Predicting mixed-meal measured glycaemic index in healthy subjects

Individual Postprandial Glycemic Responses to Meal Types by Different Carbohydrate Levels and Their Associations with Glycemic Variability Using Continuous Glucose Monitoring

This study aimed to investigate individual postprandial glycemic responses (PPGRs) to meal types with varying carbohydrate levels and examine their associations with 14-day glycemic variability using continuous glucose monitoring (CGM) in young adults. In a two-week intervention study with 34 participants connected to CGM, four meal types and glucose 75 g were tested. PPGRs were recorded for up to 2 h with a 15 min interval after meals. Data-driven cluster analysis was used to group individual PPGRs for each meal type, and correlation analysis was performed of 14-day glycemic variability and control with related factors. Participants had a mean age of 22.5 years, with 22.8% being male. Four meal types were chosen according to carbohydrate levels. The mean glucose excursion for all meal types, except the fruit bowl, exhibited a similar curve with attenuation. Individuals classified as high responders for each meal type exhibited sustained peak glucose levels for a longer duration compared to low responders, especially in meals with carbohydrate contents above 50%. A meal with 45% carbohydrate content showed no correlation with either 14-day glycemic variability or control. Understanding the glycemic response to carbohydrate-rich meals and adopting a meal-based approach when planning diets are crucial to improving glycemic variability and control.

Genotype specific starch characteristics in relation to resistant starch formation in table potatoes

Table potatoes are important staple foods with a higher satiety index than rice or pasta, but also reach a higher glycemic index (GI), leading to contradictory dietary recommendations. Previous studies identified resistant starch (RS) content as primary criterium for the GI. Hence, the relevance of starch molecular properties for genotype specific RS formation was investigated. Six common table potato varieties were used to investigate the starch pasting and digestibility in whole tubers and their isolated starches. A Micro-Visco Amylograph was used to simulate the cooking process for isolated starches and determine their pasting curves. In vitro starch digestibility was determined for raw freeze-dried cooked tubers kept at 4 °C for up to 72 h and for isolated starches. Moreover, important molecular starch properties, including granule size distribution, molar mass distribution, amylose content and inter- and intra-molecular structures were determined. The results show substantial differences in starch digestibility and pasting characteristics among genotypes. Soraya starch showed small and low-branched amylopectin and small granule size as characteristics for rapid RS formation in isolated starch, which was not evident in the whole tuber. In contrast, Huckleberry Gold formed RS in the tuber already shortly after cooking, whereas slow RS formation was evident in the isolated starch. The results suggest, that starch structural characteristics play a role in RS formation, but non-starch constituents of the tuber have to be considered as well. The results help to identify breeding goals for varieties with low GI and high nutritional value.

Dose-Dependent Associations of Dietary Glycemic Index, Glycemic Load, and Fiber With 3-Year Weight Loss Maintenance and Glycemic Status in a High-Risk Population: A Secondary Analysis of the Diabetes Prevention Study PREVIEW

OBJECTIVE

To examine longitudinal and dose-dependent associations of dietary glycemic index (GI), glycemic load (GL), and fiber with body weight and glycemic status during 3-year weight loss maintenance (WLM) in adults at high risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

In this secondary analysis we used pooled data from the PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World (PREVIEW) randomized controlled trial, which was designed to test the effects of four diet and physical activity interventions. A total of 1,279 participants with overweight or obesity (age 25-70 years and BMI ≥25 kg ⋅ m-2) and prediabetes at baseline were included. We used multiadjusted linear mixed models with repeated measurements to assess longitudinal and dose-dependent associations by merging the participants into one group and dividing them into GI, GL, and fiber tertiles, respectively.

RESULTS

In the available-case analysis, each 10-unit increment in GI was associated with a greater regain of weight (0.46 kg ⋅ year-1; 95% CI 0.23, 0.68; P < 0.001) and increase in HbA1c. Each 20-unit increment in GL was associated with a greater regain of weight (0.49 kg ⋅ year-1; 0.24, 0.75; P < 0.001) and increase in HbA1c. The associations of GI and GL with HbA1c were independent of weight change. Compared with those in the lowest tertiles, participants in the highest GI and GL tertiles had significantly greater weight regain and increases in HbA1c. Fiber was inversely associated with increases in waist circumference, but the associations with weight regain and glycemic status did not remain robust in different analyses.

CONCLUSIONS

Dietary GI and GL were positively associated with weight regain and deteriorating glycemic status. Stronger evidence on the role of fiber is needed.

