Search Results (519)

Background: Low-glycemic index (GI) carbohydrates like isomaltulose (ISO) are known to enhance incretin release and to improve postprandial glucose control at the following meal (an effect known as second meal effect, or SME), which is particularly beneficial for individuals with metabolic syndrome (MetS). This study aimed to assess the most effective preprandial interval of ISO- or saccharose (SUC) snacks (1 h vs. 3 h preload) to enhance prandial incretin responses to a subsequent meal. Methods: In a randomized crossover design, 15 participants with MetS completed four experimental conditions on four non-consecutive days, combining two preload types (ISO or SUC) and two preload timings (Intervention A: 3 h preload; Intervention B: 1 h preload). Specifically, the four conditions were (1) ISO + Intervention A, (2) SUC + Intervention A, (3) ISO + Intervention B, and (4) SUC + Intervention B. The order of conditions was randomized and separated by a 3–7-day washout period to minimize carryover effects. On each study day, participants consumed two mixed meal tests (MMT-1 and MMT-2) with a standardized preload (50 g ISO or SUC) administered either 3 h or 1 h prior to MMT-2. Blood samples were collected over 9 h at 15 predefined time points for analysis of glucose, insulin, C-peptide, and incretin hormones (GLP-1, GIP, and PYY). Results: The unique digestion profile of ISO resulted in a blunted glucose ascent rate (ΔG/Δt: 0.28 vs. 0.53 mmol/L/min for SUC, p < 0.01), paralleled by synonyms PYY elevation over 540 min monitoring, compared with SUC. ISO also led to higher and more sustained GLP-1 and PYY levels, while SUC induced a stronger GIP response. Notably, the timing of ISO consumption significantly influenced PYY secretion, with the 3 h preload showing enhanced PYY responses and a more favorable SME compared to the 1 h preload. Conclusions: ISO, particularly when consumed 3 h before a meal (vs. 1 h), offers significant advantages over SUC by elevating PYY levels, blunting the glucose ascent rate, and sustaining GLP-1 release. This synergy enhances the second meal effect, suggesting ISO’s potential for managing postprandial glycemic excursions in MetS. Full article

Salivary α-amylase, primarily encoded by the AMY1 gene, initiates the enzymatic digestion of dietary starch in the oral cavity and has recently emerged as a potential biomarker in metabolic research. Variability in salivary amylase activity (SAA), driven largely by copy number variation of AMY1, has been associated with postprandial glycemic responses, insulin secretion dynamics, and susceptibility to obesity. This review critically examines current analytical approaches for quantifying SAA, including enzymatic assays, colorimetric techniques, immunoassays, and emerging biosensor technologies. The methodological limitations related to sample handling, intra-individual variability, assay standardization, and specificity are highlighted in the context of metabolic and clinical studies. Furthermore, the review explores the physiological relevance of SAA in energy homeostasis and its associations with visceral adiposity and insulin resistance. We discuss the potential integration of SAA measurements into obesity risk stratification and personalized dietary interventions, particularly in individuals with altered starch metabolism. Finally, the review identifies key research gaps and future directions necessary to validate SAA as a reliable metabolic biomarker in clinical practice. Understanding the diagnostic and prognostic value of salivary amylase may offer new insights into the prevention and management of obesity and related metabolic disorders. Full article

