Glycemia In Healthy Subjects Research Articles

Effects of different types of meals on postprandial glycaemia in healthy subjects.

Nowadays, continuous glycaemic monitoring systems are used primarily for diabetic patients. The most popular continuous glycaemic monitoring (CGMs) measure the glucose concentration in the interstitial fluid every 1 or 5 minutes, providing the patient with 288 or 1,440 measurements in aday. CGM is also useful for observing sudden changes in glycaemia after the introduction of dietary interventions and those related to physical activity. Peri-prandial glycaemia is defined as the change in blood glucose levels depending on the carbohydrate-containing meal consumed. A state of peri-prandial hyperglycaemia begins when blood glucose levels rise above the level of 140 mg/dl (7.8 mmol/l) within 1-2 hours after food intake in healthy people without diabetes. The influence of the peri-prandial glycaemic response is briefly related to the amount and type of food consumed. Optimising the glycaemic profile is important for our health. The purpose of this article is to summarise the current knowledge of the effects of various meals on peri-prandial glycaemia in healthy individuals.

Postprandial glycemia in healthy subjects: Which probiotic dairy food is more adequate?

The consumption of probiotic-enriched dairy products has been associated with many health benefits, including anti-hyperglycemic activity. The effect on health is dependent on the type of probiotic culture used and the dairy product consumed. This study evaluated the effect of different probiotic-enriched dairy matrices (Minas Frescal cheese, Prato cheese, and whey dairy beverage) containing Lactobacillus casei on in vitro and in vivo anti-hyperglycemic activity. For this purpose, in vitro anti-hyperglycemic activity was determined by the inhibition of α-glucosidase and α-amylase activities, and a human study was performed with healthy individuals (n = 15, consumption of bread as a control; bread + Minas Frescal cheese; bread + Prato cheese; bread + dairy beverage) to assess the effects of different probiotic foods on postprandial glycemia. In vitro data showed that Prato cheese presented the highest lipid (36.9 g/100 g) and protein (26.5 g/100 g) contents as well as the highest α-amylase (60.7%) and α-glucosidase (52.6%) inhibition. The consumption of Prato cheese resulted in a lesser increase in blood glucose level (13 mg/dL) compared with the consumption of bread alone (19 mg/dL), Minas Frescal cheese (20 mg/dL), and whey dairy beverage (30 mg/dL), with glycemic indices similar to that observed for the control. The present results demonstrated a good correlation between in vitro and in vivo data, in which the type of dairy matrix affects the anti-hyperglycemic activity. It is concluded that the consumption of probiotic Prato cheese can contribute to the reduction of postprandial glycemia in healthy individuals.

Postprandial Effects of Individual and Combined GIP and GLP-1 Receptor Antagonization in Healthy Subjects

