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1.
The effect of bedtime snacks on fasting blood glucose levels in gestational diabetes mellitus.
Henze, M, Burbidge, H, Nathan, E, Graham, DF
Diabetic medicine : a journal of the British Diabetic Association. 2022;(3):e14718
Abstract
AIM: To investigate the effect of different bedtime snacks (higher carbohydrate versus lower carbohydrate versus no snack) on first morning fasting blood glucose levels (BGLs) in women with diet-controlled gestational diabetes mellitus (GDM) and borderline fasting glucose levels. METHODS This prospective randomised crossover trial enrolled women with diet controlled GDM between 24 and 34 weeks gestation who had two or more first morning fasting BGLs between 4.7 and 5.4 mmol/L in the week prior to recruitment. The women were randomly allocated to 6 different orders of 5 days each of a standardised higher carbohydrate bedtime snack, a lower carbohydrate bedtime snack and no bedtime snack. The primary outcome was fasting capillary BGL as measured with a home glucometer, and the secondary outcome was requirement for insulin as assessed by a physician. RESULTS A total of 68 women with GDM were enrolled in and completed the study at a median gestation of 30.8 weeks. Compared with no bedtime snack, the higher carbohydrate snack (4.96 vs 4.87 mmol/L, mean difference: 0.09 mmol/L, 95% CI 0.05-0.13, p < 0.001) and the lower carbohydrate snack (5.01 vs 4.87 mmol/L, mean difference: 0.14 mmol/L, 95% CI 0.09-0.18, p < 0.001) were both associated with a slightly higher fasting BGL the following morning. CONCLUSIONS Taking a bedtime snack was associated with slightly higher fasting BGLs in women with diet-controlled GDM compared with no bedtime snack (Clinical trial registration: ACTRN12617000659303).
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2.
Temporal Patterns of Glucagon and Its Relationships with Glucose and Insulin following Ingestion of Different Classes of Macronutrients.
Göbl, C, Morettini, M, Salvatori, B, Alsalim, W, Kahleova, H, Ahrén, B, Tura, A
Nutrients. 2022;(2)
Abstract
BACKGROUND glucagon secretion and inhibition should be mainly determined by glucose and insulin levels, but the relative relevance of each factor is not clarified, especially following ingestion of different macronutrients. We aimed to investigate the associations between plasma glucagon, glucose, and insulin after ingestion of single macronutrients or mixed-meal. METHODS thirty-six participants underwent four metabolic tests, based on administration of glucose, protein, fat, or mixed-meal. Glucagon, glucose, insulin, and C-peptide were measured at fasting and for 300 min following food ingestion. We analyzed relationships between time samples of glucagon, glucose, and insulin in each individual, as well as between suprabasal area-under-the-curve of the same variables (ΔAUCGLUCA, ΔAUCGLU, ΔAUCINS) over the whole participants' cohort. RESULTS in individuals, time samples of glucagon and glucose were related in only 26 cases (18 direct, 8 inverse relationships), whereas relationship with insulin was more frequent (60 and 5, p < 0.0001). The frequency of significant relationships was different among tests, especially for direct relationships (p ≤ 0.006). In the whole cohort, ΔAUCGLUCA was weakly related to ΔAUCGLU (p ≤ 0.02), but not to ΔAUCINS, though basal insulin secretion emerged as possible covariate. CONCLUSIONS glucose and insulin are not general and exclusive determinants of glucagon secretion/inhibition after mixed-meal or macronutrients ingestion.
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3.
A Low-Calorie Diet with or without Exercise Reduces Postprandial Aortic Waveform in Females with Obesity.
