Diagnosis to Delivery: A Randomized Clinical Trial of Postmeal Walking in Women with Gestational Diabetes

PURPOSE

The aim of this study was to determine whether advice to perform postmeal walking could be an effective and feasible alternate to standard care continuous walking for the management of gestational diabetes (GDM).

METHODS

Forty women with GDM were randomized between 28 and 30 wk of gestation into either standard care (CTL; 30-min continuous walking, most days per week) or standard care with advice to PMW (daily 10-min walks after three main meals) for ~7 wk. The primary outcome for this randomized controlled trial was postprandial glucose assessed by continuous glucose monitors. Continuous glucose monitor and ActivPAL inclinometers (physical activity parameters) were each worn for 7 d at ~28 and ~35 wk gestation. Delivery outcomes were also collected. A linear mixed model compared the changes across time between groups.

RESULTS

Twenty-six women (PMW: n = 12, CTL: n = 14; age 34 ± 5 y) completed the trial. Mean 3 h postprandial glucose at dinner was higher in the PMW versus CTL group at baseline and across the intervention (main effect group, P = 0.04). Twenty-four hours, nocturnal, and fasting glucose were similar between groups. The PMW group spent ~57 min·d -1 more time sedentary and ~11 min·d -1 less time stepping versus CTL (main effect group: P = 0.02 and 0.05). Adherence to the prescribed 30 min·d -1 of physical activity was high, regardless of whether accumulated as 3 × 10-min or one single bout of walking.

CONCLUSIONS

Distributing activity as 10-min bouts after main meals did not improve postprandial glucose outcomes compared with standard-care control. More research on the optimal duration and intensity of postmeal walks to improve postprandial responses are needed. Strategies that mitigate sedentary time and increase the minutes of physical activity accumulated across the day in pregnancy are also warranted.

No difference in postprandial mesenteric blood flow between healthy younger and elderly individuals

We recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in patients with Parkinson's disease compared to age- and sex-matched healthy controls. Since both groups showed substantial inter-individual variations, we extended the cohort of controls with a group of young individuals to investigate possible age-related effects. Seventeen healthy young subjects aged < 30 years and 17 elderly subjects aged > 50 years underwent serial PC-MRI to measure the postprandial blood flow response in the SMA after ingestion of a standardized liquid test meal (∼400 kcal). Postprandial blood flow dynamics in SMA did not differ between young and elderly subjects. A noticeable inter-individual variation in postprandial intestinal blood flow increase was found, and approximately 30% of the variation could be explained by the preprandial blood flow. Regardless of age, some subjects showed a remarkable transient SMA blood flow increase immediately after meal intake. This study provides tentative evidence that postprandial blood flow dynamics in SMA in healthy young and elderly subjects do not substantially differ, indicating that age is without impact on vascular response in SMA as an indicator for regulation of mesenteric perfusion in response to food intake.

Effect of Single Oral Coingestion of GABA and Malic Acid on Postprandial GLP-1, Glucose, and Insulin Responses in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

SCOPE

This study examines whether coingestion of γ-aminobutyric acid (GABA) and malic acid (MA) before meals enhances glucagon-like peptide-1 (GLP-1) secretion, and which affects subsequent insulin and glycemic responses in humans.

METHODS AND RESULTS

Initially, a murine enteroendocrine STC-1 cell line is used to verify coadministration of GABA and MA synergistically induces GLP-1 secretion. Next, 22 healthy adults are given water (50 mL) containing 400 mg GABA and 400 mg MA (Test), or only 400 mg citric acid (CA) (Placebo) 20 min before meal tolerance test (MTT). Interval blood samples are taken postprandially over 180 min to determine GLP-1, insulin, and glucose responses. By comparison to preload of Placebo, preload of Test significantly increases plasma GLP-1 (total/active) levels (incremental area under the curve by 1.2- and 1.6-fold), respectively. However, there are no significant differences in postprandial blood glucose and insulin.

CONCLUSION

Coingestion of GABA and MA before meals enhances postprandial GLP-1 secretion. Future studies should explore optimal dosage regimens to find the efficacy of the mixture on insulin and glycemic response.

Short-term recovery of insulin secretion in response to a meal is associated with future glycemic control in type 2 diabetes patients

AIMS/INTRODUCTION

Endogenous insulin secretion could be recovered by improving hyperglycemia in patients with type 2 diabetes. This study aimed to investigate the association between short-term recovery of insulin secretion during hospitalization and clinical background or future glycemic control in patients with type 2 diabetes.

MATERIALS AND METHODS

A total of 127 patients with type 2 diabetes were included. The recovery of endogenous insulin secretion was determined using the following indices: index A: fasting C-peptide index (CPI) at discharge - fasting CPI on admission; index B: postprandial CPI at discharge - postprandial CPI on admission; and index C: Δ C-peptide immunoreactivity (CPR) (postprandial CPR - fasting CPR) at discharge - ΔCPR on admission. We examined the associations of each index with clinical background and future glycemic control measured by glycosylated hemoglobin and continuous glucose monitoring.

RESULTS

Using index A and B, the age was significantly younger, whereas BMI and visceral fat area were significantly higher in the high-recovery group than in the low-recovery group. Changes in glycosylated hemoglobin levels were significantly greater at 6 and 12 months in the high-recovery group in the analysis of index C. The receiver operating characteristic curve analysis identified the index B and index C as indicators to predict glycosylated hemoglobin <7.0% at 6 months after discharge. Furthermore, index C was positively correlated with the time in the target glucose range, and inversely correlated with the standard deviation of glucose at 3 and 12 months after discharge.

CONCLUSIONS

Short-term recovery of insulin secretion in response to a meal during hospitalization, evaluated with the index-C, might predict future glycemic control.

GLP-1 response during pregnancy: variations between trimesters and associations with appetite sensations and usual energy intake

Further research is required to understand hormonal regulation of food intake during pregnancy and its association with energy intake. The objectives are to (i) compare postprandial responses of plasma glucagon-like peptide-1 (GLP-1) between trimesters, (ii) compare postprandial appetite sensations between trimesters, and (iii) examine trimester-specific associations between GLP-1 levels, appetite sensations, and usual energy intake. At each trimester, participants (n = 26) consumed a standard test meal following a 12 h fast. Plasma GLP-1 levels were measured by enzyme-linked immunosorbent assay method at fasting and at 30, 60, 120, and 180 min postprandial. A visual analogue scale assessing appetite sensations was completed at fasting and at 15, 30, 45, 60, 90, 120, 150, and 180 min postprandial. Mean energy intake was assessed using three web-based 24 h dietary recalls at each trimester. Lower postprandial GLP-1 responses were observed in the 2nd (p = 0.004) and 3rd trimesters (p < 0.001) compared to the 1st trimester. Greater postprandial sensations of desire to eat, hunger, and prospective food consumption were noted in the 3rd trimester compared to the 1st trimester (p < 0.04, for all). Fasting GLP-1 was negatively associated with fasting appetite sensations (except fullness) at the 2nd trimester (p < 0.02, for all). Postprandially, significant associations were observed for incremental areas under the curve from 0 to 30 min between GLP-1 and fullness at the 2nd (p = 0.01) and 3rd trimesters (p = 0.03). No associations between fasting or postprandial GLP-1 and usual energy intake were observed. Overall, GLP-1 and appetite sensation responses significantly differ between trimesters, but few associations were observed between GLP-1, appetite sensations, and usual energy intake.

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.

Randomized trial in postprandial functional dyspepsia: Reassurance and diagnostic explanation with or without traditional dietary advice

BACKGROUND

Almost 80% of individuals with functional dyspepsia experience meal-related symptoms and are diagnosed with postprandial distress syndrome (PDS). However, studies evaluating dietary modifications in PDS are sparse. We performed a single-center randomized trial comparing reassurance and diagnostic explanation (RADE) with or without traditional dietary advice (TDA) in PDS.

METHODS

Following a normal upper gastrointestinal endoscopy, individuals with PDS were randomized to a leaflet providing RADE ± TDA; the latter recommending small, regular meals and reducing the intake of caffeine/alcohol/fizzy drinks and high-fat/processed/spicy foods. Questionnaires were completed over 4 weeks, including self-reported adequate relief of dyspeptic symptoms, and the validated Leuven Postprandial Distress Scale (LPDS), Gastrointestinal Symptom Rating Scale, and Nepean Dyspepsia Index for quality of life. The primary endpoint(s) to define clinical response were (i) ≥50% adequate relief of dyspeptic symptoms and (ii) >0.5-point reduction in the PDS subscale of the LPDS (calculated as the mean scores for early satiety, postprandial fullness, and upper abdominal bloating).

KEY RESULTS

Of the 53 patients with PDS, 27 were assigned RADE-alone and 26 to additional TDA. Baseline characteristics were similar between groups, with a mean age of 39 years, 70% female, 83% white British, and coexistent irritable bowel syndrome in 66%. The primary endpoints of (i) adequate relief of dyspeptic symptoms were met by 33% (n = 9) assigned RADE-alone versus 39% (n = 10) with TDA; p-value = 0.70, while (ii) a reduction of >0.5 points in the PDS subscale was met by 37% (n = 10) assigned RADE-alone versus 27% (n = 7) with TDA; p-value = 0.43. Response rates did not differ according to irritable bowel syndrome status. There were no significant between-group changes in the gastrointestinal symptom rating scale and dyspepsia quality of life.

CONCLUSIONS & INFERENCES

This study of predominantly white British patients with PDS found the addition of TDA did not lead to significantly greater symptom reduction compared with RADE alone. Alternate dietary strategies should be explored in this cohort.