The gut-derived incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are known for insulinotropic and glucose-lowering effects. However, their individual roles in postprandial glucose homeostasis are unknown. We infused the GIP receptor antagonist GIP(3-30)NH2 and the GLP-1 receptor antagonist exendin(9-39) during a meal to determine the roles of endogenous GIP and GLP-1 on postprandial glucose metabolism. On four separate days, 12 healthy men (age 19-65 years, BMI 20-25 kg/m2) received a liquid mixed meal test with randomized and double-blinded infusions of GIP(3-30)NH2 (800 pmol/kg/min) + Ex(9-39) (450 pmol/kg/min) (A), GIP(3-30)NH2 (B), Ex(9-39) (C), and saline (D). On Day A, B and C, glucose excursions were significantly increased by 85%, 55% and 15%, respectively, compared to D. Day A and B excursions were significantly higher than C (Figure). Glucagon levels at 60 min differed between Day A and B (11.5±1.2 vs. 7.5±0.6 pmol/l, P=0.01), and Day B and C (11.5±1.2 vs. 12.9±1.5 pmol/l, P=0.008). GLP-1 was higher on Day A (P=0.01) and C (P=0.02) than D. No significant effects on insulin, C-peptide, gastric emptying, or GIP were observed. We conclude that endogenous GIP affects postprandial plasma glucose excursions more pronouncedly than GLP-1, and that both hormones additively contribute to control postprandial glycemia in healthy subjects. Disclosure L.S. Gasbjerg: Stock/Shareholder; Self; Antag Therapeutics. M.M. Helsted: None. A.H. Sparre-Ulrich: Employee; Self; Antag Therapeutics ApS. A.R. Lanng: None. S. Stensen: None. M. Jakobsen: None. B. Hartmann: None. M.B. Christensen: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. Board Member; Self; Zealand Pharma A/S. Speaker's Bureau; Self; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Self; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Self; Antag Therapeutics. Other Relationship; Spouse/Partner; Antag Therapeutics. T. Vilsbøll: Advisory Panel; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Consultant; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Speaker's Bureau; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Research Support; Self; Eli Lilly and Company, Novo Nordisk A/S. M.M. Rosenkilde: Other Relationship; Self; Antag Therapeutics. Advisory Panel; Spouse/Partner; Novo Nordisk A/S. Board Member; Spouse/Partner; Zealand Pharma A/S. Speaker's Bureau; Spouse/Partner; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Spouse/Partner; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Spouse/Partner; Antag Therapeutics. F.K. Knop: Advisory Panel; Self; AstraZeneca. Consultant; Self; AstraZeneca. Research Support; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Advisory Panel; Self; Eli Lilly and Company. Speaker's Bureau; Self; Eli Lilly and Company. Advisory Panel; Self; Amgen Inc.. Speaker's Bureau; Self; Merck Sharp & Dohme Corp.. Advisory Panel; Self; Novo Nordisk A/S. Consultant; Self; Novo Nordisk A/S. Speaker's Bureau; Self; Novo Nordisk A/S. Consultant; Self; Amgen Inc.. Advisory Panel; Self; MedImmune, Sanofi. Consultant; Self; Sanofi. Research Support; Self; Sanofi. Speaker's Bureau; Self; Sanofi.

Oleuropein, a component of extra virgin olive oil, lowers postprandial glycaemia in healthy subjects.

Extra virgin olive oil lowers postprandial glycaemia. We investigated if oleuropein, a component of extra virgin olive oil, exerts a similar effect on postprandial glycaemia and the underlying mechanism. Twenty healthy subjects were randomly allocated in a cross-over design to 20mg oleuropein or placebo immediately before lunch. Postprandial glycaemia along with blood insulin, dipeptidyl-peptidase-4 (DPP-4) and glucagon-like peptide-1 and oxidative stress, which included soluble NADPH oxidase-derived peptide activity (sNox2-dp), 8-iso-prostaglandin-2α and platelet p47phox phosphorylation, were analysed before and 2 h after meal. After 2 h, subjects who assumed oleuropein had significantly lower blood glucose, DPP-4 activity and higher insulin and glucagon-like peptide-1 compared to placebo. Furthermore, sNox2-dp, 8-iso-PGF2α and platelet p47phox phosphorylation were significantly lower in oleuropein- compared to placebo-treated subjects. DPP-4 significantly correlated with sNox2-dp [Spearman's rho (Rs)=0.615; P<0.001], p47phox phosphorylation (Rs=0.435; P<0.05) and 8-iso- prostaglandin-2α (Rs=0.33; P<0.05). In vitro study demonstrated that hydroxytyrosol, a metabolite of oleuropein, significantly reduced p47phox phosphorylation and isoprostane formation. These findings indicate that oleuropein improves postprandial glycaemic profile via hampering Nox2-derived oxidative stress.

