Metabolic effects of reducing rate of glucose ingestion by single bolus versus continuous sipping

Features extracted using tensor decomposition reflect the biological features of the temporal patterns of human blood multimodal metabolome

High-throughput omics technologies have enabled the profiling of entire biological systems. For the biological interpretation of such omics data, two analyses, hypothesis- and data-driven analyses including tensor decomposition, have been used. Both analyses have their own advantages and disadvantages and are mutually complementary; however, a direct comparison of these two analyses for omics data is poorly examined.We applied tensor decomposition (TD) to a dataset representing changes in the concentrations of 562 blood molecules at 14 time points in 20 healthy human subjects after ingestion of 75 g oral glucose. We characterized each molecule by individual dependence (constant or variable) and time dependence (later peak or early peak). Three of the four features extracted by TD were characterized by our previous hypothesis-driven study, indicating that TD can extract some of the same features obtained by hypothesis-driven analysis in a non-biased manner. In contrast to the years taken for our previous hypothesis-driven analysis, the data-driven analysis in this study took days, indicating that TD can extract biological features in a non-biased manner without the time-consuming process of hypothesis generation.

Associations between Conventional and Emerging Indicators of Dietary Carbohydrate Quality and New-Onset Type 2 Diabetes Mellitus in Chinese Adults

Dietary glycemic index (GI), carbohydrate to fiber ratio (CF) and carbohydrate quality index (CQI) are conventional and emerging indicators for carbohydrate quality. We aimed to investigate the associations between these indicators and new-onset type 2 diabetes mellitus (T2DM) risk among Chinese adults. This prospective cohort study included 14,590 adults from the China Health and Nutrition Survey without cardiometabolic diseases at baseline. The associations between dietary GI, CF and CQI and T2DM risk were assessed using Cox proportional hazard regression analysis and dose-response relationships were explored using restricted cubic spline and threshold analysis. After a mean follow-up duration of 10 years, a total of 1053 new-onset T2DM cases occurred. There were U-shaped associations between dietary GI and CF and T2DM risk (both P-nonlinear < 0.0001), and T2DM risk was lowest when dietary GI was 72.85 (71.40, 74.05) and CF was 20.55 (17.92, 21.91), respectively (both P-log likelihood ratio < 0.0001). Inverse associations between CQI and T2DM risk specifically existed in participants < 60 y or attended middle school or above (both P-trend < 0.05). These findings indicated that moderate dietary GI and CF range and a higher dietary CQI score may be suggested for T2DM prevention in Chinese adults.

Effects of Diet, Lifestyle, Chrononutrition and Alternative Dietary Interventions on Postprandial Glycemia and Insulin Resistance

As years progress, we are found more often in a postprandial than a postabsorptive state. Chrononutrition is an integral part of metabolism, pancreatic function, and hormone secretion. Eating most calories and carbohydrates at lunch time and early afternoon, avoiding late evening dinner, and keeping consistent number of daily meals and relative times of eating occasions seem to play a pivotal role for postprandial glycemia and insulin sensitivity. Sequence of meals and nutrients also play a significant role, as foods of low density such as vegetables, salads, or soups consumed first, followed by protein and then by starchy foods lead to ameliorated glycemic and insulin responses. There are several dietary schemes available, such as intermittent fasting regimes, which may improve glycemic and insulin responses. Weight loss is important for the treatment of insulin resistance, and it can be achieved by many approaches, such as low-fat, low-carbohydrate, Mediterranean-style diets, etc. Lifestyle interventions with small weight loss (7–10%), 150 min of weekly moderate intensity exercise and behavioral therapy approach can be highly effective in preventing and treating type 2 diabetes. Similarly, decreasing carbohydrates in meals also improves significantly glycemic and insulin responses, but the extent of this reduction should be individualized, patient-centered, and monitored. Alternative foods or ingredients, such as vinegar, yogurt, whey protein, peanuts and tree nuts should also be considered in ameliorating postprandial hyperglycemia and insulin resistance. This review aims to describe the available evidence about the effects of diet, chrononutrition, alternative dietary interventions and exercise on postprandial glycemia and insulin resistance.

Impact of income and eating speed on new-onset diabetes among men: a retrospective cohort study

OBJECTIVE

To examine the impact of income and eating speed on new-onset diabetes among men.

DESIGN

This was a retrospective cohort study.

SETTING

We used the administrative claims and health check-up data for fiscal years 2010-2015 obtained from the Fukuoka branch of the Japan Health Insurance Association.

PARTICIPANTS

Participants were 15 474 non-diabetic male employees, aged between 40 and 74 years. They were categorised based on their eating speeds (ie, fast, normal and non-fast).

PRIMARY AND SECONDARY OUTCOME MEASURES

To calculate the OR of the development of diabetes, we created generalised linear regression models with diabetes onset as the dependent variable and eating speed and income as covariates and calculated corresponding 95% CI values. The analyses were performed after adjusting the data for age, obesity and comorbidities.

RESULTS

Of the total participants, 620 developed diabetes during the 5-year study period. A univariate analysis using the generalised linear regression model revealed that eating fast (OR: 1.35, 95% CI 1.17 to 1.55) and having a low income wereincome (OR: 1.47, 95% CI 1.24 to 1.74) were significantly associated with the onset of diabetes. After adjusting for age, obesity and comorbidities, both eating fast (OR: 1.17, 95% CI 1.02 to 1.35) and having a low income (OR: 1.24, 95% CI 1.03 to 1.50) were recognised as independent risk factors for diabetes onset.

CONCLUSIONS

The study revealed that eating fast and having a low income were independent risk factors, leading to the development of diabetes. While it is difficult to address income differences, it may be possible to address the factors that contribute to income differences to manage diabetes appropriately and at low healthcare costs. However, eating speed can be controlled. Hence, the provision of education and coaching on dietary habits, including eating speed, may be effective in preventing diabetes onset.

From clinical guidelines to practice: The nutrition elements for enhancing recovery after colorectal surgery

The Enhanced Recovery After Surgery (ERAS) Care System improves patient outcomes. The ERAS Protocol describes multimodal, evidence-based processes that are bundled into >20 care elements, and the ERAS Implementation Program provides strategies to guide the successful adoption of the care elements. Although formal training is essential to implement ERAS correctly, with this article we aim to bridge the gap between the nutritionally relevant care elements of the protocol and their implementation for colorectal surgery. This article also describes how dietitians can support optimal patient outcomes by playing an active role in implementing, monitoring, and evaluating ERAS practices.

