Impact of postprandial glycaemia on health and prevention of disease

Chronometabolism: The Timing of the Consumption of Meals Has a Greater Influence Than Glycemic Index (GI) on the Postprandial Metabolome

Eating late in the day is associated with circadian desynchrony, resulting in dysregulated metabolism and increased cardiometabolic disease risk. However, the underlying mechanisms remain unclear. Using targeted metabolomics of postprandial plasma samples from a secondary analysis of a randomised 2 × 2 crossover study in 36 healthy older Chinese adults, we have compared postprandial metabolic responses between high (HI) glycemic index (GI) or low-GI (LO) meals, consumed either at breakfast (BR) or at dinner (DI). 29 out of 234 plasma metabolites exhibited significant differences (p < 0.05) in postprandial AUC between BR and DI sessions, whereas only five metabolites were significantly different between HI and LO sessions. There were no significant interactions between intake timing and meal GI. Lower glutamine: glutamate ratio, lower lysine and higher trimethyllysine (TML) levels were found during DI compared with BR, along with greater postprandial reductions (δAUC) in creatine and ornithine levels during DI, indicating a worse metabolic state during the evening DI period. Greater reductions (δAUC) in postprandial creatine and ornithine were also observed during HI compared with LO (both p < 0.05). These metabolomic changes may indicate potential molecular signatures and/or pathways linking metabolic responses with cardiometabolic disease risk between different meal intake timings and/or meals with variable GI.

Dose-response efficacy of mulberry fruit extract for reducing post-prandial blood glucose and insulin responses: randomised trial evidence in healthy adults

Extracts of mulberry have been shown to reduce post-prandial glucose (PPG) and insulin (PPI) responses, but reliability of these effects and required doses and specifications are unclear. We previously found that 1·5 g of a specified mulberry fruit extract (MFE) significantly reduced PPG and PPI responses to 50 g carbohydrate as rice porridge, with no indications of intolerance. The trials reported here aimed to replicate that work and assess the efficacy of lower MFE doses, using boiled rice as the carbohydrate source. Two separate randomised controlled intervention studies were carried out with healthy Indian males and females aged 20-50 years (n 84 per trial), with PPG area under the curve over 2 h as the primary outcome. Trial 1 used doses of 0, 0·37, 0·75, 1·12 and 1·5 g MFE in boiled rice and 0 or 1·5 g MFE in rice porridge. Trial 2 used doses of 0, 0·04, 0·12, 0·37 g MFE in boiled rice. In trial 1, relative to control, all MFE doses significantly decreased PPG (-27·2 to -22·9 %; all P ≤ 0·02) and PPI (-34·6 to -14·0 %, all P < 0·01). Breath hydrogen was significantly increased only at 1·5 g MFE (in rice porridge), and self-reported gastrointestinal symptoms were uniformly low. In trial 2, only 0·37 g MFE significantly affected PPG (-20·4 %, P = 0·002) and PPI (-17·0 %, P < 0·001). Together, these trials show that MFE in doses as low as 0·37 g can reliably reduce PPG and PPI responses to a carbohydrate-rich meal, with no apparent adverse effects.

Essential Oils: Recent Advances on Their Dual Role as Food Preservatives and Nutraceuticals against the Metabolic Syndrome

Essential oils (EO) are compounds synthesized by plants as secondary products and are a complex mixture of volatile molecules. Studies have demonstrated their pharmacological activity in the prevention and treatment of metabolic syndrome (MetS). Moreover, they have been used as antimicrobial and antioxidant food additives. The first part of this review discusses the role of EO as nutraceuticals to prevent metabolic syndrome-related disorders (i.e., obesity, diabetes, and neurodegenerative diseases), showing results from in vitro and in vivo studies. Likewise, the second part describes the bioavailability and mechanisms of action of EO in preventing chronic diseases. The third part presents the application of EO as food additives, pointing out their antimicrobial and antioxidant activity in food formulations. Finally, the last part explains the stability and methods for encapsulating EO. In conclusion, EO dual role as nutraceuticals and food additives makes them excellent candidates to formulate dietary supplements and functional foods. However, further investigation is needed to understand EO interaction mechanisms with human metabolic pathways and to develop novel technological approaches to enhance EO stability in food systems to scale up these processes and, in this way, to overcome current health problems.

A New Approach to Personalized Nutrition: Postprandial Glycemic Response and its Relationship to Gut Microbiota

A prolonged and elevated postprandial glucose response (PPGR) is now considered a main factor contributing for the development of metabolic syndrome and type 2 diabetes, which could be prevented by dietary interventions. However, dietary recommendations to prevent alterations in PPGR have not always been successful. New evidence has supported that PPGR is not only dependent of dietary factors like the content of carbohydrates, or the glycemic index of the foods, but is also dependent on genetics, body composition, gut microbiota, among others. In recent years, continuous glucose monitoring has made it possible to establish predictions on the effect of different dietary foods on PPGRs through machine learning methods, which use algorithms that integrate genetic, biochemical, physiological and gut microbiota variables for identifying associations between them and clinical variables with aim of personalize dietary recommendations. This has allowed to improve the concept of personalized nutrition, since it is now possible to recommend through these predictions specific dietary foods to prevent elevated PPGRs that are highly variable among individuals. Additional components that can enrich the predictive algorithms are findings of nutrigenomics, nutrigenetics and metabolomics. Thus, this review aims to summarize the evidence of the components that integrate personalized nutrition focused on the prevention of PPGRs, and to show the future of personalized nutrition by laying the groundwork for the development of individualized dietary management and its impact on the improvement of metabolic diseases.

Obesity and overweight are linked to increased sodium-glucose cotransporter 1 and glucose transporter 5 levels in duodenum

OBJECTIVE

Prior evidence indicates that individuals with obesity have an accelerated intestinal glucose absorption. This cross-sectional study evaluated whether those with overweight or obesity display higher duodenal protein levels of the glucose carriers sodium-glucose cotransporter 1 (SGLT-1), glucose transporter 2 (GLUT-2), and glucose transporter 5 (GLUT-5).

METHODS

SGLT-1, GLUT-2, and GLUT-5 protein levels were assessed on duodenal mucosa biopsies of 52 individuals without diabetes categorized on the basis of their BMI as lean, with overweight, or with obesity.

RESULTS

Individuals with overweight and obesity exhibited progressively increased duodenal protein levels of SGLT-1 and GLUT-5 as compared with the lean group. Conversely, no differences in duodenal GLUT-2 abundance were found among the three groups. Univariate analysis showed that SGLT-1 and GLUT-5 protein levels were positively correlated with BMI, waist circumference, 1-hour post-load glucose, fasting and post-load insulin, and insulin secretion and resistance levels. Furthermore, a positive relationship was detected between intestinal GLUT-5 levels and serum uric acid concentrations, a product of fructose metabolism known to be involved in the pathogenesis of obesity and its complications.

CONCLUSIONS

Individuals with overweight and obesity display enhanced duodenal SGLT-1 and GLUT-5 abundance, which correlates with increased postprandial glucose concentrations, insulin resistance, and hyperinsulinemia.