Effect of clarified Brazilian native fruit juices on postprandial glycemia in healthy subjects

Brazilian native fruits have been shown as excellent sources of polyphenols which are associated with multiple biological activities including inhibition of carbohydrate-hydrolyzing enzymes, α-amylase and α-glucosidase. Postmeal blood glucose elevations and high glycemic index diets can play a major role in the development of type 2 diabetes, therefore alternative approaches to reduce postprandial hyperglycemia are of growing interest in order to reduce diabetes risk. Here we investigated the effect of six Brazilian native clarified fruit juices from Amazon, Savannah and Atlantic Forest biomes on postprandial glycemia after consumption of a carbohydrate meal. For this, 23 healthy subjects were selected to consume seven meal tests, with a 1-week interval among them, consisting in 50g white bread plus 300mL of water (control) or cambuci, cagaita, maracujá-alho, cupuaçu, camu-camu and jaboticaba clarified fruit juices. The results showed that serum glucose concentrations were significantly lower after consumption of cambuci, cagaita, camu-camu and jaboticaba juices, whereas maracujá-alho and cupuaçu juices did not decrease the amount of glucose absorbed, compared to control (p<0.05). In addition, cagaita, cambuci, cupuaçu and jaboticaba juices increased the oxygen radical absorbance capacity in plasma, whereas all juices augmented the ferric reducing ability of plasma, except for cambuci (p<0.05). These results indicate that juices from Brazilian native fruits may be considered as adjuvant treatment for reduction of postprandial glycemia in healthy subjects.

Extra virgin olive oil improves post-prandial glycemic and lipid profile in patients with impaired fasting glucose

Extra virgin olive oil (EVOO) improves post-prandial glycaemia in healthy subjects but it has never been investigated if this can be detected in pre-diabetic patients. We investigated if EVOO affects post-prandial glucose and lipid profile in patients with impaired fasting glucose (IFG). Thirty IFG patients were randomly allocated to a meal containing or not 10g of EVOO in a cross-over design. Before, 60min and 120min after lunch a blood sample was taken to measure glucose, insulin, Glucagon-like peptide-1 (GLP1), dipeptidyl-peptidase-4 (DPP4) activity, triglycerides (TG), total cholesterol, HDL-cholesterol and Apo B-48. The meal containing EVOO was associated with a reduction of glucose (p=0.009) and DPP4 activity (p<0.001) and a significant increase of insulin (p<0.001) and GLP-1 (p<0.001) compared with the meal without EVOO. Furthermore, the meal containing EVOO showed a significant decrease of triglycerides (p=0.002) and Apo B-48 (p=0.002) compared with the meal without EVOO. Total cholesterol and HDL cholesterol levels did not significantly change between the two groups. This is the first study to show that in IFG patients EVOO improves post-prandial glucose and lipid profile with a mechanism probably related to incretin up-regulation.

Pharmacokinetics and pharmacodynamics of gliclazide from immediate and modified release formulation tablets in rats.

The objective of the study was to compare pharmacokinetic and pharmacodynamic parameters of gliclazide after administration of immediate (IR) and modified release (MR) tablets. The experiment included rats with both normoglycemia and streptozocin (STZ)-induced hyperglycemia. Several MR formulations were designed and in-vitro drug release profile was assessed by a dissolution test. For the further in-vivo study the most suitable formulation was chosen. For pharmacokinetic analysis concentrations of gliclazide in plasma were determined by a validated high performance liquid chromatography (HPLC) method with UV detection. Pharmacodynamic efficacy of the drug was evaluated by measuring blood glucose concentrations. Gliclazide bioavailability was totally different for two formulations in both healthy and diabetic rats based on area under the curve (AUC), time to peak concentration (tmax) and peak concentration (Cmax). Reduction of blood glucose level was significantly higher after the administration of IR than MR formulation. The highest pharmacodynamic efficacy of gliclazide was observed in the normal animals group after administration of the IR tablets, while hypoglycemic effect of the drug was diminished in animals with induced diabetes. Our study suggested that results of reduction in blood glucose level for STZ-induced groups were not comparable with pharmacodynamic effect for normal group. It may be assumed that a decrease in glycemia in healthy subjects might not be a suitable factor for characterizing anti-diabetic drugs.