Dietary impact on fasting and stimulated GLP-1 secretion in different metabolic conditions - a narrative review

Glucagon-like peptide 1 (GLP-1), a gastrointestinal peptide and central mediator of glucose metabolism, is secreted by L cells in the intestine in response to food intake. Postprandial secretion of GLP-1 is triggered by nutrient-sensing via transporters and G-protein-coupled receptors (GPCRs). GLP-1 secretion may be lower in adults with obesity/overweight (OW) or type 2 diabetes mellitus (T2DM) than in those with normal glucose tolerance (NGT), but these findings are inconsistent. Because of the actions of GLP-1 on stimulating insulin secretion and promoting weight loss, GLP-1 and its analogs are used in pharmacologic preparations for the treatment of T2DM. However, physiologically stimulated GLP-1 secretion through the diet might be a preventive or synergistic method for improving glucose metabolism in individuals who are OW, or have impaired glucose tolerance (IGT) or T2DM. This narrative review focuses on fasting and postprandial GLP-1 secretion in individuals with different metabolic conditions and degrees of glucose intolerance. Further, the influence of relevant diet-related factors (e.g., specific diets, meal composition, and size, phytochemical content, and gut microbiome) that could affect fasting and postprandial GLP-1 secretion are discussed. Some studies showed diminished glucose- or meal-stimulated GLP-1 response in participants with T2DM, IGT, or OW compared with those with NGT, whereas other studies have reported an elevated or unchanged GLP-1 response in T2DM or IGT. Meal composition, especially the relationship between macronutrients and interventions targeting the microbiome can impact postprandial GLP-1 secretion, although it is not clear which macronutrients are strong stimulants of GLP-1. Moreover, glucose tolerance, antidiabetic treatment, grade of overweight/obesity, and sex were important factors influencing GLP-1 secretion. The results presented in this review highlight the potential of nutritional and physiologic stimulation of GLP-1 secretion. Further research on fasting and postprandial GLP-1 concentrations and the resulting metabolic consequences under different metabolic conditions is needed.

Prior acute exercise restores postprandial fat oxidation in active cannabis users

Data suggest cannabis users have similar or lower levels of blood lipids compared to nonusers. However, the extent to which cannabis users experience postprandial lipemia is not known. Eleven cannabis users and 11 nonusers completed either rest or 1 h of exercise at their ventilatory threshold the evening before a meal tolerance test (MTT). Substrate oxidation, blood pressure, and capillary blood were obtained before and every 30-60 min post-meal for 3 h. Linear mixed models were utilized to examine differences in variables between groups, conditions, across time, and their interactions. Exercise led to increased fat oxidation post-MTT (p < 0.05), with cannabis users exhibiting higher AUC compared to the control trial (p < 0.05). Exercise also caused significantly lower levels of triglycerides (p < 0.05). Metabolic flexibility was improved in cannabis users in the exercise trial only (p < 0.05). No effect of group, trial, or interactions were detected for other variables of interest (all p > 0.05). This study indicated that prior exercise improves lipid metabolism in cannabis users and nonusers after a high-fat meal test. Cannabis users appear sensitive to the effects of exercise. Future studies should incorporate additional meals and variables related to cardiovascular health and metabolism.

Timing and Nutrient Type of Isocaloric Snacks Impacted Postprandial Glycemic and Insulinemic Responses of the Subsequent Meal in Healthy Subjects

The aim of the study was to explore the impact of both the macronutrient composition and snacking timing on the postprandial glycemic insulinemic responses and food intake. Seventeen healthy female volunteers completed the randomized crossover trials. The volunteers were provided a standard breakfast and lunch at 8:00 and 13:00, respectively, and an ad libitum dinner at 18:00. Provided at either 10:30 (midmorning) or 12:30 (preload), the glycemic effects of the three types of 70 kcal snacks, including chicken breast (mid-C and pre-C), apple (mid-A and pre-A), and macadamia nut (mid-M and pre-M), were compared with the non-snack control (CON), evaluated by continuous glucose monitoring (CGM). The mid-M showed increased insulin resistance after lunch compared with CON, while the pre-M did not. The pre-A stabilized the glycemic response in terms of all variability parameters after lunch, while the mid-A had no significant effect on postprandial glucose control. Both the mid-C and pre-C improved the total area under the glucose curve, all glycemic variability parameters, and the insulin resistance within 2 h after lunch compared with CON. The pre-C attained the lowest energy intake at dinner, while the mid-A and the mid-M resulted in the highest. In conclusion, the chicken breast snack effectively stabilized postprandial glycemic excursion and reduced insulin resistance while the macadamia snack did not, regardless of ingestion time. Only as a preload could the apple snack mitigate the glucose response after the subsequent meal.

Postprandial kinetics of digestive function in rainbow trout (Oncorhynchus mykiss): genes expression, enzymatic activity and blood biochemistry as a practical tool for nutritional studies

Postprandial kinetics of genes expression of gastric (chitinase, pepsinogen) and intestinal (alkaline phosphatase, maltase) digestive enzymes and nutrient transporters (peptide transporter 1, sodium-glucose transporter 1), Brush Border Membrane (BBM) enzymes activity (alkaline phosphatase, leucine aminopeptidase, maltase, saccharase) and blood biochemistry (triglycerides, cholesterol, protein, albumin, glucose, amino acids) through NMR spectroscopy, were investigated in rainbow trout (Oncorhynchus mykiss) fed a commercial aquafeed. For this purpose, fish were starved 72 h and digestive tract and blood were sampled before the meal and at 1.5, 3, 6, 9, 12, and 24 h after feeding (T0, T1.5, T3, T6, T9, T12 and T24). The postprandial kinetic showed that the expression of the genes involved in digestion and nutrient transport, the activity of BBM enzymes, and the presence of metabolites in blood were stimulated in different ways by the presence of feed in the digestive tract. The expression of most genes peaked 3 h after meal except gastric pepsinogen and maltase in distal intestine that peaked at T9 and T12, respectively. The activity of BBM enzymes were stimulated differently based on the intestine tract. The plasma proteins level increased from T1.5 until T9, while the other blood parameters unvariated during the postprandial period. This study supplied useful information about the physiological effects a single meal as a potential tool for planning nutritional studies involving the digestive functions.

Lower basal and postprandial muscle protein synthesis after 2 weeks single-leg immobilization in older men: No protective effect of anti-inflammatory medication

Muscle inactivity may reduce basal and postprandial muscle protein synthesis (MPS) rates in humans. Anti-inflammatory treatment alleviates the MPS impairments in younger individuals. The present study explored the influence of nonsteroidal anti-inflammatory drugs (NSAIDs) upon MPS during a period of inactivity in older humans. Eighteen men (age 60-80 years) were allocated to ibuprofen (1200 mg/day, Ibu) or control (Plc) groups. One lower limb was cast immobilized for 2 weeks. Postabsorptive and postprandial MPS was measured before and after the immobilization by L-[ring-13 C6 ]-phenylalanine infusion. The protein expression of select anabolic signaling molecules was investigated by western blot. Basal (0.038 ± 0.002%/h and 0.039 ± 0.005%/h, Plc and Ibu, respectively) and postprandial (0.064 ± 0.004%/h and 0.067 ± 0.010%/h, Plc and Ibu, respectively) MPS rate were higher pre-immobilization compared to basal (0.019 ± 0.005%/h and 0.020 ± 0.010%/h, Plc and Ibu, respectively) and postprandial (0.033 ± 0.005%/h and 0.037 ± 0.006%/h, Plc and Ibu, respectively) MPS rate post-immobilization (p < 0.001). NSAID treatment did not affect the suppression of MPS (p > 0.05). The anabolic signaling were in general reduced after immobilization (p < 0.05). These changes were unaffected by NSAID treatment (p > 0.05). Basal and postprandial MPS dropped markedly after 2 weeks of lower limb immobilization. NSAID treatment neither influenced the reduction in MPS nor the anabolic signaling after immobilization in healthy older individuals.

Delayed dinnertime impairs glucose tolerance in healthy young adults

To explore the relationship between mealtime delays of up to 3 h and subsequent glucose fluctuations, healthy young adults were allocated to three delayed dinnertimes in randomized order. Participants consumed test meals for lunch and dinner. After assessing the glucose responses using intermittently scanned continuous glucose monitoring devices (isCGM), the peak glucose elevation, and incremental area under the curve (iAUC) of postprandial glucose during certain intervals increased significantly when the time between lunch and dinner was delayed by 1 h or more. Our results support the importance of improving irregular mealtime habits, such as late eating.

Twelve Weeks of Daily Lentil Consumption Improves Fasting Cholesterol and Postprandial Glucose and Inflammatory Responses-A Randomized Clinical Trial

Lentils have potential to improve metabolic health but there are limited randomized clinical trials evaluating their comprehensive impact on metabolism. The aim of this study was to assess the impact of lentil-based vs. meat-based meals on fasting and postprandial measures of glucose and lipid metabolism and inflammation. Thirty-eight adults with an increased waist circumference (male ≥ 40 inches and female ≥ 35 inches) participated in a 12-week dietary intervention that included seven prepared midday meals totaling either 980 g (LEN) or 0 g (CON) of cooked green lentils per week. Linear models were used to assess changes in fasting and postprandial markers from pre- to post-intervention by meal group. Gastrointestinal (GI) symptoms were assessed through a survey randomly delivered once per week during the intervention. We found that regular consumption of lentils lowered fasting LDL (F = 5.53, p = 0.02) and total cholesterol levels (F = 8.64, p < 0.01) as well as postprandial glucose (β = -0.99, p = 0.01), IL-17 (β = -0.68, p = 0.04), and IL-1β (β = -0.70, p = 0.03) responses. GI symptoms were not different by meal group and all symptoms were reported as "none" or "mild" for the duration of the intervention. Our results suggest that daily lentil consumption may be helpful in lowering cholesterol and postprandial glycemic and inflammatory responses without causing GI stress. This information further informs the development of pulse-based dietary strategies to lower disease risk and to slow or reverse metabolic disease progression in at-risk populations.

