A new breakfast cereal containing guar gum reduces postprandial plasma glucose and insulin concentrations in normal-weight human subjects

Low molecular weight galactomannans-based standardized fenugreek seed extract ameliorates high-fat diet-induced obesity in mice via modulation of FASn, IL-6, leptin, and TRIP-Br2

Background: Obesity is a complex, chronic metabolic disorder and its prevalence is increasing throughout most of the world. Low molecular weight galactomannans-based standardized fenugreek seed extract (LMWGAL-TF) has previously shown anti-diabetic and anti-hyperlipidemic potential. Aim: To evaluate the efficacy and mechanism of action of LMWGAL-TF in treating high fat diet (HFD)-induced obesity and hyperlipidemia in mice. Materials and methods: Male C57BL/6 mice were fed the HFD for 12 weeks and were co-administered with LMWGAL-TF (10, 30 and 100 mg kg-1, p.o.). Variables measured were behavioral, biochemical, molecular and histopathological. In a separate in vitro experiment, copper-ascorbate (Cu-As)-induced mitochondrial oxidative damage was evaluated. Results: The HFD-induced increase (p < 0.001) in body weight, fat mass, lean mass, adipose tissue (brown, mesenteric, epididymal and retroperitoneal) and liver weight was significantly attenuated (p < 0.001) by LMWGAL-TF (30 and 100 mg kg-1). The HFD-induced elevated levels of serum lipid, interleukins (ILs)-6 and leptin were significantly decreased (p < 0.001) by LMWGAL-TF (30 and 100 mg kg-1). Elevated fatty acid synthase (FASn), IL-6, leptin and transcriptional regulator interacting with the PHD-bromodomain 2 (TRIP-Br2) mRNA expression in brown adipose tissue (BAT), liver, and epididymal fat were significantly down-regulated (p < 0.001) by LMWGAL-TF (30 and 100 mg kg-1). Additionally, HFD-induced histological alterations in skeletal muscle, liver, white adipose tissue (WAT) and BAT were also reduced by LMWGAL-TF. Furthermore, the Cu-As-induced alteration in mitochondria oxidative stress (lipid peroxidation, protein carbonylation, glutathione, glutathione reductase, glutathione peroxidase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase) in skeletal muscle and BAT was significantly (p < 0.001) ameliorated by LMWGAL-TF (2, 4 and 6 mg mL-1) treatment. It also reduced the Cu-As-induced mitochondrial swelling. Conclusion: LMWGAL-TF showed its beneficial effect in reducing HFD-induced obesity via down-regulation of FASn, IL-6, leptin, and TRIP-Br2 in mice.

Nanotechnological approaches for the development of herbal drugs in treatment of diabetes mellitus - a critical review

Diabetes mellitus (DM) is a chronic illness that requires continuing medical care and patient self-management education to prevent acute complications and to reduce the risk of long-term complications. The number of people with diabetes is increasing due to population growth, ageing, urbanisation and increasing prevalence of obesity and physical inactivity. Apart from currently available therapeutic options, many herbal medicines have been recommended for the treatment of diabetes. Herbal drugs are prescribed widely because of their effectiveness, less side effects and relatively low cost. Several pharmacopoeias have provided parameters to maintain quality and standardise procedures in identification/authentication of herbal inputs and their products. Available literature related to folklore medicine used in the treatment of diabetes extended to nanoformulation of herbal drugs up to date was cited. The use of bioactive compounds leads to new hope to improve the life expectancy and health status of the population for the formulation of novel drugs. Recently, many studies have shown that nanotechnology has the potential to be used in different biological and medical applications, mainly as targeted drug delivery systems to minimise and delay the chronic effects of diabetes. Herein, the authors presented a thorough review of the available herbal medicines and the possibilities of developing their nanoformulations in the treatment of DM.

Effects of Ready-to-Eat-Cereals on Key Nutritional and Health Outcomes: A Systematic Review

BACKGROUND

In many countries breakfast cereals are an important component of breakfast. This systematic review assesses the contribution of consumption of ready-to eat cereal (RTEC) to the recommended nutrient intake. Furthermore, the effects of RTEC consumption on key health parameters are investigated as well as health promoting properties of RTEC.

