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Effects of carbohydrate and protein co-ingestion during short-term moderate-intensity exercise on cognitive function.
Sun, FH, Cooper, SB, Gui, Z
The Journal of sports medicine and physical fitness. 2020;(4):656-663
Abstract
BACKGROUND This study aimed to investigate the effects of isocaloric carbohydrate-electrolyte solution (CES) and carbohydrates-electrolyte-protein solution (CEPS) consumed during moderate-intensity exercise on cognitive function. METHODS Twenty-three healthy participants (age: 21.7±1.5 years, Body Mass Index: 21.8±2.0 kg/m2, and peak oxygen consumption (VO2peak): 42.4±6.9 mL/kg/min) were recruited in the study. Participants completed two main experiment trials using a cross-over study design. In each trial, they completed 30 minutes of 70% VO2peak cycling, and one of two solutions (CES or CEPS) was consumed. A battery of cognitive function tests (imPACT Package) was administrated at rest and immediately post-exercise. RESULTS Blood glucose concentrations decreased in both trials. Heart rate and blood lactate concentrations increased in both trials. However, no significant main effects of the exercise on all cognitive function variables (verbal and visual memory, visual-motor speed, reaction time, impulse control, and cognitive efficiency index) were observed (all P>0.05). Also, there was no difference in any of the cognitive function variables between the CES and CEPS trials (all P>0.05). CONCLUSIONS There was no difference in the cognitive performance when CES or CES-PRO solutions was consumed during 30 minutes moderate-intensity cycling.
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A Carbohydrate Beverage Reduces Monocytes Expressing TLR4 in Children with Overweight or Obesity.
Niemiro, GM, Chiarlitti, NA, Khan, NA, De Lisio, M
The Journal of nutrition. 2020;(3):616-622
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Abstract
BACKGROUND Childhood obesity is increasing, with about one-third of children overweight or obese. Obesity is characterized by a state of chronic low-grade inflammation that is related to cardiometabolic comorbidities. Inflammatory monocytes, which are classified into 3 different groups-classical, intermediate, and nonclassical monocytes, with Toll-like receptor 4 (TLR4+) expression indicating a proinflammatory state-underlie several obesity-associated morbidities. OBJECTIVES This study aimed to assess the responses of monocyte populations to beverages of differing macronutrient composition in children with healthy weight (HW) or overweight/obesity (OW/OB). METHODS Ten HW children (5th to 84.9th percentile; mean age 12.29 ± 2.5 y) and 7 children with OW/OB (85th to 99.99th percentile; mean age 11.96 ± 3.8 y) completed the study. Adiposity was determined via DXA. Using a double-blinded, randomized, crossover design, participants consumed either a high-carbohydrate (CHO; 210 kcal; 0 g fat/56 g carbohydrates/0 g protein) or a whole-egg-based high-protein/fat (EGG; 210 kcal; 15 g fat/0 g carbohydrates/18 g protein) beverage. Venous blood was collected at baseline and 2 h postprandially for evaluation of metabolic and inflammatory responses. Repeated measures ANOVA and Pearson correlations were conducted. RESULTS Consuming the CHO beverage significantly reduced the primary outcome: TLR4+ expression on classical monocytes in children with OW/OB only (25.60% decrease from baseline in OW/OB compared with 1.61% increase in HW). Children with OW/OB had significantly less percentages of TLR4+ nonclassical monocytes than HW (47.66% lower after CHO). Insulin and glucose (secondary outcomes), were significantly higher after the CHO condition compared with baseline (230.61% and 9.93% increase, respectively). Changes in glucose were significantly and negatively related to changes in monocyte populations in the CHO condition. CONCLUSIONS These data suggest that high-carbohydrate beverages alter monocyte populations in the blood in children with OW/OB, which is related to glucose metabolism. These findings have implications for nutritional recommendations in children with overweight/obesity. National Clinical Trial registry trial number: NCT03597542.
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The Effects of Low- and High-Glycemic Index Sport Nutrition Bars on Metabolism and Performance in Recreational Soccer Players.