Reproducibility and determinants of the metabolic responses during a mixed-meal tolerance test

OBJECTIVE

The aim of this study was to assess the reproducibility and physiological determinants of mixed-meal tolerance tests (MMTTs) on glucose and insulin responses.

METHODS

While inpatients on a weight-maintaining diet, 894 individuals (574 with normal and 267 with impaired glucose regulation and 53 with type 2 diabetes [T2D]) underwent 9-hour MMTTs (breakfast and lunch; 30% weight-maintaining diet each; 40% carbohydrate, 40% fat, and 20% protein). Total/incremental areas under the curve (AUC/iAUC) were calculated from MMTT plasma glucose/insulin concentrations. Acute insulin response (AIR) was quantified by intravenous glucose tolerance test and insulin action (M) via hyperinsulinemic-euglycemic clamp. A subset had repeat MMTTs (median follow-up = 1.4 years).

RESULTS

In individuals without T2D, for breakfast-versus-lunch reproducibility of glucose, AUCs were moderate (intraclass correlation coefficients [ICCs]: 0.44-0.61), and iAUCs were poor (ICCs < 0.15). For repeated MMTTs, reproducibility of AUC/iAUCs was low (ICCs: 0.11-0.36). For insulin, AUC reproducibility was high (ICCs > 0.70), and iAUCs were moderate (ICCs: 0.64-0.71). For repeated MMTTs, ICC AUC/iAUCs were 0.34 to 0.54. In those with T2D, ICC glucose AUC/iAUCs were >0.80 and >0.50, respectively, and for insulin were <0.40. For repeated MMTTs, ICC glucose/insulin AUC/iAUCs were moderate. Glucose AUCs associated with M/AIR (partial Rs < -0.25), and insulin AUCs negatively/positively associated with M/AIR (partial Rs = -0.51/0.24).

CONCLUSIONS

Reproducibility of glucose/insulin responses to MMTTs varied by subtraction of fasting values, glucose status, and time. Insulin secretion and action explained ~20% of MMTT responses. The substantial variability in MMTT response requires consideration in studies using MMTT outcomes.

Physically active men present a healthier cardiometabolic profile in response to a balanced meal compared to inactive men

PURPOSE

Post-meal cardiometabolic responses are critical for health, and may be influenced by physical activity. The objective of this study was to investigate the effect of habitual physical activity level on the metabolic, autonomic nervous system and cardiovascular responses to a balanced meal in healthy men.

METHODS

12 active and 12 inactive healthy males, matched for age and body composition, attended the laboratory in fasting condition. Participants were asked to sit quietly and comfortably in an armchair for the whole duration of the experiment (~ 2h30). Metabolic, autonomic nervous system and cardiovascular measurements were performed in fasting conditions, and at regular intervals until one hour after the end of a balanced breakfast.

RESULTS

No significant difference was observed between groups in glycaemia or energy expenditure throughout the experiment. Fat oxidation rate was significantly higher one-hour post-meal in active vs inactive men (Respiratory Quotient: 0.78 ± 0.04 vs 0.88 ± 0.03; p < 0.01). Heart rate was significantly lower in active compared to inactive individuals (p < 0.001) throughout the experiment and active participants displayed significantly enhanced vagal tone one-hour post-meal (square root of the sum of successive differences between adjacent normal R-R intervals squared: 72.4 ± 27.9 vs 46.4 ± 14.1 ms; p < 0.05).

CONCLUSION

In healthy men, habitual physical activity level seems discriminant to decipher specific profiles in terms of cardiometabolic responses to a meal. Overall, it may suggest pre-signal cardiometabolic impairments in healthy inactive individuals and highlight the need to consider primary prevention in inactive subjects as a key factor for health management.

Dietary treatment of type 1 diabetes: Beyond carbohydrate counting to fight cardiovascular risk

AIMS

Type 1 diabetes (T1D) is tied to an increased risk of cardiovascular morbidity and mortality. Dietary treatment would be an elective therapeutic strategy to fight this risk. However, it is not known what the best dietary approach is. We revisited the currently available literature on the nutritional treatment of T1D in the light of their potential comprehensive effects on the management of cardio-metabolic risk factors (body weight, fasting and postprandial glucose and lipid metabolism).

DATA SYNTHESIS

Nutritional research in T1D is mainly focused on blood glucose control, with most of the trials aiming at evaluating the acute effects of nutrients on postprandial glycemic response. The effects of the quantity and quality of nutrients and some specific foods on other metabolic risk factors have been explored mainly in cross-sectional analysis. Very few well-designed nutritional trials evaluated the best dietary approach to comprehensively manage cardiovascular risk by targeting along with blood glucose control, overweight, fasting and postprandial dyslipidemia. Therefore, the current best practice guidance for the dietary management of cardiovascular risk in T1D is generally based on evidence from patients with type 2 diabetes.

CONCLUSIONS

Well-conducted nutritional trials specifically designed for T1D are needed to identify the best dietary treatment to fight cardiovascular risk in these patients.

Glycemic Responses of Milk and Plant-Based Drinks: Food Matrix Effects

The consumption of food items containing digestible carbohydrates in food products leads to postprandial increases in blood glucose levels and glycemic responses. The extent to which these occur depends on many factors, including concentration and type of carbohydrate, but also other physicochemical properties of the food matrix, which determine the rate of uptake of monosaccharides into the bloodstream, including product structure and factors affecting gastric emptying. For milk, control of postprandial glycemic responses appears to be multifaceted, including a controlled rate of gastric emptying, a rate of glucose and galactose uptake into the bloodstream controlled by enzymatic hydrolysis, as well as stimulated insulin secretion to enhance uptake of blood glucose from the bloodstream. Altogether, this allows milk to deliver comparatively high levels of carbohydrate with limited glycemic responses. For plant-based drinks positioned as milk alternatives, however, compositional differences (including carbohydrate type and concentration) as well as matrix factors limiting control over gastric emptying and insulin secretion can, in some cases, lead to much stronger glycemic responses, which are undesirable in relation to non-communicable diseases, such as type-2 diabetes. This review discusses glycemic responses to milk and plant-based drinks from this perspective, focusing on mechanistic insights and food matrix effects.

Mining the A.E. Watkins Wheat Landrace Collection for Variation in Starch Digestibility Using a New High-Throughput Assay

Breeding for less digestible starch in wheat can improve the health impact of bread and other wheat foods. The application of forward genetic approaches has lately opened opportunities for the discovery of new genes that influence the digestibility of starch, without the burden of detrimental effects on yield or on pasta and bread-making quality. In this study we developed a high-throughput in vitro starch digestibility assay (HTA) for use in forward genetic approaches to screen wheat germplasm. The HTA was validated using standard maize and wheat starches. Using the HTA we measured starch digestibility in hydrothermally processed flour samples and found wide variation among 118 wheat landraces from the A. E. Watkins collection and among eight elite UK varieties (23.5 to 39.9% and 31.2 to 43.5% starch digested after 90 min, respectively). We further investigated starch digestibility in fractions of sieved wholemeal flour and purified starch in a subset of the Watkins lines and elite varieties and found that the matrix properties of flour rather than the intrinsic properties of starch granules conferred lower starch digestibility.

