Anne Nilsson

Effects of GI and content of indigestible carbohydrates of cereal-based evening meals on glucose tolerance at a subsequent standardised breakfast

Objective:To evaluate the impact of four low-glycaemic index (GI) and one high-GI cereal-based evening meals on glucose tolerance at a subsequent standardised breakfast.Design:Wheat kernels, barley kernels, spaghetti, spaghetti with added wheat bran and white wheat bread (WWB) were consumed in the evening in a random order at five different occasions. At the subsequent breakfast, blood glucose, serum insulin, plasma short chain fatty acid, plasma free fatty acid (FFA) and breath hydrogen were measured.Setting:The study was performed at Applied Nutrition and Food Chemistry, Lund University, Sweden.Subjects:Fifteen healthy volunteers were recruited. One subject was later excluded owing to abnormal blood glucose values.Results:The blood glucose response (0–120 min) to the standardised breakfast was significantly lower after consuming barley kernels in the evening compared with evening meals with WWB (P=0.019) or spaghetti+wheat bran (P=0.046). There were no significant differences in insulin concentrations at breakfast. Breath hydrogen excretion at breakfast was significantly higher after an evening meal with barley kernels compared with WWB, wheat kernels or spaghetti (P=0.026, 0.026 and 0.015, respectively), and the concentration of plasma propionate at breakfast was significantly higher following an evening meal with barley kernels compared with an evening meal with WWB (P=0.041). In parallel, FFA concentrations were significantly lower after barley kernels compared with WWB (P=0.042) or spaghetti evening meals (P=0.019).Conclusions:The improved glucose tolerance at breakfast, following an evening meal with barley kernels appeared to emanate from suppression of FFA levels, mediated by colonic fermentation of the specific indigestible carbohydrates present in this product, or, to the combination of the low-GI features and colonic fermentation.Sponsorship:European Commission QLK1-2001-00431 (EUROSTARCH).

A Cereal-Based Evening Meal Rich in Indigestible Carbohydrates Increases Plasma Butyrate the Next Morning

Epidemiological studies have shown an inverse relation between a whole grain consumption and risk of type-2 diabetes and cardiovascular disease. One tentative mechanism relates to colonic metabolism of indigestible carbohydrates. In a previous study, we reported a positive relation between colonic fermentation and improved glucose tolerance. This work can be seen as an extension of that study, focusing on the tentative role of specific colonic metabolites, i.e. SCFA. Plasma concentrations of acetate, propionate, and butyrate were determined in the morning in healthy participants (5 women and 10 men, mean ± SD: 25.9 ± 3.2 y, BMI < 25) following 8 different cereal-based evening meals (50 g available starch) varying in content of indigestible carbohydrates. Each participant consumed all test meals in a random order on separate evenings. At a standardized breakfast following evening test meals, the postprandial glucose response (incremental area under the curve, 0-120 min) was inversely related to plasma butyrate (r = -0.26; P < 0.01) and acetate (r = -0.20; P < 0.05) concentrations. Evening meals composed of high-amylose barley kernels or high-β-glucan barley kernels resulted in higher plasma butyrate concentrations the following morning compared with an evening meal with white wheat bread (P < 0.05). The results support the view that cereal products rich in indigestible carbohydrates may improve glucose tolerance through a mechanism involving colonic fermentation and generation of SCFA, where in particular butyric acid may be involved. This mechanism may be one explanation by which whole grain is protective against type 2 diabetes and cardiovascular disease.

Effects of GI vs content of cereal fibre of the evening meal on glucose tolerance at a subsequent standardized breakfast

