Effects of a low-glycaemic index spaghetti meal on glucose tolerance and lipaemia at a subsequent meal in healthy subjects

OBJECTIVE: The aim of the study was to evaluate the impact of a low glycaemic index (GI) breakfast on glucose tolerance and lipaemia at a subsequent lunch meal. DESIGN: A low GI spaghetti meal and a high-GI white wheat bread (WWB) reference meal were served in the morning after an overnight fast in random order. Four hours after the breakfast, the subjects were given a second meal-a standardized high-GI lunch-and the blood glucose, insulin and lipid responses were measured after the lunch meal. SETTING: The study was performed at the Department of Applied Nutrition and Food Chemistry, Lund University, Sweden. SUBJECTS: Ten healthy volunteers, eight women and two men, aged 25-51 y, with normal body mass indices, were recruited. RESULTS: Lowered glucose and insulin responses and reduced serum triglyceride (TG) level were found at the subsequent lunch meal when the low-GI spaghetti meal was given as a breakfast. No differences in total serum cholesterol or HDL cholesterol were seen after lunch, when preceded by the WWB reference breakfast or the spaghetti breakfast, respectively. CONCLUSIONS: Improved glucose tolerance and lowered serum TG levels can appear in the course of a single day. As insulin resistance and raised postprandial TG concentration are known risk factors for cardiovascular disease, the present study adds evidence for a beneficial role of a low-GI diet. SPONSORSHIP: Cerealia Foundation for Research and Development (project no. 232) and the Swedish Council for Forestry and Agricultural Research. European Journal of Clinical Nutrition (2000) 54, 24-28     

Prediction of glycemic response to mixed meals in noninsulin-dependent diabetic subjects

Recent studies suggest the glycemic response of different mixed meals cannot be predicted from the glycemic index (GI) of individual carbohydrate foods. Postprandial glucose levels following five different mixed meals in six noninsulin-dependent diabetic volunteers were therefore assessed. Each meal comprised 50% carbohydrate, 30% fat, and 20% protein, varying only in type of carbohydrate. The carbohydrate exchanged in each meal (potato, white bread, rice, spaghetti, or lentils and barley) contributed 37% of total meal calories. The correlation between predicted glucose response and postprandial glucose area was highly significant; estimated meal GI was virtually proportional to the actual mean glycemic response. These results demonstrate that the relative glycemic effects of mixed meals can be predicted from the GI of their carbohydrate components, again stressing the importance of type of carbohydrate in regulating postprandial blood-glucose levels.     

Relationship between the rate of gastric emptying and glucose and insulin responses to starchy foods in young healthy adults

Twelve young healthy adults (five men, seven women) ingested four test meals on four occasions so we could examine the relationship between the rate of gastric emptying (GE) and the glucose response to different starchy foods. Each meal consisted of one food product containing 50 g starch: spaghetti, rice, French bread, or mashed potato. Basal and postprandial glucose and insulin responses were measured for 3 h. The foods were labeled with 3.7 MBq Tc99m-albumin and GE was studied by scintigraphy for 3 h. The rate of GE (expressed by the GE half-time) was fastest for mashed potatoes, then bread, rice, and slowest for spaghetti. Blood glucose and serum insulin responses were similar. A significant negative correlation was found between the GE half-time and the maximum variation in blood glucose level (r = -0.6, p less than 0.0001). The glucose response to all four foods is strongly related to the GE rate.     

Effect of meal timing and glycaemic index on glucose control and insulin secretion in healthy volunteers

Shiftworkers have a higher risk of CHD and type 2 diabetes. They consume a large proportion of their daily energy and carbohydrate intake in the late evening or night-time, a factor which could be linked to their increase in disease risk. We compared the metabolic effects of varying both dietary glycaemic index (GI) and the time at which most daily energy intake was consumed. We hypothesised that glucose control would be optimal with a low-GI diet, consumed predominantly early in the day. A total of six healthy lean volunteers consumed isoenergetic meals on four occasions, comprising either high- or low-GI foods, with 60?% energy consumed predominantly early (breakfast) or late (supper). Interstitial glucose was measured continuously for 20?h. Insulin, TAG and non-esterified fatty acids were measured for 2?h following every meal. Highest glucose values were observed when large 5021?kJ (1200?kcal) high-GI suppers were consumed. Glucose levels were also significantly higher in predominantly late high- v. low-GI meals (P?相似文献   