Eating Fast and Until Full Is Associated with Elevated Alanine Aminotransferase Activity in Japanese Schoolchildren: A Cross-Sectional Study

Alanine aminotransferase (ALT) activity has been recognized as a marker for monitoring the risk of metabolic syndrome, diabetes and non-alcoholic fatty liver disease in children. Higher ALT activity was reported to be associated with eating fast in Japanese adults, but the association in children is unclear. Moreover, eating fast and eating until full are reported to be associated with being overweight. This study examined the association between elevated ALT and eating behaviors (eating fast and eating until full) among population-based schoolchildren (aged 9-10 years) in Ina Town, Saitama, Japan. Data for eating behaviors were obtained from a self-written questionnaire. Blood samples were drawn to measure ALT. Elevated ALT was defined as > 30 U/L in boys and > 19 U/L in girls. Logistic regression models and structural equation models were used to calculate the effect of eating behaviors on elevated ALT. Final data analysis was carried out for 1,870 boys and 1,739 girls. "Eating fast and eating until full" was significantly associated with elevated ALT in each sex. "Eating fast and not eating until full" was significantly associated with elevated ALT in boys, but after adjusting for exercise and body mass index, this association was not significant. In conclusion, "eating fast and eating until full" was associated with elevated ALT in schoolchildren. A sex difference in the association of "eating fast and not eating until full" with elevated ALT was observed. Modifying the behaviors of eating fast and eating until full is important for schoolchildren to prevent ALT elevation.

Regulation of Postabsorptive and Postprandial Glucose Metabolism by Insulin-Dependent and Insulin-Independent Mechanisms: An Integrative Approach

Glucose levels in blood must be constantly maintained within a tight physiological range to sustain anabolism. Insulin regulates glucose homeostasis via its effects on glucose production from the liver and kidneys and glucose disposal in peripheral tissues (mainly skeletal muscle). Blood levels of glucose are regulated simultaneously by insulin-mediated rates of glucose production from the liver (and kidneys) and removal from muscle; adipose tissue is a key partner in this scenario, providing nonesterified fatty acids (NEFA) as an alternative fuel for skeletal muscle and liver when blood glucose levels are depleted. During sleep at night, the gradual development of insulin resistance, due to growth hormone and cortisol surges, ensures that blood glucose levels will be maintained within normal levels by: (a) switching from glucose to NEFA oxidation in muscle; (b) modulating glucose production from the liver/kidneys. After meals, several mechanisms (sequence/composition of meals, gastric emptying/intestinal glucose absorption, gastrointestinal hormones, hyperglycemia mass action effects, insulin/glucagon secretion/action, de novo lipogenesis and glucose disposal) operate in concert for optimal regulation of postprandial glucose fluctuations. The contribution of the liver in postprandial glucose homeostasis is critical. The liver is preferentially used to dispose over 50% of the ingested glucose and restrict the acute increases of glucose and insulin in the bloodstream after meals, thus protecting the circulation and tissues from the adverse effects of marked hyperglycemia and hyperinsulinemia.

The Role of Pulses in Cardiovascular Disease Risk for Adults With Diabetes

Cardiovascular disease (CVD) is a leading cause of death among adults while associated comorbidities like diabetes further increase risks of CVD-related complications and mortality. Strategies to prevent and manage CVD risk, such as dietary change, are a key component for CVD and diabetes prevention and management. Pulses, defined as the dried edible seeds of plants in the legume family, have received attention for their superior nutritional composition as high-fiber, low-glycemic index foods and have been studied for their potential to reduce CVD and diabetes risk. Both observational and experimental studies conducted among adults with and without diabetes have provided support for pulses in their ability to improve lipid profiles, glycemic control, and blood pressure, all of which are major modifiable risk factors of CVD. These capabilities have been attributed to various mechanisms associated with the nutrient and phytochemical composition of pulses. Overall, this evidence provides support for the consumption of pulses as an important dietary strategy to reduce risk of CVD for those living with and without diabetes.

Validation and Implementation of an Automated Chew Sensor-Based Remote Monitoring Device as Tool for Equine Grazing Research

Field studies characterizing equine grazing activity primarily rely on observational protocols, limiting the quantity and accuracy of collected data. The objectives of this study were to validate an automated chew sensor technology, the EquiWatch System (EWS), for detecting grazing behaviors and to demonstrate potential applications of the EWS in equine grazing research. Eight mature standardbred mares were used in this study. EquiWatch System validation was completed in two phases: grazing time was evaluated in experiment 1 and chew counts in experiment 2. The correlation between visual observations and system-recorded grazing time was high (concordance correlation coefficient [CCC] = 0.997). There was also a high agreement between the sum of manually counted bites and chews and total chew counts reported by the EWS (CCC = 0.979). Following validation, a pilot study was conducted using the EWS to assess feeding behaviors of horses with unrestricted pasture access (PAS) versus horses offered ad libitum hay (HAY). Horses spent more time engaged in feeding behavior on PAS (14.79 ± 0.48 hr/d) than HAY (11.98 ± 0.48 hr/d; P < .0001). Chewing rate also differed by forage (PAS 83.92 ± 1.61; HAY 68.50 ± 1.61 chews/min; P < .0001). However, although the magnitude of these behavioral parameters was influenced by treatment, the underlying 24-hour patterns were largely preserved regardless of forage type. These results demonstrate that the EWS can generate data necessary for characterizing feeding behavior in horses. Future studies implementing this tool could provide a greater understanding of biological, environmental, and nutritive factors driving grazing behavior in horses.

High or low glycemic index (GI) meals at dinner results in greater postprandial glycemia compared with breakfast: a randomized controlled trial

INTRODUCTION

While circadian control of glucose metabolism is well known, how glycemic index (GI) of carbohydrate-rich meals interacts with time of consumption (breakfast or dinner) to influence postprandial (PP) glucose homeostasis is less well established. The objective of the study was to assess markers of PP glucose homeostasis following high or low GI test meals (TM) consumed either at breakfast or at dinner and following consumption of the subsequent standardized meals (SSM).

RESEARCH DESIGN AND METHODS

Randomized crossover trial in 34 healthy, Chinese, elderly volunteers (mean±SEM age, 56.8±0.83 years), who completed 4 separate study sessions per-protocol, consisting of a high-GI breakfast, low-GI breakfast, high-GI dinner and low-GI dinner TM, followed by a SSM at the subsequent eating occasion. Blood samples were taken for 3 hours after each TM and SSM for glucose, insulin, glucagon, free fatty acids (FFA) and triglycerides (TG) measurements.

RESULTS

Consuming TM at dinner produced greater PP glycemia than breakfast both after TM and SSM (both p<0.0001), irrespective of GI. High-GI TM also produced greater PP glycemia than low-GI TM, both after TM and SSM (both p<0.01), irrespective of time of consumption. No interaction between GI and time were found on PP glycemia, indicating parallel, but independent effects. Combined total areas under the curve of TM+SSM for PP glucose (p<0.0001), PP TG (p<0.0001) and PP FFA (p<0.0001) were all greater when TM taken during dinner compared with breakfast.

CONCLUSIONS

Carbohydrate-rich meals consumed at dinner leads to significantly worse PP glucose homeostasis than when consumed at breakfast, on top of the independent GI effect of the meal. This may have implications to future type 2 diabetes risk. Moreover, future studies investigating GI/glycemic load (GL) and disease risk associations should factor in timing of GL consumption as an additional variable.

TRIAL REGISTRATION NUMBER

NCT02927600.