Diabetes-Specific Complete Smoothie Formulas Improve Postprandial Glycemic Response in Obese Type 2 Diabetic Individuals: A Randomized Crossover Trial

This study aimed to compare newly developed diabetes-specific complete smoothie formulas with a standard diabetes-specific nutritional formula (DSNF) regarding their effects on glucose homeostasis, insulin levels, and lipid metabolism in obese type 2 diabetes (T2DM) patients. We conducted a randomized, double-blind, crossover study with 41 obese T2DM participants to compare two developed diabetes-specific complete smoothie formulas, a soy-based regular smoothie (SM) and a smoothie with modified carbohydrate content (SMMC), with the standard DSNF, Glucerna. Glycemic and insulin responses were assessed after the participants randomly consumed 300 kilocalories of each formulation on three separate days with a 7-day gap between. Postprandial effects on glycemic control, insulin levels, and lipid metabolism were measured. SMMC resulted in a significantly lower glucose area under the curve (AUC0-240) compared to Glucerna and SM (p < 0.05 for both). Insulin AUC0-240 after SMMC was significantly lower than that after SM and Glucerna (p < 0.05). During the diets, the suppression of NEFA was more augmented on SM, resulting in a less total AUC0-240 of NEFA compared to the SMMC diet (p < 0.05). C-peptide AUC0-240 after SMMC was significantly lower than that after Glucerna (p < 0.001). Conversely, glucagon AUC0-240 after SMMC was significantly higher than that after SM and Glucerna (p < 0.05). These results highlight SMMC as the better insulin-sensitive formula, potentially achieved through increased insulin secretion or a direct reduction in glucose absorption. The unique composition of carbohydrates, amino acids, and fats from natural ingredients in the smoothies may contribute to these positive effects, making them promising functional foods for managing diabetes and obesity.

Electrogastrography in patients with gastric motility disorders

Electrogastrography (EGG) is a novel diagnostic modality for assessing the gastrointestinal tract (GI) that generates spontaneous electrical activity and monitors gastric motility. The aim of this study was to compare patients with functional dyspepsia (FD) and diabetic gastroparesis (D-GP) with healthy controls (CT) to use established findings on abnormalities of gastric motility based on EGG characteristics. In this study, 50 patients with FD, 50 D-GP patients, and 50 CT subjects were studied to compare EGG with discrete wavelet transform models (DWT) to extract signal characteristics using a variety of different qualitative and quantitative metrics from pre-prandial and postprandial states. As a result, higher statistically significant (p < 0.05*) were found in the DWT models based on power spectral density (PSD) analysis in both states. We also present that the correlations between EGG metrics and the presence of FD, D-GP, and CT symptoms were inconsistent. This paper represents that EGG assessments of FD and D-GP patients differ from healthy controls in terms of abnormalities of gastric motility. Additionally, we demonstrate that diverse datasets showed adequate gastric motility responses to a meal. We anticipate that our method will provide a comprehensive understanding of gastric motility disorders for better treatment and monitoring in both clinical and research settings. In conclusion, we present potential future opportunities for precise gastrointestinal electrophysiological disorders.

Neurohormonal response patterns to hunger, satiation, and postprandial fullness in normal weight, anorexia nervosa, and obesity

BACKGROUND

Food intake is regulated by homeostatic and hedonic systems that interact in a complex neuro-hormonal network. Dysregulation in energy intake can lead to obesity (OB) or anorexia nervosa (AN). However, little is known about the neurohormonal response patterns to food intake in normal weight (NW), OB, and AN.

MATERIAL & METHODS

During an ad libitum nutrient drink (Ensure®) test (NDT), participants underwent three pseudo-continuous arterial spin labeling (pCASL) MRI scans. The first scan was performed before starting the NDT after a > 12 h overnight fast (Hunger), the second after reaching maximal fullness (Satiation), and the third 30-min after satiation (postprandial fullness). We measured blood levels of ghrelin, cholecystokinin (CCK), glucagon-like peptide (GLP-1), and peptide YY (PYY) with every pCASL-MRI scan. Semiquantitative cerebral blood flow (CBF) maps in mL/100 gr brain/min were calculated and normalized (nCBF) with the CBF in the frontoparietal white matter. The hypothalamus (HT), nucleus accumbens [NAc] and dorsal striatum [DS] were selected as regions of interest (ROIs).

RESULTS

A total of 53 participants, 7 with AN, 17 with NW (body-mass index [BMI] 18.5-24.9 kg/m2 ), and 29 with OB (BMI ≥30 kg/m2 ) completed the study. The NW group had a progressive decrease in all five ROIs during the three stages of food intake (hunger, satiation, and post-prandial fullness). In contrast, participants with OB showed a minimal change from hunger to postprandial fullness in all five ROIs. The AN group had a sustained nCBF in the HT and DS, from hunger to satiation, with a subsequent decrease in nCBF from satiation to postprandial fullness. All three groups had similar hormonal response patterns with a decrease in ghrelin, an increase in GLP-1 and PYY, and no change in CCK.

CONCLUSION

Conditions of regulated (NW) and dysregulated (OB and AN) energy intake are associated with distinctive neurohormonal activity patterns in response to hunger, satiation, and postprandial fullness.

Postprandial triglycerides across the aging spectrum: A secondary analysis utilizing an abbreviated fat tolerance test

BACKGROUND & AIMS

Elevated postprandial triglycerides are an independent cardiovascular disease risk factor and observed in older adults. However, differences in postprandial triglycerides across the spectrum of adulthood remain unclear.

METHODS AND RESULTS

We performed a secondary analysis of six studies where adults (aged 18-84 years; N = 155) completed an abbreviated fat tolerance test (9 kcal/kg; 70% fat). Differences in postprandial triglycerides were compared in those ≥50 and <50 years and by decade of life, adjusting for sex and BMI. Compared to those <50 years, participants ≥50 years had higher fasting, 4 h, and Δ triglycerides from baseline (p's < 0.05). When examining triglyceride parameters by decade, no differences were observed for fasting triglycerides, but 50 s, 60 s, and 70s-80 s displayed greater 4 h and Δ triglycerides versus 20 s (p's ≤ 0.001). The frequency of adverse postprandial triglyceride responses (i.e., ≥220 mg/dL) was higher in participants ≥50 versus <50 years (p < 0.01), and in 60 s compared to all other decades (p = 0.01).

CONCLUSION

Older age was generally associated with higher postprandial triglycerides, with no divergence across the spectrum of older adulthood. In our sample, postprandial triglyceride differences in older and younger adults were driven by those >50 years relative to young adults in their 20 s.

REGISTRATION

N/A (secondary analysis).

The Overlap Subgroup of Functional Dyspepsia Exhibits More Severely Impaired Gastric and Autonomic Functions

GOALS

A combination of multiple tests was introduced to noninvasively investigate the differences in pathophysiologies among functional dyspepsia (FD) subgroups, including postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and overlap.

BACKGROUND

It has not been extensively evaluated whether different pathophysiologies are involved in FD subgroups.

STUDY

This multicenter study included 364 FD patients fulfilling Rome IV criteria and 47 healthy controls. A combined noninvasive gastric and autonomic function test was performed: The electrogastrogram and electrocardiogram were recorded simultaneously in the fasting state and after a drink test. Symptoms after drinking were recorded using visual analog scale.

RESULTS

(1) Compared with HC, FD patients showed a decreased maximum tolerable volume (MTV) ( P <0.01) and percentage of normal gastric slow waves [normal gastric slow waves (%NSW)] ( P <0.01), and increased postdrinking symptoms, anxiety ( P <0.01), and depression ( P <0.01). The drink reduced %NSW in both FD patients and HC; however, the effect was more potent in patients. (2) The PDS and overlap groups displayed a reduced MTV ( P <0.05). The overlap group exhibited a higher symptom score at 30 minutes after drinking, and higher anxiety and depression scores, and a higher sympathovagal ratio than the EPS ( P <0.05 for all) and PDS ( P <0.01 for all). (3) In the PDS subgroup, the MTV, postprandial sympathovagal ratio, and depression were associated with the overall dyspepsia symptom scale (DSS, P =0.034, 0.021, 0.043, respectively). No significant associations were found in the other 2 subgroups.

CONCLUSIONS

The combination of multiple tests can detect pathophysiological abnormities in FD patients. Overall, patients with overlap symptoms display more severe pathophysiologies.

Are There Interindividual Responses of Cardiovascular Disease Risk Markers to Acute Exercise? A Replicate Crossover Trial

PURPOSE

Using a replicated crossover design, we quantified the response heterogeneity of postprandial cardiovascular disease risk marker responses to acute exercise.

METHODS

Twenty men (mean (SD) age, 26 (6) yr; body mass index, 23.9 (2.4) kg·m -2 ) completed four 2-d conditions (two control, two exercise) in randomized orders. On days 1 and 2, participants rested and consumed two high-fat meals over 9 h. Participants ran for 60 min (61 (7)% of peak oxygen uptake) on day 1 (6.5 to 7.5 h) of both exercise conditions. Time-averaged total area under the curve (TAUC) for triacylglycerol, glucose, and insulin were calculated from 11 venous blood samples on day 2. Arterial stiffness and blood pressure responses were calculated from measurements at baseline on day 1 and at 2.5 h on day 2. Consistency of individual differences was explored by correlating the two replicates of control-adjusted exercise responses for each outcome. Within-participant covariate-adjusted linear mixed models quantified participant-by-condition interactions and individual response SDs.

RESULTS

Acute exercise reduced mean TAUC-triacylglycerol (-0.27 mmol·L -1 ·h; Cohen's d = 0.29, P = 0.017) and TAUC-insulin (-25 pmol·L -1 ·h; Cohen's d = 0.35, P = 0.022) versus control, but led to negligible changes in TAUC-glucose and the vascular outcomes (Cohen's d ≤ 0.36, P ≥ 0.106). Small-to-moderate, but nonsignificant, correlations were observed between the two response replicates ( r = -0.42 to 0.15, P ≥ 0.066). We did not detect any individual response heterogeneity. All participant-by-condition interactions were P ≥ 0.137, and all individual response SDs were small with wide 95% confidence intervals overlapping zero.

CONCLUSIONS

Large trial-to-trial within-subject variability inhibited detection of consistent interindividual variability in postprandial metabolic and vascular responses to acute exercise.

Impaired gastric accommodation in patients with postprandial distress syndrome type of functional dyspepsia assessed by 2D ultrasonography

BACKGROUND AND PURPOSE

The pathophysiology of postprandial distress syndrome includes impaired gastric accommodation, hypersensitivity to gastric distension and delayed gastric emptying. 2D-ultrasonography is one of the methods to assess gastric accommodation by measuring proximal gastric area and we evaluated its role in calculating proximal gastric area and thus assessing gastric accommodation in Indian patients with postprandial distress syndrome.