Background/Objectives: Diatomaceous earth (DE), a natural substance rich in amorphous silica and recognized as a food additive, is gaining attention as a dietary silicon supplement. However, its bioavailability and impact on lipid digestion and absorption remain poorly characterized. This study aimed to investigate silicon bioavailability after short-term DE supplementation and its effects on postprandial glycemia and triglyceridemia, the expression of lipid metabolism-related proteins, and the modulation of the intestinal mucosal barrier. Methods: Female Wistar rats received daily oral supplementation of DE (equivalent to 2 or 4 mg silicon/kg body weight) for one week. Silicon digestibility, excretion, and hepatic accumulation were quantified. Postprandial glycemia and triglyceridemia were monitored. Lipid profile was analyzed by HPSEC in gastric and intestinal contents. Jejunal morphology and mucin-secreting cells were assessed histologically. Lipid metabolism markers were evaluated by immunohistochemistry and Western blot in both intestinal and hepatic tissues. Results: DE supplementation enhanced silicon absorption and increased hepatic levels. Fecal output and moisture content were also elevated, especially at the higher dose. DE significantly reduced postprandial triglyceridemia and consequently increased luminal triglyceride retention. These changes were associated with decreased jejunal levels of IFABP, ACAT2, and MTP, as well as reduced hepatic levels of MTP and LDLr, alongside increased levels of ABCG5/G8 and LXRα/β, indicating a partial blockage of lipid absorption and enhanced cholesterol efflux. The effects on the intestinal barrier were evidenced by villi shortening and an increase in mucin-producing cells. Conclusion: Food-grade DE is a bioavailable source of silicon with hypolipidemic potential, mainly by reducing intestinal lipid absorption. This is supported by lower postprandial triglycerides, increased luminal lipid retention, and decreased expression of lipid transport proteins. The study in healthy female rats underscores the importance of sex-specific responses and supports DE as a dietary strategy to improve lipid metabolism. Full article

Background/Objectives: Asprosin is the endogenous ligand of the olfactory Olfr734 receptor linked to MASLD and glucose metabolism. Despite the involvement of asprosin in these processes, little has been published on the specific role of Olfr734 in liver function. The aim of this work is therefore to study the specific role of the olfactory Olfr734 receptor in MASLD and glucose metabolism. Methods: To achieve this objective, we performed a genetic inhibition specifically to inhibit Olfr734 in the livers of male mice. We then studied the progression of MASLD in DIO mice. In addition, we studied the glucose metabolism in hypoglycemia states and postprandial glucose production in standard diet-fed mice. Finally, analyses of liver biopsies from patients with obesity and with or without T2DM were conducted. Results: We found that hepatic Olfr734 levels vary according to changes in nutritional status and its knockdown effect in the liver is to increase the hepatic lipid content in DIO mice. Our results also showed that OLFR734 expression is involved in the adaptive response in terms of glucose production to nutrient availability. Finally, the hepatic human Olfr734 ortholog named OR4M1 has been observed to be at significantly higher levels in male patients with T2DM. Conclusions: This study increases understanding of the mechanisms by which the modulation of Olfr734 expression affects liver function. Full article

Postprandial dysmetabolism, which refers to the impaired regulation of glucose and lipid levels after meals, is recognized as an independent risk factor for cardiovascular diseases (CVDs). Diets rich in polyphenols have demonstrated potential in improving postprandial hyperglycemia and hyperlipidemia. This study investigates the effects of olive leaf polyphenols on postprandial metabolic outcomes following a high-fat and high-carbohydrate meal. A total of 36 healthy adults participated in a three-arm randomized crossover trial. They ingested either a biscuit made from olive leaf powder (OLB), olive leaf tea (OLT), or a placebo meal (CTRL) to assess the impact of olive leaf polyphenols on postprandial glycemia, lipid levels, platelet aggregation factor (PAF), and plasma antioxidant status (TAC). Although no statistically significant differences were observed in the primary biomarkers, including glucose and lipid profiles, a delayed insulin response was noted in the interventions involving olive leaf. These findings suggest that while acute olive leaf supplementation did not significantly alter postprandial glycemia or lipidemia, it may subtly influence insulin kinetics. Further research is needed to explore the long-term effects of olive leaf polyphenols on metabolic health, especially in populations at risk for CVDs. Full article