Glycemia and insulinemia in healthy subjects after lactose-equivalent meals of milk and other food proteins: the role of plasma amino acids and incretins

BACKGROUND: Milk products deviate from other carbohydrate-containing foods in that they produce high insulin responses, despite their low GI. The insulinotropic mechanism of milk has not been elucidated. OBJECTIVE: The objective was to evaluate the effect of common dietary sources of animal or vegetable proteins on concentrations of postprandial blood glucose, insulin, amino acids, and incretin hormones [glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1] in healthy subjects. DESIGN: Twelve healthy volunteers were served test meals consisting of reconstituted milk, cheese, whey, cod, and wheat gluten with equivalent amounts of lactose. An equicarbohydrate load of white-wheat bread was used as a reference meal. RESULTS: A correlation was found between postprandial insulin responses and early increments in plasma amino acids; the strongest correlations were seen for leucine, valine, lysine, and isoleucine. A correlation was also obtained between responses of insulin and GIP concentrations. Reconstituted milk powder and whey had substantially lower postprandial glucose areas under the curve (AUCs) than did the bread reference (-62% and -57%, respectively). Whey meal was accompanied by higher AUCs for insulin (90%) and GIP (54%). CONCLUSIONS: It can be concluded that food proteins differ in their capacity to stimulate insulin release, possibly by differently affecting the early release of incretin hormones and insulinotropic amino acids. Milk proteins have insulinotropic properties; the whey fraction contains the predominating insulin secretagogue.     

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 (H(2)) 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 H(2) 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.     

Impact of overweight and glucose tolerance on postprandial responses to high- and low-glycaemic index meals

The beneficial effects of a low-glycaemic index (GI) meal on postprandial glucose and insulin levels have been demonstrated. However, limited data are available on the impact of overweight and glucose tolerance on postprandial responses to different GI meals. Our aim was to study the effects of physiological characteristics on postprandial glucose, insulin and lipid responses and the relative glycaemic response (RGR) of a low-GI (LGI) and a high-GI (HGI) meal. We recruited twenty-four normal-weight and twenty-four overweight subjects, twelve with normal glucose tolerance (NGT) and twelve with impaired glucose tolerance (IGT) in each group. Both test meals were consumed once and the glucose reference twice. Blood glucose and insulin were measured in the fasting state and over a 2 h period after each study meal, and TAG and NEFA were measured in the fasting state and over a 5 h period. The glucose responses of subjects with IGT differed significantly from those of subjects with NGT. The highest insulin responses to both meals were observed in overweight subjects with IGT. Physiological characteristics did not influence TAG or NEFA responses or the RGR of the meals. The LGI meal resulted in lower glucose (P < 0·001) and insulin (P < 0·001) responses, but higher TAG responses (P < 0·001), compared with the HGI meal. The GI of the meals did not affect the NEFA responses. In conclusion, the LGI meal causes lower glucose and insulin responses, but higher TAG responses, than the HGI meal. The RGR of the meals does not differ between normal-weight and overweight subjects with NGT or IGT.     

The acute impact of ingestion of breads of varying composition on blood glucose, insulin and incretins following first and second meals

Structural characteristics and baking conditions influence the metabolic responses to carbohydrate-containing foods. We hypothesized that consumption of whole wheat or sourdough breads would have a favourable effect on biomarkers of glucose homeostasis after first and second meals, compared with those for white bread. Ten overweight volunteers consumed 50 g available carbohydrate of each of the four breads (white, whole wheat, sourdough, whole wheat barley) followed 3 h later by a standard second meal. Blood was sampled for 3 h following bread ingestion and a further 2 h after the second meal for determination of glucose, insulin, paracetamol (indirect marker of gastric emptying), glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Glucose and GLP-1 responses to sourdough bread were lower (P < 0.05) than whole wheat and whole wheat barley breads. Glucose area under the curve (AUC) for sourdough bread was lower than those for whole wheat (P < 0.005) and whole wheat barley (P < 0.03) breads for the entire study. GIP AUC after sourdough bread ingestion was lower compared to white (P < 0.004) and whole wheat barley (P < 0.002) breads following the second meal. There were no significant differences in insulin and paracetamol concentrations among the test breads. Ultra-fine grind whole wheat breads did not result in postprandial responses that were lower than those of white bread, but sourdough bread resulted in lower glucose and GLP-1 responses compared to those of these whole wheat breads following both meals.     