METHOD

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL have been searched up till 16th of June 2015. Randomized controlled trials were excluded if RTEC were used during hypocaloric diets, if RTEC were eaten at other times than breakfast and if breakfasts included other products than RTEC, milk and fruit. Observational studies were excluded when "breakfast cereals" were not defined or their definition included cooked cereals. From cross-sectional studies only data concerning energy and nutrient intake as well as micronutrient status were used.

RESULTS

From 4727 identified citations 64 publications met the inclusion criteria of which 32 were cross-sectional studies, eight prospective studies and 24 randomized controlled trials. Consumption of RTEC is associated with a healthier dietary pattern, concerning intake of carbohydrates, dietary fiber, fat and micronutrients, however total sugar intake is higher. Persons consuming RTEC frequently (≥ 5 times/week) have a lower risk of inadequate micronutrient intake especially for vitamin A, calcium, folate, vitamin B 6, magnesium and zinc. Evidence from prospective studies suggests that whole grain RTEC may have beneficial effects on hypertension and type 2 diabetes. Consumption of RTEC with soluble fiber helps to reduce LDL cholesterol in hypercholesterolemic men and RTEC fortified with folate can reduce plasma homocysteine.

DISCUSSION

One of the review's strengths is its thorough ex/inclusion of studies. Limitations are that results of observational studies were based on self-reported data and that many studies were funded by food-industry.

CONCLUSION

Consumption of RTEC, especially of fiber-rich or whole grain RTEC, is implicated with several beneficial nutritional and health outcomes. The effect on body weight, intestinal health and cognitive function needs further evaluation. Of concern is the higher total sugar intake associated with frequent RTEC consumption.

The Effects of Breakfast Consumption and Composition on Metabolic Wellness with a Focus on Carbohydrate Metabolism

Findings from epidemiologic studies indicate that there are associations between breakfast consumption and a lower risk of type 2 diabetes mellitus (T2DM) and metabolic syndrome, prompting interest in the influence of breakfast on carbohydrate metabolism and indicators of T2DM risk. The objective of this review was to summarize the available evidence from randomized controlled trials assessing the impact of breakfast on variables related to carbohydrate metabolism and metabolic wellness. Consuming compared with skipping breakfast appeared to improve glucose and insulin responses throughout the day. Breakfast composition may also be important. Dietary patterns high in rapidly available carbohydrate were associated with elevated T2DM risk. Therefore, partial replacement of rapidly available carbohydrate with other dietary components, such as whole grains and cereal fibers, proteins, and unsaturated fatty acids (UFAs), at breakfast may be a useful strategy for producing favorable metabolic outcomes. Consumption of fermentable and viscous dietary fibers at breakfast lowers glycemia and insulinemia. Fermentable fibers likely act through enhancing insulin sensitivity later in the day, and viscous fibers have an acute effect to slow the rate of carbohydrate absorption. Partially substituting protein for rapidly available carbohydrate enhances satiety and diet-induced thermogenesis, and also favorably affects lipoprotein lipids and blood pressure. Partially substituting UFA for carbohydrate has been associated with improved insulin sensitivity, lipoprotein lipids, and blood pressure. Overall, the available evidence suggests that consuming breakfast foods high in whole grains and cereal fiber, while limiting rapidly available carbohydrate, is a promising strategy for metabolic health promotion.

Nutrient pathways and breast cancer risk: the Long Island Breast Cancer Study Project

The relative importance of biochemical pathways has not been previously examined when considering the influence of diet on breast cancer risk. To address this issue, we used interview data from a population-based sample of 1463 breast cancer cases and 1500 controls. Dietary intake was assessed shortly after diagnosis using a 101-item food frequency questionnaire. Age- and energy-adjusted odds ratios (ORs) for individual micro- and macronutrients were estimated with logistic regression. Hierarchical modeling was used to account for biologically plausible nutrient pathways (1-carbon metabolism, oxidative stress, glycemic control, and phytoestrogens). Effect estimates from hierarchical modeling were more precise and plausible compared to those from multivariable models. The strongest relationship observed was for the glycemic control pathway, but confidence intervals (CI) were wide [OR (95% CI): 0.86 (0.62, 1.21)]. Little or no effect was observed for the 1-carbon metabolism, oxidative stress, and phytoestrogen pathways. Associations were similar when stratified by supplement use. Our approach that emphasizes biochemical pathways, rather than individual nutrients, revealed that breast cancer risk may be more strongly associated with glycemic control factors than those from other pathways considered. Our study emphasizes the importance of accounting for multiple nutrient pathways when examining associations between dietary intake and breast cancer.

