Postprandial Vascular Function Research Articles

The impact of whey protein and leucine on postprandial vascular function: findings from the Whey2Glo Study

The impact of whey protein and leucine on postprandial vascular function: findings from the Whey2Glo Study

Effects of L-citrulline supplementation and watermelon consumption on longer-term and postprandial vascular function and cardiometabolic risk markers: A meta-analysis of randomized controlled trials in adults.

L-citrulline may improve non-invasive vascular function and cardiometabolic risk markers through increases in L-arginine bioavailability and nitric oxide synthesis. A meta-analysis of randomized controlled trials (RCTs) was performed to examine longer-term and postprandial effects of L-citrulline supplementation and watermelon consumption on these markers for cardiovascular disease in adults. Summary estimates of weighted mean differences (WMDs) in vascular function and cardiometabolic risk markers with accompanying 95% confidence intervals (CIs) were calculated using random or fixed-effect meta-analyses. Seventeen RCTs were included involving an L-citrulline intervention, of which six studied postprandial and twelve longer-term effects. Five studies investigated longer-term effects of watermelon consumption and five assessed effects during the postprandial phase. Longer-term L-citrulline supplementation improved brachial artery flow-mediated vasodilation (FMD) by 0.9 %-point (95 % CI: 0.7 to 1.1, P < 0.001). Longer-term watermelon consumption improved pulse wave velocity by 0.9 m/s (95% CI: 0.1 to 1.5, P < 0.001), while effects on FMD were not studied. No postprandial effects on vascular function markers were found. Postprandial glucose concentrations decreased by 0.6 mmol/L (95% CI: 0.4 to 0.7, P < 0.001) following watermelon consumption, but no other longer-term or postprandial effects were observed on cardiometabolic risk markers. To conclude, longer-term L-citrulline supplementation and watermelon consumption may improve vascular function, suggesting a potential mechanism by which increased L-citrulline intake beneficially affects cardiovascular health outcomes in adults. No effects on postprandial vascular function markers were found, while more research is needed to investigate effects of L-citrulline and watermelon on risk markers related to cardiometabolic health.

Traditional weight loss and dukan diets as to nutritional and laboratory results

Traditional weight loss and dukan diets as to nutritional and laboratory results

Glu298Asp (rs1799983) Polymorphism Influences Postprandial Vascular Reactivity and the Insulin Response to Meals of Varying Fat Composition in Postmenopausal Women: Findings from the Randomized, Controlled Dietary Intervention and VAScular function (DIVAS)-2 Study

Previous acute studies suggest the Glu298Asp polymorphism (rs1799983) may influence vascular reactivity in response to long-chain n-3 PUFA intake. However, the effects of this genotype on postprandial vascular function after meals rich in SFAs, n-6 PUFAs, and MUFAs are unclear. This study determined the impact of the Glu298Asp polymorphism on changes in vascular function and cardiometabolic risk biomarkers in response to sequential meals of varying fat composition. In a randomized, double-blind, crossover, acute study, 32 postmenopausal women (mean±SD age: 58±5y; BMI: 25.9±4.1kg/m2) consumed mixed meals (breakfast: 0min, 50g fat; lunch: 330min, 30g fat) containing SFAs, n-6 PUFAs, or MUFAs on 3 occasions. Blood samples for cardiometabolic disease risk markers and real-time measures of vascular reactivity [including flow-mediated dilatation (FMD; primary outcome)] were collected/performed before and regularly for 480min after breakfast. Participants were retrospectively genotyped for the Glu298Asp (rs1799983) polymorphism. Data were analyzed using linear mixed models. For the postprandial %FMD response, a test fat × genotype interaction was observed for the AUC (P=0.019) but not incremental AUC (IAUC), with the AUC being ∼24% greater after MUFA- than after SFA- and n-6 PUFA-rich meals in the Glu298 homozygotes (P≤0.026). Test fat × genotype interactions were also evident for postprandial insulin (P≤0.005), with the MUFA-rich meals demonstrating significantly higher AUC (12.8%/14.9%), IAUC (14.6%/20.0%), and maximum concentration (20.0%/34.5%) than the SFA- and n-6 PUFA-rich meals, respectively, in Asp298 carriers (P<0.05). Genotype did not influence other study outcome measures in response to the test fats. Our findings suggest the Glu298Asp polymorphism may represent a potential determinant of the inter-individual variability in postprandial responsiveness of %FMD and insulin to acute meal fat composition in postmenopausal women. Further studies are required to confirm these observations.This trial was registered at clinicaltrials.gov as NCT02144454.