Kaviani, M, Chilibeck, PD, Gall, S, Jochim, J, Zello, GA
Nutrients. 2020;(4)
Abstract
Consumption of low-glycemic index (GI) carbohydrates (CHO) may be superior to high-GI CHO before exercise by increasing fat oxidation and decreasing carbohydrate oxidation. We compared the effects of pre-exercise feeding of a low-GI lentil-based sports nutrition bar with a high-GI bar on metabolism and performance during a simulated soccer match. Using a randomized, double-blind, counterbalanced, crossover design, participants (n = 8) consumed 1.5 g/kg available CHO from a low-GI bar (GI = 45) or high-GI bar (GI = 101) two hours before a 90 min simulated soccer match, and 0.38 g/kg body mass during a 15 min half-time break. The test involved alternating 6 min intervals of paced jogging, running, walking, and sprinting, and 3 min intervals of soccer-specific skills (timed ball dribbling, agility running, heading, kicking accuracy). Carbohydrate oxidation rate was lower during the match after consuming the low-GI compared to high-GI bar (2.17 ± 0.6 vs. 2.72 ± 0.4 g/min; p < 0.05). Participants performed better during the low-GI versus high-GI bar condition on the agility test (5.7 ± 0.4 versus 6.1 ± 0.6 s; p < 0.01) and heading (i.e., jumping height 24.7 ± 4.3 versus 22.2 ± 4.5 cm; p < 0.01) late in the soccer match (72 min). A low-GI lentil-based sports nutrition bar provides a metabolic benefit (lower carbohydrate oxidation rate) and a modest improvement in agility running and jumping height (heading) late in the test.
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Effects of Evening-Only Low-Carbohydrate Meal on Healthy Volunteers.
Yaegashi, A, Suzuki, J
Journal of nutritional science and vitaminology. 2020;(3):229-236
Abstract
We performed a pre/post-interventional study with participants as self-controls to evaluate the effects of consuming an evening-only low-carbohydrate meal (LCM) at 1800 h on biochemical measures of glucose and lipid metabolism. Study participants comprised 14 healthy men (age range, 20-29 y) who, consumed standard test meals (STMs) or LCM at 1800 h. Blood samples were collected at fasting, and at 60-, 120-, and 240 min after the start of the meals. The 60-min postprandial levels and the area under the curve (AUC) 0-120 min for plasma glucose were significantly lower after the LCM than after the STMs. The 60- and 120-min postprandial levels and the AUC 0-240 min for plasma insulin were significantly lower after the LCM than after the STMs (p<0.01). Postprandial triglyceride (TG) levels at 120- and 240 min and the AUC 0-240 min were significantly higher after the LCM than after the STMs (p<0.05, p<0.01, and p<0.05, respectively). The interleukin-6 levels were significantly higher 240 min after the STMs than before the meals (p<0.05), but not after the LCM. In these healthy volunteers, consuming an LCM at 1800 h suppressed postprandial hyperglycemia and insulin secretion; however, postprandial TG increased. Consuming an LCM at 1800 h was beneficial as it inhibited elevation of blood glucose; however, it may also increase the risk of arteriosclerosis through increasing TG levels.
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Pectin-Alginate Does Not Further Enhance Exogenous Carbohydrate Oxidation in Running.
Barber, JFP, Thomas, J, Narang, B, Hengist, A, Betts, JA, Wallis, GA, Gonzalez, JT
Medicine and science in sports and exercise. 2020;(6):1376-1384
Abstract
PURPOSE Maximizing carbohydrate availability is important for many endurance events. Combining pectin and sodium alginate with ingested maltodextrin-fructose (MAL + FRU + PEC + ALG) has been suggested to enhance carbohydrate delivery via hydrogel formation, but the influence on exogenous carbohydrate oxidation remains unknown. The primary aim of this study was to assess the effects of MAL + FRU + PEC + ALG on exogenous carbohydrate oxidation during exercise compared with a maltodextrin-fructose mixture (MAL + FRU). MAL + FRU has been well established to increase exogenous carbohydrate oxidation during cycling compared with glucose-based carbohydrates (MAL + GLU). However, much evidence focuses on cycling, and direct evidence in running is lacking. Therefore, a secondary aim was to compare exogenous carbohydrate oxidation rates with MAL + FRU versus MAL + GLU during running. METHODS Nine trained runners completed two trials (MAL + FRU and MAL + FRU + PEC + ALG) in a double-blind, randomized crossover design. A subset (n = 7) also completed a MAL + GLU trial to address the secondary aim, and a water trial to establish background expired CO2 enrichment. Participants ran at 60% V˙O2peak for 120 min while ingesting either water only or carbohydrate solutions at a rate of 1.5 g carbohydrate per minute. RESULTS At the end of 120 min of exercise, exogenous carbohydrate oxidation rates were 0.9 (SD 0.5) g·min with MAL + GLU ingestion. MAL + FRU ingestion increased exogenous carbohydrate oxidation rates to 1.1 (SD 0.3) g·min (P = 0.038), with no further increase with MAL + FRU + PEC + ALG ingestion (1.1 (SD 0.3) g·min; P = 1.0). No time-treatment interaction effects were observed for plasma glucose, lactate, insulin, or nonesterified fatty acids, or for ratings of perceived exertion or gastrointestinal symptoms (all, P > 0.05). CONCLUSION To maximize exogenous carbohydrate oxidation during moderate-intensity running, athletes may benefit from consuming glucose(polymer)-fructose mixtures over glucose-based carbohydrates alone, but the addition of pectin and sodium alginate offers no further benefit.