Disordered Control of Intestinal Sweet Taste Receptor Expression and Glucose Absorption in Type 2 Diabetes

We previously established that the intestinal sweet taste receptors (STRs), T1R2 and T1R3, were expressed in distinct epithelial cells in the human proximal intestine and that their transcript levels varied with glycemic status in patients with type 2 diabetes. Here we determined whether STR expression was 1) acutely regulated by changes in luminal and systemic glucose levels, 2) disordered in type 2 diabetes, and 3) linked to glucose absorption. Fourteen healthy subjects and 13 patients with type 2 diabetes were studied twice, at euglycemia (5.2 ± 0.2 mmol/L) or hyperglycemia (12.3 ± 0.2 mmol/L). Endoscopic biopsy specimens were collected from the duodenum at baseline and after a 30-min intraduodenal glucose infusion of 30 g/150 mL water plus 3 g 3-O-methylglucose (3-OMG). STR transcripts were quantified by RT-PCR, and plasma was assayed for 3-OMG concentration. Intestinal STR transcript levels at baseline were unaffected by acute variations in glycemia in healthy subjects and in type 2 diabetic patients. T1R2 transcript levels increased after luminal glucose infusion in both groups during euglycemia (+5.8 × 104 and +5.8 × 104 copies, respectively) but decreased in healthy subjects during hyperglycemia (−1.4 × 104 copies). T1R2 levels increased significantly in type 2 diabetic patients under the same conditions (+6.9 × 105 copies). Plasma 3-OMG concentrations were significantly higher in type 2 diabetic patients than in healthy control subjects during acute hyperglycemia. Intestinal T1R2 expression is reciprocally regulated by luminal glucose in health according to glycemic status but is disordered in type 2 diabetes during acute hyperglycemia. This defect may enhance glucose absorption in type 2 diabetic patients and exacerbate postprandial hyperglycemia.

Characterization and effect of clarified araçá (Psidium guineenses Sw.) juice on postprandial glycemia in healthy subjects

Brazilian native fruits are excellent sources of bioactive compounds of phenolic nature. Some of these compounds are able to inhibit carbohydrate- metabolizing enzymes (in vitro), α-amylase and α-glucosidase, delaying carbohydrate digestion. This study aimed to evaluate the effect of clarified araçá (Psidium guineenses Sw.) juice on postprandial glycemia in humans after consumption of 25 g of available carbohydrates (approximately 50 g of white bread) and characterize the phenolic compounds and in vitro antioxidant capacity of araçá juice and pulp. The results showed that the clarified juice had a positive effect on postprandial glycemia reducing the total amount of glucose absorbed, lengthening the time to reach maximum blood glucose concentration, reducing glucose incremental velocity, and decreasing glucose incremental percentage. Both frozen pulp and clarified juice had high amounts of phenolic compounds, antioxidant capacity, and proanthocyanidins, among which oligomers (monomers to tetramers), pentamers, hexamers, heptamers, octamers, nonamers, decamers, and polymers were detected, and they are probably associated with in vivo effects.

Electroretinography in healthy subjects in relation to systemic glucocorticoid intake