Heiston, EM, Gilbertson, NM, Eichner, NZM, Malin, SK
Medicine and science in sports and exercise. 2021;(4):796-803
Abstract
PURPOSE Arterial stiffness is considered a predictor of cardiovascular disease. Females have higher values of arterial stiffness than males, suggesting a greater risk of heart-related complications. Although a low-calorie diet (LCD) reduces fasting arterial stiffness, in part through weight loss, it is unknown if interval exercise (INT) adds to the benefit of LCD on fasting and postprandial arterial stiffness in females with obesity. METHODS Twenty-five females (47 ± 2.6 yr, 37.6 ± 1.3 kg·m-2) were randomized to 13 d of LCD (n = 12; mixed meals of ~1200 kcal·d-1) or LCD + INT (n = 13; 60 min·d-1 of supervised 3-min intervals at 90% HRpeak and 50% HRpeak). Arterial stiffness (augmentation index [AIx] and carotid-femoral pulse wave velocity [cfPWV]) and blood biochemistries were measured during a 75-g oral glucose tolerance test before and after the intervention to determine fasting and postprandial arterial stiffness as well as insulin sensitivity (simple index of insulin sensitivity [SIIS]) and inflammation (C-reactive protein, interleukin 8, and tumor necrosis factor alpha). RESULTS Although LCD + INT increased V˙O2peak and HDL compared with LCD (P = 0.04 and P < 0.01, respectively), both interventions decreased body fat, LDL, total cholesterol, and triglycerides (all P < 0.01) and increased SIIS (P = 0.03). Despite no effect on fasting AIx (P = 0.27), LCD and LCD + INT decreased AIx60min (-7.4% ± 4.3% vs -7.0% ± 5.0%, P = 0.04) and tAUC120min (-663 ± 263 vs -457 ± 406, P = 0.03). There were no changes in fasting cfPWV (P = 0.91) or cfPWV120min (P = 0.62). Increased SIIS and decreased interleukin 8 were associated with reduced fasting AIx (r = -0.44, P = 0.03, and r = 0.40, P = 0.055), whereas decreased C-reactive protein correlated with reduced postprandial AIx60min (r = 0.43, P = 0.04). CONCLUSION Independent of exercise, 13 d of LCD reduces postprandial AIx in females with obesity. Insulin sensitivity and inflammation correlated with improved arterial stiffness, suggesting unique mechanisms regulate fasted versus postprandial arterial stiffness.
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4.
Divergent serum metabolomic, skeletal muscle signaling, transcriptomic, and performance adaptations to fasted versus whey protein-fed sprint interval training.
Aird, TP, Farquharson, AJ, Bermingham, KM, O'Sulllivan, A, Drew, JE, Carson, BP
American journal of physiology. Endocrinology and metabolism. 2021;(6):E802-E820
Abstract
Sprint interval training (SIT) is a time-efficient alternative to endurance exercise, conferring beneficial skeletal muscle metabolic adaptations. Current literature has investigated the nutritional regulation of acute and chronic exercise-induced metabolic adaptations in muscle following endurance exercise, principally comparing the impact of training in fasted and carbohydrate-fed (CHO) conditions. Alternative strategies such as exercising in low CHO, protein-fed conditions remain poorly characterized, specifically pertaining to adaptations associated with SIT. Thus, this study aimed to compare the metabolic and performance adaptations to acute and short-term SIT in the fasted state with preexercise hydrolyzed (WPH) or concentrated (WPC) whey protein supplementation. In healthy males, preexercise protein ingestion did not alter exercise-induced increases in PGC-1α, PDK4, SIRT1, and PPAR-δ mRNA expression following acute SIT. However, supplementation of WPH beneficially altered acute exercise-induced CD36 mRNA expression. Preexercise protein ingestion attenuated acute exercise-induced increases in muscle pan-acetylation and PARP1 protein content compared with fasted SIT. Acute serum metabolomic differences confirmed greater preexercise amino acid delivery in protein-fed compared with fasted conditions. Following 3 wk of SIT, training-induced increases in mitochondrial enzymatic activity and exercise performance were similar across nutritional groups. Interestingly, resting muscle acetylation status was downregulated in WPH conditions following training. Such findings suggest preexercise WPC and WPH ingestion positively influences metabolic adaptations to SIT compared with fasted training, resulting in either similar or enhanced performance adaptations. Future studies investigating nutritional modulation of metabolic adaptations to exercise are warranted to build upon these novel findings.NEW & NOTEWORTHY These are the first data to show the influence of preexercise protein on serum and skeletal muscle metabolic adaptations to acute and short-term sprint interval training (SIT). Preexercise whey protein concentrate (WPC) or hydrolysate (WPH) feeding acutely affected the serum metabolome, which differentially influenced acute and chronic changes in mitochondrial gene expression, intracellular signaling (acetylation and PARylation) resulting in either similar or enhanced performance outcomes when compared with fasted training.