Impact of processing techniques on the glycemic index of rice

Rice is an important starchy staple food and generally, rice varieties are known to have a higher glycemic index (GI). Over the years, the significance of GI on human health is being better understood and is known to be associated with several lifestyle disorders. Apart from the intrinsic characteristics of rice, different food processing techniques are known to have implications on the GI of rice. This work details the effect of domestic and industrial-level processing techniques on the GI of rice by providing an understanding of the resulting physicochemical changes. An attempt has been made to relate the process-dependent digestion behavior, which in turn reflects on the GI. The role of food constituents is elaborated and the various in vitro and in vivo approaches that have been used to determine the GI of foods are summarized. Considering the broader perspective, the effect of cooking methods and additives is explained. Given the significance of the cereal grain, this work concludes with the challenges and key thrust areas for future research.

Mens Sana in Corpore Sano: Does the Glycemic Index Have a Role to Play?

Although diet interventions are mostly related to metabolic disorders, nowadays they are used in a wide variety of pathologies. From diabetes and obesity to cardiovascular diseases, to cancer or neurological disorders and stroke, nutritional recommendations are applied to almost all diseases. Among such disorders, metabolic disturbances and brain function and/or diseases have recently been shown to be linked. Indeed, numerous neurological functions are often associated with perturbations of whole-body energy homeostasis. In this regard, specific diets are used in various neurological conditions, such as epilepsy, stroke, or seizure recovery. In addition, Alzheimer’s disease and Autism Spectrum Disorders are also considered to be putatively improved by diet interventions. Glycemic index diets are a novel developed indicator expected to anticipate the changes in blood glucose induced by specific foods and how they can affect various physiological functions. Several results have provided indications of the efficiency of low-glycemic index diets in weight management and insulin sensitivity, but also cognitive function, epilepsy treatment, stroke, and neurodegenerative diseases. Overall, studies involving the glycemic index can provide new insights into the relationship between energy homeostasis regulation and brain function or related disorders. Therefore, in this review, we will summarize the main evidence on glycemic index involvement in brain mechanisms of energy homeostasis regulation.

At a high dose even partially degraded beta-glucan with decreased solubility significantly reduced the glycaemic response to bread

Cereal beta-glucan can reduce post-prandial glycaemic responses, which makes it an interesting ingredient to improve the health impact of bread, a staple food with a high glycaemic index (GI). Here we compare the ability of different wheat-based breads prepared with oat bran concentrate and barley flour and a Norwegian type of soft wrap (lompe) for their ability to reduce glycaemic responses in healthy adults. Both breads with the highest beta-glucan content (3.8 g per serving) significantly reduced peak blood glucose rise (PBGR), incremental area under the blood glucose curve (iAUC) and GI compared to wheat control regardless of beta-glucan Mw and solubility. At a medium dose of 1.7 g per serving breads with beta-glucan of high MW and solubility significantly lowered iAUC, but not GI or PBGR compared to white bread. In contrast to previous studies, no significant correlation between viscosity after in vitro digestion and any of the glycaemia variables was found. However, the amount of soluble beta-glucan per serving was inversely correlated with GI. Lompe had a similar medium GI (63) than the high dose beta-glucan breads (56 and 64). However, while "lompe" had significantly lower amounts of rapidly digestible starch, no differences in in vitro starch digestion were found between the different breads. Instead, increased local viscosity at the intestinal border (e.g. soluble beta-glucan interacting with the mucus layer), dilution of nutrients (higher water content and serving size) and/or reduced gastric emptying are proposed as potential explanations for the lower glycaemic responses to high dose beta-glucan breads.

Subjective Satiety Following Meals Incorporating Rice, Pasta and Potato

The satiating capacity of carbohydrate staples eaten alone is dependent upon the energy density of the food but relative satiety when starchy staples are incorporated into mixed meals is uncertain. Our aim was to assess the satiating effects of three carbohydrate staples; jasmine rice, penne pasta, and Agria potato, each consumed within a standard mixed meal. Cooked portions of each staple containing 45 g carbohydrate were combined with 200 g of meat sauce and 200 g of mixed vegetables in three mixed meals. The quantities of staple providing 45 g carbohydrate were: Rice, 142 g; pasta, 138 g and potato 337 g. Participants (n = 14) consumed each of the mixed meals in random order on separate days. Satiety was assessed with using visual analogue scales at baseline and for 3 h post meal. In an area-under-the-curve comparison, participants felt less hungry (mean (SD)) following potato 263 (230) than following rice 374 (237) or pasta 444 (254) mm∙min, and felt fuller, more satisfied, and wanted to eat less following the potato compared with the rice and pasta meals (p for all <0.01). The superior satiating effect of potato compared with rice and pasta in a mixed meal was consistent with its lower energy density.