Background/Objectives: Postprandial hyperglycemia is a risk factor for diabetes and cardiovascular diseases, even in healthy individuals. Kanzaki mulberry leaf and water chestnut tea (MW tea), a blend of mulberry (Morus alba) leaves and water chestnut (Trapa japonica) leaves and husks, is rich in polyphenols and 1-deoxynojirimycin (DNJ) and may suppress postprandial glucose spikes, but evidence regarding its short-term daily intake is limited. This study aimed to evaluate the postprandial glycemic response and safety of two-week MW tea consumption using continuous glucose monitoring (CGM). Methods: We conducted a randomized, double-blind, placebo-controlled, two-period crossover trial involving 31 participants. Each intervention period lasted two weeks, separated by a one-week washout. Participants consumed either MW tea or a placebo before meals. Interstitial glucose levels were measured every 15 min using CGM. Postprandial glucose responses were recorded every 15 min for 180 min after a standardized meal on the first day of each period. The primary outcome was the coefficient of variation (CV) in glucose levels, calculated using data from the central 10 days of each intervention period. Safety was assessed using CGM-derived hypoglycemia metrics and blood test results. Results: The CV of glucose levels during the MW tea period was significantly lower than during the placebo period (mean difference: 0.02, p = 0.0006). A significant reduction in 1 h postprandial glucose area under the curve was also observed. No significant differences were found in hypoglycemia occurrence, liver/renal/inflammatory markers, or self-reported adverse symptoms. Notably, 1,5-anhydroglucitol (1,5-AG) levels significantly increased during MW tea intake, suggesting improved glycemic control. Conclusions: Short-term consumption of Kanzaki MW tea effectively suppressed postprandial glucose variability without safety concerns. These findings support MW tea as a promising natural supplement for glycemic management and the prevention of diabetes. Full article

Background: The New Zealand pine bark has been demonstrated in vitro to inhibit digestive enzymes involved in carbohydrate digestion (alpha-amylase, alpha-glucosidase, and dipeptidyl-peptidase 4 (DPP-4)). Objective: This study aims to investigate the inhibitory effects of the New Zealand pine bark on sucrose uptake and glycaemic responses in humans. Methods: A single-blind, randomised, placebo-controlled, crossover trial was carried out involving healthy adults (n = 40 (M: 12, F: 28), 30.1 ± 1.3 years, BMI 23.4 ± 0.5 kg/m², HbA1c 32.5 ± 0.6 mmol/mol, FBG 4.7 ± 0.1 mmol/L). A control (75 g of sucrose powder only), and two doses of the pine bark extract (50 and 400 mg) were provided on separate occasions, with 75 g of sucrose mixed in 250 mL of water. Blood samples were collected at −10, 0, 15, 30, 45, 60, 90, and 120 min via a finger prick test. A linear mixed model for repeated measures (SPSS v30, IBM) was applied, and data presented as model-adjusted mean ± SEM. Results: Compared to control (247.5 ± 14.0 mmol/L⋅min), the iAUCglucose was significantly reduced with the 400 mg dose (211.8 ± 13.9 mmol/L⋅min, 14.4% reduction, and p = 0.037), but not with 50 mg dose (220.8 ± 14.2 mmol/L⋅min, 10.8% reduction, and p = 0.184). Compared to control (9.1 ± 0.2 mmol/L), glucose peak value was significantly reduced with the 50 mg dose (8.6 ± 0.2 mmol/L, 5.5% reduction, and p = 0.016) but not with the 400 mg dose (8.7 ± 0.2 mmol/L, 4.4% reduction, and p = 0.093). There were no statistically significant changes in postprandial insulin levels with the pine bark extract compared to control. Conclusions: The New Zealand pine bark extract attenuated sucrose uptake with improved glycaemic responses, and may therefore be useful as a hypoglycaemic adjunct to the diet. Full article

