution by up-regulation of eNOS and calcium-activated potassium channels expression, respectively, in association to a substantial reduction of microvascular inflammation and superoxide anion formation. These data agrees with the beneficial actions of RBEE on dyslipidemia, hyperinsulinemia and hypertension in obesity. CONCLUSION: The multi-factorial properties of RBEE-diet, especially for restoring the function of small resistance arteries shows this dietary-based approach to be a promising candidate for prevention of microvascular alterations in obesity, which are crucial in cardiovascular events in obese subjects.

Exercise is more effective than diet control in preventing high fat diet-induced ß-amyloid deposition and memory deficit in amyloid precursor protein transgenic mice.

Accumulating evidence suggests that some dietary patterns, specifically high fat diet (HFD), increase the risk of developing sporadic Alzheimer disease (AD). Thus, interventions targeting HFD-induced metabolic dysfunctions may be effective in preventing the development of AD. We previously demonstrated that amyloid precursor protein (APP)-overexpressing transgenic mice fed HFD showed worsening of cognitive function when compared with control APP mice on normal diet. Moreover, we reported that voluntary exercise ameliorates HFD-induced memory impairment and ß-amyloid (Aß) deposition. In the present study, we conducted diet control to ameliorate the metabolic abnormality caused by HFD on APP transgenic mice and compared the effect of diet control on cognitive function with that of voluntary exercise as well as that of combined (diet control plus exercise) treatment. Surprisingly, we found that exercise was more effective than diet control, although both exercise and diet control ameliorated HFD-induced memory deficit and Aß deposition. The production of Aß was not different between the exercise- and the diet control-treated mice. On the other hand, exercise specifically strengthened the activity of neprilysin, the Aß-degrading enzyme, the level of which was significantly correlated with that of deposited Aß in our mice. Notably, the effect of the combination treatment (exercise and diet control) on memory and amyloid pathology was not significantly different from that of exercise alone. These studies provide solid evidence that exercise is a useful intervention to rescue HFD-induced aggravation of cognitive decline in transgenic model mice of AD.

Evaluation of two dietary treatments in obese hyperinsulinemic adolescents.

UNLABELLED: Hyperinsulinemia increases the risk of cardiovascular disease in obese children. Only a few treatments are available to decrease insulin resistance. The reduction of hyperinsulinemia by dietary means would be a simple, physiologic and economic way to reduce the risk of metabolic disease. OBJECTIVE: To compare the effects of two low-energy diets on serum insulin concentrations and weight loss in obese hyperinsulinemic adolescents. MATERIALS AND METHODS: Eighty-six randomly assigned insulin-resistant obese adolescents completed a 16 week calorie-restricted diet. The experimental diet had a reduced glycemic index designed to evoke a low insulin response (LIR), with carbohydrates and proteins ingested in separate meals. The control diet was a conventional (CD) with similar proportions (60%, 20% and 20%). Variables studied were blood glucose and insulin concentrations after an oral glucose load, body mass index, waist circumference, and insulin resistance (homeostasis model assessment, HOMA). RESULTS: Mean weight [+/- Standard Deviation (SD)] was significantly reduced after the LIR (-0.53 +/- 0.5) and the CD (-0.54 +/- 0.4), but a greater decrease of waist circumference (cm) was observed after the LIR (-9.1 +/- 4.8 vs. -6.6 +/- 4.6, p = 0.02). Fasting insulin concentrations (-17.9 +/- 27.9 vs. -9.4 +/- 14.8, p = 0.01) and HOMA dropped significantly more after the LIR than after the CD (-3.5 +/- 4.9SD vs. -2.4 +/- 1SD, p < 0.0001). CONCLUSIONS: The LIR diet reduces serum insulin concentrations and waist circumference more than conventional treatment and appears to be a promising alternative to a conventional diet in insulin-resistant obese adolescents. Long-term follow-up is needed to evaluate the maintenance of weight loss and metabolic parameters.

Alternative Foods in Cardio-Healthy Dietary Models That Improve Postprandial Lipemia and Insulinemia in Obese People.