Differential Glycemic Effects of Low- versus High-Glycemic Index Mediterranean-Style Eating Patterns in Adults at Risk for Type 2 Diabetes: The MEDGI-Carb Randomized Controlled Trial

A Mediterranean-style healthy eating pattern (MED-HEP) supports metabolic health, but the utility of including low-glycemic index (GI) foods to minimize postprandial glucose excursions remain unclear. Therefore, we investigated the relative contribution of GI towards improvements in postprandial glycemia and glycemic variability after adopting a MED-HEP. We conducted a randomized, controlled dietary intervention, comparing high- versus low-GI diets in a multi-national (Italy, Sweden, and the United States) sample of adults at risk for type 2 diabetes. For 12 weeks, participants consumed either a low-GI or high-GI MED-HEP. We assessed postprandial plasma glucose and insulin responses to high- or low-GI meals, and daily glycemic variability via continuous glucose monitoring at baseline and post-intervention. One hundred sixty adults (86 females, 74 males; aged 55 ± 11 y, BMI 31 ± 3 kg/m², mean ± SD) with ≥two metabolic syndrome traits completed the intervention. Postprandial insulin concentrations were greater after the high-GI versus the low-GI test meals at baseline (p = 0.004), but not post-intervention (p = 0.17). Postprandial glucose after the high-GI test meal increased post-intervention, being significantly higher than that after the low-GI test meal (35%, p < 0.001). Average daily glucose concentrations decreased in both groups post-intervention. Indices of 24-h glycemic variability were reduced in the low-GI group as compared to baseline and the high-GI intervention group. These findings suggest that low-GI foods may be an important feature within a MED-HEP.     

Effects of acute chromium supplementation on postprandial metabolism in healthy young men

BACKGROUND: Chromium (Cr) potentiates the action of insulin in the cell and improves glucose tolerance after long-term supplementation. OBJECTIVE: We hypothesized that Cr may also have acute effects and might be beneficial in lowering the glycemic index of a meal. METHODS: We studied the effects of short-term Cr supplementation using a randomized crossover design. Thirteen apparently healthy, non-smoking young men of normal body mass index performed three trials each separated by one week. Test meals, providing 75 g of available carbohydrates, consisted of white bread with added Cr (400 or 800 microg as Cr picolinate) or placebo. RESULTS: After addition of 400 and 800 microg Cr incremental area under the curve (AUC) for capillary glucose was 23% (p = 0.053) and 20% (p = 0.054), respectively, lower than after the white bread meal. These differences reached significance if the subjects were divided into responders (n = 10) and non-responders (n = 3). For the responders AUC after 400 and 800 microg Cr was reduced by 36% and 30%, respectively (Placebo 175 +/- 22, Cr400 111 +/- 14 (p < 0.01), Cr800 122 +/- 15 mmol. min/L (p < 0.01)). Glycemia was unchanged after addition of Cr in the non-responders. Responders and non-responders differed significantly in their nutrient intake and eating pattern, and total serum iron concentration tended to be lower in the responder group (p = 0.07). CONCLUSIONS: Acute chromium supplementation showed an effect on postprandial glucose metabolism in most but not all subjects. The response to Cr may be influenced by dietary patterns.     

Inconsistency between glycemic and insulinemic responses to regular and fermented milk products.