This study examined electroretinographic function in healthy subjects before and after prednisolone intake. To separate the effect of prednisolone on the retina from the potentially confounding hyperglycemia-inducing effect of prednisolone, electroretinography was made while fasting and at a pre-specified level of clamped hyperglycemia. The study included 10 eyes in 10 healthy lean men aged 25 ± 3 years (mean ± SD). The subjects were examined before and after oral intake of prednisolone 37.5 mg/day for 9.1 ± 1.4 days. The diabetogenic potential of prednisolone was reinforced by the intake of a high-caloric diet and by the reduction of physical activity. Full-field electroretinography (ffERG) demonstrated no significant change (P < 0.05) in amplitudes or implicit times in relation to prednisolone intake, neither at fasting glycemia levels, which were 4.9 ± 0.2 mM before and 5.0 ± 0.3 mM (P = 0.467) after the intervention, nor at 10 mM clamped hyperglycemia. Specifically, the fasting b-wave amplitude of the combined rod-cone response was 432 ± 84 mV before and 463 ± 71 mV (P = 0.13) after prednisolone intake. Furthermore, the ffERG could not be shown to be influenced by the doubling of glycemia from fasting to clamped hyperglycemia, neither before, nor after prednisolone (P > 0.05). The stability of ffERG performance in the face of shifting glycemia levels, which differs from what has been found in diabetes, was not influenced by the mild diabetogenic effect of the intervention on insulin resistance (P = 0.011) and post-prandial glycemia (P = 0.023). We conclude that prednisolone had no detectable effect on the ffERG in healthy lean men in this study. Retinal function may be less sensitive to changes in glycemia in healthy subjects than in people with diabetes, a characteristic that was unchanged by a short course of prednisolone.

A novel wheat variety with elevated content of amylose increases resistant starch formation and may beneficially influence glycaemia in healthy subjects

BackgroundPrevious studies indicate that elevated amylose content in products from rice, corn, and barley induce lower postprandial glycaemic responses and higher levels of resistant starch (RS). Consumption of slowly digestible carbohydrates and RS has been associated with health benefits such as decreased risk of diabetes and cardiovascular disease.ObjectiveTo evaluate the postprandial glucose and insulin responses in vivo to bread products based on a novel wheat genotype with elevated amylose content (38%).DesignBread was baked from a unique wheat genotype with elevated amylose content, using baking conditions known to promote amylose retrogradation. Included test products were bread based on whole grain wheat with elevated amylose content (EAW), EAW with added lactic acid (EAW-la), and ordinary whole grain wheat bread (WGW). All test breads were baked at pumpernickel conditions (20 hours, 120°C). A conventionally baked white wheat bread (REF) was used as reference. Resistant starch (RS) content was measured in vitro and postprandial glucose and insulin responses were tested in 14 healthy subjects.ResultsThe results showed a significantly higher RS content (on total starch basis) in breads based on EAW than in WGW (p<0.001). Lactic acid further increased RS (p<0.001) compared with both WGW and EAW. Breads baked with EAW induced lower postprandial glucose response than REF during the first 120 min (p<0.05), but there were no significant differences in insulin responses. Increased RS content per test portion was correlated to a reduced glycaemic index (GI) (r= − 0.571, p<0.001).ConclusionsThis study indicates that wheat with elevated amylose content may be preferable to other wheat genotypes considering RS formation. Further research is needed to test the hypothesis that bread with elevated amylose content can improve postprandial glycaemic response.

Reduction in postprandial glucose excursion and prolongation of satiety: possible explanation of the long-term effects of whole grain Salba (Salvia Hispanica L.)

Despite strong correlations linking whole-grain consumption to reductions in heart disease, the physiological mechanisms involved remain ambiguous. We assessed whether Salba (Salvia Hispanica L.) whole grain reduces postprandial glycemia in healthy subjects, as a possible explanation for its cardioprotective effects observed in individuals with diabetes. The study used acute, randomized, double-blind, controlled design in which 11 healthy individuals (6 males and 5 females; body mass index 22.3+/-2.8 kg/m(2)) received 0, 7, 15 or 24 g of Salba baked into white bread. Capillary samples and appetite ratings were collected over 2 h after consumption. A dose-response reduction in postprandial glycemia (P=0.002, r(2)=0.203) was observed with all three doses of Salba, significantly decreasing incremental areas under the curve (iAUCs) and time point-specific blood glucose (P<0.05). Appetite ratings were decreased at 60 min after high, 90 min after high and intermediate and at 120 min after all treatments (P<0.05). Decrease in postprandial glycemia provides a potential explanation for improvements in blood pressure, coagulation and inflammatory markers previously observed after 12-week Salba supplementation in type II diabetes.