Hypoglycemic and hypolipidemic potential of a high fiber diet in healthy versus diabetic rabbits

The aim of this study was to investigate potential hypoglycaemic and hypolipidemic effects of Plantago ovata husk included in the diet, in healthy and diabetic rabbits. We also examined the effects of this fiber in other biochemical parameters. Two groups of 18 rabbits were used. The first group was fed with standard chow and the second with chow supplemented with Plantago ovata husk (3.5 mg/kg/day). On day 14 diabetes mellitus was induced by the intravenous administration of alloxan (80 mg/kg). After an oral glucose load (3 g), glucose, insulin, and other biochemical parameters were determined on day 14 (healthy rabbits) and on day 28 (diabetic rabbits). In healthy rabbits, fiber did not modify glucose or insulin levels but decreased significantly total cholesterol, LDL-cholesterol, atherogenic index, and glycosylated hemoglobin. In diabetic rabbits, fiber was more beneficial in mild diabetics than in severe diabetics with significant decreases in glucose levels and increases in insulin concentrations. In these animals fiber caused an important reduction in cholesterol, indicating a beneficial effect of Plantago ovata husk in diabetic rabbits. Although further studies in patients are necessary, we think that Plantago ovata husk offers interesting perspectives to be administered to patients with diabetes mellitus.

The effect of dietary fibre on reducing the glycaemic index of bread

As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies have been carried out in order to decrease the GI of bread. The most relevant strategy that has been applied so far is the addition of fibre-rich flours or pure dietary fibre. However, the effectiveness of dietary fibre in bread in reducing the GI is controversial. The purpose of the present review was to discuss critically the effects obtained by adding different kinds of fibre to bread in order to modulate its glycaemic response. The studies were selected because they analysed in vivo whether or not dietary fibre, naturally present or added during bread making, could improve the glucose response. The reviewed literature suggests that the presence of intact structures not accessible to human amylases, as well as a reduced pH that may delay gastric emptying or create a barrier to starch digestion, seems to be more effective than dietary fibre per se in improving glucose metabolism, irrespective of the type of cereal. Moreover, the incorporation of technologically extracted cereal fibre fractions, the addition of fractions from legumes or of specifically developed viscous or non-viscous fibres also constitute effective strategies. However, when fibres or wholemeal is included in bread making to affect the glycaemic response, the manufacturing protocol needs to reconsider several technological parameters in order to obtain high-quality and consumer-acceptable breads.

Dietary fibers reduce food intake by satiation without conditioned taste aversion in mice

It is well known that intake of dietary fiber (DF) potently decreases food intake and feelings of hunger and/or promotes satiety ratings. However, the mechanisms explaining these effects are not well characterized. This work was performed to determine which of satiation and/or satiety mechanisms provoke the decrease of food intake induced by DF in mice. We tested in an intra-group protocol a low-viscosity (LV, fructo-oligosaccharide), a viscous (VP, guar gum) and a high-viscosity (HV, mixture of guar gum and fructo-oligosaccharide) preload. These were given to mice by intra-gastric gavage. It appeared that viscous preloads such as VP and HV reduced the daily energy intake by 14% and 21% respectively. The strong effect of HV was mainly due to a large decrease of meal size (by 57%) and meal duration (by 65%) with no effect on ingestion rate during the first 30 min after administration. Therefore, the DF-induced decrease of energy intake was due to a satiation mechanism. This is further supported by a 3-fold increased sensitization of neurons in the nucleus of the solitary tract as observed by c-Fos protein immunolabelling. No compensation of food intake was observed during the rest of the day, a phenomenon that may be explained by the fact that metabolic rate remained high despite the lower food intake. We have also shown that the DF-induced inhibition of food intake was not paired with a conditioned taste aversion. To conclude, this work demonstrates that DF inhibits food intake by increasing satiation during ~1h after administration.