Enzyme-treated orange pomace alters acute glycemic response to orange juice

The goal of the present study was to determine the impact of the addition of enzyme-treated orange pomace to orange juice on postprandial glycemic response. Ten healthy subjects (aged 27.9 ± 7.7 years, body mass index 22.1 ± 1.1 kg m⁻²) participated in a randomized, 2-arm, cross-over clinical trial to test the glycemic response to 100% orange juice (OJ) or 100% orange juice with 5 g of enzyme-treated orange pomace fiber (OPF). Blood samples were collected and glucose and insulin concentrations were measured at fasting (0 min) and every 15 min for 2 h after consuming the study juice products. Analysis of the 2 h incremental area under the curve (iAUC_0–2h) indicated a significant reduction in blood glucose after ingesting the OPF juice compared to the OJ, p = 0.02. Peak glucose concentrations were also lowered after the OPF juice compared to the OJ, p < 0.05. No significant difference was observed in insulin responses between treatments, p > 0.05. Overall, this study demonstrated that adding 5 g of fiber from orange pomace into a serving of OJ attenuated the postprandial glucose response.

Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill’s criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost–benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

Longitudinal association between eating frequency and hemoglobin A1c and serum lipids in diabetes in the SEARCH for Diabetes in Youth study

BACKGROUND

Few studies have evaluated the prospective association of eating frequency with HbA1c levels and cardiovascular disease risk markers among youth with diabetes.

OBJECTIVE

To examine the 5-year longitudinal association of eating frequency with HbA1c and serum lipid levels among youth with type 1 diabetes (T1D) or type 2 diabetes (T2D).

METHODS

One-thousand and forty-nine youth (≥10-year old) with incident T1D (n = 821) or T2D (n = 228) who participated in the SEARCH for Diabetes in Youth study were included. Eating frequency (≤3, 4-5, or 6-10 times/d) measured at baseline and follow-up visits was related to HbA1c and serum lipid levels measured repeatedly over 5 years.

RESULTS

Increased eating frequency was associated with larger increases in HbA1c among youth T1D. For example, for youth with T1D who ate ≤3 times/d at the outset and ate 6-10 times/d 5 years later, the longitudinal model predicted greater absolute increases in HbA1c (2.77%); whereas for youth with T1D who ate 6-10 times/d at the outset and ate ≤3 times/d 5 years later, the model predicted lesser absolute increases in HbA1c (1.33%). Eating frequency was not associated with changes in serum lipid levels among youth with T1D or T2D.

CONCLUSIONS

Youth with T1D who increased their eating frequency vs those who decreased it had larger increases in HbA1c over 5 years.

Nutrition management for head and neck cancer patients improves clinical outcome and survival

Up to 80% of patients with head and neck cancers are malnourished because of their lifestyle and the risk factors associated with this disease. Unfortunately, nutrition management systems are not implemented in most head and neck cancer clinics. Even worse, many head and neck surgeons as well as hospital management authorities disregard the importance of nutrition management in head and neck cancer patients. In addition, the often extensive resection and reconstruction required for tumors in the upper aerodigestive tract pose special challenges for swallowing and sufficient food intake, placing special demands on nutrition management. This article presents the basics of perioperative metabolism and nutrition management of head and neck cancer patients and makes recommendations for clinical practice. Implementing a nutrition management system in head and neck cancer clinics will improve the clinical outcome and the survival of the patients.

The acute effects of inulin and resistant starch on postprandial serum short-chain fatty acids and second-meal glycemic response in lean and overweight humans

BACKGROUND/OBJECTIVES

Colonic fermentation of dietary fiber to short-chain fatty acids (SCFA) may protect against obesity and diabetes, but excess production of colonic SCFA has been implicated in the promotion of obesity. We aimed to compare the effects of two fermentable fibers on postprandial SCFA and second-meal glycemic response in healthy overweight or obese (OWO) vs lean (LN) participants.

SUBJECTS/METHODS

Using a randomized crossover design, 13 OWO and 12 LN overnight fasted participants were studied for 6 h on three separate days after consuming 300 ml water containing 75 g glucose (GLU) as control or with 24 g inulin (IN) or 28 g resistant starch (RS). A standard lunch was served 4 h after the test drink.

RESULTS

Within the entire group, compared with control, IN significantly increased serum SCFA (P<0.001) but had no effect on free-fatty acids (FFA) or second-meal glucose and insulin responses. In contrast, RS had no significant effect on SCFA but reduced FFA rebound (P<0.001) and second-meal glucose (P=0.002) and insulin responses (P=0.024). OWO had similar postprandial serum SCFA and glucose concentrations but significantly greater insulin and FFA than LN. However, the effects of IN and RS on SCFA, glucose, insulin and FFA responses were similar in LN and OWO.

CONCLUSIONS

RS has favorable second-meal effects, likely related to changes in FFA rather than SCFA concentrations. However, a longer study may be needed to demonstrate an effect of RS on SCFA. We found no evidence that acute increases in SCFA after IN reduce glycemic responses in humans, and we were unable to detect a significant difference in SCFA responses between OWO vs LN subjects.

Consumption of a drink containing extruded sorghum reduces glycaemic response of the subsequent meal

PURPOSE

Glycaemic control is essential to prevent the manifestation of diabetes in predisposed individuals and the development of associated comorbidities. It is believed that sorghum may modulate the glucose response. In this study, we investigated the effect of extruded sorghum consumption, and the profile of bioactive compounds, on postprandial glycaemia of a subsequent meal in normal weight and normoglycaemic subjects.

METHODS

This was a randomized, single-blind, crossover designed study. After a 12 h overnight fasting, ten subjects reported to the laboratory to participate in four experimental sessions, and consumed one of three sorghum test drinks: sorghum P 3-DXAs (with proanthocyanidins-P and rich in 3-deoxyanthocyanidins-3-DXAs); 3-DXAs (without proanthocyanidins and rich in 3-DXAs); and control (low in 3-DXAs and without proanthocyanidins); or a non-sorghum drink. 30 min later, the subjects consumed a glucose solution (25 g glucose). Glycaemic response was monitored at times 0 (before glucose solution), 15, 30, 45, 60, 90, 120 min (after glucose solution consumption). The incremental areas under the glycaemic curve (iAUC) were calculated by the trapezoidal method.

RESULTS

Intake of P 3-DXAs drink before the glucose solution resulted in a postprandial iAUC lower than the other sorghum test drinks. Sorghum drinks minimized the postprandial glycaemia peak.

CONCLUSION

Sorghum drinks consumption, especially the P 3-DXAs drink, 30 min before the glucose solution resulted in lower iAUC compared to the non-sorghum drink, leading to a lower glycaemic response.

Combination of 5-aminolevulinic acid and ferrous ion reduces plasma glucose and hemoglobin A1c levels in Zucker diabetic fatty rats

Mitochondrial dysfunction is associated with type 2 diabetes mellitus (T2DM). 5‐Aminolevulinic acid (ALA), a natural amino acid produced only in the mitochondria, is a precursor of heme. Cytochromes that contain heme play an important role in aerobic energy metabolism. Thus, ALA may help reduce T2DM‐associated hyperglycemia. In this study, we investigated the effect of ALA combined with sodium ferrous citrate (SFC) on hyperglycemia in Zucker diabetic fatty (ZDF) rats. We found that the gavage administration of ALA combined with SFC (ALA/SFC) for 6 weeks reduced plasma glucose and hemoglobin A1c (HbA1c) levels in rats without affecting plasma insulin levels. The glucose‐lowering effect depended on the amount of ALA/SFC administered per day. Furthermore, the glucose tolerance was also significantly improved by ALA/SFC administration. Although food intake was slightly reduced in the rats administered ALA/SFC, there was no effect on their body weight. Importantly, ALA/SFC administration induced heme oxygenase‐1 (HO‐1) expression in white adipose tissue and liver, and the induced expression levels of HO‐1 correlated with the glucose‐lowering effects of ALA/SFC. Taken together, these results suggest that ALA combined with ferrous ion is effective in reducing hyperglycemia of T2DM without affecting plasma insulin levels. HO‐1 induction may be involved in the mechanisms underlying the glucose‐lowering effect of ALA/SFC.