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5.
Effect of Dosage Reduction of Hypoglycemic Multidrug Regimens on the Incidences of Acute Glycemic Complications in People With Type 2 Diabetes Who Fast During Ramaḍān: A Randomized Controlled Trial.
Zaghlol, LY, Beirat, AF, Amarin, JZ, Hassoun Al Najar, AM, Hasan, YY, Qtaishat, A, Tierney, ME, Zaghlol, RY, Zayed, AA
Frontiers in endocrinology. 2021;:613826
Abstract
OBJECTIVE We aimed to investigate the effect of dosage reduction of four hypoglycemic multidrug regimens on the incidences of acute glycemic complications in people with type 2 diabetes who fast during Ramaḍān. METHODS We conducted an open-label, parallel-group, randomized controlled trial at a tertiary care center in Amman, Jordan. We recruited adults with type 2 diabetes who expressed an intention to fast during Ramaḍān and were adherent to one of four regimens-namely: metformin and glimepiride; metformin and vildagliptin; metformin and insulin glargine U100; or, metformin, insulin glargine U100, and human regular insulin. We randomly assigned participants in a 2:1 ratio to low- or regular-dosage therapy. The primary outcomes were the incidences of hypoglycemia and hyperglycemia during the 29 days of Ramaḍān 2017, and the secondary outcomes were the incidences of diabetic ketoacidosis and hyperosmolar hyperglycemic state during the same period. RESULTS We randomly assigned 687 participants to low-dosage therapy (n = 458) or regular-dosage therapy (n = 229) and included 678 (452 and 226, respectively) in the final analysis. The incidence of hypoglycemia was lower in the low-dosage group compared with the regular-dosage group (19 [4.2%] vs. 52 [23.0%], respectively; OR, 0.15 [95% CI, 0.08-0.26]; P < 0.001). The incidence of hyperglycemia did not differ between the low- and regular-dosage groups (319 [70.6%] vs. 154 [68.1%], respectively; OR, 1.12 [95% CI, 0.79-1.58]; P = 0.5). No participants experienced diabetic ketoacidosis or hyperosmolar hyperglycemic state. Each 1% decrease in the baseline HbA1c concentration was associated with a 19.9-fold (95% CI, 9.6-41.5; P < 0.001) increase in the odds of hypoglycemia, and each 1% increase in the baseline HbA1c concentration was associated with a 15.7-fold (95% CI, 10.0-24.6; P < 0.001) increase in the odds of hyperglycemia. CONCLUSION Dosage reduction decreases the incidence of hypoglycemia without a concomitant increase in the incidences of hyperglycemia, diabetic ketoacidosis, and hyperosmolar hyperglycemic state in people with type 2 diabetes who fast during Ramaḍān. CLINICAL TRIAL REGISTRATION www.ClinicalTrials.gov, identifier NCT04237493.
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6.
A Low-Glucose Eating Pattern Improves Biomarkers of Postmenopausal Breast Cancer Risk: An Exploratory Secondary Analysis of a Randomized Feasibility Trial.
Schembre, SM, Jospe, MR, Giles, ED, Sears, DD, Liao, Y, Basen-Engquist, KM, Thomson, CA
Nutrients. 2021;(12)
Abstract
Postmenopausal breast cancer is the most common obesity-related cancer death among women in the U.S. Insulin resistance, which worsens in the setting of obesity, is associated with higher breast cancer incidence and mortality. Maladaptive eating patterns driving insulin resistance represent a key modifiable risk factor for breast cancer. Emerging evidence suggests that time-restricted feeding paradigms (TRF) improve cancer-related metabolic risk factors; however, more flexible approaches could be more feasible and effective. In this exploratory, secondary analysis, we identified participants following a low-glucose eating pattern (LGEP), defined as consuming energy when glucose levels are at or below average fasting levels, as an alternative to TRF. Results show that following an LGEP regimen for at least 40% of reported eating events improves insulin resistance (HOMA-IR) and other cancer-related serum biomarkers. The magnitude of serum biomarkers changes observed here has previously been shown to favorably modulate benign breast tissue in women with overweight and obesity who are at risk for postmenopausal breast cancer. By comparison, the observed effects of LGEP were similar to results from previously published TRF studies in similar populations. These preliminary findings support further testing of LGEP as an alternative to TRF and a postmenopausal breast cancer prevention strategy. However, results should be interpreted with caution, given the exploratory nature of analyses.