METHODS

In a hospital-based comparative analysis, proximal gastric area was measured with 2D-ultrasonography of postprandial distress syndrome (PDS) patients and compared with healthy controls. Five readings were measured every five minutes till 25 minutes after 400 mL of vegetable soup. The Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life (PAGI-QOL score) and diets aggravating PDS symptoms were studied through detailed questionnaires. Sample size was calculated at 80% study power and alpha error of 0.05 to be 30 subjects in each group.

RESULTS

The mean age of patients (18 males) vs. 30 healthy controls (25 males) was 40.8 ± 11.50 years vs. 36.37 ± 7.58, respectively, (p = 0.084). Proximal gastric area was significantly lower in patients versus healthy controls at five minutes (22.54 ± 2.77 vs. 30.66 ± 2.55 cm2), 10 minutes (23.03 ± 2.45 vs. 31.10 ± 2.06 cm2), 15 minutes (23.06 ± 2.27 vs. 30.31 ± 2.11 cm2), 20 minutes (22.21 ± 2.31 vs. 29.73 ± 1.71 cm2) and 25 minutes (22.02 ± 2.33 vs. 28.39 ± 1.55 cm2); p < 0.001 at all intervals of time, indicating impaired gastric accommodation. The QOL was poor in all patients with PDS with mean PAGI-QOL score of 31.30 ± 15.05, median of 30, minimum score of 12 and maximum score of 66.

CONCLUSIONS

Measurement of proximal gastric area with 2D-ultrasonography is simple and non-invasive. Proximal gastric area in patients was lower than controls, indicating impaired gastric accommodation. Poor quality of life was universal in patients with postprandial distress syndrome.

Metabolic adaptation is associated with a greater increase in appetite following weight loss: a longitudinal study

BACKGROUND

Weight loss is associated with a disproportionate reduction in energy expenditure, along with increases in hunger feelings and ghrelin concentrations. These changes are presumed to be homeostatic mechanisms to counteract the energy deficit. The possibility that these 2 components of the energy balance equation are mechanistically linked has never been examined.

OBJECTIVE

This study aimed to determine if the disproportionate reduction in resting metabolic rate (RMR) seen with weight loss is associated with changes in the plasma concentration of gastrointestinal hormones involved in appetite regulation and subjective appetite ratings.

METHODS

This was a longitudinal study with repeated measurements. Fifty-six individuals with obesity (body mass index [BMI]: 34.5±0.5 kg/m2; age: 47±1 y; 26 males) underwent an 8 wk low-energy diet, followed by 4 wk of refeeding and weight stabilization. The RMR, respiratory quotient (RQ), body composition, plasma concentrations of ghrelin, glucagon-like peptide 1, peptide YY, cholecystokinin, insulin, and appetite ratings in the fasting and postprandial states were measured at baseline, Wk9 and 13. Metabolic adaptation was defined as significantly lower when measured versus the predicted RMR (pRMR) (from own regression model using baseline data).

RESULTS

A 14.2±0.6 kg weight loss was seen at Wk9 and maintained at Wk13. RQ was significantly reduced at Wk9 (0.82±0.06 vs. 0.76±0.05, P< 0.001) but returned to baseline at Wk13. Metabolic adaptation was seen at Wk9, but not Wk13 (-341±58, P <0.001 and -75±72 kJ/d, P = 0.305, respectively). The larger the difference between measured and predicted RMR at both timepoints, the greater the increase in hunger, desire to eat, and composite appetite score (fasting and postprandial at Wk9, postprandial only at Wk13), even after adjusting for weight loss and RQ.

CONCLUSION

A larger metabolic adaptation during weight loss is accompanied by a greater drive to eat. This might help explain the interindividual differences in weight loss outcomes to dietary interventions.

Interrupting prolonged sitting with frequent short bouts of light-intensity activity in people with type 1 diabetes improves glycaemic control without increasing hypoglycaemia: The SIT-LESS randomised controlled trial

AIM

To examine the impact of interrupting prolonged sitting with frequent short bouts of light-intensity activity on glycaemic control in people with type 1 diabetes (T1D).

MATERIALS AND METHODS

In total, 32 inactive adults with T1D [aged 27.9 ± 4.7 years, 15 men, diabetes duration 16.0 ± 6.9 years and glycated haemoglobin 8.4 ± 1.4% (68 ± 2.3 mmol/mol)] underwent two 7-h experimental conditions in a randomised crossover fashion with >7-day washout consisting of: uninterrupted sitting (SIT), or, interrupted sitting with 3-min bouts of self-paced walking at 30-min intervals (SIT-LESS). Standardised mixed-macronutrient meals were administered 3.5 h apart during each condition. Blinded continuous glucose monitoring captured interstitial glucose responses during the 7-h experimental period and for a further 48-h under free-living conditions.

RESULTS

SIT-LESS reduced total mean glucose (SIT 8.2 ± 2.6 vs. SIT-LESS 6.9 ± 1.7 mmol/L, p = .001) and increased time in range (3.9-10.0 mmol/L) by 13.7% (SIT 71.5 ± 9.5 vs. SIT-LESS 85.1 ± 7.1%, p = .002). Hyperglycaemia (>10.0 mmol/L) was reduced by 15.0% under SIT-LESS (SIT 24.2 ± 10.8 vs. SIT-LESS 9.2 ± 6.4%, p = .002), whereas hypoglycaemia exposure (<3.9 mmol/L) (SIT 4.6 ± 3.0 vs. SIT-LESS 6.0 ± 6.0%, p = .583) was comparable across conditions. SIT-LESS reduced glycaemic variability (coefficient of variation %) by 7.8% across the observation window (p = .021). These findings were consistent when assessing discrete time periods, with SIT-LESS improving experimental and free-living postprandial, whole-day and night-time glycaemic outcomes (p < .05).

CONCLUSIONS

Interrupting prolonged sitting with frequent short bouts of light-intensity activity improves acute postprandial and 48-h glycaemia in adults with T1D. This pragmatic strategy is an efficacious approach to reducing sedentariness and increasing physical activity levels without increasing risk of hypoglycaemia in T1D.

Reversal of Conditioned Food Aversion Using a Cognitive Intervention: A Sham-Controlled, Randomized, Parallel Study

BACKGROUND

Aversive conditioning weakens the gratifying value of a comfort meal. The aim was to determine the effect of a cognitive intervention to reverse aversive conditioning and restore hedonic postprandial response.

METHODS

This was a randomized, sham-controlled, single-blind, parallel study that was conducted on 12 healthy women (n = 6 in each group). The reward value of a comfort meal was measured on different days: at initial exposure, after aversive conditioning (administration of the same meal with a masked fat overload on the previous day) and after a cognitive intervention (disclosing the aversive conditioning paradigm in the test group vs. no explanation in the control group). The primary outcome, digestive wellbeing, was determined using graded scales at regular intervals before and after ingestion.

RESULTS

At initial exposure, the comfort meal produced a rewarding experience that was impaired using aversive conditioning; upon re-exposure to the original meal, the cognitive intervention increased meal wanting and liking; improved digestive wellbeing and mood; tended to reduce postprandial satiety, bloating/fullness; and abolished discomfort/pain, thereby restoring the hedonic value of the comfort meal. By contrast, sham intervention had no effects, and the postprandial sensations remained like the responses to the offending meal.

CONCLUSION

In this proof-of-concept study, we demonstrate that in healthy women, a mild, short-term acquired aversion to a comfort meal can be reversed using a cognitive intervention.

CLINICALTRIALS

gov ID: NCT05897411.

Different post-pancreatectomy glucagon responses to a meal test between surgical approaches

Residual pancreatic endocrine function is important for maintaining metabolic status after pancreatectomy and is closely related to patient nutritional status and prognosis. In contrast to insulin secretion, the significance of glucagon secretion following pancreatectomy remains unclear. In this study, we assessed the changes in pancreatic glucagon secretion during pancreatectomy to determine their pathophysiological significance. We evaluated glucagon and insulin secretion using a liquid meal tolerance test before and after pancreatectomy in patients scheduled to undergo pancreaticoduodenectomy (PD) or distal pancreatectomy (DP). After pancreatectomy, fasting plasma glucagon levels were significantly decreased in both the PD (n = 10) and DP (n = 5) groups (PD: from 18.4 to 10.5 pg/mL, p = 0.037; DP: from 21.0 to 12.1 pg/mL, p = 0.043), whereas postprandial plasma glucagon levels were not changed. In the liquid meal tolerance test after pancreatectomy, 60-min plasma glucagon levels and the area under the curve (AUC) for 0-120 min of PD were significantly higher than those for DP (60-min plasma glucagon: PD 49.0 vs. DP 21.7 pg/mL, p = 0.040; AUC0-120min: PD 4,749 vs. DP 3,564 μg min/mL, p = 0.028). Postoperative plasma glucose, serum insulin, and serum C-peptide levels during the liquid meal tolerance test were not significantly different between the two groups. Although fasting plasma glucagon levels decreased, postprandial glucagon responses were maintained after both PD and DP. The difference in residual meal-stimulated glucagon response between PD and DP suggests that a relative excess of postprandial glucagon is involved in the postoperative nutritional status after PD through its impact on systemic metabolic status.

The effect of bodyweight exercise on 24-h glycemic responses determined by continuous glucose monitoring in healthy inactive adults: a randomized crossover study

Vigorous intermittent exercise can improve indices of glycemia in the 24 h postexercise period in apparently healthy individuals. We examined the effect of a single session of bodyweight exercise (BWE) on glycemic responses using continuous glucose monitoring (CGM) under controlled dietary conditions. Healthy inactive adults (n = 27; 8 males, 19 females; age: 23 ± 3 years) completed 2 virtually supervised trials spaced ~ 1 week apart in a randomized, crossover manner. The trials involved an 11-min BWE protocol that consisted of 5 × 1-min bouts performed at a self-selected pace interspersed with 1-min active recovery periods or a non-exercise sitting control period (CON). Mean heart rate during the BWE protocol was 147 ± 14 beats per min (75% of age-predicted maximum). Mean 24 h glucose after BWE and CON was not different (5.0 ± 0.4 vs 5.0 ± 0.5 mM respectively; p = 0.39). There were also no differences between conditions for measures of glycemic variability or the postprandial glucose responses after ingestion of a 75 g glucose drink or lunch, dinner, and breakfast meals. This study demonstrates the feasibility of conducting a remotely supervised BWE intervention using CGM under free-living conditions. Future studies should investigate the effect of repeated sessions of BWE training or responses in people with impaired glycemic control.