Sleep, circadian rhythm and body weight: parallel developments

Circadian alignment is crucial for body-weight management, and for metabolic health. In this context, circadian alignment consists of alignment of sleep, meal patterns and physical activity. During puberty a significant reduction in sleep duration occurs, and pubertal status is inversely associated with sleep duration. A consistent inverse association between habitual sleep duration and body-weight development occurs, independent of possible confounders. Research on misalignment reveals that circadian misalignment affects sleep-architecture and subsequently disturbs glucose–insulin metabolism, substrate oxidation, leptin- and ghrelin concentrations, appetite, food reward, hypothalamic–pituitary–adrenal-axis activity and gut-peptide concentrations enhancing positive energy balance and metabolic disturbance. Not only aligning meals and sleep in a circadian way is crucial, also regular physical activity during the day strongly promotes the stability and amplitude of circadian rhythm, and thus may serve as an instrument to restore poor circadian rhythms. Endogenicity may play a role in interaction of these environmental variables with a genetic predisposition. In conclusion, notwithstanding the separate favourable effects of sufficient daily physical activity, regular meal patterns, sufficient sleep duration and quality sleep on energy balance, the overall effect of the amplitude and stability of the circadian rhythm, perhaps including genetic predisposition, may integrate the separate effects in an additive way.

Gastrointestinal actions of glucagon-like peptide-1-based therapies: glycaemic control beyond the pancreas

The gastrointestinal hormone glucagon-like peptide-1 (GLP-1) lowers postprandial glucose concentrations by regulating pancreatic islet-cell function, with stimulation of glucose-dependent insulin and suppression of glucagon secretion. In addition to endocrine pancreatic effects, mounting evidence suggests that several gastrointestinal actions of GLP-1 are at least as important for glucose-lowering. GLP-1 reduces gastric emptying rate and small bowel motility, thereby delaying glucose absorption and decreasing postprandial glucose excursions. Furthermore, it has been suggested that GLP-1 directly stimulates hepatic glucose uptake, and suppresses hepatic glucose production, thereby adding to reduction of fasting and postprandial glucose levels. GLP-1 receptor agonists, which mimic the effects of GLP-1, have been developed for the treatment of type 2 diabetes. Based on their pharmacokinetic profile, GLP-1 receptor agonists can be broadly categorized as short- or long-acting, with each having unique islet-cell and gastrointestinal effects that lower glucose levels. Short-acting agonists predominantly lower postprandial glucose excursions, by inhibiting gastric emptying and intestinal glucose uptake, with little effect on insulin secretion. By contrast, long-acting agonists mainly reduce fasting glucose levels, predominantly by increased insulin and reduced glucagon secretion, with potential additional direct inhibitory effects on hepatic glucose production. Understanding these pharmacokinetic and pharmacodynamic differences may allow personalized antihyperglycaemic therapy in type 2 diabetes. In addition, it may provide the rationale to explore treatment in patients with no or little residual β-cell function.

Effect of meal frequency on glucose and insulin levels in women with polycystic ovary syndrome: a randomised trial

BACKGROUND/OBJECTIVES

The aim of the study was to compare the effect of two-meal patterns (three vs six meals per day) on glucose and insulin levels in women with polycystic ovary syndrome (PCOS).

SUBJECTS/METHODS

In a randomised, crossover, 24-week study, 40 women with PCOS, aged 27±6 years, body mass index 27±6 kg/m(2), followed a weight maintenance diet (% carbohydrates:protein:fat, 40:25:35), consumed either as a three- or a six-meal pattern, with each intervention lasting for 12 weeks. Anthropometric measurements, diet compliance and subjective hunger, satiety and desire to eat were assessed biweekly. All women underwent an oral glucose tolerance test (OGTT) with 75 g glucose for measurement of plasma glucose and insulin at the beginning and end of each intervention. HaemoglobinA1c (HbA1c), blood lipids and hepatic enzymes were measured at the beginning and end of each intervention.

RESULTS

Body weight remained stable throughout the study. Six meals decreased significantly fasting insulin (P=0.014) and post-OGTT insulin sensitivity (Matsuda index, P=0.039) vs three meals. After incorporation of individual changes over time, with adjustment for potential confounders, the only variable that remained significant was the Matsuda index, which was then used in multivariate analysis and general linear models. Six meals improved post-OGTT insulin sensitivity independently of age and body weight vs three meals (P=0.012). No significant differences were found between six and three meals for glucose, HbA1c, blood lipids, hepatic enzymes, subjective desire to eat and satiety.

CONCLUSIONS

Six meals had a more favourable effect on post-OGTT insulin sensitivity in women with PCOS compared with isocaloric three meals.

Post-prandial glucose and insulin responses of hummus alone or combined with a carbohydrate food: a dose-response study

Objectives

Pulses are low glycemic index (GI) foods and have been associated with reduced risk of heart disease, diabetes and some cancers. However the blood glucose and insulin responses of hummus, a food containing chickpea, have not been thoroughly tested.

Methods

Ten healthy subjects each consumed 11 breakfast study meals in randomized order over a period of 15 weeks. Hummus was consumed alone at three doses (2.7 g, 10.8 g and 25 g available carbohydrate [avCHO] portions) and with 50 g avCHO from white bread at three doses (2.7 g, 5.4 g and 10.8 g avCHO portions). The responses elicited by hummus alone were compared with 25 g avCHO portions of white bread, while those after hummus plus white bread were compared with 50 g avCHO from white bread. Plasma glucose and serum insulin responses were monitored over two hours and the GI and insulin index (II) calculated using standard methodology.

Results

The GI and II of hummus were 15 ± 3 and 52 ± 13, respectively, and were significantly lower than white bread (P < 0.05). The glucose and insulin incremental area under the curve (IAUC) for hummus alone were significantly lower than white bread except for insulin IAUC of hummus 25 g avCHO. The peak rise of blood glucose and insulin after hummus were significantly lower than after white bread. Glucose and insulin IAUC after adding hummus to bread did not differ significantly from white bread alone. However the blood glucose 45 min after adding 25 g avCHO from hummus to white bread was significantly lower while at 120 min it was significantly higher than after white bread alone.

Conclusions

This study demonstrated that, similar to chickpeas, hummus has a very low GI and II. Postprandial glucose responses were 4 times less than that of white bread and did not compromise insulin levels.