Nutritional benefits of sourdoughs: A systematic review

Food fermentation using sourdough-i.e., consortia of lactic bacteria and yeasts-is increasingly considered among the public as a natural transformation yielding nutritional benefits; however, it is unclear whether its alleged properties are validated by science. The aim of this study was to systematically review the clinical evidence related to the effect of sourdough bread on health. Bibliographic searches were performed in 2 different databases (The Lens and PubMed) up to February 2022. Eligible studies were randomized controlled trials involving adults, healthy or not, given any type of sourdough bread compared with those given any type of yeast bread. A total of 573 articles were retrieved and investigated, of which 25 clinical trials met the inclusion criteria. The 25 clinical trials included a total of 542 individuals. The main outcomes investigated in the retrieved studies were glucose response (N = 15), appetite (N = 3), gastrointestinal markers (N = 5), and cardiovascular markers (N = 2). Overall, it is currently difficult to establish a clear consensus with regards to the beneficial effects of sourdough per se on health when compared with other types of bread because a variety of factors, such as the microbial composition of sourdough, fermentation parameters, cereals, and flour types potentially influence the nutritional properties of bread. Nonetheless, in studies using specific strains and fermentation conditions, significant improvements were observed in parameters related to glycemic response, satiety, or gastrointestinal comfort after bread ingestion. The reviewed data suggest that sourdough has great potential to produce a variety of functional foods; however, its complex and dynamic ecosystem requires further standardization to conclude its clinical health benefits.

Effect of a High Protein Diet at Breakfast on Postprandial Glucose Level at Dinner Time in Healthy Adults

This study aimed to examine the effect of high protein breakfast diet with or without lunch on the postprandial glucose level during the day. A randomized, crossover design that recruited 12 healthy young participants (three men and nine women) was performed and four trials (normal breakfast + skipped lunch, high protein breakfast + skipped lunch, normal breakfast + lunch, and high protein breakfast + lunch) were conducted in two weeks. During each trial, breakfast, lunch, and dinner on the trial day, and dinner before the trial day, were provided as test meals, and the meal timing was fixed. Continuous glucose monitoring (CGM) was used to assess the blood glucose level during the whole experiment. Incremental area under the curve (iAUC) of the postprandial glucose level was calculated. The results suggested that compared with normal breakfast, high protein breakfast suppressed the 3 h iAUC of postprandial glucose level after breakfast (p < 0.05 or p < 0.0001) and 1.5 h iAUC after lunch (p < 0.01). During lunch, high protein breakfast diet suppressed the dinner and overall day postprandial glucose level (p < 0.05 vs. normal breakfast), but no significant difference was observed when skipping lunch. Our findings indicate that high protein breakfast could suppress the breakfast postprandial glucose level, as well as following lunch and dinner, but this effect on dinner was attenuated when skipping lunch.

Testing the Utility of Polygenic Risk Scores for Type 2 Diabetes and Obesity in Predicting Metabolic Changes in a Prediabetic Population: An Observational Study

Prediabetes is an intermediate state of hyperglycemia during which glycemic parameters are above normal levels but below the T2D threshold. T2D and its precursor prediabetes affect 6.28% and 7.3% of the world’s population, respectively. The main objective of this paper was to create and compare two polygenic risk scores (PRSs) versus changes over time (Δ) in metabolic parameters related to prediabetes and metabolic complications. The genetics of 446 prediabetic patients from the Polish Registry of Diabetes cohort were investigated. Seventeen metabolic parameters were measured and compared at baseline and after five years using statistical analysis. Subsequently, genetic polymorphisms present in patients were determined to build a T2D PRS (68 SNPs) and an obesity PRS (21 SNPs). Finally, the association among the two PRSs and the Δ of the metabolic traits was assessed. After a multiple linear regression with adjustment for age, sex, and BMI at a nominal significance of (p < 0.05) and adjustment for multiple testing, the T2D PRS was found to be positively associated with Δ fat mass (FM) (p = 0.025). The obesity PRS was positively associated with Δ FM (p = 0.023) and Δ 2 h glucose (p = 0.034). The comparison of genotype frequencies showed that AA genotype carriers of rs10838738 were significantly higher in Δ 2 h glucose and in Δ 2 h insulin. Our findings suggest that prediabetic individuals with a higher risk of developing T2D experience increased Δ FM, and those with a higher risk of obesity experience increased Δ FM and Δ two-hour postprandial glucose. The associations found in this research could be a powerful tool for identifying prediabetic individuals with an increased risk of developing T2D and obesity.

Influence of oral processing behaviour and bolus properties of brown rice and chickpeas on in vitro starch digestion and postprandial glycaemic response

PURPOSE

Oral processing behaviour may contribute to individual differences in glycaemic response to foods, especially in plant tissue where chewing behaviour can modulate release of starch from the cellular matrix. The aim of this study was to assess the impact of chewing time of two starch based foods (brown rice and chickpeas) on bolus properties, in vitro starch digestion and postprandial glycaemic excursion in healthy subjects.

METHODS

In a cross-over trial participants (n = 26) consumed two carbohydrates-identical test meals (brown rice: 233 g; chickpeas: 323 g) with either long (brown rice: 41 s/bite; chickpeas: 37 s/bite) or short (brown rice: 23 s/bite; chickpeas: 20 s/bite) chewing time in duplicate while glycaemic responses were monitored using a continuous glucose monitoring device. Expectorated boli were collected, then bolus properties (number, mean area, saliva amylase activity) and in vitro starch digestion were determined.

RESULTS

Longer chewing resulted in significantly (p < 0.05) more and smaller bolus particles, higher bolus saliva uptake and higher in vitro degree of intestinal starch hydrolysis (DH_Schewing time%) than shorter chewing for both foods (brown rice: DH_S%23 s = 84 ± 4% and DH_%S41s = 90 ± 6%; chickpeas: DH_S%20 s = 27 ± 3% and DH_%S37s = 34 ± 5%, p < 0.001). No significant effect of chewing time on glycaemic response (iAUC) (p > 0.05) was found for both meals. Brown rice showed significantly and considerably higher in vitro degree of intestinal starch hydrolysis and glycaemic response (iAUC) than chickpeas regardless of chewing time. No significant correlations were observed between bolus properties and in vitro starch hydrolysis or glycaemic response (p > 0.05).

CONCLUSION

Differences in the innate structure of starch based foods (brown rice compared to chickpeas) have a larger effect on postprandial glucose response than differences in mastication behaviour although oral processing behaviour showed consistent effects on bolus properties and in vitro starch digestion. Trial registration ClinicalTrials.gov identifier: NCT04648397 (First posted: December 1, 2020).