A New Dietary Fiber Can Enhance Satiety and Reduce Postprandial Blood Glucose in Healthy Adults: A Randomized Cross-Over Trial

BACKGROUND

Dietary fiber plays a potential role in regulating energy intake and stabilizing postprandial blood glucose levels. Soluble dietary fiber has become an important entry point for nutritional research on the regulation of satiety.

METHODS

this was a double-blind, randomized cross-over trial enrolling 12 healthy subjects to compare the effects of RPG (R+PolyGly) dietary fiber products (bread, powder, and capsule) and pectin administered with a standard meal on satiety, blood glucose, and serum insulin level.

RESULTS

Adding 3.8% RPG dietary fiber to bread significantly increased the volume, water content, hardness, and chewiness of bread compared to 3.8% pectin bread and white bread and significantly improved the sensory quality of bread. RPG bread had better appetite suppression effects at some time points than the other two groups and the best postprandial blood glucose lowering effects among the three groups. Administration of RPG capsules containing 5.6 g of RPG dietary fiber with meals improved satiety and reduced hunger compared to 6 g of RPG powder and 6 g of pectin, which had the greatest effect on suppressing appetite and reducing prospective food consumption. The peak level of serum glucagon-like peptide-1 (GLP-1) in the RPG capsule group (578.17 ± 19.93 pg/mL) was significantly higher than that in other groups at 0 min and 30 min after eating. RPG powder had the best effect in reducing postprandial blood glucose and increasing serum insulin levels; the total area under the curve (AUC) of serum insulin with RPG powder was higher than other groups (5960 ± 252.46 μU min/mL).

CONCLUSION

RPG dietary fiber products can improve the sensory properties of food, reduce postprandial blood glucose, and enhance satiety, especially in capsule and powder forms. Further research on the physiological effects of RPG dietary fiber is required to facilitate its use as a functional ingredient in food products.

Efficacy of Postprandial Exercise in Mitigating Glycemic Responses in Overweight Individuals and Individuals with Obesity and Type 2 Diabetes-A Systematic Review and Meta-Analysis

Studies investigating the acute effect of postprandial exercise (PPE) on glucose responses exhibit significant heterogeneity in terms of participant demographic, exercise protocol, and exercise timing post-meal. As such, this study aimed to further analyze the existing literature on the impact of PPE on glycemic control in overweight individuals and individuals with obesity and type 2 diabetes (T2DM). A literature search was conducted through databases such as PubMed, CINAHL, and Google Scholar. Thirty-one original research studies that met the inclusion criteria were selected. A random-effect meta-analysis was performed to compare postprandial glucose area under the curve (AUC) and 24 h mean glucose levels between PPE and the time-matched no-exercise control (CON). Subgroup analyses were conducted to explore whether the glucose-lowering effect of PPE could be influenced by exercise duration, exercise timing post-meal, and the disease status of participants. This study revealed a significantly reduced glucose AUC (Hedges' g = -0.317; SE = 0.057; p < 0.05) and 24 h mean glucose levels (Hedges' g = -0.328; SE = 0.062; p < 0.05) following PPE compared to CON. The reduction in glucose AUC was greater (p < 0.05) following PPE lasting >30 min compared to ≤30 min. The reduction in 24 h mean glucose levels was also greater (p < 0.05) following PPE for ≥60 min compared to <60 min post-meal and in those with T2DM compared to those without T2DM. PPE offers a viable approach for glucose management and can be performed in various forms so long as exercise duration is sufficient. The glucose-lowering effect of PPE may be further enhanced by initiating it after the first hour post-meal. PPE is a promising strategy, particularly for patients with T2DM. This manuscript is registered with Research Registry (UIN: reviewregistry1693).

Bioactive compounds in pomace olive oil modulate the inflammatory response elicited by postprandial triglyceride-rich lipoproteins in BV-2 cells

Modulation of microglial response could be a target to reduce neuroinflammation associated with Alzheimer's disease. In this study, we propose that lipophilic bioactive molecules present in pomace olive oil (POO), transported in triglyceride-rich lipoproteins (TRLs), are able to modulate microglial high-oleic sunflower oil (HOSO, points) or pomace olive oil (POO, stripes). In order to prove this hypothesis, a randomized crossover postprandial trial was performed in 18 healthy young women. POO was assayed in opposition to high-oleic sunflower oil (HOSO), a common dietary oil which shares with POO an almost identical fatty acid composition but lacks certain biomolecules with recognized antioxidant and anti-inflammatory activities. TRLs were isolated from blood at the baseline and 2 and 4 hours postprandially and used to treat BV-2 cells to assess their ability to modulate the microglial function. We found that the intake of POO leads to the constitution of postprandial TRLs that are able to modulate the inflammatory response in microglia compared to HOSO. TRL-derived POO reduced the release of pro-inflammatory cytokines (tumor necrosis factor-α, and interleukins 1β and 6) and nitric oxide and downregulated genes codifying for these cytokines and inducible nitric oxide synthase (iNOS) in BV-2 cells. Moreover, the ingestion of POO by healthy women slightly improved glycemic control and TRL clearance throughout the postprandial phase compared to HOSO. In conclusion, we demonstrated that consuming POO results in postprandial TRLs containing lipophilic bioactive compounds capable of regulating the inflammatory response prompted by microglial activation.

Evaluation of postprandial total triglycerides within the TIGG model for characterizing postprandial response of glucose, insulin, and GLP-1

The TIGG model is the first model to integrate glucose and insulin regulation, incretin effect, and triglyceride (TG) response in the lipoprotein subclasses of chylomicrons and VLDL-V6. This model described the response following a high-fat meal in individuals who are lean, obese, and very obese and provided insights into the possible regulation of glucose homeostasis in the extended period following a meal. Often, total TGs are analyzed within clinical studies, instead of lipoprotein subclasses. We extended the existing TIGG model to capture the observed total TGs and determined if this model could be used to predict the postprandial TG response of chylomicron and VLDL-V6 when only total TGs are available. To assess if the lipoprotein distinction was important for the model, a second model (tTIGG) was developed using only the postprandial response in total TGs, instead of postprandial TG response in chylomicrons and VLDL-V6. The two models were compared on their predictability to characterize the postprandial response of glucose, insulin, and active GLP-1. Both models were able to characterize the postprandial TG response in individuals who are lean, obese, or very obese following a high-fat meal. The extended TIGG model resulted in a better model fit of the glucose data compared to the tTIGG model, indicating that chylomicron and VLDL-V6 provided additional information compared to total TGs. Furthermore, the expanded TIGG model was able to predict the postprandial TG response of chylomicrons and VLDL-V6 using the total TGs and could therefore be used in studies where only total TGs were collected.

Acute effects of daily step count on postprandial metabolism and resting fat oxidation: a randomized controlled trial

To examine the effects of daily step count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Ten healthy participants (5 females, 30 ± 7 yr) completed four different daily step counts-2,000 (2 K), 5,000 (5 K), 10,000 (10 K), and 15,000 (15 K) steps-on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FATOX) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-min following consumption of an HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), nonesterified fatty acids (NEFAs), insulin, and glucose. Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2 K versus 10 K (+23 ± 8 mg/dL, P = 0.027), and NEFAs were significantly higher after 15 K versus 2 K (+86 ± 23 µmol/L; P = 0.006). No differences were found for insulin, glucose, or REE among conditions (all P > 0.124). Similarly, RER (P = 0.054; ηp2 = 0.24) and FATOX (P = 0.071; ηp2 = 0.23) were not significantly different among conditions. In young adults, 10 K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15 K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity.NEW & NOTEWORTHY This randomized controlled trial demonstrated that walking 10,000, compared with 2,000, steps/day significantly reduced postprandial lipemia (PPL), an independent predictor of cardiovascular disease (CVD) following same-day evening meal consumption. These experimental data support walking 10,000 steps/day to lower CVD risk.

The Postprandial Plasma Amino Acid Response Does Not Differ Following the Ingestion of a Solid Versus a Liquid Milk Protein Product in Healthy Adult Females

Dietary protein digestion and amino acid absorption rates are modulated by numerous factors such as the food matrix. It has been speculated that protein ingested in liquid form is more rapidly digested and absorbed when compared with ingestion in solid form. Here, we assessed the postprandial plasma amino acid availability following ingestion of a single bolus of protein provided in either liquid or solid form. Twelve healthy, young females were included in this randomized cross-over study. On two separate test days, participants ingested 20-g milk protein concentrate in solid form (protein bar) or in liquid form (protein drink). Products were composed of matched ingredients and, thereby, had the same macro- and micronutrient composition. On both test days, arterialized blood samples were collected at regular time intervals for up to 4 hr following protein ingestion to assess the postprandial rise in plasma amino acid concentrations. Protein ingestion robustly elevated circulating plasma amino acid concentrations (p < .001), with no significant differences between treatments (p = .088). The incremental area under the curve of the postprandial rise in total plasma amino acid concentrations did not differ following bar versus drink consumption (160 ± 73 vs. 160 ± 71 mmol·L-1·240 min-1, respectively; 95% confidence interval [-37, 37]; Cohen's dz = 0.003; p = .992). Ingestion of protein in liquid or solid form does not modulate postprandial amino acid availability in healthy, female adults. Any differences in protein digestion and amino acid absorption due to differences in food matrix are not attributed to the protein being consumed as a bar or as a drink.

Breaking Up Evening Sitting with Resistance Activity Improves Postprandial Glycemic Response: A Randomized Crossover Study

INTRODUCTION

Interrupting sedentary time during the day reduces postprandial glycemia (a risk factor for cardiometabolic disease). However, it is not known if benefits exist for postprandial glucose, insulin and triglyceride responses in the evening, and if these benefits differ by body mass index (BMI) category.