Effects of Beetroot Powder with or without L-Arginine on Postprandial Vascular Endothelial Function: Results of a Randomized Controlled Trial with Abdominally Obese Men.

Background: Through effects on nitric oxide bioavailability, vascular endothelial function is improved after the intake of a high amount of nitrate or L-arginine, but decreased after the intake of a high-fat meal. Therefore, we compared the effects of beetroot powder with or without L-arginine on postprandial brachial artery flow-mediated vasodilation (FMD) after consumption of a high-fat mixed-meal. Methods: Eighteen abdominally obese men completed this randomized, double-blinded, cross-over trial. The study consisted of five test days, each separated by a wash-out period of at least one week. Participants received in random order, a blended meal with a control or nutritional supplement consisting of beetroot powder providing 200 mg nitrate, beetroot with 0.8 g of L-arginine, beetroot with 1.5 g of L-arginine, or 3.0 g of L-arginine. Participants then fasted and 2 h postprandial FMD measurements were performed. Results: No significant differences between meals were observed for postprandial FMD (p = 0.45) levels. However, there was a non-significant trend towards a more beneficial postprandial FMD response with the beetroot-containing meals as compared with meals without beetroot. Conclusion: This trial could not provide evidence for beneficial additive effects of a single dose of beetroot powder combined with L-arginine on postprandial endothelial function in abdominally obese men.

Dietary macronutrients do not differently affect postprandial vascular endothelial function in apparently healthy overweight and slightly obese men

PurposeWell-designed trials comparing side-by-side effects of macronutrients on postprandial endothelial function are missing. Therefore, we investigated under well-controlled and isocaloric condition effects of fat, carbohydrates, and protein on postprandial endothelial function as assessed by brachial artery flow-mediated vasodilation (FMD), an important non-invasive technique to assess endothelial function.MethodsEighteen apparently healthy overweight and slightly obese men (BMI 26.0–35.0 kg/m2) completed this randomized, double-blinded, cross-over trial. The study consisted of three test days each separated by a wash-out period of at least 1 week. After an overnight fast, men received an isocaloric meal providing 3987 kJ (953 kcal) that was either high in dietary fat (En% fat [F]/carbohydrates [C]/protein [P]: 52.3, 39.2, 8.0), carbohydrates (En% F/C/P: 9.6, 81.5, 8.6), or protein (En% F/C/P: 10.6, 51.5, 36.9). Fasting and 2-h postprandial FMD responses were measured.ResultsA postprandial decrease of 1.2% point in FMD was observed after the high-protein meal (P = 0.015). However, postprandial changes did not differ between meals (P = 0.45). An increase in baseline brachial artery diameters was observed after the high-protein meal (P < 0.001) and changes differed between meals (P = 0.020). A meal*time interaction was found for plasma glucose concentrations, with the most pronounced increases after the high-carbohydrate meal at T15, T30, T60, and T90 (P < 0.05). A significant time and meal (P < 0.001), but no time*meal effect (P = 0.06) was found for serum insulin concentrations. Increases in serum triacylglycerol concentrations did not differ between meals (P = 0.014).ConclusionMacronutrients did not differently affect postprandial endothelial function in apparently healthy overweight and slightly obese men.Trial registrationTrial registration number (ClinicalTrials.gov) NCT03139890 in May 2017

Effects of diet-induced weight loss on postprandial vascular function after consumption of a mixed meal: Results of a randomized controlled trial with abdominally obese men.