Mechanistic Understanding of the Effects of Pectin on In Vivo Starch Digestion: A Review

Obesity and type II diabetes are closely related to the rapid digestion of starch. Starch is the major food-energy source for most humans, and thus knowledge about the regulation of starch digestion can contribute to prevention and improved treatment of carbohydrate metabolic disorders such as diabetes. Pectins are plant polysaccharides with complex molecular structures and ubiquitous presence in food, and have diverse effects on starch digestion. Pectins can favorably regulate in vivo starch digestion and blood glucose level responses, and these effects are attributed to several reasons: increasing the viscosity of digesta, inhibiting amylase activity, and regulating some in vivo physiological responses. Pectins can influence starch digestion via multiple mechanisms simultaneously, in ways that are highly structure-dependent. Utilizing the multi-functionalities of pectin could provide more ways to design low glycemic-response food and while avoiding the unpalatable high viscosity in food by which is commonly caused by many other dietary fibers.

Bioactive Yoghurt Containing Curcumin and Chlorogenic Acid Reduces Inflammation in Postmenopausal Women

Menopause is marked by a gradual and permanent decrease of estrogen from the ovaries, leading to metabolic and physiological changes in the body. Combined with increased body mass index, postmenopausal women have elevated systemic inflammation and metabolic disturbances leading to increased risk of developing chronic diseases. A bioactive coconut yoghurt containing curcumin and chlorogenic acid was developed with the potential to target inflammatory processes. In this randomized crossover study, healthy postmenopausal women with a BMI of 25–40 were recruited to consume 125 g of either the bioactive or placebo yoghurt. Blood samples were collected at baseline, 30 min, and 1, 2, 3 and 4 h postprandially. Plasma inflammatory markers (TNFα and IL6) and metabolic markers (triglycerides, insulin and glucose) were measured. Participants had significantly lower plasma TNFα Cmax after consumption of the bioactive yoghurt compared to placebo (mean difference = 0.3 pg/mL; p = 0.04). Additionally, plasma TNFα was significantly lower postprandially compared to baseline after consumption of the bioactive yogurt but not the placebo. No differences were observed in the metabolic markers measured. Conclusions: The bioactive yoghurt fortified with curcumin and chlorogenic acid has the potential to reduce inflammatory mediators; however, a larger and longer-term study is required to confirm these findings.

L-arabinose co-ingestion delays glucose absorption derived from sucrose in healthy men and women: a double-blind, randomised crossover trial

Dietary interventions to delay carbohydrate digestion or absorption can effectively prevent hyperglycaemia in the early postprandial phase. L-arabinose can specifically inhibit sucrase. It remains to be assessed whether co-ingestion of L-arabinose with sucrose delays sucrose digestion, attenuates subsequent glucose absorption and impacts hepatic glucose output. In this double-blind, randomised crossover study, we assessed blood glucose kinetics following ingestion of a 200-ml drink containing 50 g of sucrose with 7·5 g of L-arabinose (L-ARA) or without L-arabinose (CONT) in twelve young, healthy participants (24 ± 1 years; BMI: 22·2 ± 0·5 kg/m²). Plasma glucose kinetics were determined by a dual stable isotope methodology involving ingestion of (U-¹³C₆)-glucose-enriched sucrose, and continuous intravenous infusion of (6,6-²H₂)-glucose. Peak glucose concentrations reached 8·18 ± 0·29 mmol/l for CONT 30 min after ingestion. In contrast, the postprandial rise in plasma glucose was attenuated for L-ARA, because peak glucose concentrations reached 6·62 ± 0·18 mmol/l only 60 min after ingestion. The rate of exogenous glucose appearance for L-ARA was 67 and 57 % lower compared with CONT at t = 15 min and 30 min, respectively, whereas it was 214 % higher at t = 150 min, indicating a more stable absorption of exogenous glucose for L-ARA compared with CONT. Total glucose disappearance during the first hour was lower for L-ARA compared with CONT (11 ± 1 v. 17 ± 1 g, P < 0·0001). Endogenous glucose production was not differentially affected at any time point (P = 0·27). Co-ingestion of L-arabinose with sucrose delays sucrose digestion, resulting in a slower absorption of sucrose-derived glucose without causing adverse effects in young, healthy adults.

Sri Lankan traditional parboiled rice: A panacea for hyperglycaemia?

The research aimed to scientifically prove that parboiled Sri Lankan traditional rice elicits lower glycaemic responses comparative to raw unpolished or polished rice. Thus the proximate composition and glycaemic indices (GI) of raw, raw polished, and parboiled traditional Sri Lankan rice (Oryza sativa L.) varieties Godaheenati, Batapola el, Dik wee, Dahanala, Unakola samba, and Hangimuththan were studied as comparative data are not available. Cooked parboiled rice contained significantly high moisture (P<0.05) than raw or raw polished. Mineral content was low (<1.5%) regardless of processing. Crude protein was comparatively high (5.8–11.0% DM) with 2.1–5% (DM) fat with raw unpolished and parboiled having higher contents. Digestible starch of raw polished was highest compared to parboiled or raw unpolished (68.8–90.5% DM). Resistant starch was significantly (P<0.05) high in parboiled rice (1.1–7.2%) with the least total dietary fibre in raw polished rice. All varieties of parboiled and raw polished were found to elicit low GI and high GI respectively. High moisture, high resistant starch, and low starch in cooked parboiled rice contributed to low GI compared to raw unpolished or raw polished rice.

Short-Term Effects of Traditional Greek Meals: Lentils with Lupins, Trahana with Tomato Sauce and Halva with Currants and Dried Figs on Postprandial Glycemic Responses-A Randomized Clinical Trial in Healthy Humans

Low glycemic index (GI) diets have been associated with decreased chronic disease risk. In a randomized, cross-over study we investigated the GI and glycemic response to three traditional Greek mixed meals: Lentils, Trahana, and Halva. Twelve healthy, fasting individuals received isoglucidic test meals (25 g available carbohydrate) and 25 g glucose reference, in random order. GI was calculated and capillary blood glucose (BG) samples were collected at 0-120 min after meal consumption. Subjective appetite ratings were assessed. All three tested meals provided low GI values. Lentils GI was 27 ± 5, Trahana GI was 42 ± 6, and Halva GI was 52 ± 7 on glucose scale. Peak BG values were lowest for Lentils, followed by Trahana and then by Halva (p for all <0.05). Compared to the reference food, BG concentrations were significantly lower for all meals at all time-points (p for all <0.05). Lentils provided lower glucose concentrations at 30 and 45 min compared to Trahana (p for all <0.05) and at 30, 45, and 60 min compared to Halva (p for all <0.05). BG concentrations did not differ between Trahana and Halva at all time points. No differences were observed for fasting BG, time to peak rise for BG, and subjective appetite ratings. In conclusion, all three mixed meals attenuated postprandial glycemic response in comparison to glucose, which may offer advantages to glycemic control.

The association of Carbohydrate Quality Index with cardiovascular disease risk factors among women with overweight and obesity: A cross-sectional study

Purpose

Diet is one of the most important factors influencing cardiovascular disease (CVD). The negative relationship between carbohydrate intake with lipid profiles and body weight has been previously investigated. However, this is the first study seeking to assess the association of carbohydrate quality index (CQI) with CVD risk factors.