Background: Almond milk is often seen as a healthier alternative to cow milk. However, its effect on postprandial glycemia compared to 2% milk is unclear. Here, we compared the postprandial glycemic effect of almond milk versus carbohydrate- or caloric-matched 2% milk, each served with oatmeal to patients with type 2 diabetes (T2D). Methods: In this crossover, three-way, open-label study, 22 participants (mean age 66 ± 7.4 years, 36% female), with T2D and overweight or obesity, consumed oatmeal served with almond milk (ALM), carbohydrate-matched 2% milk (MLKCRB), or calorie-matched 2% milk (MLKCAL) on separate days and in a random order. The primary outcome was glucose incremental area under the curve for 240 min (iAUC0-240). The secondary outcomes included postprandial serum insulin, glucagon, plasma free fatty acids (FFAs), serum triglycerides, leptin, and gastrointestinal hormones (PYY, active GLP-1, GIP, amylin, cholecystokinin, and ghrelin). Results: We did not find any difference in either the primary endpoint or secondary endpoints between the three groups. However, iAUC0-240 for insulin and glucagon was significantly higher in MLKCRB vs. ALM (FDR = 0.002 and 0.02, respectively). Conclusions: Almond milk does not offer any additional glycemic benefit over 2% milk and does not differ in its postprandial effects on FFAs, serum triglycerides, leptin, and gastrointestinal hormones over 4 h. Nonetheless, carbohydrate-matched 2% milk elicited greater insulin and glucagon response compared to almond milk, warranting further investigation into its long-term implications. Full article

Background/Objectives: Nocturnal glucose regulation is a critical but underexplored determinant of next-day fasting glucose (FG), particularly in individuals with dysglycemia. This study examined the role of glucose levels after the last eating occasion (LEO) and during the overnight fast in predicting FG, considering the potential influence of carbohydrate content in LEO and insulin sensitivity. Methods: In a controlled 24 h protocol, 33 adults (50–75 years) with prediabetes or diet-controlled type 2 diabetes followed a standardized feeding schedule with meals at fixed times, including a LEO at 10:00 p.m. Continuous glucose monitoring was used to assess glucose during the 3 h postprandial period (LEO-PPGR) and two fasting intervals: chronological overnight fast (COF) and biological overnight fast (BOF). Associations with FG were tested using general linear models, adjusting for carbohydrate intake and insulin sensitivity (Matsuda index). Results: Glucose responses during LEO-PPGR—assessed by mean glucose, peak, and AUC—were strongly correlated with FG the next morning (r = 0.704, 0.535, and 0.708, p < 0.001). Similarly, glucose levels during COF and BOF were also correlated with FG (r = 0.878, p < 0.001 for both), but these associations weakened after adjustment for LEO carbohydrate content. The Matsuda index was positively correlated with glucose in all three periods (p < 0.05), yet its inclusion in the model attenuated all previously significant associations with FG. Conclusions: These findings suggest that the glycemic response to the last meal and subsequent overnight glucose levels contribute to next-day FG, but their impact is modulated by carbohydrate content and individual insulin sensitivity. Understanding nocturnal glycemic dynamics may inform strategies for improving metabolic outcomes in dysglycemia. Full article

Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor, is released pre-prandially and during periods of negative energy balance, exhibiting anti-fertility properties. In this study, twenty ewes were divided into two groups: a ghrelin-treated group receiving 1.25 μg/kg body weight (BW) of ghrelin per day via mini-pumps for 28 days and an untreated control group. Estrus was synchronized, superovulation was induced with FSH, and embryos and follicular fluid were collected six days post-estrus. Blood samples were taken to measure LH, progesterone, and anti-Müllerian hormone (AMH) concentrations. Results indicated that in treated animals, preovulatory LH surge was weaker, and progesterone levels were lower than in controls. Differences were observed in the superovulatory response and the number of collected embryos, both being higher in controls. While AMH levels did not differ between groups at the beginning of the experiment, they were lower in treated animals at the time of FSH administration. Treated ewes exhibited a reduced number of small follicles, and their follicular fluid contained lower AMH concentrations than the controls. These findings suggest that ghrelin plays a direct role in regulating LH secretion from the pituitary and in controlling ovarian follicle development, highlighting the strong interaction between nutrition and fertility. Full article