Equine hyperinsulinemia: investigation of the enteroinsular axis during insulin dysregulation

Compared with some other species, insulin dysregulation in equids is poorly understood. However, hyperinsulinemia causes laminitis, a significant and often lethal disease affecting the pedal bone/hoof wall attachment site. Until recently, hyperinsulinemia has been considered a counterregulatory response to insulin resistance (IR), but there is growing evidence to support a gastrointestinal etiology. Incretin hormones released from the proximal intestine, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide, augment insulin secretion in several species but require investigation in horses. This study investigated peripheral and gut-derived factors impacting insulin secretion by comparing the response to intravenous (iv) and oral d-glucose. Oral and iv tests were performed in 22 ponies previously shown to be insulin dysregulated, of which only 15 were classified as IR (iv test). In a more detailed study, nine different ponies received four treatments: d-glucose orally, d-glucose iv, oats, and commercial grain mix. Insulin, glucose, and incretin concentrations were measured before and after each treatment. All nine ponies showed similar iv responses, but five were markedly hyperresponsive to oral d-glucose and four were not. Insulin responsiveness to oral d-glucose was strongly associated with blood glucose concentrations and oral glucose bioavailability, presumably driven by glucose absorption/distribution, as there was no difference in glucose clearance rates. Insulin was also positively associated with the active amide of GLP-1 following d-glucose and grain. This study has confirmed a functional enteroinsular axis in ponies that likely contributes to insulin dysregulation that may predispose them to laminitis. Moreover, iv tests for IR are not reliable predictors of the oral response to dietary nonstructural carbohydrate.

Promoting Perioperative Metabolic and Nutritional Care

Surgery represents a major stressor that disrupts homeostasis and can lead to loss of body cell mass. Integrated, multidisciplinary medical strategies, including enhanced recovery programs and perioperative nutrition support, can mitigate the surgically induced metabolic response, promoting optimal patient recovery following major surgery. Clinical therapies should identify those who are poorly nourished before surgery and aim to attenuate catabolism while preserving the processes that promote recovery and immunoprotection after surgery. This review will address the impact of surgery on intermediary metabolism and describe the clinical consequences that ensue. It will also focus on the role of perioperative nutrition, including preoperative nutrition risk, carbohydrate loading, and early initiation of oral feeding (centered on macronutrients) in modulating surgical stress, as well as highlight the contribution of the anesthesiologist to nutritional care. Emerging therapeutic concepts such as preoperative glycemic control and prehabilitation will be discussed.

Potential role of meal frequency as a strategy for weight loss and health in overweight or obese adults

Improved dietary strategies for weight loss are necessary to decrease metabolic disease risk in overweight or obese adults. Varying meal frequency (MF; i.e., increasing or decreasing eating occasions beyond the traditional pattern of three meals daily) has been thought to have an influence on body weight regulation, hunger control, and blood markers of health. It is common practice for weight management clinicians to recommend increasing MF as a strategy for weight management and to improve metabolic parameters. However, limited research exists investigating the effect of MF during controlled hypocaloric dietary interventions. Furthermore, MF literature often speculates with regard to efficacy of MF treatments based on research using normal weight, overweight/obese, or some combination, where much diversity exists within these various populations. In this review, we suggest that normal-weight and overweight/obese populations, as well as free-living versus investigator-controlled research trials, should be studied independently. Therefore, the objective of the present review is to survey the literature to assess whether the alteration of MF influences body weight regulation, hunger control, and/or blood markers of health in overweight/obese participants undergoing a controlled hypocaloric diet to induce weight loss. Findings of this review indicate that there is uncertainty in the literature when interpreting the optimal MF for obesity treatment, where reduced MF may even show more favorable lipid profiles in obese individuals compared with increased MF. Furthermore, the simple relationship of comparing MF with body fatness or body mass index should also consider whether eating frequency is associated with other healthy factors (e.g., increased physical activity).

An isocaloric increase of eating episodes in the morning contributes to decrease energy intake at lunch in lean men

The effects of increasing eating frequency on human health are unclear. This study used an integrated approach to assess the short-term consequences on appetite and metabolism. Twenty normal-weight men participated in: (i) two sessions consisting of a breakfast consumed in one eating episode at T0 (F1), or in four isocaloric eating episodes at T0, T60, T120, and T180 min (F4), and followed by an ecological ad libitum buffet meal (T240) designed in an experimental restaurant. Intakes were assessed for the whole buffet meal and for each temporal quarter of the meal. (ii) two sessions consisting of the same two breakfasts F1 and F4 in a Clinical Investigation Centre. Blood sampling was performed to study the kinetics of ghrelin, glucagon-like peptide-1 (GLP-1), glucose, insulin, triglycerides and non-esterified fatty acids (NEFA). Substrate oxidation was measured by indirect calorimetry. During each of the 4 sessions, participants rated their appetite throughout the experiment. After F4, at T240 min, GLP-1 concentration was higher (P=0.006) while ghrelin concentration and hunger ratings were lower (P<0.001). We showed a trend for subjects to consume less energy (-88±61 kcal, P=0.08) at the buffet after F4, explained by a decrease in lipid intake (P=0.04). Marked differences in consumption were observed during the last temporal quarter of the meal for total energy and lipid intake (P=0.03). Mixed models highlighted differences between F1 and F4 for the kinetics of glucose, insulin and NEFA (P<0.001). The area under the curve was lower for insulin (P<0.001) and NEFA in F4 (P=0.03). Diet induced thermogenesis was reduced in F4 (P<0.05). This study demonstrated the beneficial short-term effect of increasing eating frequency on appetite in lean men considering subjective, physiological and behavioral data. However, the loss of the inter-prandial fast was associated with an inhibition of lipolysis, reflected by NEFA profiles, and a decrease in energy expenditure.

Impact of eating rate on obesity and cardiovascular risk factors according to glucose tolerance status: the Fukuoka Diabetes Registry and the Hisayama Study

AIMS/HYPOTHESIS

Medical nutrition therapy plays a critical role in the prevention and treatment of type 2 diabetes. However, appropriate measures of eating behaviours, such as eating rate, have not yet been clearly established. The aim of the present study was to examine the associations among eating rate, obesity and cardiovascular risk factors.

METHODS

A total of 7,275 Japanese individuals aged ≥40 years who had normal fasting glucose levels, impaired fasting glucose or diabetes were divided into four groups according to self-reported eating rate: slow, medium, relatively fast and very fast. The associations between eating rate and various cardiovascular risk factors were investigated cross-sectionally.

RESULTS

The proportions of participants who were obese or who had elevated waist circumference levels increased progressively with increases in eating rate (p for trend <0.001), regardless of glucose tolerance status. These associations remained significant after adjustment for potential confounders, namely, age, sex, total energy intake, dietary fibre intake, current smoking, current drinking and regular exercise (p for trend <0.001). Blood pressure and lipid levels also tended to increase in association with eating rate. HbA(1c) rose significantly as eating rate increased, even after multivariate adjustment, including BMI, in diabetic patients on insulin therapy (p = 0.02), whereas fasting plasma glucose did not increase significantly.

CONCLUSIONS/INTERPRETATION

Our findings suggest that eating rate is associated with obesity and other cardiovascular risk factors and therefore may be a modifiable risk factor in the management of cardiovascular risk factors and diabetes.