METHODS

In a randomized crossover study, 30 participants (25.4 ± 5.4 yr old; BMI 18.5-24.9: n = 10, BMI 25-29.9: n = 10, BMI ≥30: n = 10) completed two intervention arms, beginning at ~1700 h: prolonged sitting for 4 h, and sitting with regular activity breaks of 3 min of resistance exercises every 30 min. Plasma glucose, insulin, and triglyceride concentrations were measured in response to two meals fed at baseline and 120 min. Four-hour incremental area under the curve was compared between interventions. Moderation by BMI status was explored.

RESULTS

Overall, when compared with prolonged sitting, regular activity breaks lowered plasma glucose and insulin incremental area under the curve by 31.5% (95% confidence interval = -49.3% to -13.8%) and 26.6% (-39.6% to -9.9%), respectively. No significant differences were found for plasma triglyceride area under the curve. Interactions between BMI status and intervention was not statistically significant.

CONCLUSIONS

Interventions that interrupt sedentary time in the evening may improve cardiometabolic health by some magnitude in all participants regardless of bodyweight.

Whey Protein Premeal Lowers Postprandial Glucose Concentrations in Adults Compared with Water-The Effect of Timing, Dose, and Metabolic Status: a Systematic Review and Meta-analysis

BACKGROUND

Serving whey protein before a meal in order to lower postprandial blood glucose concentrations is known as a premeal. The underlying mechanisms are only partly understood but may involve stimulation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin secretion together with a slower gastric emptying rate.

OBJECTIVES

The objective of this systematic review and meta-analysis was to review all randomized clinical trials investigating premeals with whey protein in comparison with a nonactive comparator (control) that evaluated plasma glucose, GLP-1, GIP, insulin, and/or gastric emptying rate. Secondary aims included subgroup analyses on the timing and dose of the premeal together with the metabolic state of the participants [lean, obese, and type 2 diabetes mellitus (T2DM)].

METHODS

We searched EMBASE, CENTRAL, PUBMED, and clinicaltrials.gov and found 16 randomized crossover trials with a total of 244 individuals. The last search was performed on 9 August, 2022.

RESULTS

Whey protein premeals lowered peak glucose concentration by -1.4 mmol/L [-1.9 mmol/L; -0.9 mmol/L], and the area under the curve for glucose was -0.9 standard deviation (SD) [-1.2 SD; -0.6 SD] compared with controls (high certainty). In association with these findings, whey protein premeals elevated GLP-1 (low certainty) and peak insulin (high certainty) concentrations and slowed gastric emptying rate (high certainty) compared with controls. Subgroup analyses showed a more pronounced and prolonged glucose-lowering effect in individuals with T2DM compared with participants without T2DM. The available evidence did not elucidate the role of GIP. The protein dose used varied between 4 and 55 g, and meta-regression analysis showed that the protein dose correlated with the glucose-lowering effects.

CONCLUSIONS

In conclusion, whey protein premeals lower postprandial blood glucose, reduce gastric emptying rate, and increase peak insulin. In addition, whey protein premeals may elevate plasma concentrations of GLP-1. Whey protein premeals may possess clinical potential, but the long-term effects await future clinical trials.

Pre-Meal Whey Protein Alters Postprandial Insulinemia by Enhancing β-Cell Function and Reducing Insulin Clearance in T2D

CONTEXT

Treatments that reduce postprandial glycemia (PPG) independent of stimulating insulin secretion are appealing for the management of type 2 diabetes (T2D). Consuming pre-meal whey protein (WP) reduces PPG by delaying gastric emptying and increasing plasma insulin concentrations. However, its effects on β-cell function and insulin kinetics remains unclear.

OBJECTIVE

To examine the PPG-regulatory effects of pre-meal WP by modeling insulin secretion rates (ISR), insulin clearance, and β-cell function.

METHODS

This was a single-blind, randomized, placebo-controlled, crossover design study in 18 adults with T2D (HbA1c, 56.7 ± 8.8 mmol/mol) who underwent 2 240-minute mixed-meal tolerance tests. Participants consumed WP (15 g protein) or placebo (0 g protein) 10 minutes before a mixed-macronutrient breakfast meal. PPG, pancreatic islet, and incretin hormones were measured throughout. ISR was calculated by C-peptide deconvolution. Estimates of insulin clearance and β-cell function were modeled from glucose, insulin, and ISR. Changes in PPG incremental area under the curve (iAUC; prespecified) and insulin clearance (post hoc) were measured.

RESULTS

β-cell function was 40% greater after WP (P = .001) and was accompanied with a -22% reduction in postprandial insulin clearance vs placebo (P < .0001). Both the peak change and PPG iAUC were reduced by WP (-1.5 mmol/L and -16%, respectively; both P < .05). Pre-meal WP augmented a 5.9-fold increase in glucagon and glucagon-like peptide 1 iAUC (both P < .0001), and a 1.5-fold increase in insulin iAUC (P < .001). Although the plasma insulin response was greater following WP, ISR was unaffected (P = .133).

CONCLUSION

In adults with T2D, pre-meal WP reduced PPG by coordinating an enhancement in β-cell function with a reduction in insulin clearance. This enabled an efficient postprandial insulinemic profile to be achieved without requiring further β-cell stimulation.Trial registry ISRCTN ID: ISRCTN17563146 Website link: www.isrctn.com/ISRCTN17563146.

Postprandial Hypotension and Impaired Postprandial Sustained and Selective Attention in Older Inpatients: Is There a Link?

OBJECTIVES

The study aimed to investigate the prevalence of postprandial hypotension (PPH) in older inpatients, to verify the overall postprandial behavior of blood pressure and attentional performances, and to explore the overall associations between blood pressure (including PPH) and attentional performances. Eventually, we aimed to investigate differences on PPH, blood pressure values and attentional performances based on the subjects' frailty status.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

A sample of older inpatients at the Geriatric Unit of the University Hospital of Messina (Italy).

METHODS

Basal, preprandial, and postprandial blood pressures (75 minutes after the meal) were measured for each patient; PPH was detected according to its empirical definition. Global cognitive functioning, and sustained and selective attention were assessed; a 46-item Frailty Index was calculated.

RESULTS

The sample consisted of 112 inpatients (54 females), with a mean age of 80.9 years. The prevalence of PPH was 30.4%; in the postprandial window, a reduction in blood pressure between 10 and 20 mm Hg and a reduction of >20 mm Hg were reported by 27.1% and 29.9% of inpatients, respectively. In the postprandial evaluation, sustained and selective attention markedly decreased. No significant associations were found between PPH occurrence and the postprandial dip of attentional performances, and no significant cognitive differences were found between inpatients with and without PPH. On the other hand, reduced postprandial attentional performances were associated especially with preprandial lower systolic and diastolic blood pressure values. Ultimately, no significant differences in PPH occurrence were found between frail and nonfrail inpatients; frail inpatients significantly exhibited also an overall lower cognitive functioning.

CONCLUSIONS AND IMPLICATIONS

In our sample, PPH and impaired postprandial attentional performances were not associated, even though this association deserves further investigation. In hospitalized older adults, the accurate management of blood pressure levels appears relevant, because we evidenced that low blood pressure (especially preprandial) was associated with poor attentional functioning. Although the plausible occurrence of several interfering and confounder factors was observed in an acute care setting, we consider that the screening of attentional functioning among hospitalized older patients could be helpful.

Utility of the burmese Python as a model for studying plasticity of extreme physiological systems

Non-traditional animal models present an opportunity to discover novel biology that has evolved to allow such animals to survive in extreme environments. One striking example is the Burmese python (Python molurus bivittatus), which exhibits extreme physiological adaptation in various metabolic organs after consuming a large meal following long periods of fasting. The response to such a large meal in pythons involves a dramatic surge in metabolic rate, lipid overload in plasma, and massive but reversible organ growth through the course of digestion. Multiple studies have reported the physiological responses in post-prandial pythons, while the specific molecular control of these processes is less well-studied. Investigating the mechanisms that coordinate organ growth and adaptive responses offers the opportunity to gain novel insight that may be able to treat various pathologies in humans. Here, we summarize past research on the post-prandial physiological changes in the Burmese python with a focus on the gastrointestinal tract, heart, and liver. Specifically, we address our recent molecular discoveries in the post-prandial python liver which demonstrate transient adaptations that may reveal new therapeutic targets. Lastly, we explore new biology of the aquaporin 7 gene that is potently upregulated in mammalian cardiac myocytes by circulating factors in post-prandial python plasma.

Effect of Acute Walking on Endothelial Function and Postprandial Lipemia in South Asians and White Europeans

INTRODUCTION

South Asians (SAs) have an elevated risk of cardiovascular disease (CVD) compared with White Europeans (WEs). Postprandial endothelial function (flow-mediated dilatation (FMD%)) in SA women and SA men with central obesity has not been investigated. Research in other populations has highlighted that a 1% higher FMD% is associated with a ~13% lower risk of future CVD events. We investigated whether FMD% and lipemia, two markers for CVD risk, were higher in SAs versus WEs, whether walking improved FMD% and lipemia, and if there were ethnic differences in the response.

METHODS

Lean premenopausal women (study 1; 12 SA, 12 WE) and men with central obesity (study 2; 15 SA, 15 WE) completed two 2-d trials. On day 1, participants walked for 60 min at 60% of their peak oxygen uptake or rested. On day 2, participants rested and consumed two high-fat meals over 8 h. Repeated ultrasound assessments of endothelial function and venous blood samples for CVD risk markers were taken.

RESULTS

Compared with WEs, SAs had lower postprandial FMD% (study 1, -1.32%; study 2, -0.54%) and higher postprandial triacylglycerol concentrations (study 1, 0.31 mmol·L -1 ·h -1 ; study 2, 0.55 mmol·L -1 ·h -1 ). Walking improved postprandial FMD% (study 1, 1.12%; study 2, 0.94%) and resulted in no significant change or small reductions in postprandial triacylglycerol concentrations (study 1, -0.01 mmol·L -1 ·h -1 ; study 2, -0.25 mmol·L -1 ·h -1 ). Exercise-induced changes in FMD% and triacylglycerol were consistent between ethnic groups.