Interventions to lower the glycemic response to carbohydrate foods with a low-viscosity fiber (resistant maltodextrin): meta-analysis of randomized controlled trials

Background: The glycemic response to diet has been linked with noncommunicable diseases and is reduced by low-palatable, viscous, soluble fiber (1). Whether a palatable, low-viscous, soluble fiber such as resistant maltodextrin (RMD) has the same effect is unclear.

Objective: The objective was to assess evidence on the attenuation of the blood glucose response to foods by ≤10 g RMD in healthy adults.

Design: We conducted a systematic review of randomized, placebo-controlled trials with the use of fixed- and random-effects meta-analyses and meta-regression models.

Results: We found data from 37 relevant trials to April 2007. These trials investigated the attenuation of the glycemic response to rice, noodles, pastry, bread, and refined carbohydrates that included 30–173 g available carbohydrate. RMD was administered in drinks or liquid foods or solid foods. Placebo drinks and foods excluded RMD. Percentage attenuation was significant, dose-dependent, and independent of the amount of available carbohydrate coingested. Attenuation of the glycemic response to starchy foods by 6 g RMD in drinks approached ≈20%, but when placed directly into foods was ≈10%—significant (P < 0.001) by both modes of administration. Study quality analyses, funnel plots, and trim-and-fill analyses uncovered no cause of significant systematic bias. Studies from authors affiliated with organizations for-profit were symmetrical without heterogeneity, whereas marginal asymmetry and significant heterogeneity arose among studies involving authors from nonprofit organizations because of some imprecise studies.

Conclusions: A nonviscous palatable soluble polysaccharide can attenuate the glycemic response to carbohydrate foods. Evidence of an effect was stronger for RMD in drinks than in foods.

The Modifying Effects of Galactomannan from Canadian-Grown Fenugreek (Trigonella foenum-graecum L.) on the Glycemic and Lipidemic Status in Rats

Using high sucrose-fed male Sprague-Dawley rats, a study was conducted to determine the effects of feeding Galactomannan (GAL), a soluble dietary fiber extracted from Canadian-grown fenugreek seeds, on blood lipid and glucose responses. Rats (n = 8, 175-200 g) were randomly assigned to one of three high sucrose diets containing 10% cellulose (control), 7.5% cellulose + 2.5% GAL, and 5% cellulose + 5% GAL, respectively for 4 weeks. After 3 weeks, an oral glucose tolerance test (OGTT) was performed on each rat. A week later blood samples were collected to determine the effect on blood lipids. A significant reduction in glycemic response was observed only in 5% GAL group at 120 min following OGTT, when compared with that of control and 2.5% GAL groups. The plasma level of insulin was also significantly reduced (p<0.001) in 5% GAL-fed rats but at all times during OGTT. These animals also showed a reduction in body weight gain (p<0.05) in parallel with less food intake (p<0.05). All GAL-fed (2.5% and 5.0%) rats had significantly reduced plasma levels of triglycerides and total cholesterol in association with a reduction in epididymal adipose weight. Overall, this study demonstrated that feeding GAL from Canadian-grown fenugreek seeds has the potential to alter glycemic and lipidemic status and reduce abdominal fat in normal rats.

Use of guar by-products in high-production laying hen diets

A 5x5 Latin square experiment was conducted to evaluate the effect of feeding low concentrations of guar germ or a combination of guar germ and hull (guar meal) in high-production laying hen diets. A total of 125 Lohmann laying hens (21 wk old) of similar BW were randomly assigned to 5 blocks. Each block was divided into 5 experimental units, consisting of 5 hens per unit. Hens were fed either a nonguar control diet, or 1 of 4 diets containing either 2.5 or 5% guar germ, or 2.5 or 5% guar meal over a 20-wk trial period (five 4-wk periods). No significant differences were observed when feeding either 2.5 or 5% guar germ or meal (P>0.05) on hen-day egg production or feed consumption. Significant differences in egg weight, total egg mass per hen, and feed conversion ratio were detected in hens fed 2.5% guar meal, whereas they remained unchanged for diets containing either level of guar germ or 5% guar meal. Feeding either level of guar germ or guar meal did not affect shell quality (shell thickness, egg breaking force, and specific gravity), Haugh units, or egg yolk color (L*, a*, b*). The results showed that both guar germ and guar meal can be fed to high-production laying hens at up to 5% without adverse effects on laying hen performance.