Self-reported speed of eating and 7-year risk of type 2 diabetes mellitus in middle-aged Japanese men

OBJECTIVE

This cohort study investigated the association between eating speed and the incidence of type 2 diabetes in middle-aged Japanese men.

MATERIALS/METHODS

Participants were 2,050 male employees of a metal products factory in Japan. We measured self-reported categorical eating speed. The incidence of diabetes was determined in annual medical examinations over a 7-year period. The association between eating speed and the incidence of diabetes adjusted for multiple variables (age, family history of diabetes, smoking, alcohol drinking, habitual exercise, and presence of hypertension and hyperlipidemia) was evaluated using Cox proportional hazards models.

RESULTS

The prevalence of obesity (BMI≥25 kg/m(2)) across the categories of eating speed (slow, medium, and fast) was 14.6, 23.3, and 34.8%, respectively, and a faster eating speed was associated with a higher prevalence of obesity. During the study, 177 participants developed diabetes. Crude incidence rates (/1,000 person-years) across the three categories of eating speed were 9.9, 15.6, and 17.3, respectively. Multivariate-adjusted hazard ratios (95% CI) across the categories were 1.00 (reference), 1.68 (0.93-3.02), and 1.97 (1.10-3.55), respectively, and eating speed was associated with the risk of diabetes (p for trend=0.030). After further adjustment for BMI, a significant association was not observed.

CONCLUSIONS

Eating speed was associated with the incidence of diabetes. Since these associations were not significant after adjusting for BMI, eating speed may act via its effect on body weight. Eating speed is a controllable risk factor, and eating slowly could be an acceptable lifestyle intervention for the prevention of diabetes mellitus.

Glycaemic index methodology

The glycaemic index (GI) concept was originally introduced to classify different sources of carbohydrate (CHO)-rich foods, usually having an energy content of >80 % from CHO, to their effect on post-meal glycaemia. It was assumed to apply to foods that primarily deliver available CHO, causing hyperglycaemia. Low-GI foods were classified as being digested and absorbed slowly and high-GI foods as being rapidly digested and absorbed, resulting in different glycaemic responses. Low-GI foods were found to induce benefits on certain risk factors for CVD and diabetes. Accordingly it has been proposed that GI classification of foods and drinks could be useful to help consumers make 'healthy food choices' within specific food groups. Classification of foods according to their impact on blood glucose responses requires a standardised way of measuring such responses. The present review discusses the most relevant methodological considerations and highlights specific recommendations regarding number of subjects, sex, subject status, inclusion and exclusion criteria, pre-test conditions, CHO test dose, blood sampling procedures, sampling times, test randomisation and calculation of glycaemic response area under the curve. All together, these technical recommendations will help to implement or reinforce measurement of GI in laboratories and help to ensure quality of results. Since there is current international interest in alternative ways of expressing glycaemic responses to foods, some of these methods are discussed.

Impact of postprandial glycaemia on health and prevention of disease

Postprandial glucose, together with related hyperinsulinemia and lipidaemia, has been implicated in the development of chronic metabolic diseases like obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). In this review, available evidence is discussed on postprandial glucose in relation to body weight control, the development of oxidative stress, T2DM, and CVD and in maintaining optimal exercise and cognitive performance. There is mechanistic evidence linking postprandial glycaemia or glycaemic variability to the development of these conditions or in the impairment in cognitive and exercise performance. Nevertheless, postprandial glycaemia is interrelated with many other (risk) factors as well as to fasting glucose. In many studies, meal-related glycaemic response is not sufficiently characterized, or the methodology with respect to the description of food or meal composition, or the duration of the measurement of postprandial glycaemia is limited. It is evident that more randomized controlled dietary intervention trials using effective low vs. high glucose response diets are necessary in order to draw more definite conclusions on the role of postprandial glycaemia in relation to health and disease. Also of importance is the evaluation of the potential role of the time course of postprandial glycaemia.

Reduced glycaemic and insulinaemic responses following trehalose and isomaltulose ingestion: implications for postprandial substrate use in impaired glucose-tolerant subjects

The impact of slowly digestible sugars in reducing the risk of developing obesity and related metabolic disorders remains unclear. We hypothesised that such carbohydrates (CHO), resulting in a lower glycaemic and insulinaemic response, may lead to greater postprandial fat oxidation rates in subjects with impaired glucose tolerance (IGT). The present study intends to compare the postprandial metabolic responses to the ingestion of glucose (GLUC) v. trehalose (TRE) and sucrose (SUC) v. isomaltulose (IMU). In a randomised, single-blind, cross-over design, ten overweight IGT subjects were studied four times, following ingestion of different CHO drinks either at breakfast or in combination with a mixed meal at lunch. Before and 3 h after CHO ingestion, energy expenditure, substrate utilisation and circulating metabolite concentrations were determined. Ingestion of CHO drinks with a meal resulted in an attenuated rise in GLUC (-33 %) and insulin (-14 %) concentrations following TRE when compared with GLUC and following IMU, an attenuation of 43 and 34 % when compared with SUC ingestion, respectively. Additionally, there was less inhibition of the rise in NEFA concentrations and less decline in postprandial fat oxidation (22 %) after IMU when compared with SUC, whereas TRE did not differ from GLUC. The attenuated rise in GLUC and insulin concentrations following IMU ingestion attenuated the postprandial inhibition of fat oxidation compared with SUC when co-ingested with a meal. This suggests that exchange of SUC in the diet for IMU may result in a more favourable metabolic response and may help to reduce the risks associated with obesity and type 2 diabetes.

Potentiation of the early-phase insulin response by a prior meal contributes to the second-meal phenomenon in type 2 diabetes

Improved glucose tolerance following a sequential meal is known as the second-meal phenomenon. We aimed to investigate its extent and underlying mechanisms in patients with type 2 diabetes. Metabolic responses after lunch in 12 diabetic patients were compared on two separate days: one with (Day BL) and another without (Day FL) breakfast. The responses of hormones were calculated by the incremental area under the curve (iAUC) values for 180 min after each meal. Indexes of early-phase insulin secretion were assessed, and β-cell function was estimated by mathematical modeling. [iAUC(glucose(180-360 min))] was significantly lower on Day BL than on Day FL (181 ± 43 vs. 472 ± 29 mmol·liter(-1)·min, P = 0.0005). The magnitude of the The second-meal phenomenon [iAUC(glucose(180-360 min)) on Day BL/Day FL] was 35 ± 9%. The peak levels of insulin and C-peptide were attained 45 min earlier after the second meal than after the first meal. iAUC(glucose(180-360 min)) correlated negatively with iAUC(insulin(180-210 min)) (r = -0.443, P = 0.0300), insulinogenic index (r = -0.769, P < 0.0001), acute C-peptide response (r = -0.596, P = 0.0021), and potentiation factor [i.e., potentiation effect on insulin secretion] ratio (180-360)/(0-20) (r = -0.559, P = 0.0045), while correlated positively with free fatty acid level before lunch (r = 0.679, P = 0.0003). The second-meal phenomenon was evident in patients with type 2 diabetes. Potentiation of the early-phase insulin response by a prior meal contributes to this phenomenon in type 2 diabetes.