CONCLUSIONS

Walking mitigated the adverse postprandial effect of a high-fat diet on FMD% to a similar extent in SA and WE women and men, even with no/small improvements in triacylglycerol. This study highlights the importance of exercise to clinically improve FMD% in SAs and WEs.

Reproducibility and determinants of the metabolic responses during a mixed-meal tolerance test

OBJECTIVE

The aim of this study was to assess the reproducibility and physiological determinants of mixed-meal tolerance tests (MMTTs) on glucose and insulin responses.

METHODS

While inpatients on a weight-maintaining diet, 894 individuals (574 with normal and 267 with impaired glucose regulation and 53 with type 2 diabetes [T2D]) underwent 9-hour MMTTs (breakfast and lunch; 30% weight-maintaining diet each; 40% carbohydrate, 40% fat, and 20% protein). Total/incremental areas under the curve (AUC/iAUC) were calculated from MMTT plasma glucose/insulin concentrations. Acute insulin response (AIR) was quantified by intravenous glucose tolerance test and insulin action (M) via hyperinsulinemic-euglycemic clamp. A subset had repeat MMTTs (median follow-up = 1.4 years).

RESULTS

In individuals without T2D, for breakfast-versus-lunch reproducibility of glucose, AUCs were moderate (intraclass correlation coefficients [ICCs]: 0.44-0.61), and iAUCs were poor (ICCs < 0.15). For repeated MMTTs, reproducibility of AUC/iAUCs was low (ICCs: 0.11-0.36). For insulin, AUC reproducibility was high (ICCs > 0.70), and iAUCs were moderate (ICCs: 0.64-0.71). For repeated MMTTs, ICC AUC/iAUCs were 0.34 to 0.54. In those with T2D, ICC glucose AUC/iAUCs were >0.80 and >0.50, respectively, and for insulin were <0.40. For repeated MMTTs, ICC glucose/insulin AUC/iAUCs were moderate. Glucose AUCs associated with M/AIR (partial Rs < -0.25), and insulin AUCs negatively/positively associated with M/AIR (partial Rs = -0.51/0.24).

CONCLUSIONS

Reproducibility of glucose/insulin responses to MMTTs varied by subtraction of fasting values, glucose status, and time. Insulin secretion and action explained ~20% of MMTT responses. The substantial variability in MMTT response requires consideration in studies using MMTT outcomes.

Acute Insulin Secretory Effects of a Classic Ketogenic Meal in Healthy Subjects: A Randomized Cross-Over Study

The classic ketogenic diet (KD) is a high-fat, low-carbohydrate diet that mimics a starvation state with sufficient caloric intake to sustain growth and development. KD is an established treatment for several diseases, and it is currently evaluated in the management of insulin-resistant states, although insulin secretion after a classic ketogenic meal has never been investigated. We measured the insulin secretion to a ketogenic meal in 12 healthy subjects (50% females, age range 19-31 years, BMI range 19.7-24.7 kg/m²) after cross-over administrations of a Mediterranean meal and a ketogenic meal both satisfying ~40% of an individual's total energy requirement, in random order and separated by a 7-day washout period. Venous blood was sampled at baseline and at 10, 20, 30, 45, 60, 90, 120, and 180 min to measure glucose, insulin, and C-peptide concentrations. Insulin secretion was calculated from C-peptide deconvolution and normalized to the estimated body surface area. Glucose, insulin concentrations, and insulin secretory rate were markedly reduced after the ketogenic meal with respect to the Mediterranean meal: glucose AUC in the first OGTT hour -643 mg × dL^-1 × min^-1, 95% CI -1134, -152, p = 0.015; total insulin concentration -44,943 pmol/L, 95% CI -59,181, -3706, p < 0.001; peak rate of insulin secretion -535 pmol × min^-1 × m^-2, 95% CI -763, -308, p < 0.001. We have shown that a ketogenic meal is disposed of with only a minimal insulin secretory response compared to a Mediterranean meal. This finding may be of interest to patients with insulin resistance and or insulin secretory defects.

Chronic consumption of probiotics, oats, and apples has differential effects on postprandial bile acid profile and cardiometabolic disease risk markers compared with an isocaloric control (cornflakes): a randomized trial

BACKGROUND

Dietary components that impact the gut microbiota may beneficially affect cardiometabolic health, possibly by altered bile acid metabolism. However, impacts of these foods on postprandial bile acids, gut microbiota, and cardiometabolic risk markers are unclear.

OBJECTIVES

The aim of this study was to determine the chronic effects of probiotics, oats, and apples on postprandial bile acids, gut microbiota, and cardiometabolic health biomarkers.

METHODS

Using an acute within chronic parallel design, 61 volunteers (mean ± SD: age 52 ± 12 y; BMI 24.8 ± 3.4 kg/m²) were randomly assigned to consume 40 g cornflakes (control), 40 g oats or 2 Renetta Canada apples each with 2 placebo capsules per day or 40 g cornflakes with 2 Lactobacillus reuteri capsules (>5 × 10⁹ CFU) per day, for 8 wk. Fasting and postprandial serum/plasma bile acids and cardiometabolic health biomarkers, fecal bile acids, and gut microbiota composition were determined.

RESULTS

At week 0, oats and apples significantly decreased postprandial serum insulin [area under the curve (AUC): 25.6 (17.4, 33.8) and 23.4 (15.4, 31.4) vs. 42.0 (33.7, 50.2) pmol/L × min and incremental AUC (iAUC): 17.8 (11.6, 24.0) and 13.7 (7.7, 19.8) vs. 29.6 (23.3, 35.8) pmol/L × min] and C-peptide responses [AUC: 599 (514, 684) and 550 (467, 632) vs. 750 (665, 835) ng/mL × min], whereas non-esterified fatty acids were increased [AUC 135 (117, 153) vs. 86.3 (67.9, 105) and iAUC 96.2 (78.8, 114) vs. 60 (42.1, 77.9) mmol/L × min] after the apples vs. control (P ≤ 0.05). Postprandial unconjugated [AUC: predicted means (95% CI) 1469 (1101, 1837) vs. 363 (-28, 754) μmol/L × min and iAUC: 923 (682, 1165) vs. 22.0 (-235, 279) μmol/L × min)] and hydrophobic [iAUC: 1210 (911, 1510) vs. 487 (168, 806) μmol/L × min] bile acid responses were increased after 8 wk probiotic intervention vs. control (P ≤ 0.049). None of the interventions modulated the gut microbiota.

CONCLUSIONS

These results support beneficial effects of apples and oats on postprandial glycemia and the ability of the probiotic Lactobacillus reuteri to modulate postprandial plasma bile acid profiles compared with control (cornflakes), with no relationship evident between circulating bile acids and cardiometabolic health biomarkers.

Device-guided slow breathing alters postprandial oxidative stress in young adult males: A randomized sham-controlled crossover trial

BACKGROUND AND AIMS

Slow, deep breathing (SDB) lowers blood pressure (BP) though the underlying mechanisms are unknown. Redox improvements could facilitate hemodynamic adjustments with SDB though this has not been investigated. The purpose of this randomized, sham-controlled trial was to examine the acute effects of SDB on oxidative stress and endothelial function during a physiological perturbation (high-fat meal) known to induce oxidative stress.

METHODS AND RESULTS

Seventeen males (ages 18-35 years) were enrolled, and anthropometric measurements and 7-day physical activity monitoring were completed. Testing sessions consisted of 24-h diet recalls (ASA24), blood sample collection for superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS) analysis, and flow-mediated dilation (FMD). High-fat meals were ingested and 2-min breathing exercises (SDB or sham control breathing) were completed every 15 min during the 4-h postprandial phase. Blood sample collection and FMD were repeated 1-, 2-, and 4-h post meal consumption. Mean body mass index and step counts were 25.6 ± 4.3 kg/m2 and 8165 ± 4405 steps per day, respectively. Systolic and diastolic BP and nutrient intake 24 h prior were similar between conditions. No time or time by condition interaction effects were observed for FMD. The total area under the curve (AUC) for SOD was significantly lower during SDB compared to the sham breathing condition (p < 0.01). No differences were observed in TBARS AUC (p = 0.538).

CONCLUSIONS

Findings from the current investigation suggest that SDB alters postprandial redox in the absence of changes in endothelial function in young, healthy males.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04864184.

CLINICAL TRIALS IDENTIFIER

NCT04864184.

Walking Attenuates Postprandial Glycemic Response: What Else Can We Do without Leaving Home or the Office?

We evaluated the effects of different exercise types suitable for a home/work setting on the postprandial glucose response. Twenty-three healthy, active, young individuals performed one of two studies (12 in Study 1 and 11 in Study 2), with four randomized protocols each. After a meal high in carbohydrate content (1 g of carbohydrate per kg of body weight), in Study 1, participants performed 30 min of either walking (WALK), bench stepping exercise (STEP) or isometric wall squat (SQUAT); in Study 2, participants performed 30 min of either walking (WALK), neuromuscular electrical stimulation alone (P_NMES) or superimposed on voluntary muscle contraction (VC_NMES). In both studies, participants performed a prolonged sitting condition (CON) that was compared to the exercise sessions. In Study 1, WALK and STEP significantly reduced the glucose peak compared to CON (p < 0.011). In Study 2, the peak was significantly reduced in WALK compared to CON, P_NMES and VC_NMES (p < 0.011) and in VC_NMES compared to CON and P_NMES (p < 0.011). A significant reduction of 3 h glucose iAUC was found for WALK and VC_NMES compared to CON and P_NMES (p < 0.033). In conclusion, WALK is the most effective strategy for improving the postprandial glycemic response. However, STEP and VC_NMES can also be used for reducing postprandial glycemia.

The effect of postprandial exercise on mean blood glucose concentrations following high and maintenance carbohydrate content meals in healthy dogs

OBJECTIVES

To compare the effect of 15 min of exercise 30 min post-meal on mean blood glucose concentrations in 5 well-conditioned versus 5 over-conditioned dogs. To compare the effect of exercise on glycemic control in dogs eating their maintenance diet as compared to a high carbohydrate meal.