Effects of weight loss on postprandial vascular function have not been studied so far. We therefore examined (i) effects of diet-induced weight loss on postprandial changes in various vascular function markers after consumption of a mixed meal and (ii) differences between normal-weight and abdominally obese men of comparable age at baseline and after weight loss. Fifty-four apparently healthy abdominally obese (waist circumference: 102-110cm) and 25 normal-weight men (waist circumference: <94cm) participated. The abdominally obese men were randomly allocated to a diet-induced weight-loss program or a no-weight loss control group. Men assigned to the weight-loss program followed a calorie-restricted diet for six weeks targeting a waist circumference of less than 102cm, followed by a weight-maintenance period for two weeks. The control group maintained their habitual diet and physical activity levels. Measurements were performed before and two hours after consumption of the test meal consisting of two muffins (containing 56.6g fat) and 300mL low-fat milk. The mean weight loss was 10.3kg in the weight-loss compared with the control group. The postprandial change in flow-mediated vasodilation of the brachial artery (FMD) was significantly higher at baseline in normal-weight as compared with the postprandial change in abdominally obese men (1.89±2.52 versus 0.48±2.50 percentage points; P=0.027). However, no differences in postprandial changes were observed in the abdominally obese men after weight loss compared with the control treatment. Also, weight reduction did not affect postprandial changes in carotid-to-femoral pulse wave velocity, retinal microvascular caliber properties, or plasma markers of microvascular endothelial function. Even though postprandial increases in triacylglycerol (P=0.028), insulin (P=0.029) and C-peptide concentrations (P<0.001) were reduced in the abdominally obese men following weight loss, postprandial changes in FMD at the end of the weight-loss treatment were still more unfavorable as compared with those observed in normal-weight individuals. In this trial with abdominally obese men, we did not find effects of diet-induced weight loss on postprandial changes in vascular endothelial function, arterial stiffness and markers of microvascular function. This trial was registered on ClinicalTrials.gov under study number NCT01675401.

Hypoglycemia Abrogates the Vascular Endothelial Protective Effect of Exenatide in Type 2 Diabetes Mellitus.

Glucagon-like peptide-1 (GLP-1) receptor agonists improve postprandial glucose, lipid metabolism, and vascular endothelial function. However, little is known about the effect of hypoglycemia on vascular endothelial function in patients on GLP-1 receptor agonist therapy. The aim of the present study was to determine the effect of hypoglycemia on vascular endothelial function in patients with type 2 diabetes mellitus (T2DM) treated with exenatide. Seventeen patients with T2DM underwent a meal tolerance test to examine the changes in vascular endothelial function and in glucose metabolism, both without exenatide and after a single subcutaneous injection of 10 μg exenatide. Vascular endothelial function was evaluated using reactive hyperemia index (RHI) measured by peripheral arterial tonometry before and 120 min after the meal loading test. The primary endpoint was the difference in changes in postprandial vascular endothelial function between the baseline and exenatide test. The results were analyzed in relation to the presence of absence of hypoglycemia. The natural logarithmically scaled RHI (L_RHI) was significantly lower after the baseline meal test but not in the exenatide test. Administration of exenatide caused symptomatic hypoglycemia in two patients during the meal tolerance test. The difference in the change in L_RHI was 0.125 ± 0.085 in the non-hypoglycemic group, whereas it was lower, − 0.487 ± 0.061, in the hypoglycemic group. The results of this study also suggest that the presence of hypoglycemia induces vascular endothelial dysfunction even during GLP-1 receptor agonist therapy.Trial registration: UMIN000015699.Electronic supplementary materialThe online version of this article (10.1007/s13300-019-0596-4) contains supplementary material, which is available to authorized users.

Acute Effects of Hibiscus Sabdariffa Calyces on Postprandial Blood Pressure, Vascular Function, Blood Lipids, Biomarkers of Insulin Resistance and Inflammation in Humans.

Background/Objectives: The acute impact of Hibiscus sabdariffa calyces (HSC) extract on postprandial vascular function and other cardiometabolic risk factors have not been studied previously. This study investigated the acute impact of HSC extract consumption on blood pressure (BP), vascular function and other cardiometabolic risk markers. Subjects/Methods: Twenty-five men with 1% to 10% cardiovascular disease (CVD) risk (determined by QRISK®2) were randomised to consume either 250 mL of the aqueous extract of HSC or water with breakfast in a randomised, controlled, single-blinded, 2-meal cross-over study (ClinicalTrials.gov, NTC02165553) with a two weeks washout period between study days. BP was measured at baseline and hourly for 4 h. Flow mediated dilatation (FMD) of the branchial artery was measured at baseline, 2 and 4 h post intervention drink consumption. Results: Acute consumption of aqueous extract of HSC caused a significant increase in % FMD (p < 0.001), a non-significant decrease in systolic BP (SBP) and diastolic BP (DBP); non-significant increase in urinary and plasma nitric oxide (NOx) and reduced response of serum glucose, plasma insulin, serum triacylglycerol and C-reactive protein (CRP) levels; significant (p = 0.026) improvement in the area under systemic antioxidant response curve (0 to 2 h); no significant changes in arterial stiffness following the acute consumption of the extract of HSC. Gallic acid, 4-O-methylgallic acid, 3-O-methylgallic acid and hippuric acid reached a maximum plasma concentration at 1 to 2 h post consumption of the extract of HSC. Conclusion: The extract of HSC improved postprandial vascular function and may be a useful dietary strategy to reduce endothelial dysfunction and CVD risk, although this requires confirmation.