Breakfast frequency and quality may affect glycemia and appetite in adults and children

Observational studies of breakfast frequency in children and adults suggest an inverse (protective) association between the frequency of eating breakfast and the risk for obesity and chronic diseases such as type 2 diabetes. More prospective studies with stronger designs are needed, as are experimental studies on this topic. In addition, above and beyond breakfast frequency, the roles of dietary quality and composition need to be studied in the context of eating or skipping breakfast. Experimental studies are also necessary to rigorously test causality and biological mechanisms. Therefore, we conducted 2 pilot experimental studies to examine some of the effects of breakfast skipping and breakfast composition on blood glucose and appetite in children and adults. Our results suggest that breakfast frequency and quality may be related in causal ways to appetite controls and blood sugar control, supporting the hypothesis that the breakfast meal and its quality may have important causal implications for the risk of obesity and type 2 diabetes.

Effects of PGX, a novel functional fibre, on acute and delayed postprandial glycaemia

Background:

Viscous fibre in food has established health benefits, but few functional fibre preparations are both effective and palatable. Our objective was to determine the most effective dose, formulation and timing of consumption of a novel fibre supplement (PolyGlycopleX (PGX)) in reducing postprandial glycaemia.

Subjects/methods:

Three trials were undertaken, each with 10 subjects (8M and 8F; age 24.4±2.6 years). Granular supplement was tested at four doses (0, 2.5, 5.0 and 7.5 g) with breakfast (study 1). Granular and capsule forms of the supplement were given in a single dose (5 g for granules and 4.5 g in capsules) at −60, −45, −30, −15 and 0 before, and +15 min after a bread meal (study 2). Capsules at increasing doses (1.5, 3, 4.5 and 6 g) were consumed with the evening meal to determine effects on glucose tolerance at breakfast (study 3). Incremental area under the blood glucose curve was determined.

Results:

Granular PGX at breakfast time at doses of 2.5, 5 and 7.5 g reduced the incremental area under the curve by up to 50% in a linear dose–response fashion (P<0.001). The granular form of PGX (5 g), but not the capsules, reduced glycaemia by up to 28% when consumed from −45 to +15 min (P<0.001). Capsules containing 3, 4.5 and 6 g PGX consumed with the evening meal reduced glycaemia at breakfast by up to 28% (P<0.001).

Conclusions:

PGX has biologically important, dose-related effects on acute and delayed (second meal) postprandial glycaemia.

Manipulation of glycemic response with isomaltulose in a milk-based drink does not affect cognitive performance in healthy adults

Previous research suggests that glucoregulation and nutrient interventions, which alter circulating glucose, impact cognitive function. To examine the effect of modulating glycemic response using isomaltulose on cognitive function 24 healthy male adult participants consumed energy and macronutrient-matched milk-based drinks containing 50 g isomaltulose, 50 g sucrose or a water control in a counterbalanced within-subject design. Interstitial glucose was measured continuously in 12 subjects and all provided 9 capillary measures on each test day. A 30-min cognitive test battery was administered before and twice (+35 and +115 min) after drink ingestion. Immediate, delayed, recognition, verbal and working memory, and psychomotor performance were assessed. Glycemic profiles induced by the drinks differed significantly during the first but not the second post-drink test battery. Neither administration of the sucrose nor isomaltulose drinks produced consistent effects on verbal or working memory, or psychomotor performance. This study used isomaltulose as an investigative tool to lower glycemic response. Importantly, it demonstrates a lack of effect of modulating glucose on cognitive performance based on reliable, continuously measured glycemia. It refutes the hypothesis that glycemia is associated with cognitive performance and questions the suggestion that isomaltulose has an effect on cognitive performance.

Association between eating frequency, weight, and health

There is speculation amongst health professionals, the media, and the public regarding eating frequency (EF) and its impact on weight and health. Nutritional weight-loss and -maintenance interventions of longer than 1 week's duration were reviewed for associations between EF and weight and health. Of the 176 studies identified, 25 relevant studies matched the criteria and only 10 of these were weight-loss interventions. Generally, sample sizes were small, interventions were short-term, and a wide array of definitions was used to define an eating occasion. Several key outcomes such as physical activity, adherence to assigned EF, and hunger were often not measured. The limited evidence available suggests there is no association between EF and weight or health in either weight-loss or -maintenance interventions, with a possible inverse association between EF and lipids in weight-maintenance interventions. Longer term, larger studies that include important weight and health outcomes are needed.

The effect of feeding frequency on insulin and ghrelin responses in human subjects

Recent work shows that increased meal frequency reduces ghrelin responses in sheep. Human research suggests there is an interaction between insulin and ghrelin. The effect of meal frequency on this interaction is unknown. Therefore, we investigated the effect of feeding frequency on insulin and ghrelin responses in human subjects. Five healthy male volunteers were recruited from the general population: age 24 (SEM 2)years, body mass 75.7 (SEM 3.2) kg and BMI 23.8 (SEM 0.8) kg/m(2). Volunteers underwent three 8-h feeding regimens: fasting (FAST); low-frequency(two) meal ingestion (LOFREQ(MEAL)); high-frequency (twelve) meal ingestion (HIFREQ(MEAL)). Meals were equi-energetic within trials,consisting of 64% carbohydrate, 23% fat and 13% protein. Total energy intake was equal between feeding trials. Total area under the curve for serum insulin and plasma ghrelin responses did not differ between trials (P>0.05), although the hormonal response patterns to the two meal feeding regimens were different. An inverse relationship was found between serum insulin and plasma ghrelin during the FAST andLOFREQ(MEAL) trials (P<0.05); and, in the postprandial period, there was a time delay between insulin responses and successive ghrelin responses.This relationship was not observed during the HIFREQ(MEAL) trial (P>0.05). This study provides further evidence that the postprandial fall in ghrelin might be due, at least partially, to the rise in insulin and that high-frequency feeding may disrupt this relationship.

Eating fast leads to insulin resistance: findings in middle-aged Japanese men and women

OBJECTIVE

To examine relationships between speed of eating and insulin resistance.

METHODS

Cross-sectional study of 2704 male (mean age and BMI: 48.2 y and 23.3 kg/m(2)) and 761 female (46.3 y and 21.8 kg/m(2)) non-diabetic Japanese civil servants, 75% clerical, and 25% manual laborers, using a two-part questionnaire on life-style factors and diet history with self-assessment of categorical speed of eating and energy intake over a 1-month period. We measured BMI, blood glucose and insulin concentrations and calculated insulin resistance using the homeostasis model assessment of insulin resistance: (HOMA-IR).

RESULTS

BMI correlated with eating rate in both sexes, and with daily energy intake in men. Multiple regression analysis of log HOMA-IR by categorical speed of eating, adjusting for age, energy intake and lifestyle factors showed a statistically significant gradual increase in HOMA-IR with increases in relative eating rate in men (p<0.001, for trend) and in women (p<0.01). Adjusting for BMI, this positive relationship appeared only in men (p=0.03).

CONCLUSIONS

Our results suggest that eating fast is independently associated with insulin resistance in middle-aged Japanese men and women.