BACKGROUND: Foods with a low glycemic index are increasingly being acknowledged as beneficial in relation to the insulin resistance syndrome. Certain organic acids can lower the glycemic index of bread products. However, the possible effect of acids in fermented milk products on the glycemic index and on insulinemic characteristics has not been addressed. The metabolic effects of fermented milk or pickled products used as additives to mixed meals have also not been addressed. OBJECTIVES: One objective was to characterize the glycemic and insulinemic responses after intake of regular or fermented milk products (study 1). In addition, the acute metabolic effect of fermented milk (yogurt) and pickled cucumber as supplements to a traditional breakfast based on a high-glycemic index bread was evaluated (study 2). DESIGN: Ten healthy volunteers were served different breakfast meals after an overnight fast. Capillary blood samples were collected before and during 2 (study 1) or 3 (study 2) h after the meal. White-wheat bread was used as a reference meal in both studies. RESULTS: The lactic acid in the fermented milk products did not lower the glycemic and insulinemic indexes. Despite low glycemic indexes of 15-30, all of the milk products produced high insulinemic indexes of 90-98, which were not significantly different from the insulinemic index of the reference bread. Addition of fermented milk (yogurt) and pickled cucumber to a breakfast with a high-glycemic index bread significantly lowered postprandial glycemia and insulinemia compared with the reference meal. In contrast, addition of regular milk and fresh cucumber had no favorable effect on the metabolic responses. CONCLUSIONS: Milk products appear insulinotropic as judged from 3-fold to 6-fold higher insulinemic indexes than expected from the corresponding glycemic indexes. The presence of organic acids may counteract the insulinotropic effect of milk in mixed meals.     

Metabolic response to beet fibre test meals

Test meals with 10.9 g dietary fibre from sugar beet and corresponding control meals were given to eight healthy subjects, aged 67 ± 9 years. The postprandial glucose, triglyceride, hormone and glycerol responses were monitored during 3 hours. After the beet fibre meal the insulin and C-peptide areas were reduced by 28 ( P < 0.01) and 22% ( P > 0.025), respectively, and the somatostatin levels increased by approximately 30% ( P > 0.05). Further, the maximum relative postprandial reduction of plasma glycerol levels was less evident after the fibre-rich meal than after the control meal (36 ± 4% v. 46 ± 4%, P < 0.05). There was no apparent difference in the overall glycaemic response between the meals. The triglyceride levels were similar after both test meals.
Suspension of beet fibre bread given to rats by oro-gastric intubation induced lower blood glucose response than a control bread at 15 and 30 min ( P < 0.001), respectively, but a similar insulin response.
The results suggest an effect of beet fibre on the rate of carbohydrate absorption, expressed as a lower insulin response in the healthy volunteers and a reduced glucose response in the rat.
The mechanism behind this effect in healthy subjects could possibly be mediated by an increased somatostatin response.     

Application of glycemic index to mixed meals

Plasma glucose and insulin responses to six different meals were determined and compared with values predicted by published glycemic indices of the component foods. The test meals were of different ethnic origins: Indian (lentil curry with rice), Italian (spaghetti bolognaise), Chinese (stir-fried vegetables and chicken with rice), Greek (lentil stew), Western (sirloin chop and vegetables); and Lebanese (sandwich with unleavened bread and hummos). Eight healthy volunteers were given 50 g carbohydrate portions of the above meals after an overnight fast. The glycemic and insulin indices were highest for the Lebanese meal and lowest for the Greek with significant differences among the meals (ANOVA, p less than 0.05). The observed glycemic indices correlated well with the predicted glycemic indices (r = 0.88, p less than 0.01) and insulin responses parallelled the glycemic responses (r = 0.83, p less than 0.05). These results suggest that the glycemic index approach will be useful in planning diets for diabetic people.     