Effect of whey on blood glucose and insulin responses to composite breakfast and lunch meals in type 2 diabetic subjects

Whey proteins have insulinotropic effects and reduce the postprandial glycemia in healthy subjects. The mechanism is not known, but insulinogenic amino acids and the incretin hormones seem to be involved. The aim was to evaluate whether supplementation of meals with a high glycemic index (GI) with whey proteins may increase insulin secretion and improve blood glucose control in type 2 diabetic subjects. Fourteen diet-treated subjects with type 2 diabetes were served a high-GI breakfast (white bread) and subsequent high-GI lunch (mashed potatoes with meatballs). The breakfast and lunch meals were supplemented with whey on one day; whey was exchanged for lean ham and lactose on another day. Venous blood samples were drawn before and during 4 h after breakfast and 3 h after lunch for the measurement of blood glucose, serum insulin, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1). The insulin responses were higher after both breakfast (31%) and lunch (57%) when whey was included in the meal than when whey was not included. After lunch, the blood glucose response was significantly reduced [-21%; 120 min area under the curve (AUC)] after whey ingestion. Postprandial GIP responses were higher after whey ingestion, whereas no differences were found in GLP-1 between the reference and test meals. It can be concluded that the addition of whey to meals with rapidly digested and absorbed carbohydrates stimulates insulin release and reduces postprandial blood glucose excursion after a lunch meal consisting of mashed potatoes and meatballs in type 2 diabetic subjects.

Effect of whey on blood glucose and insulin responses to composite breakfast and lunch meals in type 2 diabetic subjects

Background:Whey proteins have insulinotropic effects and reduce the postprandial glycemia in healthy subjects. The mechanism is not known, but insulinogenic amino acids and the incretin hormones seem to be involved. Objective:The aim was to evaluate whether supplementation of meals with a high glycemic index (GI) with whey proteins may increase insulin secretion and improve blood glucose control in type 2 diabetic subjects. Design:Fourteen diet-treated subjects with type 2 diabetes were served a high-GI breakfast (white bread) and subsequent high-GI lunch (mashed potatoes with meatballs). The breakfast and lunch meals were supplemented with whey on one day; whey was exchanged for lean ham and lactose on another day. Venous blood samples were drawn before and during 4 h after breakfast and 3 h after lunch for the measurement of blood glucose, serum insulin, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1). Results:The insulin responses were higher after both breakfast (31%) and lunch (57%) when whey was included in the meal than when whey was not included. After lunch, the blood glucose response was significantly reduced [−21%; 120 min area under the curve (AUC)] after whey ingestion. Postprandial GIP responses were higher after whey ingestion, whereas no differences were found in GLP-1 between the reference and test meals. Conclusions:It can be concluded that the addition of whey to meals with rapidly digested and absorbed carbohydrates stimulates insulin release and reduces postprandial blood glucose excursion after a lunch meal consisting of mashed potatoes and meatballs in type 2 diabetic subjects.

Initially more rapid small intestinal glucose delivery increases plasma insulin, GIP, and GLP-1 but does not improve overall glycemia in healthy subjects

The rate of gastric emptying of glucose-containing liquids is a major determinant of postprandial glycemia. The latter is also dependent on stimulation of insulin secretion by glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Although overall emptying of glucose approximates 1-3 kcal/min, the "early phase" of gastric emptying is usually more rapid. We have evaluated the hypothesis that increased stimulation of incretin hormones and insulin by a more rapid initial rate of small intestinal glucose delivery would reduce the overall glycemic response to a standardized enteral glucose load. Twelve healthy subjects were studied on two separate days in which they received an intraduodenal (id) glucose infusion for 120 min. On one day, the infusion rate was variable, being more rapid (6 kcal/min) between t = 0 and 10 min and slower (0.55 kcal/min) between t = 10 and 120 min, whereas on the other day the rate was constant (1 kcal/min) from t = 0-120 min, i.e., on both days 120 kcal were given. Between t = 0 and 75 min, plasma insulin, GIP, and GLP-1 were higher with the variable infusion. Despite the increase in insulin and incretin hormones, blood glucose levels were also higher. Between t = 75 and 180 min, blood glucose and plasma insulin were lower with the variable infusion. There was no difference in the area under the curve 0-180 min for blood glucose. We conclude that stimulation of incretin hormone and insulin release by a more rapid initial rate of id glucose delivery does not lead to an overall reduction in glycemia in healthy subjects.