Methods

This cross-sectional study was conducted on 291 Iranian overweight and obese women, with a body mass index (BMI) ranging between 25 and 40 kg/m², and aged 18–48 years. CQI scores were calculated by using a validated 168-item semi-quantitative food frequency questionnaire (FFQ). Biochemical and anthropometric measures were assessed using standard methods, and bioelectrical impedance was used to measure body composition.

Results

We observed that fruits (P < 0.001), vegetables (P < 0.001), and protein (P = 0.002) intake were higher in participants with a higher score of the CQI. When we adjusted for potential confounders, we observed that the CQI was negatively related to systolic blood pressure (SBP) (β = −6.10; 95% CI = −10.11, −2.10; P = 0.003) and DBP (β = −3.11; 95% CI = −6.15, −0.08; P = 0.04). Also, greater adherence to a high CQI dietary pattern, compared to the reference group, was negatively related to HOMA-IR (β = −0.53; 95% CI = −0.94, −0.12) (P for trend = 0.01), WC (β = −3.18; 95% CI = −6.26, −0.10) (P for trend = 0.04), BMI (β = −1.21; 95% CI = −2.50, 0.07) (P for trend = 0.06), and BF (β = −2.06; 95% CI = −3.82, −0.30) (P for trend = 0.02).

Conclusion

In line with previous studies, the CQI was inversely associated with blood pressure, WC, BMI, and BF. Further prospective and clinical trial studies are suggested to confirm these data.

Maternal diabetes negatively impacts fetal health

Diabetes is a chronic metabolic disease affecting an increasing number of people. Although diabetes has negative health outcomes for diagnosed individuals, a population at particular risk are pregnant women, as diabetes impacts not only a pregnant woman's health but that of her child. In this review, we cover the current knowledge and unanswered questions on diabetes affecting an expectant mother, focusing on maternal and fetal outcomes.

Postprandial glycemic and circulating SCFA concentrations following okara- and biovalorized okara-containing biscuit consumption in middle-aged and older adults: a crossover randomized controlled trial

Okara is a high-fiber food by-product that can be biotransformed with Rhizopus oligosporus to improve its nutritional value and palatability. This research aims to assess postprandial changes in glycemic-related and lipid-related outcomes in middle-aged and older Singaporeans following okara- and biovalorized okara-containing biscuit consumption. Fifteen participants (58 ± 6 years old, mean ± SD) completed the randomized crossover study. Participants were provided control (C), okara (AOK)-, and biovalorized okara (RO)-containing biscuits in separate 4 h mixed meal tolerance tests. Serum glucose and insulin, insulin indices, serum short-chain fatty acids (SCFA) and lipid-lipoprotein panels, and sensory analysis were assessed. Glucose-stimulated insulin secretion was significantly lower for RO than for C (p: 0.035) while log insulin incremental area under the curve (AUC) was significantly lower for AOK compared to that for C (p: 0.023). The estimated insulin sensitivity index and estimated metabolic clearance rate were significantly higher for AOK compared to that for C (p: 0.025 and 0.016 respectively). Normalized AUC for total SCFA was significantly higher for RO compared to that for C (p: 0.038). Normalized AUC for LDL-cholesterol was significantly higher for AOK than for C (p: 0.010). No significant difference was noted for glucose, total cholesterol, HDL-cholesterol, and triglyceride concentrations. RO had greater flavor and overall liking than AOK (p: 0.007 and 0.017 respectively). Biscuits incorporated with okara or biovalorized okara can attenuate postprandial insulin responses. RO offered a greater SCFA response than C, indicating improved SCFA concentrations upon consumption of okara improved with fermentation. The trial was registered under https://www.clinicaltrials.gov (NCT03978104, 25 May 2019).

The impact of glycaemic load on cognitive performance: A meta-analysis and guiding principles for future research

The effect of breakfast glycaemic load (GL) on cognition was systematically examined. Randomised and non-randomised controlled trials were identified using PubMed, Scopus, and Cochrane Library (up to May 2022). 15 studies involving adults (aged 20 - 80 years) were included. Studies had a low risk, or some concerns, of bias. A random-effects meta-analysis model revealed no effect of GL on cognition up to 119 min post-consumption. However, after 120 min, immediate episodic memory scores were better following a low-GL compared to a high-GL (SMD = 0.16, 95% confidence interval [CI] = -0.00 to 0.32, p = 0.05, I2 = 5%). Subgroup analyses indicated that the benefit was greater in younger adults (<35 years) and those with better GT. A qualitative synthesis of 16 studies involving children and adolescents (aged 5 - 17 years) suggested that a low-GL breakfast may also benefit episodic memory and attention after 120 min. Methodological practises were identified which could explain a failure to detect benefits in some studies. Consequently, guiding principles were developed to optimise future study design.

Comparative Effects of Co-Ingesting Whey Protein and Glucose Alone and Combined on Blood Glucose, Plasma Insulin and Glucagon Concentrations in Younger and Older Men

The ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycemia, but its effect in older people, who have an increased predisposition for type 2 diabetes, has not been clarified. Blood glucose, plasma insulin and glucagon concentrations were measured for 180 min following a drink containing either glucose (120 kcal), whey-protein (120 kcal), whey-protein plus glucose (240 kcal) or control (~2 kcal) in healthy younger (n = 10, 29 ± 2 years; 26.1 ± 0.4 kg/m2) and older men (n = 10, 78 ± 2 years; 27.3 ± 1.4 kg/m2). Mixed model analysis was used. In both age groups the co-ingestion of protein with glucose (i) markedly reduced the increase in blood glucose concentrations following glucose ingestion alone (p < 0.001) and (ii) had a synergistic effect on the increase in insulin concentrations (p = 0.002). Peak insulin concentrations after protein were unaffected by ageing, whereas insulin levels after glucose were lower in older than younger men (p < 0.05) and peak insulin concentrations were higher after glucose than protein in younger (p < 0.001) but not older men. Glucagon concentrations were unaffected by age. We conclude that the ability of whey-protein to reduce carbohydrate-induced postprandial hyperglycemia is retained in older men and that protein supplementation may be a useful strategy in the prevention and management of type 2 diabetes in older people.

Monitoring the effect of cell wall integrity in modulating the starch digestibility of durum wheat during different steps of bread making

Reduction of starch digestibility in starchy foods is beneficial for lowering the risks for major non-communicable diseases. Preserving cell integrity is known to delay starch digestibility in flour but its effect in bread is not clear. In this study, the effect of increasing particle size on in vitro starch digestibility of durum wheat flour, dough, and bread was investigated. Cell integrity was retained during bread processing for medium (1000 µm-1800 µm), and large (>1800 µm) flour, whereas in small one cell walls were mostly damaged (<350 µm). In vitro starch digestibility of flour decreased increasing particle size, but no difference was found in dough. In bread, instead, a modest decrease of starch digestibility for the bread made by large particle was observed, likely due to its dense structure. In conclusion, a high particle size could limit starch digestibility in durum wheat flour but not in bread.