Low glycaemic-index foods

Accumulating data indicate that a diet characterized by low glycaemic-index (GI) foods not only improves certain metabolic ramifications of insulin resistance, but also reduces insulin resistance per se. Epidemiological data also suggest a protective role against development of non-insulin-dependent diabetes mellitus and cardiovascular disease. A major disadvantage in this connection is the shortage of low-GI foods, and many common starchy staple foods, such as bread products, breakfast cereals and potato products, have a high GI. Studies in our laboratory show that it is possible to significantly lower the GI of starchy foods, for example by choice of raw material and/or by optimizing the processing conditions. Such low-GI foods may or may not influence glucose tolerance at a subsequent meal. Consequently, certain low-GI breakfasts capable of maintaining a net increment in blood glucose and insulin at the time of the next meal significantly reduced post-prandial glycaemia and insulinaemia following a standardized lunch meal, whereas others had no 'second-meal' impact. These results imply that certain low-GI foods may be more efficient in modulating metabolism in the long term. Although the literature supports a linear correlation between the GI and insulinaemic index (II) of foods, this is not always the case. Consequently, milk products elicited elevated IIs, indistinguishable from a white bread reference meal, despite GIs in the lower range. This inconsistent behaviour of milk products has not been acknowledged, and potential metabolic consequences remain to be elucidated.     

Effects of varying the carbohydrate:fat ratio in a hot lunch on postprandial variables in male volunteers

1. Healthy male volunteers consumed at noon, hot test meals with four different carbohydrate:fat ratios varying between 2.64 and 0.50, and composed of fried beefsteak, mashed potatoes, French beans, and a dessert of custard with mashed peaches. The energy content of the meals was 40% of the daily intake of the volunteers, estimated from their individual dietary histories. 2. Before, and at different times after the start of the meal, blood samples were taken and a number of indices of carbohydrate and lipid metabolism were determined in the samples, i.e. glucose, insulin, free fatty acid, free and total glycerol, free and total cholesterol, high-density-lipoprotein (HDL)-cholesterol and low-density-lipoprotein (LDL)-cholesterol. 3. Increasing the carbohydrate:fat ratio resulted in higher postprandial peaks of glucose and insulin. In addition, the peak area under the postprandial glucose curve showed a significant increase. The peak area under the postprandial insulin curve had also increased, indicating that a larger amount of insulin was secreted by the pancreas on increasing the carbohydrate content in the meal. There was no significant correlation between the height of the postprandial peak of blood glucose and the size of the meal. 4. All four meals caused elevated postprandial blood triacylglycerol levels. However, the decline of this elevated level took a much longer time after the meals with the lower carbohydrate:fat ratios, i.e. containing larger amounts of triacylglycerols. There was a significant decreasing linear relation between the carbohydrate content of the meals and the peak area under the postprandial triacylglycerol curve. Free glycerol and free fatty acids showed lower postprandial levels in the blood after the meals with the higher carbohydrate:fat ratios, and the peak areas of the postprandial curves of both variables displayed a significant decrease. Little or no effect of the meal carbohydrate:fat ratio was observed on the postprandial concentrations of total cholesterol, unesterified cholesterol, HDL-cholesterol or LDL-cholesterol.     

High-fiber foods at breakfast: influence on plasma glucose and insulin responses to lunch

This study evaluates acute effects of red kidney bean consumption on postprandial glucose and insulin responses in six healthy young men. Comparisons were made among three mixed-food breakfast meals comprised predominantly of either red kidney beans, bran cereal, or white bread. These meals provided equivalent levels of digestible carbohydrate, protein, and fat. The bean and bran meals contained equivalent levels of fiber while the white-bread meal contained a lower level. The postprandial glucose and insulin responses to the three meals were similar and responses also were similar after a standard whole-wheat-bread meal 4 h later. There appeared to be a reciprocal relationship between glucose and insulin responses after the lunch meal. This would influence interpretation of data regarding second-meal response.     

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.     

Glucose and insulin responses in healthy women after intake of composite meals containing cod-, milk-, and soy protein