Blood glucose control in healthy subject and patients receiving intravenous glucose infusion or total parenteral nutrition using glucagon-like peptide 1

Aims: It was the aim of the study to examine whether the insulinotropic gut hormone GLP-1 is able to control or even normalise glycaemia in healthy subjects receiving intravenous glucose infusions and in severely ill patients hyperglycaemic during total parenteral nutrition. Patients and methods: Eight healthy subjects and nine patients were examined. The volunteers received, in six separate experiments in randomised order, intravenous glucose at doses of 0, 2 and 5mg kg −1 min −1, each with intravenous GLP-1 or placebo for 6 h. Patients were selected on the basis of hyperglycaemia (>150 mg/dl) during complete parenteral nutrition with glucose (3.2±1.4 mg kg −1 min −1), amino acids ( n=8; 0.9±0.2 mg kg −1 min −1), with or without lipid emulsions. Four hours (8 a.m. to 12 a.m. on parenteral nutrition plus NaCl as placebo) were compared to 4 h (12 a.m. to 4 p.m.) with additional GLP-1 administered intravenously. The dose of GLP-1 was 1.2 pmol kg −1 min −1. Blood was drawn for the determination of glucose, insulin, C-peptide, GLP-1, glucagon, and free fatty acids. Results: Glycaemia was raised dose-dependently by glucose infusions in healthy volunteers ( p<0.0001). GLP-1 (∼100–150 pmol/l) stimulated insulin and reduced glucagon secretion and reduced glucose concentrations into the normoglycaemic fasting range (all p<0.05). In hyperglycaemic patients, glucose concentrations during the placebo period averaged 211±24 mg/dl. This level was reduced to 159±25 mg/dl with GLP-1 ( p<0.0001), accompanied by a rise in insulin ( p=0.0002) and C-peptide ( p<0.0001), and by trend towards a reduction in glucagon ( p=0.08) and free fatty acids ( p=0.02). GLP-1 was well tolerated. Conclusions: Hyperglycaemia during parenteral nutrition can be controlled by exogenous GLP-1, e.g. the natural peptide (available today), whereas the chronic therapy of Type 2 diabetes requires GLP-1 derivatives with longer duration of action.

Delayed gastric emptying rate may explain improved glycaemia in healthy subjects to a starchy meal with added vinegar.

The aim of the study was to evaluate the possible influence of acetic acid (administered as vinegar) on the postprandial glucose and insulin responses, and the potential involvement of a modified gastric emptying rate was studied by use of paracetamol as a marker. The white bread reference meal as well as the corresponding meal supplemented with vinegar had the same content of starch, protein and fat. The meals were served in the morning after an over-night fast and in random order. Capillary blood samples for analysis of glucose, insulin and paracetamol were collected postprandially. The study was performed at the Department of Applied Nutrition and Food Chemistry, Lund University, Sweden. Ten healthy volunteers, seven women and three men, aged 22-51 y, with normal body mass indices were recruited. The presence of acetic acid, given as vinegar, significantly reduced the postprandial glucose (GI=64) and insulin responses (II=65) to a starchy meal. As judged from lowered paracetamol levels after the test meal with vinegar, the mechanism is probably a delayed gastric emptying rate. Fermented foods or food products with added organic acids should preferably be included in the diet in order to reduce glycaemia and insulin demand.