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7.
Pre-Exercise Carbohydrate or Protein Ingestion Influences Substrate Oxidation but Not Performance or Hunger Compared with Cycling in the Fasted State.
Rothschild, JA, Kilding, AE, Broome, SC, Stewart, T, Cronin, JB, Plews, DJ
Nutrients. 2021;(4)
Abstract
Nutritional intake can influence exercise metabolism and performance, but there is a lack of research comparing protein-rich pre-exercise meals with endurance exercise performed both in the fasted state and following a carbohydrate-rich breakfast. The purpose of this study was to determine the effects of three pre-exercise nutrition strategies on metabolism and exercise capacity during cycling. On three occasions, seventeen trained male cyclists (VO2peak 62.2 ± 5.8 mL·kg-1·min-1, 31.2 ± 12.4 years, 74.8 ± 9.6 kg) performed twenty minutes of submaximal cycling (4 × 5 min stages at 60%, 80%, and 100% of ventilatory threshold (VT), and 20% of the difference between power at the VT and peak power), followed by 3 × 3 min intervals at 80% peak aerobic power and 3 × 3 min intervals at maximal effort, 30 min after consuming a carbohydrate-rich meal (CARB; 1 g/kg CHO), a protein-rich meal (PROTEIN; 0.45 g/kg protein + 0.24 g/kg fat), or water (FASTED), in a randomized and counter-balanced order. Fat oxidation was lower for CARB compared with FASTED at and below the VT, and compared with PROTEIN at 60% VT. There were no differences between trials for average power during high-intensity intervals (367 ± 51 W, p = 0.516). Oxidative stress (F2-Isoprostanes), perceived exertion, and hunger were not different between trials. Overall, exercising in the overnight-fasted state increased fat oxidation during submaximal exercise compared with exercise following a CHO-rich breakfast, and pre-exercise protein ingestion allowed similarly high levels of fat oxidation. There were no differences in perceived exertion, hunger, or performance, and we provide novel data showing no influence of pre-exercise nutrition ingestion on exercise-induced oxidative stress.
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8.
High-Protein, Low-Glycaemic Meal Replacement Decreases Fasting Insulin and Inflammation Markers-A 12-Month Subanalysis of the ACOORH Trial.
Kempf, K, Röhling, M, Banzer, W, Braumann, KM, Halle, M, McCarthy, D, Predel, HG, Schenkenberger, I, Tan, S, Toplak, H, et al
Nutrients. 2021;(5)
Abstract
Lifestyle interventions, including meal replacement, are effective in the prevention and treatment of type-2-diabetes and obesity. Since insulin is the key weight regulator, we hypothesised that the addition of meal replacement to a lifestyle intervention reduces insulin levels more effectively than lifestyle intervention alone. In the international multicentre randomised controlled ACOORH (Almased Concept against Overweight and Obesity and Related Health Risk) trial, overweight or obese persons who meet the criteria for metabolic syndrome (n = 463) were randomised into two groups. Both groups received nutritional advice focusing on carbohydrate restriction and the use of telemonitoring devices. The intervention group substituted all three main meals per day in week 1, two meals per day in weeks 2-4, and one meal per day in weeks 5-26 with a protein-rich, low-glycaemic meal replacement. Data were collected at baseline and after 1, 3, 6 and 12 months. All datasets providing insulin data (n = 446) were included in this predefined subanalysis. Significantly higher reductions in insulin (-3.3 ± 8.7 µU/mL vs. -1.6 ± 9.8 µU/mL), weight (-6.1 ± 5.2 kg vs. -3.2 ± 4.6 kg), and inflammation markers were observed in the intervention group. Insulin reduction correlated with weight reduction and the highest amount of weight loss (-7.6 ± 4.9 kg) was observed in those participants with an insulin decrease > 2 µU/mL. These results underline the potential for meal replacement-based lifestyle interventions in diabetes prevention, and measurement of insulin levels may serve as an indicator for adherence to carbohydrate restriction.