OBJECTIVE: To evaluate the metabolic effect of three different kinds of dietary proteins as part of composite meals with similar macronutrient composition in healthy subjects. DESIGN: A randomised meal study. SETTING: Metabolic ward. SUBJECTS AND METHODS: In total, 17 healthy women, 30-65 years old, consumed three meals in randomised order. The meals consisted of foodstuffs with similar nutrient composition but different types of protein (cod, cottage cheese, or soy protein isolate). The distribution of energy from protein, fat and carbohydrates was 33, 26, and 41 energy percent, respectively. Total amount of energy was 2300 kJ. Blood samples were drawn for assay of B-glucose, S-insulin, S-free fatty acids, S-triglycerides, and C-peptide in the fasting state and at seven times (20, 40, 60, 90, 120, 180, and 240 min) after starting to eat the test meal. RESULTS: The blood glucose response after the cod protein meal differed from that of the soy protein meal, with a larger area under the curve (AUC) calculated up to 120 min. The serum insulin response after the milk protein meal differed from that of the cod protein meal with a larger AUC calculated up to 240 min. The insulin/C-peptide and the insulin/glucose ratios differed between the meals; the insulin/C-peptide ratio was higher after the milk protein meal compared to the cod, and soy protein meal at 120 min. The insulin/glucose ratio was lower after the cod protein meal compared to the milk, and soy protein meals at 120 min. The results showed that the metabolic responses differed after meals with similar macronutrient composition containing cod-, milk-, or soy protein.     

Muesli with 4 g oat beta-glucans lowers glucose and insulin responses after a bread meal in healthy subjects

OBJECTIVE: To evaluate the impact of an extruded muesli product based on beta-glucan-rich oat bran on postprandial glycaemia and insulinaemia. SUBJECT/DESIGN: The study is divided in two series. Blood glucose and serum insulin responses were studied after subjects consuming test meals including a serving of muesli with 3 g (series 1) and 4 g (series 2) of beta-glucans, respectively. The muesli was a component in a single serving packet with muesli and yoghurt. This was served together with white wheat bread in the morning after an overnight fast. The compositions were standardized to contain 50 g available carbohydrates. As a reference meal a serving packet without beta-glucans was included. The study was performed at Applied Nutrition and Food Chemistry, Lund University, Sweden. Nineteen and thirteen healthy volunteers with normal body mass index were recruited for series 1 and 2, respectively. RESULTS: Muesli with 3 g of beta-glucans, included in a mixed bread meal, gave no significant differences in glycaemic response compared to a reference meal without muesli and beta-glucans. In contrast, muesli with 4 g of beta-glucans significantly (P<0.05) lowered the glucose and insulin responses compared to the reference meal. CONCLUSIONS: Muesli enriched with 4 g of beta-glucans reduces postprandial glucose and insulin levels to a breakfast based on high glycaemic index products. A total of 4 g of beta-glucans from oats seems to be a critical level for a significant decrease in glucose and insulin responses in healthy people.     

Inflammation markers are modulated by responses to diets differing in postprandial insulin responses in individuals with the metabolic syndrome

BACKGROUND: Inflammation may be a mechanism by which high postprandial insulin and glucose responses increase the risk of type 2 diabetes mellitus. OBJECTIVE: We hypothesized that dietary carbohydrates characterized by different postprandial insulin responses may differentially modify cytokine concentrations in plasma and gene expression in subcutaneous adipose tissue. DESIGN: Individuals (n = 47) with the metabolic syndrome were randomly assigned to a 12-wk diet with oat and wheat bread and potato (high postprandial insulin response) or rye bread and pasta (low postprandial insulin response). Postprandial glucose and insulin responses to the oat and wheat bread meal and to the rye bread meal were determined in 19 individuals before intervention. RESULTS: During the 12-wk diet, the change in the gene expression of interleukin (IL)-10 receptor alpha and tumor necrosis factor-alpha in subcutaneous adipose tissue differed between the groups (P = 0.002 and P = 0.083, respectively). Moreover, the change in fasting plasma concentrations of IL-1beta and IL-6 differed between the groups (P = 0.020 and P = 0.055, respectively). In the postprandial challenge, the insulin response to the rye bread meal was lower than that to the oat and wheat bread meal (P < 0.001), whereas there were no differences in the mean blood glucose response. In contrast, plasma glucose concentrations decreased more below fasting concentrations 2.5-3 h after the oat and wheat bread meal than after the rye bread meal. A late postprandial rebound of free fatty acids was detected after the oat and wheat bread meal (P = 0.048). CONCLUSIONS: Long-term intake of cereal foods with differing postprandial insulin responses may be a factor that modulates the inflammatory status in individuals with the metabolic syndrome.