Effect of Different Nutritional Supplements on Glucose Response of Complete Meals in Two Crossover Studies

Postprandial hyperglycemia is an important risk factor in the development and progression of type-2 diabetes and cardiometabolic diseases. Therefore, maintaining a low postprandial glucose response is key in preventing these diseases. Carbohydrate-rich meals are the main drivers of excessive glycemic excursions during the day. The consumption of whey protein premeals or mulberry leaf extract was reported to reduce postprandial glycemia through different mechanisms of action. The efficacy of these interventions was shown to be affected by the timing of the consumption or product characteristics. Two randomised crossover studies were performed, aiming to identify the optimal conditions to improve the efficacy of these nutritional supplements in reducing a glycemic response. The acute postprandial glycemic response was monitored with a continuous glucose monitoring device. The first study revealed that a preparation featuring 10 g of whey protein microgel reduced the postprandial glucose response by up to 30% (p = 0.001) and was more efficient than the whey protein isolates, independently of whether the preparation was ingested 30 or 10 min before a complete 320 kcal breakfast. The second study revealed that a preparation featuring 250 mg mulberry leaf extract was more efficient if it was taken together with a complete 510 kcal meal (−34%, p < 0.001) rather than ingested 5 min before (−26%, p = 0.002). These findings demonstrate that the efficacy of whey proteins premeal and mulberry leaf extracts can be optimised to provide potential nutritional solutions to lower the risk of type-2 diabetes or its complications.

Diets high in glycemic index and glycemic load are associated with an increased risk of metabolic syndrome among Korean women

BACKGROUND AND AIMS

Accurate estimation of the glycemic index (GI) and glycemic load (GL) of diets is essential when assessing health implications of dietary GI and GL. The present study aimed to estimate dietary GI and GL utilizing the updated GI tables with a large number of new, reliable GI values and assess their associations with metabolic syndrome among Korean adults.

METHODS AND RESULTS

We analyzed data from 3317 men and 6191 women for this cross-sectional study. Dietary intake was assessed with a validated food frequency questionnaire. Metabolic syndrome and its components were defined based on the harmonized criteria with Korean-specific cutoffs for waist circumference. Multivariate logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Compared with women in the lowest quintiles of energy-adjusted dietary GI and GL, women in the highest quintiles had significantly greater risks of metabolic syndrome (GI, OR = 1.56, 95% CI = 1.18-2.06; GL, OR = 1.80, 95% CI = 1.27-2.57), elevated blood pressure, reduced high-density lipoprotein cholesterol (HDL-C, both GI and GL), elevated triglycerides (GI only), elevated waist circumference, and elevated fasting glucose (GL only). Among men, no significant association was noted except for a higher risk of reduced HDL-C (OR = 1.59, 95% CI = 1.01-2.29) in the highest quintile of energy-adjusted dietary GI than in the lowest quintile.

CONCLUSION

Our findings suggest that dietary GI and GL are positively associated with metabolic syndrome risk among women, but not men, in Korea.

Habitual- and Meal-Specific Carbohydrate Quality Index and Their Relation to Metabolic Syndrome in a Sample of Iranian Adults

Aim

Most studies on diet quality have focused on the habitual and overall intake of foods without considering intakes at specific eating occasions. This study aimed to assess the association between habitual- and meal-specific carbohydrate quality index (CQI) and metabolic syndrome (MetS) in Iranian adults.

Methods

In this cross-sectional study, data from 850 participants were analyzed. Dietary information was obtained from a 3-day nonconsecutive 24 h recall. CQI was calculated from three criteria: dietary fiber, glycemic index, and solid carbohydrate/total carbohydrate ratio. The association between CQI and MetS was assessed by logistic regression.

Results

The prevalences of MetS in the lowest and highest tertile of CQI were 30.1 and 33.7, respectively (P = 0.6). In habitual diet and all the three meals, we failed to find any significant association between tertiles of CQI and MetS either before or after adjustment for covariates. However, in the habitual meals [odds ratio (OR): 0.69, 95% CI: 0.47–0.96] and lunch meals (OR: 0.66; 95% CI: 0.47–0.94), the highest CQI in comparison to the lowest one, significantly decreased the low high-density lipoprotein (HDL). In addition, the trend of low-HDL with CQI in habitual meal and lunch meal was statistically significant.

Conclusion

The results of this study showed that CQI was not associated with MetS and its components. Further investigations into the mechanisms underlying the role of carbohydrate quality in developing metabolic disorders are warranted.

Postprandial Glycemic Dips Are Associated With Metabolic Disorders and CVD Risk in Euglycemic Individuals

CONTEXT

Metabolic disorders and cardiovascular disease (CVD) threaten human health. Many studies have assessed the phenomenon of metabolic disorders and CVD in patients with diabetes. However, in euglycemic individuals, the relationships between glucose regulation, metabolism, and CVD remain unclear.

OBJECTIVE

This work aimed to explore the associations between postprandial glucose dips, metabolic disorders, and CVD risk.

METHODS

We analyzed data from the Thyroid disorders, Iodine status and Diabetes Epidemiological survey (TIDE study), which included 38 878 euglycemic individuals from all 31 provinces of mainland China. The prevalence of metabolic disorders and their related components and CVD risk were calculated according to postprandial glucose dips. Logistic regression models of quartiles of postprandial glucose dips were used to further explore whether the prevalence of these disorders was associated with postprandial glucose dips.

RESULTS

Odds ratios for the fourth vs the first quartile of glucose dips were 0.59 (95% CI, 0.55-0.63) (P < .001) for metabolic disorders, 0.48 (95% CI 0.44-0.53) (P < .001) for metabolic syndrome (MetS), and 0.54 (95% CI, 0.50-0.59) (P < .001) for hyperuricemia. The odds ratio of a 10-year CVD risk greater than 20% for the fourth vs the first glucose dip quartile was 0.67 (95% CI, 0.52-0.85) (P < .001). Models adjusted for body mass index yielded similar results.

CONCLUSION

Postprandial glucose dips are associated with metabolic disorders, MetS and its related component diseases, and CVD risk. Glucose dips may be a marker of underlying metabolic abnormalities.

Significance of Postprandial Insulin and Triglycerides to Evaluate the Metabolic Response of Composite Meals Differing in Nutrient Composition – A Randomized Cross-Over Trial

Background and aims

GlucoTRIG, based on postprandial plasma insulin and triglyceride concentrations, has been recently developed as a novel index to determine the postprandial metabolic response to the meals. This study aimed to test GlucoTRIG as a measure for ranking composite meals for their metabolic effects.

Methods

In a randomized cross-over trial, healthy adult volunteers (both males and females; n = 10 for each meal) consumed three is caloric (2000 kj) test meals (meal 1, meal 2, meal 3) of varying macronutrient composition. Postmeal consumption, venous blood samples were collected to determine plasma insulin and plasma triglycerides for estimating the GlucoTRIG value using (Triglycerides_180min × Insulin_180min) - (Triglycerides_0min × Insulin_0min).