Carbohydrate digestibility and metabolic effects

There is a history of interest in the metabolic effects of alterations in small intestinal digestion and colonic fermentation of carbohydrate. It is believed that the rate of digestion of carbohydrate determines the place and form in which carbohydrate is absorbed. Slowly absorbed or lente carbohydrate sources may reduce postprandial glucose surges and the need for insulin with important implications for lowering coronary heart disease risk and reducing diabetes incidence. Carbohydrates that are not digested in the small intestine will enter the colon, and those that are fermentable will be salvaged as short-chain fatty acids in the colon and at the same time may stimulate colonic microflora, such as bifidobacteria. This process may have metabolic effects in the gut and throughout the host, possibly related to short-chain fatty acid products, although these effects are less well documented. One important aspect of colonic fermentation is the stimulation of certain populations of the colonic microflora, which may assist in the biotransformation of bioactive food components including the cleaving of plant phenolics from their glycone to produce the more rapidly absorbed aglycone. However, human studies have been limited. Therefore, further studies are required to explore these important aspects of metabolism related to the rate of carbohydrate absorption and fermentation and their implications in health and disease.

Effects of sucromalt on postprandial responses in human subjects

BACKGROUND/OBJECTIVE

To compare postprandial responses elicited by sucromalt, a nutritive sweetener produced by treating a blend of sucrose and corn syrup with an enzyme from Leuconostoc mesenteroides, with those after 42% of high-fructose corn syrup (HFCS), and to see if the reduced responses after sucromalt could be accounted for by carbohydrate malabsorption.

SUBJECT AND METHODS

Three experiments were performed in separate groups of normal subjects studied after overnight fasts using double-blind, randomized, cross-over designs. HFCS was used as the control because it contained a similar amount of fructose as sucromalt. Experiment 1 (n = 10): plasma glucose and insulin were measured after 50 g sucromalt and 50 g HFCS. Experiment 2 (n = 10): metabolic profiles were measured after 80 g HFCS, 80 g sucromalt or 56 g fructose/glucose blend plus 24 g inulin. Experiment 3 (n = 20): the glycaemic indices of sucromalt and HFCS were determined.

RESULTS

Mean glucose and insulin responses after sucromalt were 66 and 62%, respectively, of those after HFCS (P < 0.05). The inulin treatment, used to mimic the effects of carbohydrate malabsorption, elicited higher breath hydrogen (H2), lower glucose and insulin responses, and a significantly earlier rise in serum free fatty acids (FFA) than those of HFCS (all P < 0.05). Sucromalt elicited no rise in breath H2, and delayed falls in glucose and insulin, and a delayed rebound of FFA compared to HFCS (all P < 0.05).

CONCLUSIONS

The reduced glucose and insulin responses elicited by sucromalt are not explained by malabsorption and are more likely related to differences in either rate of digestion and absorption or postabsorptive handling by body.

Use of sourdough lactobacilli and oat fibre to decrease the glycaemic index of white wheat bread

This work was aimed at decreasing the glycaemic index (GI) of white wheat bread. Breads made with wheat flour (WF) or wholemeal flour (WMF) and fermented with baker's yeast had similar values of resistant starch (RS; 1.4-1.7 %, starch basis). Sourdough Lactobacillus plantarum P1 and Lactobacillus brevis P2 favoured the highest formation of RS (approximately 5 %) when fermented with WF and WMF. The mixture (1:1) of WF and WMF (WF/WMF) was selected. The effect of dietary fibres, chemical or sourdough acidification on the hydrolysis index (HI) of WF/WMF bread was determined. Among fibres, only the addition of oat fibre (5 %) decreased the HI to 90.84 %. Lactic acid determined the lowest HI, and the effect was related to the decrease of pH. For the same decrease of pH, breads fermented with L. plantarum P1 and L. brevis P2 (sourdough WF/WMF) showed values of HI lower than chemical acidification. The glucose response and GI of WF bread or sourdough WF/WMF bread enriched with oat fibre was determined by using fifteen healthy volunteers. Anhydrous glucose was used as reference. The area under the glucose response curve and the value of GI (72 %) of WF bread were significantly (P < 0.05) higher than sourdough WF/WMF bread enriched with oat fibre (GI = 53.7 %). The decrease of GI of the sourdough WF/WMF bread may be due to both fibre content and decreased pH. Compared to WMF bread, sourdough WF/WMF bread, enriched with oat fibre, had higher specific volume, better cell crumb structure and more appreciated acidulous smell, taste and aroma.

[Association between dietary carbohydrates and type 2 diabetes mellitus: epidemiological evidence]

The prevalence of type 2 diabetes has been escalating throughout the world and usual food consumption is regarded as one of the most important environmental determinants for chronic diseases. Thus, the role of type and quality of carbohydrates on the etiology of type 2 diabetes is still poorly understood. The present review discusses the available epidemiological evidence regarding the effect of the type and source of carbohydrate of the usual diet and the risk of type 2 diabetes in adults. Although epidemiological investigations support the hypothesis for a potential risk effect of high glycemic index and low fiber content diets for diabetes, the results are controversial and the benefit may be related to the magnesium content of the structure of the grains, suggesting the relevance of taking into account the food sources instead of nutrients on investigations of diet and risk of chronic diseases. The available evidence suggests that eating a diet rich in whole grain cereals and vegetables and low in refined grains, sucrose and fructose contents is beneficial in the prevention of diabetes. Thus, more clinical trials are required to support the associations and establish biologically plausible pathways.

Eating fast leads to obesity: findings based on self-administered questionnaires among middle-aged Japanese men and women

BACKGROUND

Few epidemiologic studies have examined the association between the rate of eating and obesity. In this study, we cross-sectionally examined the association of the self-reported rate of eating with current Body Mass Index (BMI), and BMI-change from 20 years of age to the current age.

METHODS

Subjects were 3737 male (mean age +/- standard deviation and mean BMI +/- standard deviation: 48.2 +/- 7.1 years and 23.3 +/- 2.7 kg/m(2)) and 1005 female (46.3 +/- 7.0 years and 21.8 +/- 2.8 kg/m(2)) Japanese civil servants. We measured self-reported categorical rate of eating, current BMI, BMI at age 20, and BMI-change from age 20. Energy intake was assessed over a 1-month period with a brief-type diet history questionnaire.

RESULTS

The multiple regression analysis in which the current BMI was regressed by categorical rate of eating, energy intake, age, and lifestyle factors showed that current BMI steadily increased by -0.99, -0.67, 0.81, and 1.47 kg/m(2) along with the progress of categorical rate of eating from the 'medium' group to 'very slow', 'relatively slow', 'relatively fast', and 'very fast' groups, respectively, in men. In women, the corresponding values were -1.06, -0.35, 0.50, and 1.34 kg/m(2). When the BMI increment from age 20 to current age was regressed in the same manner, the increment was -0.63, -0.34, 0.57, and 1.05 kg/m(2) in men and -0.71, -0.32, 0.34, and 1.14 kg/m(2) in women, respectively. Additionally, both BMI at age 20 and current height were positively associated with rate of eating.

CONCLUSIONS

Our results among middle-aged men and women suggest that eating fast would lead to obesity.