Effects of diet supplementation with olive oil and guar upon fructose-induced insulin resistance in normal rats

Exposure of normal rats to fructose-containing drinking water represents a current model of insulin resistance. The major aim of the present study was to assess the possible effect of diet supplementation with either olive oil or guar upon the metabolic consequences of exposure to exogenous fructose. For this purpose, the changes in body weight, plasma D-glucose and insulin concentrations, and D-glucose infusion rate during a hyperinsulinemic-euglycemic clamp were measured after 65 days exposure to exogenous fructose and either olive oil- or guar-enriched diet. The results were compared to those previously collected in control animals exposed for the same period to either tap water or the fructose-containing drinking water and a standard diet. Diet supplementation with olive oil or guar failed to affect the increase in the insulinogenic index and the decrease in insulin sensitivity and fasted/fed ratio for plasma insulin concentration caused by exogenous fructose. In the rats exposed to exogenous fructose, the olive oil-fed rats differed from other animals by the absence of a decrease in food intake and body weight gain, whilst the guar-fed rats differed from other animals in a lower plasma D-glucose concentration in fed state and an absence, at day 65, of a higher plasma D-glucose concentration than that at day 0 measured in after overnight fasting state. These findings argue in favour of guar, rather than olive oil, to oppose the effect of exogenous fructose on glucose homeostasis.

Muesli with 4 g oat β-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.

African plant foods rich in non-starch polysaccharides reduce postprandial blood glucose and insulin concentrations in healthy human subjects

The effects of two vegetable flours, prepared from the African plants Detarium senegalense Gmelin, a legume, and Cissus rotundifolia, a shrub, on postprandial blood glucose and insulin concentrations in human subjects, were investigated. Chemical analysis indicated that these flours contained significant amounts of NSP. The detarium in particular was found to be a rich source of water-soluble NSP (SNSP). The flours were incorporated into two types of breakfast meal, a stew meal and a wheat bread meal, containing 50 g and 70 g available carbohydrate respectively. Both meals also contained 10–12g NSP, the major fraction of which was SNSP. Control and fibre-rich meals were consumed on separate days in randomized order by two different groups of subjects (n 5, stew meals; n 10, bread meals). Venous blood samples were taken at fasting (0 min) and postprandially at 30 min intervals for 2·5 h and the plasma analysed for glucose and insulin. Compared with the controls, detarium and cissus meals elicited significant reductions (P < 0·006) in plasma glucose levels at most postprandial time points and for area-under-the-curve (AUC) values (AUC reductions 38–62%). Significant reductions (P < 0·002) in plasma insulin levels at various postprandial time points and for AUC values were also seen after detarium and cissus breads (AUC reductions 43 and 36% respectively), but not after the fibre-rich stew meals. SNSP and starch are possibly the main, but not the only, components responsible for the glucose- and insulin-lowering effects of cissus flour. The main SNSP fraction of detarium, identified as a high-molecular-weight xyloglucan, is likely to be a primary factor in determining the physiological activity of detarium flour.

Inclusion of guar gum and alginate into a crispy bar improves postprandial glycemia in humans

A novel induced viscosity fiber (IVF) crispy bar was formulated with the viscous dietary fibers alginate and guar gum. To evaluate the glycemic response and gastrointestinal tolerance to IVF crispy bars, nondiabetic healthy adult subjects (n = 48) were studied in a randomized, double-masked, crossover design. The control crispy bars and IVF crispy bars were identical except for the 2 dietary fibers contained in the experimental (IVF) bars. After an overnight fast, subjects consumed test bars containing 50 g carbohydrate. Their capillary blood glucose response was determined for 180 min postprandially. When subjects consumed IVF, the incremental blood glucose excursions were reduced (P < 0.05) at 15, 30, 45, and 120 min. At 180 min, the subjects' blood glucose concentration was maintained above the basal blood glucose concentration for both bars. Compared with controls, the incremental peak blood glucose concentration was reduced (P < 0.001) 30% when subjects consumed IVF. When subjects consumed IVF, the positive incremental area under the curve for glucose was reduced (P < 0.01) by 33% compared with controls. In the 24-h postprandial period after each treatment, the frequency and intensity of gastrointestinal tolerance symptoms did not differ. In conclusion, compared with a control crispy bar, the IVF crispy bar attenuated the postprandial glycemic excursion without gastrointestinal intolerance in healthy adult subjects.