Objective:To investigate if the improved glucose tolerance previously observed at breakfast following an evening meal with boiled barley kernels derives from colonic events related to the fermentation of the elevated amounts of indigestible carbohydrates present and/or from the low-GI features.Subjects/Methods:Twenty healthy volunteers aged 19–30 years.Design:High-GI white wheat bread (WWB), WWB+barley dietary fibre (DF) corresponding to the DF content of barley kernels, low-GI spaghetti+ barley DF, spaghetti+double amounts of barley DF (2*DF), spaghetti+oat DF, or whole grain barley flour porridge, were provided as late evening meals. At a subsequent standardised WWB breakfast, B-glucose, s-insulin, p-SCFA, p-FFA, and breath hydrogen (H2) were measured.Results: The B-glucose response (incremental areas under the curves (IAUC) 0–120 min and total areas under the curves 0–180 min) to the standardized breakfast was significantly lower after consuming spaghetti+2*DF in the evening compared with barley porridge (P=0.012). The spaghetti+2*DF meal also resulted in the highest breath H2 excretion (P<0.02). The glucose IAUC (0–120 min) after the standardized breakfast was positively correlated to fasting p-FFA (r=0.29, P<0.02), and the total glucose area (0–180 min) was negatively correlated to the p-propionate level (0–30 min) (r=−0.24, P<0.02).Conclusions:The prolonged digestive and absorptive phase per se, like with a low-glycaemic index (GI) spaghetti evening meal, did not induce overnight benefits on glucose tolerance. Addition of barley DF in high amounts (2*DF) was required to improve overnight glucose tolerance. The correlations observed between glycaemia and p-propionate implicate colonic fermentation as a modulator of glucose tolerance through a mechanism leading to suppressed free fatty acids levels. It is proposed that the overnight benefits on glucose tolerance previously reported for boiled barley kernels is mediated through colonic fermentation of the prebiotic carbohydrates present in this product.

Effects of a brown beans evening meal on metabolic risk markers and appetite regulating hormones at a subsequent standardized breakfast: a randomized cross-over study.

Background Dietary prevention strategies are increasingly recognized as essential to combat the current epidemic of obesity and related metabolic disorders. The purpose of the present study was to evaluate the potential prebiotic effects of indigestible carbohydrates in Swedish brown beans (Phaseolus vulgaris var. nanus) in relation to cardiometabolic risk markers and appetite regulating hormones. Methods Brown beans, or white wheat bread (WWB, reference product) were provided as evening meals to 16 healthy young adults in a randomised crossover design. Glucose, insulin, appetite regulatory hormones, GLP-1, GLP-2, appetite sensations, and markers of inflammation were measured at a following standardised breakfast, that is at 11 to 14 h post the evening meals. Additionally, colonic fermentation activity was estimated from measurement of plasma short chain fatty acids (SCFA, including also branched chain fatty acids) and breath hydrogen (H2) excretion. Results An evening meal of brown beans, in comparison with WWB, lowered blood glucose (−15%, p<0.01)- and insulin (−16%, p<0.05) responses, increased satiety hormones (PYY 51%, p<0.001), suppressed hunger hormones (ghrelin −14%, p<0.05), and hunger sensations (−15%, p = 0.05), increased GLP-2 concentrations (8.4%, p<0.05) and suppressed inflammatory markers (IL-6 −35%, and IL-18 −8.3%, p<0.05) at a subsequent standardised breakfast. Breath H2 (141%, p<0.01), propionate (16%, p<0.05), and isobutyrate (18%, P<0.001) were significantly increased after brown beans compared to after WWB, indicating a higher colonic fermentative activity after brown beans. Conclusions An evening meal with brown beans beneficially affected important measures of cardiometabolic risk and appetite regulatory hormones, within a time frame of 11–14 h, in comparison to a WWB evening meal. Concentrations of plasma SCFA and H2 were increased, indicating involvement of colonic fermentation. Indigestible colonic substrates from brown beans may provide a preventive tool in relation to obesity and the metabolic syndrome. Trial Registration ClinicalTrials.gov NCT01706042

Effects of indigestible carbohydrates in barley on glucose metabolism, appetite and voluntary food intake over 16 h in healthy adults

BackgroundRecent knowledge in animals suggests that gut microbial metabolism may affect host metabolism, including appetite regulating hormones. The aim of the present study was to evaluate the potential effects of a whole grain barley kernel product, rich in intrinsic indigestible carbohydrates (dietary fibre and resistant starch), on markers of metabolism and appetite regulation in healthy subjects.MethodsBoiled barley kernels (BK) or white wheat bread (WWB; reference) were provided as late evening meals to 19 young adults in random order using a cross-over design. During subsequent ad libitum standardized breakfast and lunch meals (10.5-16 h), blood was collected for analysis of glucose, plasma insulin, adiponectin, ghrelin, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), serum free fatty acids (FFA) and interleukin (IL)-6. In addition, appetite sensations, voluntary energy intake and breath H2 were determined.ResultsBK as evening meal increased plasma GLP-1 at fasting (P < 0.05) and during the experimental day (P < 0.01) compared with WWB. In addition the BK evening meal decreased fasting serum FFA (P < 0.05) and tended to decrease fasting serum IL-6 (P = 0.06). At lunch, preceded by BK evening meal, voluntary energy intake was decreased (P < 0.05) when compared to WWB evening meal. The BK evening meal decreased incremental blood glucose area (P < 0.01), promoted higher breath H2 (P < 0.001), maintained adiponectin concentrations (P < 0.05) and reduced perceived hunger (P < 0.05) during 10.5-16 h after the meal.ConclusionsThe results indicate that the BK evening meal, facilitate glucose regulation, increase the release of GLP-1, reduce subsequent energy intake while at the same time decreasing hunger over 2 subsequent meals, and reduce fasting FFA the subsequent morning, possibly mediated through gut microbial fermentation of the indigestible carbohydrates.