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Nitrate-rich beetroot juice offsets salivary acidity following carbohydrate ingestion before and after endurance exercise in healthy male runners.
Burleigh, MC, Sculthorpe, N, Henriquez, FL, Easton, C
PloS one. 2020;(12):e0243755
Abstract
There have been recent calls for strategies to improve oral health in athletes. High carbohydrate diets, exercise induced dehydration and transient perturbations to immune function combine to increase oral disease risk in this group. We tested whether a single dose of nitrate (NO3-) would offset the reduction in salivary pH following carbohydrate ingestion before and after an exercise bout designed to cause mild dehydration. Eleven trained male runners ([Formula: see text] 53 ± 9 ml∙kg-1∙min-1, age 30 ± 7 years) completed a randomised placebo-controlled study comprising four experimental trials. Participants ingested the following fluids one hour before each trial: (a) 140 ml of water (negative-control), (b) 140 ml of water (positive-control), (c) 140 ml of NO3- rich beetroot juice (~12.4 mmol NO3-) (NO3- trial) or (d) 140 ml NO3- depleted beetroot juice (placebo-trial). During the negative-control trial, participants ingested 795 ml of water in three equal aliquots: before, during, and after 90 min of submaximal running. In the other trials they received 795 ml of carbohydrate supplements in the same fashion. Venous blood was collected before and after the exercise bout and saliva was sampled before and repeatedly over the 20 min following carbohydrate or water ingestion. As expected, nitrite (NO2-) and NO3- were higher in plasma and saliva during the NO3- trial than all other trials (all P<0.001). Compared to the negative-control, salivary-pH was significantly reduced following the ingestion of carbohydrate in the positive-control and placebo trials (both P <0.05). Salivary-pH was similar between the negative-control and NO3- trials before and after exercise despite ingestion of carbohydrate in the NO3- trial (both P≥0.221). Ingesting NO3- attenuates the expected reduction in salivary-pH following carbohydrate supplements and exercise-induced dehydration. NO3- should be considered by athletes as a novel nutritional strategy to reduce the risk of developing acidity related oral health conditions.
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Effect of a Moderate Carbohydrate-Restricted Diet on DPP-4 Inhibitor Action among Individuals with Type 2 Diabetes Mellitus: A 6-Month Intervention Study.
Kobayashi, M, Miura, T, Miura, K, Hiroyama, N, Akashi, K
Journal of nutritional science and vitaminology. 2020;(2):114-118
Abstract
To decrease body weight and insulin resistance, a calorie-restricted diet-with minimal caloric intake required for daily activities-is the primary treatment strategy for patients with type 2 diabetes (T2D) in Japan. However, many patients cannot continue with this diet for long, because calorie restriction is difficult and nutritional balance is hard to understand. Carbohydrate-restricted diets are easier for patients than conventional calorie-restricted diet. In this study we aimed to elucidate the effects of a moderate carbohydrate-restricted diet on glucose metabolism and renal function in patients with T2D on dipeptidyl peptidase-4 (DPP-4) inhibitors. Nineteen outpatients with T2D continued on a moderate carbohydrate-restricted diet (targeting 50% of calories) for 6 mo. Meanwhile, 10 other outpatients with T2D on DPP-4 inhibitors had the conventional calorie-restricted diet using the food exchange table. No change in prescription drugs occurred for both groups during the study period. After the intervention, the carbohydrate content in dietary intake was lowered significantly from 56.8±8.3 to 46.8±10.1%, while the lipid concentration, primarily n-6 polyunsaturated fatty acids, was significantly increased. There was no significant change in protein intake. Hemoglobin A1c (HbA1c) fell from 7.22±0.74% to 6.95±0.72% (mean±SD). Furthermore, salt intake decreased significantly from 6.8±2.5 g prior to the intervention, to 5.7±1.9 g after the intervention. The estimated glomerular filtration rates (eGFR) decreased slightly, while serum creatinine levels did not change. These findings suggest that a moderate carbohydrate-restricted diet (50%) is effective in patients with T2D, without affecting kidney function.