Therapeutic effects of psyllium in type 2 diabetic patients

OBJECTIVE

The aim of this study was to evaluate the effects of psyllium in type 2 diabetic patients.

DESIGN

The study included three phases: phase 1 (1 week), phase 2 (treatment, 14 g fibre/day, 6 weeks) and phase 3 (4 weeks). At the end of each phase a clinical evaluation was performed after the ingestion of a test breakfast of 1824.2 kJ (436 kcal). Measurements included concentrations of blood glucose, insulin, fructosamine, GHbA(1c), C-peptide and 24 h urinary glucose excretion. In addition, uric acid, cholesterol and several mineral and vitamin concentrations were also evaluated.

SETTING

The study was performed at the Department of Pharmacology, Toxicology and Nursing at the University of León (Spain).

SUBJECTS

Twenty type 2 diabetic patients (12 men and 8 women) participated in the study with a mean age of 67.4 y for men and 66 y for women. The mean body mass index of men was 28.2 kg/m(2) and that of women 25.9 kg/m(2).

RESULTS

Glucose absorption decreased significantly in the presence of psyllium (12.2%); this reduction is not associated with an important change in insulin levels (5%). GHbA(1c), C-peptide and 24 h urinary glucose excretion decreased (3.8, 14.9 and 22.5%, respectively) during the treatment with fibre (no significant differences) as well as fructosamine (10.9%, significant differences). Psyllium also reduced total and LDL cholesterol (7.7 and 9.2%, respectively, significant differences), and uric acid (10%, significant difference). Minerals and vitamins did not show important changes, except sodium that increased significantly after psyllium administration.

CONCLUSIONS

The results obtained indicate a beneficial therapeutic effect of psyllium (Plantaben) in the metabolic control of type 2 diabetics as well as in lowering the risk of coronary heart disease. We also conclude that consumption of this fibre does not adversely affect either mineral or vitamin A and E concentrations. Finally, for a greater effectiveness, psyllium treatment should be individually evaluated.

Dietary fiber intakes and insulin requirements in pregnant women with type 1 diabetes

OBJECTIVE

To determine whether higher dietary fiber intake (water soluble and insoluble) is associated with lower insulin requirements and better glycemic control in pregnant women with type 1 diabetes consuming a self-selected diet.

DESIGN

A longitudinal, observational study.

SUBJECTS

Pregnant women (n=141) with type 1 diabetes participating in an interdisciplinary program examining the effects of glycemic control on pregnancy outcome (Diabetes and Pregnancy Program, University of Cincinnati Medical Center).

MEASUREMENTS

We determined total, water soluble and insoluble fiber intakes from 3-day food records kept each trimester during pregnancy. Outcome measures were insulin dose, pre-meal blood glucose, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES

Correlation coefficients, multiple regression, mixed-model analysis of variance.

RESULTS

Mean intakes (g/day) of total, water soluble fiber, and insoluble fiber were 14.0 (range, 1.8-33.1), 4.8 (range, 0.6-10.5) and 9.0 (range, 1.1-24.0), respectively. In the second and third trimesters of pregnancy, insulin requirements were inversely associated with total, water soluble, and insoluble fiber intakes; the correlation coefficients ranged from -0.22 to -0.17 (P=.02 to .08). Insulin requirements associated with a higher fiber intake (20.5 g/day) were 16% to 18% lower than for a lower fiber intake (8.1 g/day). These relations remained after adjustment for body weight, disease severity and duration, insulin type, and study year in the second (P=.03 to .10) but not in the third trimester. Pre-meal blood glucose and glycated hemoglobin concentrations were not associated with fiber intake.

CONCLUSIONS

Among pregnant women with type 1 diabetes, higher fiber intake is associated with lower daily insulin requirements. Dietary fiber intake should be considered when counseling patients about the management of blood glucose concentrations.