Effects of supplementation with n-3 polyunsaturated fatty acids on cognitive performance and cardiometabolic risk markers in healthy 51 to 72 years old subjects: a randomized controlled cross-over study

BackgroundHigher plasma n-3 polyunsaturated fatty acids (PUFA) have been associated with a lower risk of age related cognitive decline, and to beneficially affect cardiometabolic risk factors. A relation exists between metabolic disorders such as diabetes type 2 and cognitive decline. Results regarding the potential effects of n-3 PUFA on risk factors in healthy subjects are divergent, and studies regarding the possible relation between cardiometabolic parameters and cognitive performance are scarce. The objective was to evaluate the effects of five weeks intake of long chain n-3 PUFA on cognitive performance in healthy individuals, and to exploit the possible relation between outcomes in cognitive tests to cardiometabolic risk parameters.MethodsFish oil n-3 PUFA (3g daily) were consumed during 5weeks separated by a 5 week washout period in a cross-over placebo controlled study, including 40 healthy middle aged to elderly subjects. Cognitive performance was determined by tests measuring working memory (WM) and selective attention.ResultsSupplementation with n-3 PUFA resulted in better performance in the WM-test compared with placebo (p < 0.05). In contrast to placebo, n-3 PUFA lowered plasma triacylglycerides (P < 0.05) and systolic blood pressure (p < 0.0001). Systolic blood pressure (p < 0.05), f-glucose (p = 0.05), and s-TNF-α (p = 0.05), were inversely related to the performance in cognitive tests.ConclusionsIntake of n-3 PUFA improved cognitive performance in healthy subjects after five weeks compared with placebo. In addition, inverse relations were obtained between cardiometabolic risk factors and cognitive performance, indicating a potential of dietary prevention strategies to delay onset of metabolic disorders and associated cognitive decline.

Effects of differences in postprandial glycaemia on cognitive functions in healthy middle aged subjects

Objective:To find useful methods for the studies of cognitive function during a postprandial period, and to use these methods to evaluate function after test meals differing in post meal glycaemia.Subjects/Methods:Forty healthy volunteers aged 49–70 years were studied. A glucose solution (glucose 50 g) was provided through either a bolus or sipping regimen at breakfast to simulate a high-GI or a low-GI breakfast, respectively. Cognitive tests of working memory (WM) were performed at 35, 90, 120 and 150 min after commencing the breakfast, and a test of selective attention (SA) was performed at 170 min.Results:Subjects with higher glucose tolerance performed better in the cognitive tests (P<0.05). After entering glucose tolerance as covariate, the subjects performed better in the working memory test at 90 min (P<0.034) and in the selective attention test at 170 min (P<0.017) after the simulated low-glycaemic index (GI) breakfast compared with the simulated high-GI breakfast.Conclusion:Possibly, the cognitive functions tested were enhanced by avoiding a sharp decline in blood glucose concentration and by maintaining a higher glycaemia in the late postprandial period, respectively. A low-GI diet is preferable in the prevention of the risk of cognitive decline as a result of less efficient glucose regulation.

Effects on cognitive performance of modulating the postprandial blood glucose profile at breakfast.

Background/Objectives:Considering the importance of glucose as a brain substrate, the postprandial rate of glucose delivery to the blood could be expected to affect cognitive functions. The purpose was to evaluate to what extent the rate of glucose absorption affected measures of cognitive performance in the postprandial period. In addition, cognitive performance was evaluated in relation to individual glucoregulation.Subjects/Methods:A white wheat bread (WWB) enriched with guar gum (G-WWB) with the capacity to produce a low but sustained blood glucose net increment was developed. The G-WWB was evaluated in the postprandial period after breakfast with respect to effects on cognitive function (working memory and selective attention (SA)) in 40 healthy adults (49–71 years, body mass index 20–29 kg/m2), using a high glycaemic index WWB for comparison in a randomised crossover design.Results:The G-WWB improved outcome in the cognitive tests (SA test) in the later postprandial period (75–225 min) in comparison with the WWB (P<0.01). Subjects with better glucoregulation performed superior in cognitive tests compared with subjects with worse glucoregulation (P<0.05).Conclusions:Beneficial effects on cognitive performance were observed with the G-WWB in the late postprandial period. The positive effect is suggested to emanate from improved insulin sensitivity, possibly in a combination with an enhanced neural energy supply. The results highlight the importance of carbohydrate foods that induces a low but sustained blood glucose profile in enhancing postprandial cognitive functions.