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9.
The Effects of Exercise on β-Hydroxybutyrate Concentrations over a 36-h Fast: A Randomized Crossover Study.
Deru, LS, Bikman, BT, Davidson, LE, Tucker, LA, Fellingham, G, Bartholomew, CL, Yuan, HL, Bailey, BW
Medicine and science in sports and exercise. 2021;(9):1987-1998
Abstract
PURPOSE This study assessed β-hydroxybutyrate (BHB) concentration during a short-term fast and the degree to which an initial bout of exercise influences the rate of ketogenesis. METHODS Twenty subjects (11 male, 9 female) completed two 36-h fasts, with one protocol requiring the subject to complete a treadmill exercise session at the beginning of the fast. BHB levels were assessed via portable meter every 2 h, along with mood and hunger ratings. Venipuncture was performed every 12 h. RESULTS The mean (SD) areas under the curve for BHB concentration were 19.19 (2.59) mmol·L-1 (nonexercised) and 27.49 (2.59) mmol·L-1 (exercised), yielding a difference of 8.30 mmol·L-1 between conditions (95% posterior probability interval (PPI), 1.94 to 14.82 mmol·L-1; posterior probability (PP) = 0.99). The mean (SD) times to BHB concentration of 0.5 mmol·L-1 were 21.07 (2.95) h (nonexercised) and 17.5 (1.69) h (exercised), a 3.57-h difference (95% PPI, -2.11 to 10.87 h; PP = 0.89). The differences in area under the curve between conditions were 5.07 μU·mL-1 (95% PPI, -21.64 to 36.18 μU·mL-1; PP = 0.67) for insulin, 97.13 pg·mL-1 (95% PPI, 34.08 to 354.21 pg·mL-1; PP = 0.98) for glucagon, and 20.83 (95% PPI, 4.70 to 24.22; PP = 0.99) for the insulin/glucagon ratio. CONCLUSIONS Completing aerobic exercise at the beginning of a fast accelerates the production of BHB throughout the fast without altering subjective feelings of hunger, thirst, stomach discomfort, or mood. Insulin and the insulin/glucagon ratio experience a marked reduction within the first 12 h of fasting and was not altered with exercise. Thus, exercising at the beginning of a fast may improve the metabolic outcomes of fasting.
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10.
Safety of Every-Other-Day Fasting in the Treatment of Spinal Cord Injury: A Randomized Controlled Trial.
Zheng, J, Liu, J, Jiang, Y, Pang, R, Yang, X, Liu, H, Lin, N, Li, Y, Xiong, D, Chen, X, et al
American journal of physical medicine & rehabilitation. 2021;(12):1184-1189
Abstract
Every-other-day fasting is effective for a variety of major human diseases, but the safety of these interventions is uncertain for patients with spinal cord injury. A randomized controlled study was conducted to investigate the safety of every-other-day fasting in patients with spinal cord injury. Participants who met the diagnostic inclusion and exclusion criteria were randomly divided into the control and every-other-day fasting groups. In the every-other-day fasting group, fasting lasted from 09:00 p.m. on day 1 to 06:00 p.m. on the following day (day 2). Dinner on day 2 was restricted to approximately 30% of the average daily calorie intake. The changes in plasma glucose were recorded daily for 2 days and every other day from the third day after every-other-day fasting intervention. The changes in albumin, prealbumin, plasma potassium, serum sodium, blood calcium, body weight, and body mass index were monitored at the baseline and at the end of the every-other-day fasting intervention. The results showed that compared with the control group, the mean blood glucose levels were significantly decreased from the second week after every-other-day fasting intervention. The body weight of patients in the every-other-day fasting group was notably reduced compared with that at baseline, whereas in body mass index, no obvious differences were observed before and after treatment with every-other-day fasting. In general, every-other-day fasting could be considered as a safe approach for individuals with spinal cord injury.