An examination of the possibility of lowering the glycemic index of oat and barley flakes by minimal processing

Differences in glycemic responses to various starchy foods are related to differences in the rate of starch digestion and absorption. In this study, the importance of the degree of gelatinization and the product thickness for postprandial glycemic and insulinemic responses to rolled oats and barley were studied in healthy subjects (5 men and 5 women). Thick (1.0 mm) rolled oats were made from raw or preheated (roasted or steamed) kernels. In addition, thin (0.5 mm) rolled oats were made from roasted or roasted and steamed (processed under conditions simulating commercial production) oat kernels. Finally, steamed rolled barley kernels (0.5 or 1.0 mm) were prepared. All thin flakes elicited high glucose and insulin responses [glycemic index (GI), 88-118; insulinemic index (II), 84-102], not significantly different from white wheat bread (P: > 0.05). In contrast, all varieties of thick oat flakes gave significantly lower metabolic responses (GI, 70-78; II, 58-77) than the reference bread (P: < 0.05). Thick barley flakes, however, gave high glucose and insulin responses (GI, 94; II, 84), probably because the botanical structure underwent more destruction than the corresponding oat flakes. We conclude that minimal processing of oat and barley flakes had a relatively minor effect on GI features compared with the more extensive commercial processing. One exception was thick oat flakes, which in contrast to the corresponding barley flakes, had a low GI.

Arabinoxylan fiber, a byproduct of wheat flour processing, reduces the postprandial glucose response in normoglycemic subjects

BACKGROUND

Arabinoxylan (AX) is the major component of dietary fiber in the cereal grains that make up a large proportion of our diet. However, the physiologic effect of AX is unknown.

OBJECTIVE

The objective of this study was to determine whether AX improves postprandial glucose and insulin responses in healthy humans.

DESIGN

AX-rich fiber was extracted from the byproduct of wheat-flour processing. Three isoenergic breakfasts, comprising bread, margarine, and jam, had 75 g available carbohydrate, 10 g protein, and 14 g fat and contained 0, 6, and 12 g AX-rich fiber, respectively. Fourteen healthy subjects consumed the 3 breakfast meals in random order on 3 mornings >/=3 d apart after an overnight fast. Blood was taken from the subjects at regular intervals over 2 h and was analyzed for glucose and insulin. The palatability of bread containing AX-rich fiber was compared with that of a control bread.

RESULTS

Compared with the control meal containing 0 g AX-rich fiber, the peak postprandial glucose concentration after meals containing 6 and 12 g AX-rich fiber was significantly lower (6. 3 +/- 1.3 compared with 7.2 +/- 1.0 mmol/L, P < 0.01; 5.9 +/- 0.9 compared with 7.2 +/- 1.0 mmol/L, P < 0.001, respectively). The incremental area under the curve (IAUC) for glucose was 20.2% (95% CI: 5.8%, 34.7%; P < 0.01) and 41.4% (25.9%, 56.8%; P < 0.001) lower, whereas IAUC for insulin was 17.0% (2.0%, 32.1%; P < 0.05) and 32. 7% (18.8%, 46.6%; P < 0.001) lower, respectively. Bread containing AX-rich fiber was as pala as 50% whole-wheat bread when evaluated with sensory analysis by 30 volunteers.

CONCLUSIONS

Postprandial glucose and insulin responses were improved by ingestion of AX-rich fiber. Further research is required to determine whether AX-rich fiber is of benefit to people with type 2 diabetes.

The influence of sugar-beet fibre, guar gum and inulin on nutrient digestibility, water consumption and plasma metabolites in healthy Beagle dogs

The aim of the present study was to evaluate the effects of three fibres (sugar-beet fibre, guar gum and inulin) incorporated in the basal diet of healthy dogs at 7 per cent of dry matter (DM). Parameters examined included stool output, water consumption, nutrient digestibility and fasting and postprandial plasma metabolites. All fibres increased wet faecal output; an increase in faecal DM output being observed with sugar-beet fibre only. Sugar-beet fibre and inulin increased daily water consumption. Sugar-beet fibre and guar gum decreased DM digestibility. The three fibres diminished organic matter and crude protein digestibility while ether extract digestibility was decreased by guar gum and inulin. Guar gum induced lower postprandial insulin, alpha-amino-nitrogen and urea plasma concentrations. Guar gum also lowered fasting cholesterolaemia. Sugar-beet fibre and inulin showed no metabolic effects. These physiological properties suggest that guar gum would be a suitable ingredient for dietary therapy of chronic diseases such as diabetes mellitus or hyperlipidaemia in the dog.