Increased gut hormones and insulin sensitivity index following a 3-d intervention with a barley kernel-based product: a randomised cross-over study in healthy middle-aged subjects.

Certain purified indigestible carbohydrates such as inulin have been shown to stimulate gut-derived hormones involved in glycaemic regulation and appetite regulation, and to counteract systemic inflammation through a gut microbiota-mediated mechanism. Less is known about the properties of indigestible carbohydrates intrinsic to food. The aim of this study was to investigate the possibility to affect release of endogenous gut hormones and ameliorate appetite control and glycaemic control by ingestion of a whole-grain cereal food product rich in NSP and resistant starch in healthy humans. In all, twenty middle-aged subjects were provided with a barley kernel-based bread (BB) or a reference white wheat bread during 3 consecutive days, respectively, in a randomised cross-over design study. At a standardised breakfast the following day (day 4), blood was collected for the analysis of blood (b) glucose regulation, gastrointestinal hormones, markers of inflammation and markers of colonic fermentation; 3 d of intervention with BB increased gut hormones in plasma (p) the next morning at fasting (p-glucagon-like peptide-1; 56%) and postprandially (p-glucagon-like peptide-2; 13% and p-peptide YY; 18%). Breath H₂ excretion and fasting serum (s) SCFA concentrations were increased (363 and 18%, respectively), and b-glucose (22%) and s-insulin responses (17%) were decreased after BB intervention. Insulin sensitivity index (ISI(composite)) was also improved (25%) after BB. In conclusion, 3 d of intervention with BB increased systemic levels of gut hormones involved in appetite regulation, metabolic control and maintenance of gut barrier function, as well as improved markers of glucose homoeostasis in middle-aged subjects, altogether relevant for the prevention of obesity and the metabolic syndrome.

Combining functional features of whole-grain barley and legumes for dietary reduction of cardiometabolic risk: a randomised cross-over intervention in mature women.

The usefulness of dietary strategies against cardiometabolic risk is increasingly being acknowledged. Legumes and whole grains can modulate risk markers associated with cardiometabolic diseases, but their possible additive/synergistic actions are unknown. The objective of the present study was to assess, in healthy subjects, the effect of a diet including specific whole-grain barley products and legumes with prior favourable outcomes on cardiometabolic risk parameters in semi-acute studies. A total of forty-six overweight women (50-72 years, BMI 25-33 kg/m² and normal fasting glycaemia) participated in a randomised cross-over intervention comparing a diet rich in kernel-based barley products, brown beans and chickpeas (D1, diet 1 (functional diet)) with a control diet (D2, diet 2 (control diet)) of similar macronutrient composition but lacking legumes and barley. D1 included 86 g (as eaten)/d brown beans, 82 g/d chickpeas, 58 g/d whole-grain barley kernels and 216 g/d barley kernel bread. Both diets followed the Nordic Nutrition Recommendations, providing similar amounts of dietary fibre (D1: 46·9 g/d; D2: 43·5 g/d), with wheat-based products as the main fibre supplier in D2. Each diet was consumed for 4 weeks under weight-maintenance conditions. Both diets decreased serum total cholesterol, LDL-cholesterol and HDL-cholesterol levels, but D1 had a greater effect on total cholesterol and LDL-cholesterol levels (P< 0·001 and P< 0·05, respectively). D1 also reduced apoB (P< 0·001) and γ-glutamyl transferase (P< 0·05) levels, diastolic blood pressure (P< 0·05) and the Framingham cardiovascular risk estimate (P< 0·05). D1 increased colonic fermentative activity, as judged from the higher (P< 0·001) breath hydrogen levels recorded. In conclusion, a specific barley/legume diet improves cardiometabolic risk-associated biomarkers in a healthy cohort, showing potential preventive value beyond that of a nutritionally well-designed regimen.