Obesity is one of the major health problems worldwide. Following healthy dietary patterns can be difficult in some countries due to the lack of availability of certain foods; thus, alternative foods are needed. Our aim was to evaluate the effect of a dietary pattern consisting of fruit, avocado, whole grains, and trout (FAWGT) on postprandial insulinemia and lipemia in obese Colombian subjects. A randomized controlled crossover study was conducted, in which 44 subjects with BMI ≥ 30 kg/m2 followed either a FAWGT diet or a diet high in saturated fat and rich in processed carbohydrates. Levels of lipids and carbohydrates were measured during the postprandial state. The FAWGT diet reduced fasting insulin, VLDL, and HOMA-IR after 8 weeks (p < 0.05), while there was a lower postprandial increase in TG, VLDL, and insulin levels after both acute and chronic intake of FAWGT diet (p < 0.05). The intake of FAWGT-diet was characterized by high consumption of foods rich in fiber, MUFAs, and vitamins C and E (p < 0.05). The consumption of a diet composed of fruit, avocado, whole grains, and trout has emerged as a valid alternative to the foods included in other heart-healthy diets since it improves postprandial lipemia and insulinemia in obese people and has similar beneficial effects to these healthy models.

Adaptation of colonic fermentation and glucagon-like peptide-1 secretion with increased wheat fibre intake for 1 year in hyperinsulinaemic human subjects.

High cereal fibre intake is associated with reduced risk for type 2 diabetes, but wheat fibre had little or no effect on glycaemic control or oral glucose tolerance in clinical trials lasting 4-12 weeks. To explain this discrepancy, we hypothesised that colonic adaptation to increased wheat fibre intake takes many months but eventually results in increased SCFA production and glucagon-like peptide-1 (GLP-1) secretion. Thus, the primary objective was to determine the time-course of the effects of increased wheat fibre intake on plasma acetate, butyrate and GLP-1 concentrations in hyperinsulinaemic human subjects over 1 year. Subjects with fasting plasma insulin >or= 40 pmol/l were randomly assigned by computer to receive either a high-wheat fibre cereal (fibre group; 24 g fibre/d; twenty assigned; six dropped out, fourteen included) or a low-fibre cereal (control group; twenty assigned; six dropped-out, fourteen included) daily for 1 year. Acetate, butyrate and GLP-1 were measured during 8 h metabolic profiles performed every 3 months. There were no differences in body weight in the fibre group compared with the control group. After 9 months baseline-adjusted mean 8 h acetate and butyrate concentrations were higher on the high-fibre than the control cereal (P < 0.05). After 12 months on the high-fibre cereal, baseline-adjusted mean plasma GLP-1 was 1.3 (95 % CI 0.4, 2.2) pmol/l (P < 0.05) higher than at baseline (about 25 % increase) and 1.4 (95 % CI 0.1, 2.7) pmol/l (P < 0.05) higher than after 12 months on control. It is concluded that wheat fibre increased SCFA production and GLP-1 secretion in hyperinsulinaemic humans, but these effects took 9-12 months to develop. Since GLP-1 may increase insulin sensitivity and secretion, these results may provide a mechanism for the epidemiological association between high cereal fibre intake and reduced risk for diabetes.

Metabolic and appetite hormone responses of hyperinsulinemic normoglycemic males to meals with varied macronutrient compositions.

AIMS: The aim of this study was to investigate the appetite hormones and metabolic responses of hyperinsulinemic subjects to high-protein (HP) meals as compared to high-carbohydrate (HC) and high-fat (HF) meals. DESIGN: Fifteen hyperinsulinemic normoglycemic men received, on 3 separate occasions, HP, HC, or HF meals in a randomized crossover design. Blood samples were collected before and after the ingestion of each meal. Postprandially, acylated ghrelin, PYY(3-36), insulin, glucose, and triglycerides were measured. RESULTS: While the HC meal induced an acutely greater postprandial ghrelin decrease below baseline, the HP meal maintained this decline significantly more than the HF meal at 240 min. Postprandial PYY(3-36) responses did not significantly vary with time and meal composition. Postprandial insulin and glucose peaks were significantly lower following the HP and HF meals in comparison to the HC meal, whereas triglyceride responses were significantly higher following the HF meal. Significant correlations, negative between acylated ghrelin and insulin and positive between PYY(3-36) and insulin, were observed. CONCLUSIONS: In hyperinsulinemic normoglycemic men, HP meals ensure a longer-lasting suppression of circulating ghrelin levels and result in more favorable metabolic responses, characterized by a lower surge of postprandial insulin and glucose and a reduced postprandial triglyceride response, as compared to both HC and HF meals.

Multiple dietary fiber for gestational hyperinsulinism: A protocol of systematic review and meta-analysis of randomized clinical trials.