Effects of diet-induced weight loss on postprandial vascular function after consumption of a mixed meal: results of a randomized controlled trial in abdominally obese men

Aim: Effects of weight loss on postprandial vascular function have not been studied so far. Therefore, we examined (i) effects of diet-induced weight loss on vascular function after consumption of a mixed meal and (ii) differences between age-matched abdominally obese and normal-weight men.

Comparative Metabolomics Elucidates Postprandial Metabolic Modifications in Plasma of Obese Individuals with Metabolic Syndrome

Although higher intakes of dairy milk are associated with a lower risk of metabolic syndrome (MetS), the underlying protective mechanism remains unclear. This study investigated the dynamic metabolic profile shift following the ingestion of low-fat milk or an isocaloric volume of rice milk in obese individuals with metabolic syndrome (MetS). In a randomized, double-blind, crossover study, postprandial plasma samples ( n = 266) were collected from 19 MetS participants. Plasma samples were analyzed by a targeted metabolomics platform which specifically detects 117 metabolites from 25 metabolic pathways. The comprehensive time-course metabolic profiling in MetS participants indicated that the postprandial metabolic profiles distinguish low-fat milk and rice milk consumption in a time-dependent manner. Metabolic biomarkers, such as orotate, leucine/isoleucine and adenine, showed significantly different trends in the two test beverages. Bayesian statistics identified 12 metabolites associated with clinical characteristics of postprandial vascular endothelial function, such as flow-mediated dilation (FMD), postprandial plasma markers of oxidative stress and NO status. Furthermore, metabolic pathway analysis based on these metabolite data indicated the potential utility of metabolomics to provide mechanistic insights of dietary interventions to regulate postprandial metabolic excursions.

Theobromine consumption does not improve fasting and postprandial vascular function in overweight and obese subjects

BackgoundTheobromine, a component of cocoa, may favorably affect conventional lipid-related cardiovascular risk markers, but effects on flow-mediated dilation (FMD) and other vascular function markers are not known.ObjectiveTo evaluate the effects of 4-week theobromine consumption (500 mg/day) on fasting and postprandial vascular function markers.DesignIn a randomized, double-blind crossover study, 44 apparently healthy overweight (N = 30) and obese (N = 14) men and women with low HDL-C concentrations, consumed daily 500 mg theobromine or placebo for 4 weeks. After 4 weeks, FMD, peripheral arterial tonometry (PAT), augmentation index (AIx), pulse wave velocity (PWV), blood pressure (BP) and retinal microvasculature measurements were performed. These measurements were carried out under fasting conditions and 2.5 h after a high-fat mixed meal challenge.Results4-week theobromine consumption did not change fasting vascular function markers, except for a decrease in central AIx (cAIx, − 1.7 pp, P = 0.037) and a trend towards smaller venular calibers (− 2 µm, P = 0.074). Consuming a high-fat mixed meal decreased FMD (0.89 pp, P = 0.002), reactive hyperemia index (RHI, − 0.30, P < 0.001), peripheral systolic BP (SBP, − 3 mmHg, P ≤ 0.001), peripheral diastolic BP (DBP, − 2 mmHg, P ≤ 0.001), central SBP (− 6 mmHg, P ≤ 0.001) and central DBP (− 2 mmHg, P ≤ 0.001), but increased heart rate (HR, 2 bpm, P < 0.001). Theobromine did not modify these postprandial effects, but increased postprandially the brachial artery diameter (0.03 cm, P = 0.015), and decreased the cAIx corrected for a HR of 75 (cAIx75, − 5.0 pp, P = 0.004) and peripheral AIx (pAIx, − 6.3 pp, P = 0.017).ConclusionTheobromine consumption did not improve fasting and postprandial endothelial function, but increased postprandial peripheral arterial diameters and decreased the AIx. These findings do not suggest that theobromine alone contributes to the proposed cardioprotective effects of cocoa.This trial was registered on clinicaltrials.gov under study number NCT02209025.