Background: Effective management of postprandial glycemic control is critical for diabetic patients, as elevated postprandial glucose levels can lead to complications such as cardiovascular disease and neuropathy. This study evaluates isomaltulose, a low-glycemic-index carbohydrate, as an alternative to sucrose in mitigating postprandial glucose spikes. Objectives: To synthesize evidence from existing studies and assess the efficacy of isomaltulose in reducing postprandial glycemic levels compared to sucrose in diabetic populations. Methods: A systematic review and meta-analysis were conducted following PRISMA guidelines. Searches were performed across PubMed, Cochrane Library, and ClinicalTrials.gov for randomized controlled trials or crossover studies comparing isomaltulose and sucrose. Data were extracted, and the Cochrane Risk of Bias tool was used to assess study quality. Results: Ten studies were included, involving 367 participants. The meta-analysis showed that isomaltulose significantly reduced plasma glucose level at 60 min post-meal, though the actual effect could be modest in terms of clinical relevance compared to sucrose (MD: −7.99, 95% CI: −8.58, −7.39, p < 0.00001). Notable variability in the study results was observed, which may be attributed to multiple factors such as participant demographics and meal composition. Conclusions: The findings from the analysis are supportive for the use of isomaltulose as a beneficial dietary alternative to sucrose for managing postprandial glycemic levels in diabetic patients. Future research effort is suggested to focus on larger, diverse populations to enhance generalizability and explore the impact of dietary context on glycemic response. Full article

Background/Objectives: Dietary protein and carbohydrate affect postprandial glycemia in individuals with type 1 diabetes (T1D). This paper aimed to determine the relationship between the types of dietary protein (Study 1) and carbohydrate (glycemic index; GI, Study 2) and postprandial glycemia. Methods: Two acute randomized crossover trials were conducted in adults with T1D comparing postprandial glycemia for test meals varying by protein type (n = 16 adults; 5 meals: egg, beef, chicken, salmon or whey (all 30 g protein), each served with fried rice (45 g carbohydrate) or GI (n = 8 adults, high or low GI bread, GI 52% vs. 76%) with peanut butter (19 g protein, 30 g fat). Insulin was dosed based on usual individualized insulin: carbohydrate ratio and capillary blood glucose levels (BGL) measured from 30 min pre- to 5 h postprandially in 15–30 min intervals. Results: Study 1: Postprandial glycemia varied over an almost 2-fold range, however responses were highly variable and there were no significant differences between sources (iAUCglucose Chicken: 203 ± 66 mmol·min/L, Egg: 263 ± 100 mmol·min/L, Beef: 309 ± 89 mmol·min/L, Salmon: 338 ± 83 mmol·min/L and Whey: 397 ± 115 mmol·min/L respectively, p > 0.05). Hypoglycemia (≤3.5 mmol/L) occurred at least once per protein type (chicken: 6/16 participants, egg 2/16, beef 3/16, salmon 1/16, whey 2/16). However, there were no statistically significant differences in the risk of hypoglycemia between protein sources (p > 0.05). Study 2: Postprandial glucose response curves were virtually identical for high GI and low GI, and the incremental area under the curve (iAUC) for glucose was not statistically significant after 1 h (p = 0.185), 3 h (p = 0.538) or 5 h (p = 0.694) following the meal. Conclusions: Clinical practice guidelines and insulin dosing algorithms likely do not need to consider differences in protein sources or in GI in the context of a high fat, high protein meals, for individuals with T1D. Full article

Pea and lentil flours are added to baked foods, pastas, and snacks to improve nutritional quality and functionality compared to products made solely with refined wheat flour. However, the effect of whole pulses versus their serving size equivalent of flour on blood glucose has not been investigated in persons with altered glycemic response. Health claims for whole pulses are based on a ½ cup amount whereas commercial pulse flour servings are typically a smaller size. The glycemic responses of four treatment meals containing 50 g available carbohydrate as ½ cup whole pulse or the dry weight equivalent of pulse flour were compared with a control beverage (Glucola^®). Eleven adults with type 2 diabetes mellitus (T2DM) and eight adults with metabolic syndrome (MetS) completed the study. Venous blood samples were collected at fasting and at 30 min intervals postprandial for three hours. Changes in net difference in plasma glucose over time from baseline and incremental area under the curve (iAUC) segments were analyzed. All four pulse meals attenuated the iAUC compared to the control from 0 to 120 min for T2DM participants and 0–180 min for MetS participants. Whole pulses produced a lower glycemic response than pulse flours in the early postprandial period for persons with T2DM and during the overall test period for those with MetS. Full article