Results

The GlucoTRIG values differed significantly (p = 0.0085) across meals. The statistical significance remains even after adjusting for confounding variables such as baseline diet, insulin, and triglycerides. The meal (M3) with a high fiber, low total fat content and containing less refined foods (fruits, beans, vegetables, plain yogurt) exhibited a significantly (p = 0.007) lower GlucoTRIG value (10 ± 7.7) compared to the other two meals, M1 (77 ± 19.8) and M2 (38 ± 12.1) which contained low processed foods, and were relatively high in fat and low in fiber meals. No statistically significant differences were observed between M1 and M2 meal.

Conclusions

GlucoTRIG is a physiologically based index that may be useful to rank composite meals for reducing the risk of metabolic diseases. Further research focusing on the application of GlucoTRIG to foods, meals, and diets is warranted.

ACTRN12619000973112 (Australian New Zealand Clinical Trials Registry, ANZCTR).

Associations Between Device-Measured Physical Activity and Glycemic Control and Variability Indices Under Free-Living Conditions

Background: Disturbances of glycemic control and large glycemic variability have been associated with increased risk of type 2 diabetes in the general population as well as complications in people with diabetes. Long-term health benefits of physical activity are well documented but less is known about the timing of potential short-term effects on glycemic control and variability in free-living conditions. Materials and Methods: We analyzed data from 85 participants without diabetes from the Food & You digital cohort. During a 2-week follow-up, device-based daily step count was studied in relationship to glycemic control and variability indices using generalized estimating equations. Glycemic indices, evaluated using flash glucose monitoring devices (FreeStyle Libre), included minimum, maximum, mean, standard deviation, and coefficient of variation of daily glucose values, the glucose management indicator, and the approximate area under the sensor glucose curve. Results: We observed that every 1000 steps/day increase in daily step count was associated with a 0.3588 mg/dL (95% confidence interval [CI]: -0.6931 to -0.0245), a 0.0917 mg/dL (95% CI: -0.1793 to -0.0042), and a 0.0022% (95% CI: -0.0043 to -0.0001) decrease in the maximum glucose values, mean glucose, and in the glucose management indicator of the following day, respectively. We did not find any association between daily step count and glycemic indices from the same day. Conclusions: Increasing physical activity level was linked to blunted glycemic excursions during the next day. Because health-related benefits of physical activity can be long to observe, such short-term physiological benefits could serve as personalized feedback to motivate individuals to engage in healthy behaviors.

New styrylquinoxaline: synthesis, structural, biological evaluation, ADMET prediction and molecular docking investigations

The organic compound (E)-3-(4-methylstyryl)quinoxalin-2(1H)-one (SQO) with molecular formula C₁₇H₁₄N₂O was synthesized and analyzed using single crystal X-ray diffraction, ¹H, ¹³C NMR and FTIR spectroscopic techniques. The geometric parameters of the molecule was optimized by density-functional theory (DFT) choosing B3LYP with 6-31++G(d,p) basis set. For compatibility, the theoretical structure and experimental structure were overlapped with each other. Frontier molecular orbitals of the title compound were made, and energy gap between HOMO and LUMO was calculated. Molecular electrostatic potential map was generated finding electrophilic and nucleophilic attack centers using DFT method. Hirshfeld surface analysis (HSA) confirms active regions at the circumference of N1 atoms and O1 atoms that form intermolecular N1-H1···O1 hydrogen bond. The acute oral toxicity study was carried out according to OECD guideline, which approve that the compound SQO was non-toxic. In addition, this quinoxaline derivative was evaluated for its in vitro antidiabetic activity against α-glucosidase and α-amylase enzymes and for antioxidant activity by utilizing several tests as 1,1-diphenyl-2-picryl hydrazyl, (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonicacid), reducing power test (FRAP) and hydrogen peroxide activity H₂O₂. The molecular docking studies were performed to investigate the antidiabetic activity of SQO and compared with the experimental results. SQO is a potent antidiabetic from both the experimental and molecular docking results. Finally, the physicochemical, pharmacokinetic and toxicological properties of SQO have been evaluated by using in silico absorption, distribution, metabolism, excretion and toxicity analysis prediction.

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

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

Effect of high-amylose starch branching enzyme II wheat mutants on starch digestibility in bread, product quality, postprandial satiety and glycaemic response

High-amylose starch branching enzyme II (sbeII) mutant wheat has potential to be low-glycaemic compared to conventional wheat; however, the effects of bread made from sbeII wheat flour on glycaemic response and product quality require investigation. We report the impact of white bread made from sbeII wheat flour on in vitro starch digestibility and product quality, and on postprandial glycaemia in vivo, compared to an isoglucidic wild-type (WT) control white bread. Starch in sbeII bread was ∼20% less susceptible to in vitro amylolysis leading to ∼15% lower glycaemic response measured in vivo, compared to the WT control bread, without major effects on bread appearance or texture, measured instrumentally. Despite the early termination of the in vivo intervention study due to the COVID-19 outbreak (n = 8 out of 19), results from this study indicate that sbeII wheat produces bread with lower starch digestibility than conventional white bread.

Impact of white bread made from sbeII wheat flour on postprandial glycaemic response.

Three minutes of moderate-intensity stair walking improves glucose and insulin but not insulin sensitivity or total antioxidant capacity

BACKGROUND AND AIMS

This study examined the effect of moderate intensity stair stepping exercise on the glycemic response, and antioxidant capacity (TAC) during an oral glucose tolerance test (OGTT).

METHODS AND RESULTS

Thirty participants (women = 12) completed 4 OGTTs during rest or stair walking bouts of 1, 3, and 10 min in a randomized order. Blood was collected at baseline and 30 min during the OGTTs and analyzed for glucose, insulin, TAC, and lactate. Glucose concentrations were decreased following the 10 min (-22.69 (-34.66 to -10.72) mg/dL, p < 0.002) and 3 min (-15.37 (-25.05 to -5.69) mg/dL, p < 0.004) bouts but not the 1 min bout (-6.18 (-19.54 to 7.18) mg/dL, p = 0.352). Insulin concentrations were decreased following the 10 min (-6.11 (-8.86 to -3.36 μIU/dL), p < 0.001) and 3 min (-2.589 (-4.54 to -0.63) μIU/dL, p < 0.012) bouts but not the 1 min bout (-0.37 (-1.87 to 1.13) μIU/dL, p = 0.616). Insulin sensitivity index values showed a significant increase in the 10-min trial (1.81 (0.03-3.58), p < 0.048), but not during the 3 min (0.65 (-0.66 to 1.96) p = 0.317) or 1 min trial (0.13 (-1.58 to 1.84) p = 0.878). There was no omnibus effect for trial in TAC (p = 0.132, η² = 0.07). There was no interaction between trial and time for blood lactate (p = 0.621, η² = 0.02).

CONCLUSION

This study provides evidence bouts as short as 3 min decrease postprandial blood glucose and insulin levels but longer bouts are needed to affect insulin sensitivity.

Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions

AIMS/HYPOTHESIS

Sleep, diet and exercise are fundamental to metabolic homeostasis. In this secondary analysis of a repeated measures, nutritional intervention study, we tested whether an individual's sleep quality, duration and timing impact glycaemic response to a breakfast meal the following morning.