The Divergent Effect of Coffee Polyphenol and Hydroxyhydroquinone Ingestion on Postprandial Hyperglycemia and Vascular Function in Healthy Men

Epidemiological studies indicate that coffee consumption reduces the risk of diabetes and cardiovascular diseases. However, interventional studies have failed to clarify the beneficial effects of coffee consumption on blood glucose and the cardiovascular system. We previously demonstrated that 1) coffee polyphenol (CPP) consumption improved postprandial hyperglycemia and vascular endothelial function in humans, and 2) improvement in vascular endothelial function due to CPP was impaired by hydroxyhydroquinone (HHQ) in rats. This study aimed to elucidate the impact of concomitant consumption of HHQ, a prooxidant in coffee, on the beneficial effects of CPP consumption on postprandial blood glucose and vascular function in humans. We conducted a single-blind, randomized, placebo-controlled, crossover intervention study in healthy male adults, measuring blood and urine parameters and flow-mediated dilation after ingestion of a meal with CPP with or without HHQ up to 180 min postprandially. Ten healthy male adults consumed a test meal with either a placebo, control (CPP with HHQ), or active (CPP without HHQ) beverage. The CPP-including active (without HHQ) beverage significantly blunted the postprandial increase in blood glucose and decline in flow-mediated dilation but not the control (with HHQ) beverage, compared with the placebo beverage. The active beverage reduced blood oxidative stress biomarker response compared with the control beverage. In conclusion, these results demonstrate that concomitant ingestion of HHQ, which increases oxidative stress, interferes with the improvement of postprandial blood glucose and vascular endothelial function after CPP consumption in healthy humans.

Acute Effect of Dietary Fats on Postprandial Vascular Function in Healthy Individuals: A Randomized, Controlled Trial

IntroductionResearch has shown an association between fat consumption and vascular function. Recent evidence suggests that a high saturated fat meal may impair vasodilatory mechanisms post‐ingestion, while other types of dietary fats, depending on chain length, saturation and omega 3:6 ratio may potentially improve vascular function. There have been no head to head comparisons of postprandial effects on commonly consumed sources of dietary cooking oils on vascular function.ObjectivesThe purpose of the study was to assess the effects of 5 different dietary fat sources of varied fatty acid profiles (coconut oil, canola oil, grapeseed oil, Salba‐chia seed oil, and butter) on indices of vascular function and the glycemic response in a healthy adult population.MethodsThe study recruited 15 healthy individuals (10F:5M; age 29±8; SBP/DBP: 121±10/82±4 mmHg) in a double blind, randomized, crossover, controlled design. Participants visited the clinic at St. Michael's Hospital 5 different times following an overnight fast. At each visit, following collection of anthropometric data and baseline outcome measures, 1 of 5 500ml study shakes were consumed containing 50g of fat (from either: coconut oil, canola oil, grapeseed oil, chia oil or butter) and 50g of available carbohydrate. Over a 3 hour period following intake of study interventions, vascular measures were obtained at hourly intervals and fingerprick blood samples at 0,15, 30, 45, 60, 90 and 180min. The primary outcome was a change in pulse wave reflection (augmentation index‐AIx (%)). Secondary outcome measures included postprandial blood glucose area under the curve (AUC), peripheral and central systolic and diastolic blood pressures.ResultsIntervention high in omega‐3 fatty acids (Salba‐chia seed oil) produced a reduction in pulse wave reflection relative to the butter control (1h AIx:−5.9±6%, p=0.041; 3h AIx: −3.8±7% p=0.048). All study beverages resulted in a similar acute blood pressure response (−1.2±3mmHg, p=0.25), independently of the type of oil ingested. No significant differences in blood glucose AUC (p=0.69) to the 5 fat‐rich glucose beverages were observed.ConclusionsNo difference was found in the acute effect of the ingestion of different vegetable oils on hemodynamic indices. All vegetable oils produced a postprandial decrease in hemodynamic indices in healthy participants.Support or Funding InformationInternal