ANIMALS

Ten healthy staff or student owned dogs, five well- and five over-conditioned.

PROCEDURES

This was a crossover study over 5 days. Continuous glucose monitors (CGM) were placed on day 1. On days 2 and 3, dogs received their maintenance diet and a high carbohydrate meal, respectively and were walked on the treadmill for 15 min following each meal. On day 4, dogs were given their maintenance diet in hospital without treadmill activity. On day 5, the CGM were removed. The mean blood glucose 30 min post-meal, during exercise, 15 min after completing exercise, and the 1-3 h period after completing the exercise were compared to detect any effect of exercise, diet composition, or body condition.

RESULTS

Dogs consuming a high carbohydrate meal had a significantly higher mean blood glucose 15 min post-exercise. Mean glucose values at all time points following a high carbohydrate meal were significantly higher than mean glucose values on the non-exercise day.

CONCLUSIONS AND CLINICAL RELEVANCE

No impact of post-prandial exercise on glucose concentrations were identified in this study, however, the carbohydrate content of the meal impacted post-prandial glycemic responses in healthy dogs regardless of body condition. Evaluating the impact of post-prandial exercise in insulin-dependent or glucose-intolerant dogs is warranted to determine if these findings persist.

Breaking Sitting Time with Physical Activity Increases Energy Expenditure but Does Not Alter Postprandial Metabolism in Girls

PURPOSE

Young people spend a substantial proportion of their time at school sedentary; therefore, this setting represents an important target for interventions aimed at displacing sedentary time with physical activity. This study aimed to examine the postprandial metabolic effects of breaking sedentary time by accumulating walking and repeated bouts of nonambulatory standing during simulated school days in inactive adolescent girls.

METHODS

Seventeen girls (mean ± SD = 12.8 ± 0.4 yr) completed two 3-d experimental conditions. On days 1 and 2 of the standing + walking (STD-WLK) experimental trial, participants interrupted sedentary time by completing 4 × 10 min bouts of self-paced walking and accumulated 18 × 5 min standing bouts during each simulated school day. On day 3 of STD-WLK, participants attended school as normal with no additional physical activity or standing prescribed. On all 3 d of the control condition (CON), participants attended school as normal with no physical activity intervention. On days 2 and 3 of both STD-WLK and CON, a baseline capillary blood sample was provided to determine fasting [TAG] and [glucose]. Participants then consumed a standardized breakfast (0 h) and lunch (4.7 h), and blood samples were provided postprandially at 2.7, 5.3, and 7.3 h for [TAG] and [glucose].

RESULTS

Energy expenditure was 28% (95% confidence interval = 8% to 52%) higher during school hours on day 1 and day 2 during STD-WLK compared with CON (2171 vs 1693 kJ; effect size = 0.89, P = 0.008). However, no reduction of fasting or postprandial [TAG] or [glucose] was observed on day 2 or day 3 ( P ≥ 0.245).

CONCLUSIONS

Two consecutive days of breaking prolonged sitting with self-paced walking and intermittent standing had no meaningful effect on postprandial metabolism in adolescent girls.

Impaired postprandial adipose tissue microvascular blood flow responses to a mixed-nutrient meal in first-degree relatives of adults with type 2 diabetes

Adipose tissue microvascular blood flow (MBF) is stimulated postprandially to augment delivery of nutrients and hormones to adipocytes. Adipose tissue MBF is impaired in type 2 diabetes (T2D). Whether healthy individuals at-risk of T2D show similar impairments is unknown. We aimed to determine whether adipose tissue MBF is impaired in apparently healthy individuals with a family history of T2D. Overnight-fasted individuals with no family history of T2D for two generations (FH-, n = 13), with at least one parent with T2D (FH+, n = 14) and clinically diagnosed T2D (n = 11) underwent a mixed meal challenge (MMC). Metabolic responses [blood glucose, plasma insulin, plasma nonesterified fatty acids (NEFAs), and fat oxidation] were measured before and during the MMC. MBF in truncal subcutaneous adipose tissue was assessed by contrast ultrasound while fasting and 60 min post-MMC. FH+ had normal blood glucoses, increased adiposity, and impaired post-MMC adipose tissue MBF (Δ0.70 ± 0.22 vs. 2.45 ± 0.60 acoustic intensity/s, P = 0.007) and post-MMC adipose tissue insulin resistance (Adipo-IR index; Δ45.5 ± 13.9 vs. 7.8 ± 5.1 mmol/L × pmol/L, P = 0.007) compared with FH-. FH+ and T2D had an impaired ability to suppress fat oxidation post-MMC. Fat oxidation incremental area under the curve (iAUC) (35-55 min post-MMC, iAUC) was higher in FH+ and T2D than in FH- (P = 0.005 and 0.009, respectively). Postprandial MBF was negatively associated with postprandial fat oxidation iAUC (P = 0.01). We conclude that apparently healthy FH+ individuals display blunted postprandial adipose tissue MBF that occurs in parallel with adipose tissue insulin resistance and impaired suppression of fat oxidation, which may help explain their heightened risk for developing T2D.NEW & NOTEWORTHY Adipose tissue blood flow plays a key role in postprandial nutrient storage. People at-risk of type 2 diabetes have impaired postmeal adipose tissue blood flow. Impaired adipose tissue blood flow is associated with altered fat oxidation. Risk of type 2 diabetes may be elevated by poor adipose tissue blood flow.

Postprandial Responses to a Standardised Meal in Hypertension: The Mediatory Role of Visceral Fat Mass

Postprandial insulinaemia, triglyceridaemia and measures of inflammation are thought to be more closely associated with cardiovascular risk than fasting measures. Although hypertension is associated with altered fasting metabolism, it is unknown as to what extent postprandial lipaemic and inflammatory metabolic responses differ between hypertensive and normotensive individuals. Linear models adjusting for age, sex, body mass index (BMI), visceral fat mass (VFM) and multiple testing (false discovery rate), were used to investigate whether hypertensive cases and normotensive controls had different fasting and postprandial (in response to two standardised test meal challenges) lipaemic, glycaemic, insulinaemic, and inflammatory (glycoprotein acetylation (GlycA)) responses in 989 participants from the ZOE PREDICT-1 nutritional intervention study. Compared to normotensive controls, hypertensive individuals had significantly higher fasting and postprandial insulin, triglycerides, and markers of inflammation after adjusting for age, sex, and BMI (effect size: Beta (Standard Error) ranging from 0.17 (0.08), p = 0.04 for peak insulin to 0.29 (0.08), p = 4.4 × 10^-4 for peak GlycA). No difference was seen for postprandial glucose. When further adjusting for VFM effects were attenuated. Causal mediation analysis suggests that 36% of the variance in postprandial insulin response and 33.8% of variance in postprandial triglyceride response were mediated by VFM. Hypertensive individuals have different postprandial insulinaemic and lipaemic responses compared to normotensive controls and this is partially mediated by visceral fat mass. Consequently, reducing VFM should be a key focus of health interventions in hypertension. Trial registration: The ClinicalTrials.gov registration identifier is NCT03479866.

The Beneficial Effect of Cinnamon and Red Capsicum Intake on Postprandial Changes in Plasma Metabolites Evoked by a High-Carbohydrate Meal in Men with Overweight/Obesity

The relationship of high-carbohydrate (HC) meal intake to metabolic syndrome is still not fully explained. Metabolomics has the potential to indicate metabolic pathways altered by HC meals, which may improve our knowledge regarding the mechanisms by which HC meals may contribute to metabolic syndrome development. The fasting and postprandial metabolic response to HC or normo-carbohydrate (NC) meals with/without cinnamon + capsicum intake was evaluated using untargeted metabolomics and compared between normal-weight (NW) and overweight/obese (OW/OB) healthy men. Healthy male participants (age-matched) were divided into two groups (12 subjects per group). One was composed of men with normal weight (NW) and the other of men with overweight/obesity (OW/OB). On separate visits (with 2-3 week intervals), the participants received standardized HC or NC meals (89% or 45% carbohydrates, respectively). Fasting (0 min) and postprandial (30, 60, 120, 180 min) blood were collected for untargeted plasma metabolomics. Based on each metabolic feature's intensity change in time, the area under the curve (AUC) was calculated. Obtained AUCs were analyzed using multivariate statistics. Several metabolic pathways were found dysregulated after an HC meal in people from the OW/OB group but not the NW group. The consumption of HC meals by people with overweight/obesity led to a substantial increase in AUC, mainly for metabolites belonging to phospholipids and fatty acid amides. The opposite was observed for selected sphingolipids. The intake of cinnamon and capsicum normalized the concentration of selected altered metabolites induced by the intake of HC meals. A HC meal may induce an unfavourable postprandial metabolic response in individuals with overweight/obesity, and such persons should avoid HC meals.

African American Females Are Less Metabolically Flexible Compared with Caucasian American Females following a Single High-Fat Meal: A Pilot Study

The relationship between metabolic flexibility (MF) and components of metabolic disease has not been well-studied among African American (AA) females and may play a role in the higher incidence of chronic disease among them compared with Caucasian American (CA) females. This pilot study aimed to compare the metabolic response of AA and CA females after a high-fat meal. Eleven AA (25.6 (5.6) y, 27.2 (6.0) kg/m², 27.5 (9.7) % body fat) and twelve CA (26.5 (1.5) y, 25.7 (5.3) kg/m², 25.0 (7.4) % body fat) women free of cardiovascular and metabolic disease and underwent a high-fat meal challenge (55.9% fat). Lipid oxidation, insulin, glucose, and interleukin (IL)-8 were measured fasted, 2 and 4 h postprandial. AA females had a significantly lower increase in lipid oxidation from baseline to 2 h postprandial (p = 0.022), and trended lower at 4 h postprandial (p = 0.081) compared with CA females, indicating worse MF. No group differences in insulin, glucose or HOMA-IR were detected. IL-8 was significantly higher in AA females compared with CA females at 2 and 4 h postprandial (p = 0.016 and p = 0.015, respectively). These findings provide evidence of metabolic and inflammatory disparities among AA females compared with CA females that could serve as a predictor of chronic disease in individuals with a disproportionately higher risk of development.