Type 2 diabetes mellitus (T2DM) represents a significant global health burden, especially in populations where rice constitutes a dietary staple. Parboiled rice (PBR), known for its lower glycemic index compared to conventional white rice (WR), may offer benefits in managing postprandial hyperglycemia. Nevertheless, the impact of PBR consumption on insulin sensitivity, β-cell function, and incretin hormone responses remains poorly understood. Methods: This randomized crossover pilot study aimed to assess and compare the acute effects of PBR and WR intake on postprandial glucose regulation, insulin sensitivity, β-cell functionality, and glucagon-like peptide-1 (GLP-1) responses in healthy subjects and individuals with T2DM. A total of 20 participants were recruited and evenly allocated into healthy (n = 10) and T2DM (n = 10) groups. Following the ingestion of either PBR or WR, blood samples were collected at fasting and various postprandial intervals to determine glucose, insulin, and GLP-1 levels. Insulin sensitivity and β-cell function were evaluated using HOMA-IR, Matsuda Index (MI), and Disposition Index (DI). Results: As expected, T2DM participants exhibited significantly elevated fasting glucose and insulin levels compared to healthy controls. Consumption of PBR led to significantly lower postprandial glucose responses in healthy subjects relative to WR. Although a similar trend of reduced glucose levels was observed in T2DM subjects after PBR intake, this reduction did not reach statistical significance. Parallel trends were observed in insulin secretion patterns. Moreover, GLP-1 responses were notably diminished in T2DM individuals compared to healthy participants. Importantly, MI and DI values significantly increased after PBR consumption in healthy individuals compared to those with T2DM, indicating improved insulin sensitivity and β-cell responsiveness. Conclusions: These preliminary findings suggest that PBR consumption may confer beneficial effects by lowering postprandial glucose and enhancing insulin sensitivity. Further studies with larger cohorts are warranted to confirm these outcomes and elucidate the physiological mechanisms behind PBR’s potential role in dietary management strategies for T2DM. Full article

Background: Alzheimer’s disease (AD) is the most common cause of dementia. In addition to cognitive decline, non-cognitive symptoms, including dysautonomia, have been reported, although these symptoms are rarely acknowledged by patients. Dysautonomia in AD is thought to arise from either cholinergic deficits or hypothalamic involvement. A wide range of tests has been used to investigate the role of the autonomic nervous system; however, the results have been inconsistent. Aim: To systematically review all published research investigating autonomic nervous system (ANS) involvement in patients with AD. A comprehensive literature search was conducted in December 2024 across the following databases: PubMed, Cochrane Library, ScienceDirect, and Scopus. Results: A total of 1422 records were identified, of which 30 studies fulfilled the inclusion criteria and were included in the review. Several autonomic tests were employed, with Heart Rate Variability (HRV) being the most frequently used. Other tests included assessments of orthostatic hypotension (OH), postprandial hypotension (PPH), sympathetic skin response (SSR), the tilt test, 123I-MIBG cardiac scintigraphy, norepinephrine (NE) measurements in serum and cerebrospinal fluid, and baroreflex sensitivity. In most studies, AD patients were compared to either healthy controls or patients with other types of dementia. Discussion: The primary finding of this review is that, although patients with AD rarely report dysautonomic symptoms, they frequently exhibit abnormal results on various autonomic tests. In some cases, these findings were sufficient to differentiate AD patients from healthy controls as well as from patients with Diffuse Lewy Body disease (DLB). The inconsistency in reporting symptoms, along with the variability in test results, suggests that autonomic dysfunction in AD may be under-recognized and warrants further investigation. Conclusions: The heterogeneity of the included studies limits the generalizability of the results. However, given the potential impact of dysautonomia on both quality of life and mortality, it is recommended that AD patients be systematically assessed for autonomic dysfunction. Even in the absence of overt symptoms, appropriate treatment should be considered where indicated to mitigate potential risks. Full article