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Short-term effects of carbohydrates differing in glycemic index (GI) consumed at lunch on children's cognitive function in a randomized crossover study.
Jansen, K, Tempes, J, Drozdowska, A, Gutmann, M, Falkenstein, M, Buyken, AE, Libuda, L, Rudolf, H, Lücke, T, Kersting, M
European journal of clinical nutrition. 2020;(5):757-764
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Abstract
BACKGROUND Intervention studies suggest an influence of breakfast dietary glycemic index (GI) on children's cognition. The Cognition Intervention Study Dortmund-GI-I study examined whether lunch dietary GI might have short-term effects on selected cognitive parameters. METHODS A randomized crossover study was performed at a comprehensive school on 2 test days. One hundred and eighty-nine participants (5th and 6th grade) were randomly assigned to one of the two sequences, medium-high GI (m-hGI) or high-medium GI (h-mGI), following block randomization. In the first period, one group received a dish containing hGI rice (GI: 86) ad libitum, the other mGI rice (GI: 62)-1 week later, in the second period, vice versa. Tonic alertness, task switching, and working memory updating were tested with a computerized test battery 45 min after beginning of lunch break. Treatment effects were estimated using the t test for normally distributed data or the Wilcoxon rank-sum test for non-normally distributed data. RESULTS The crossover approach revealed no effects of lunch dietary GI on the tested cognitive parameters in the early afternoon. However, we determined carryover effects for two parameters, and therefore analyzed only data of the first period. The reaction time of the two-back task (working memory updating) was faster (p = 0.001) and the count of commission errors in the alertness task was lower (p = 0.04) in the hGI group. CONCLUSION No evidence of short-term effects of lunch dietary GI on cognition of schoolchildren was found. Potential positive effects on single parameters of working memory updating and tonic alertness favoring hGI rice need to be verified.
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Postprandial regulation of prouroguanylin in humans of a healthy weight and those who are overweight or with obesity.
Patterson, M, Ward, H, Halvai, D, Holm Nilsen, HA, Reeves, S
Peptides. 2020;:170179
Abstract
Uroguanylin is a peptide gut hormone proposed to have a role in signalling post meal satiety. Uroguanylin circulates as its pro-hormone, prouroguanylin. There has been limited investigation of the regulation of prouroguanylin by food; therefore we investigated prouroguanylin regulation following meals. In separate experiments we investigated the effects of high calorie (1451 kcal) and medium calorie (725 kcal), high fat meals, on plasma prouroguanylin concentrations. We then examined the effect of a 722.5 kcal high carbohydrate breakfast on prouroguanylin concentrations, comparing the response in healthy weight adults versus those who are overweight/ with obesity. The 1451 kcal meal increased prouroguanylin concentrations, versus fasting at 60 (P < 0.05), 90 (P < 0.01) and 120 (P < 0.001) minutes. After the 725 kcal meal hormone concentrations rose more slowly and were significant versus fasting concentrations at 120 min (P < 0.01). The high carbohydrate breakfast 722.5 kcal, led to an initial suppression of hormone concentrations at 30 min. post meal (P < 0.05) followed by an increase in concentrations until they were significant versus fasting at 120 min. (P < 0.01). Participants overweight/ with obesity had lower fasting prouroguanylin concentrations (P < 0.05), but post meal concentrations did not differ between the groups. Our results suggest there is a delayed increase in prouroguanylin concentrations following, large and regular sized mixed macronutrient meals rich in fat or carbohydrate. Fasting levels are suppressed in people who are overweight/ with obesity, but the post meal response remains intact. There may be potential to target post meal release of prouroguanylin in obesity.
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Iron Metabolism: Interactions with Energy and Carbohydrate Availability.
McKay, AKA, Pyne, DB, Burke, LM, Peeling, P
Nutrients. 2020;(12)
Abstract
The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.