INTRODUCTION: Gestational hyperinsulinism is a metabolic disease which is widely concerned at home and abroad. It is a clinical consensus that the embryo implantation ability of patients with hyperinsulinemia is decreased and the abortion rate after implantation is high. The treatment of gestational hyperinsulinism with Multiple dietary fiber diets has been proven. However, due to the lack of evidence, there is no specific method or recommendation, it is necessary to carry out a systematic evaluation of Multiple dietary fiber diet, to provide effective evidence for further research. METHODS AND ANALYSIS: The following databases will be searched from their inception to August 2020: Electronic database includes PubMed, Embase, Cochrane Library, Web of Science, Nature, Science online, Chinese Biomedical Database WanFang, VIP medicine information, and CNKI. Primary outcomes: Fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance, glycosylated hemoglobin. Additional outcomes: Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL), triglycerides (TG), total serum cholesterol (TC). Data will be extracted by 2 researchers independently, risk of bias of the meta-analysis will be evaluated based on the Cochrane Handbook for Systematic Reviews (SR) of Interventions. All data analysis will be conducted by data statistics software Review Manager V.5.3. and Stata V.12.0. RESULTS: The results of this study will systematically evaluate the effectiveness and safety of Multiple dietary fiber diet interventions in the treatment of gestational hyperinsulinism. CONCLUSION: The SR of this study will summarize the current published evidence of Multiple dietary fiber for the treatment of gestational hyperinsulinism, which can further guide the promotion and application of it. ETHICS AND DISSEMINATION: This study is a SR, the outcomes are based on the published evidence, so examination and agreement by the ethics committee are not required in this study. We intend to publish the study results in a journal or conference presentations. OPEN SCIENCE FRA NETWORK (OSF) REGISTRATION NUMBER: August 19, 2020. osf.io/tbc7z. (https://osf.io/tbc7z).

New Insight into Diabetes Management: From Glycemic Index to Dietary Insulin Index.

BACKGROUND: Despite efforts to control hyperglycemia, diabetes management is still challenging. This may be due to focusing on reducing hyperglycemia and neglecting the importance of hyperinsulinemia; while insulin resistance and resultant hyperinsulinemia preceded diabetes onset and may contribute to disease pathogenesis. OBJECTIVE: The present narrative review attempts to provide a new insight into the management of diabetes by exploring different aspects of glycemic index and dietary insulin index. RESULTS: The current data available on this topic is limited and heterogeneous. Conventional diet therapy for diabetes management is based on reducing postprandial glycemia through carbohydrate counting, choosing foods with low-glycemic index and low-glycemic load. Since these indicators are only reliant on the carbohydrate content of foods and do not consider the effects of protein and fat on the stimulation of insulin secretion, they cannot provide a comprehensive approach to determine the insulin requirements. CONCLUSION: Selecting foods based on carbohydrate counting, glycemic index or glycemic load are common guides to control glycemia in diabetic patients, but neglect the insulin response, thus leading to failure in diabetes management. Therefore, paying attention to insulinemic response along with glycemic response seems to be more effective in managing diabetes.

The Effects of a Low Calorie Ketogenic Diet on Glycaemic Control Variables in Hyperinsulinemic Overweight/Obese Females.

Diet is a factor which can influence both glycaemic variables and body mass. The aim of this study was to compare the influence of a 12-week, well-planned, low-calorie ketogenic diet (LCKD) on hyperglycaemic, hyperinsulinemic and lipid profile in adult, overweight or obese females. Ninety-one females who participated in the study were divided into two groups: a LCKD group who followed a hypocaloric ketogenic diet (8% of carbohydrate, 72% of fat and 20% of proteins) (n = 46), and a control group (CG) (n = 45) who continued their typical diet (50% of carbohydrates, 32% of fat and 18% of proteins). METHODS: Baseline and post-intervention glucose (Gl), insulin (I), glycated haemoglobin (HbA1c), Homeostatic model assessment HOMA-IR, triglycerides (TG) and high-density cholesterol (HDL-C) were evaluated. Also, body mass (BM), waist circumference (WC), hip circumference (HC) and thigh circumference (TC) were measured. RESULTS: Compared with the CG, there were significant changes observed in the LCKD group regarding all biochemical variables. Also, BM, TC, WC and AC changed significantly in the LCKD group compared with the CG. CONCLUSIONS: The 12-week LCKD intervention changed the glucose control variables, body mass, as well as waist, hip and thigh circumferences. A low-calorie ketogenic diet may be recommended for adult females with glucose control variables disturbance and excess body mass.