Incorporating freeze-dried strawberry powder into a high-fat meal does not alter postprandial vascular function or blood markers of cardiovascular disease risk: a randomized controlled trial1–3

Postprandial dysmetabolism-an exaggerated spike in triglycerides, glucose, and insulin-increases cardiovascular disease risk by inducing oxidative stress, inflammation, and endothelial dysfunction. Polyphenol-rich foods may blunt these effects when they are incorporated into a high-fat, calorie-dense meal. Strawberries are a rich source of polyphenols, but there is little research on their postprandial effects. This study was designed to investigate the effect of adding 40 g freeze-dried strawberry powder (∼1 lb. or 0.45 kg fresh strawberries) to a high-fat (50 g total fat) meal on postprandial vascular function, as well as triglyceride, glucose, and insulin responses. Healthy, overweight or obese [mean ± SEM body mass index (in kg/m2): 31 ± 0.5] adults (mean ± SEM age: 28 ± 2 y; 17 men and 13 women) consumed a control meal and a strawberry meal in a randomized crossover design. Testing sessions were separated by ≥1 wk for men and ∼1 mo for women to control for hormonal variations. Blood samples were obtained before the meal and 0.5, 1, 2, and 4 h after the meal. Central blood pressure and arterial stiffness indexes were measured at baseline and 2 and 4 h postmeal with the use of pulse waveform analysis. There were no significant differences between the strawberry and control meals for any outcomes. Consumption of either meal significantly decreased the augmentation index at 2 and 4 h (P < 0.002) and significantly increased triglycerides, insulin, and glucose at all time points (P < 0.001) relative to baseline. The strawberry intervention did not alter vascular function or attenuate postprandial metabolic derangements in triglycerides, glucose, or insulin relative to the control meal. Additional research is needed to clarify whether strawberries or other polyphenol-rich interventions improve postprandial responses, and future studies should take into account the acute meal-induced improvements in measures of vascular function. This trial was registered at clinicaltrials.gov as NCT01989637.

Differential effects of EPA versus DHA on postprandial vascular function and the plasma oxylipin profile in men

Our objective was to investigate the impact of EPA versus DHA on arterial stiffness and reactivity and underlying mechanisms (with a focus on plasma oxylipins) in the postprandial state. In a three-arm crossover acute test meal trial, men (n = 26, 35–55 years) at increased CVD risk received a high-fat (42.4 g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, long chain n-3 PUFA-derived oxylipins, nitrite and hydrogen sulfide, and serum lipids and glucose. Vascular function was assessed using blood pressure, reactive hyperemia index, pulse wave velocity, and augmentation index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P = 0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA- and DHA-derived oxylipins in the acute postprandial state, with an (1.3-fold) increase in 19,20-dihydroxydocosapentaenoic acid evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight into the AIx effect.

Role of cis-Monounsaturated Fatty Acids in the Prevention of Coronary Heart Disease.

The effects of cis-monounsaturated fatty acids (cis-MUFAs) on the risk of coronary heart disease (CHD) and on CHD mortality are not clear. Also, dietary recommendations for cis-MUFA as derived by various organizations are not in agreement. Earlier studies have mainly focused on the effects of cis-MUFA on serum lipids and lipoproteins. More recent studies, however, have also addressed effects of cis-MUFA on other non-traditional CHD risk markers such as vascular function markers, postprandial vascular function, and energy intake and metabolism. Although well-designed randomized controlled trials with CHD events as endpoints are missing, several large prospective cohort studies have recently been published on the relationship between cis-MUFA and CHD risk. The aim of this paper is to review these new studies that have been published in the last 3 years on the effects of cis-MUFA on cardiovascular risk markers and CHD.