METHODS

Healthy adults' data (N = 953 [41% twins]) were analysed from the PREDICT dietary intervention trial. Participants consumed isoenergetic standardised meals over 2 weeks in the clinic and at home. Actigraphy was used to assess sleep variables (duration, efficiency, timing) and continuous glucose monitors were used to measure glycaemic variation (>8000 meals).

RESULTS

Sleep variables were significantly associated with postprandial glycaemic control (2 h incremental AUC), at both between- and within-person levels. Sleep period time interacted with meal type, with a smaller effect of poor sleep on postprandial blood glucose levels when high-carbohydrate (low fat/protein) (p_interaction = 0.02) and high-fat (p_interaction = 0.03) breakfasts were consumed compared with a reference 75 g OGTT. Within-person sleep period time had a similar interaction (high carbohydrate: p_interaction = 0.001, high fat: p_interaction = 0.02). Within- and between-person sleep efficiency were significantly associated with lower postprandial blood glucose levels irrespective of meal type (both p < 0.03). Later sleep midpoint (time deviation from midnight) was found to be significantly associated with higher postprandial glucose, in both between-person and within-person comparisons (p = 0.035 and p = 0.051, respectively).

CONCLUSIONS/INTERPRETATION

Poor sleep efficiency and later bedtime routines are associated with more pronounced postprandial glycaemic responses to breakfast the following morning. A person's deviation from their usual sleep pattern was also associated with poorer postprandial glycaemic control. These findings underscore sleep as a modifiable, non-pharmacological therapeutic target for the optimal regulation of human metabolic health. Trial registration ClinicalTrials.gov NCT03479866.

Effects of Intermittent Fasting on Cardiometabolic Health: An Energy Metabolism Perspective

This review summarizes the effects of different types of intermittent fasting (IF) on human cardiometabolic health, with a focus on energy metabolism. First, we discuss the coordinated metabolic adaptations (energy expenditure, hormonal changes and macronutrient oxidation) occurring during a 72 h fast. We then discuss studies investigating the effects of IF on cardiometabolic health, energy expenditure and substrate oxidation. Finally, we discuss how IF may be optimized by combining it with exercise. In general, IF regimens improve body composition, ectopic fat, and classic cardiometabolic risk factors, as compared to unrestricted eating, especially in metabolically unhealthy participants. However, it is still unclear whether IF provides additional cardiometabolic benefits as compared to continuous daily caloric restriction (CR). Most studies found no additional benefits, yet some preliminary data suggest that IF regimens may provide cardiometabolic benefits in the absence of weight loss. Finally, although IF and continuous daily CR appear to induce similar changes in energy expenditure, IF regimens may differentially affect substrate oxidation, increasing protein and fat oxidation. Future tightly controlled studies are needed to unravel the underlying mechanisms of IF and its role in cardiometabolic health and energy metabolism.

Glycemic response, satiety, gastric secretions and emptying after bread consumption with water, tea or lemon juice: a randomized crossover intervention using MRI

PURPOSE

Numerous studies, including our previous work with lemon juice, have reported that low-pH meals reduce the glycemic response to starchy foods. However, the underlying mechanism is not yet understood. Tea, for its polyphenol content, has also been investigated. The main objective of this research was to concurrently study gastric emptying, appetite perceptions and glycemic responses to bread consumed with water, tea, or lemon juice.

METHODS

In this randomized, crossover intervention, ten participants consumed equal portions of bread (100 g) with 250 mL of water, water-diluted lemon juice, or black tea at breakfast. Gastric volumes, blood glucose concentrations and appetite perceptions were alternately assessed over 180 min using magnetic resonance imaging, the finger-prick method and visual analogue scales, respectively.

RESULTS

Compared to water, lemon juice led to a 1.5 fold increase of the volume of gastric contents, 30 min after the meal (454.0 ± 18.6 vs. 298.4 ± 19.5 mL, [Formula: see text]  ± SEM P < 0.00001). Gastric emptying was also 1.5 times faster (P < 0.01). Conversely, lemon juice elicited a lower glycemic response than water (blood glucose concentrations at t = 55 min were 35% lower, P = 0.039). Tea had no effect. Changes in appetite perceptions and gastric volumes correlated well, but with no significant differences between the meals.

CONCLUSIONS

Lemon juice lowered the glycemic response and increased both gastric secretions and emptying rate. The results are compatible with the hypothesis that the reduction of the glycemic response is mainly due to the interruption of starch hydrolysis via the acid-inhibition of salivary α-amylase.

TRIAL REGISTRATION NUMBER

NCT03265392, August 29, 2017.

Compositional, Structural, and Kinetic Aspects of Lipid Digestion and Bioavailability: In Vitro, In Vivo, and Modeling Approaches

Lipid digestion and bioavailability are usually investigated separately, using different approaches (in vitro, modeling, in vivo). However, a few inclusive studies show that their kinetics are closely linked. Lipid bioavailability kinetics is likely involved in the development and evolution of several diseases, so lipid digestion kinetics could be involved as well and can be modulated by food design or combination. To illustrate this possibility, the compositional and structural aspects of lipid digestion kinetics, as investigated using in vitro and modeling approaches, are presented first. Then, in vivo and mixed approaches enabling the study of both kinetics are reviewed and discussed. Finally, disparate modeling approaches are introduced, and a unifying modeling scheme is proposed, opening new perspectives for understanding the role and interactions of various factors (chemical, physical, and biological) involved in lipid metabolism.

Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Face Validity of Observed Meal Patterns Reported with 7-Day Diet Diaries in a Large Population-Based Cohort Using Diurnal Variation in Concentration Biomarkers of Dietary Intake

In a cross-sectional analysis of a population-based cohort (United Kingdom, N = 21,318, 1993-1998), we studied how associations between meal patterns and non-fasting triglyceride and glucose concentrations were influenced by the hour of day at which the blood sample was collected to ascertain face validity of reported meal patterns, as well as the influence of reporting bias (assessed using formula of energy expenditure) on this association. Meal size (i.e., reported energy content), mealtime and meal frequency were reported using pre-structured 7-day diet diaries. In ANCOVA, sex-specific means of biomarker concentrations were calculated by hour of blood sample collection for quartiles of reported energy intake at breakfast, lunch and dinner (meal size). Significant interactions were observed between breakfast size, sampling time and triglyceride concentrations and between lunch size, sampling time and triglyceride, as well as glucose concentrations. Those skipping breakfast had the lowest triglyceride concentrations in the morning and those skipping lunch had the lowest triglyceride and glucose concentrations in the afternoon, especially among acceptable energy reporters. Eating and drinking occasion frequency was weakly associated with glucose concentrations in women and positively associated with triglyceride concentrations in both sexes; stronger associations were observed for larger vs. smaller meals and among acceptable energy reporters. Associations between meal patterns and concentration biomarkers can be observed when accounting for diurnal variation and underreporting. These findings support the use of 7-day diet diaries for studying associations between meal patterns and health.