A methodological appraisal of postprandial vascular function following OGTT in Middle-Eastern men

A methodological appraisal of postprandial vascular function following OGTT in Middle-Eastern men

Substitution of glucose with whole eggs or egg whites during an oral glucose challenge mitigates impairments in postprandial vascular endothelial function by attenuating hyperglycemia‐mediated increases in lipid peroxidation

Postprandial hyperglycemia (PPH) is a better predictor of CVD than fasting glucose, with evidence supporting that PPH transiently impairs vascular endothelial function (VEF) in an oxidative stress‐dependent manner. We hypothesized that co‐ingesting egg‐based meals with a glucose challenge would mitigate PPH‐mediated impairments in VEF by limiting lipid peroxidation. In a randomized, cross‐over study, prediabetic obese adults (n = 20; 31.9 ± 1.6 y; 105.0 ± 0.9 mg/dL; 31.1 ± 0.7 kg/m2) ingested isocaloric test meals (400 kcal) containing 100 g glucose (GLUCOSE), or 75 g glucose with 1.5 whole eggs (EGG), 7 egg whites (EGG‐W), or 2 egg yolks (EGG‐Y) prior to evaluating brachial artery flow‐mediated dilation (FMD, %) and plasma glucose and malondialdehyde (MDA) at 30 min intervals for 3 h. Change in FMD (ΔFMD%) during GLUCOSE was maximally lowered at 30 min, and improved at 60 min relative to 30 min, and was restored to levels no different from baseline at 90–180 min. This was accompanied by increases in plasma glucose that peaked at 30 min, and remained elevated through 120 min, until returning to concentrations not different from baseline at 150 min. MDA was higher at 30–120 min relative to baseline, and by 120 min it was significantly lower than peak (60 min) concentrations and not different from baseline concentrations. Regardless of egg‐based meal, ΔFMD% was lower at 30 min relative to baseline, but only ΔFMD% of EGG‐Y was reduced to the extent observed in GLUCOSE. At 60 min, ΔFMD% of EGG and EGG‐W were restored to levels not different from baseline, whereas GLUCOSE and EGG‐Y remained lower than baseline levels, and not different from ΔFMD% at 30 min. By 90 min, ΔFMD% of all treatments were not different from each other and were restored to levels not different from baseline with the exception that EGG‐Y remained lower through 180 min. Relative to GLUCOSE, ΔFMD% AUC0–3 h was increased to a similar extent in EGG and EGG‐W whereas EGG‐Y was not different from GLUCOSE and was lower than those of EGG and EGG‐W. Plasma glucose AUC0–3 h and ΔMDA AUC0–3 h were not different between GLUCOSE and EGG‐Y, but were similarly lower in EGG and EGG‐W compared with GLUCOSE and EGG‐Y. Collectively, replacing a portion of carbohydrate during a glucose challenge with whole eggs or egg whites, but not egg yolks, mitigates PPH‐mediated impairments in VEF by limiting glycemia and lipid peroxidation. Supported by the Egg Nutrition Center.Support or Funding InformationEgg Nutrition Center

Effects of exenatide on postprandial vascular endothelial dysfunction in type 2 diabetes mellitus.

BackgroundBasic studies have shown that glucagon-like peptide-1 (GLP-1) analogs exert a direct protective effect on the vascular endothelium in addition to their indirect effects on postprandial glucose and lipid metabolism. GLP-1 analogs are also reported to inhibit postprandial vascular endothelial dysfunction. This study examined whether the GLP-1 analog exenatide inhibits postprandial vascular endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM).MethodsSeventeen patients with T2DM underwent a meal tolerance test to examine changes in postprandial vascular endothelial function and in glucose and lipid metabolism, both without exenatide (baseline) and after a single subcutaneous injection of 10 μg exenatide. Vascular endothelial function was determined using reactive hyperemia index (RHI) measured by peripheral arterial tonometry before and 120 min after the meal loading test. The primary endpoint was the difference in changes in postprandial vascular endothelial function between the baseline and exenatide tests.ResultsThe natural logarithmically-scaled RHI (L_RHI) was significantly lower after the baseline meal test but not in the exenatide test. The use of exenatide resulted in a significant decrease in triglycerides (TG) area under the curve and coefficient of variation (CV). The change in L_RHI correlated with changes in CV of triglycerides and HDL-cholesterol. Multivariate analysis identified changes in triglyceride CV as the only determinant of changes in L_RHI, contributing to 41% of the observed change.ConclusionsExenatide inhibited postprandial vascular endothelial dysfunction after the meal loading test, suggesting that exenatide has a multiphasic anti-atherogenic action involving not only glucose but also lipid metabolism.Trial registrationClinicalTrials.gov: UMIN000015699.