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Postexercise repletion of muscle energy stores with fructose or glucose in mixed meals.
Rosset, R, Lecoultre, V, Egli, L, Cros, J, Dokumaci, AS, Zwygart, K, Boesch, C, Kreis, R, Schneiter, P, Tappy, L
The American journal of clinical nutrition. 2017;(3):609-617
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Abstract
Background: Postexercise nutrition is paramount to the restoration of muscle energy stores by providing carbohydrate and fat as precursors of glycogen and intramyocellular lipid (IMCL) synthesis. Compared with glucose, fructose ingestion results in lower postprandial glucose and higher lactate and triglyceride concentrations. We hypothesized that these differences in substrate concentration would be associated with a different partition of energy stored as IMCLs or glycogen postexercise.Objective: The purpose of this study was to compare the effect of isocaloric liquid mixed meals containing fat, protein, and either fructose or glucose on the repletion of muscle energy stores over 24 h after a strenuous exercise session.Design: Eight male endurance athletes (mean ± SEM age: 29 ± 2 y; peak oxygen consumption: 66.8 ± 1.3 mL · kg-1 · min-1) were studied twice. On each occasion, muscle energy stores were first lowered by a combination of a 3-d controlled diet and prolonged exercise. After assessment of glycogen and IMCL concentrations in vastus muscles, subjects rested for 24 h and ingested mixed meals providing fat and protein together with 4.4 g/kg fructose (the fructose condition; FRU) or glucose (the glucose condition; GLU). Postprandial metabolism was assessed over 6 h, and glycogen and IMCL concentrations were measured again after 24 h. Finally, energy metabolism was evaluated during a subsequent exercise session.Results: FRU and GLU resulted in similar IMCL [+2.4 ± 0.4 compared with +2.0 ± 0.6 mmol · kg-1 wet weight · d-1; time × condition (mixed-model analysis): P = 0.45] and muscle glycogen (+10.9 ± 0.9 compared with +12.3 ± 1.9 mmol · kg-1 wet weight · d-1; time × condition: P = 0.45) repletion. Fructose consumption in FRU increased postprandial net carbohydrate oxidation and decreased net carbohydrate storage (estimating total, muscle, and liver glycogen synthesis) compared with GLU (+117 ± 9 compared with +135 ± 9 g/6 h, respectively; P < 0.01). Compared with GLU, FRU also resulted in lower plasma glucose concentrations and decreased exercise performance the next day.Conclusions: Mixed meals containing fat, protein, and either fructose or glucose elicit similar repletion of IMCLs and muscle glycogen. Under such conditions, fructose lowers whole-body glycogen synthesis and impairs subsequent exercise performance, presumably because of lower hepatic glycogen stores. This trial was registered at clinicaltrials.gov as NCT01866215.
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Increased liver fat and glycogen stores after consumption of high versus low glycaemic index food: A randomized crossover study.
Bawden, S, Stephenson, M, Falcone, Y, Lingaya, M, Ciampi, E, Hunter, K, Bligh, F, Schirra, J, Taylor, M, Morris, P, et al
Diabetes, obesity & metabolism. 2017;(1):70-77
Abstract
AIM: To investigate the acute and longer-term effects of low (LGI) versus high glycaemic index (HGI) diets on hepatic fat and glycogen accumulation and related blood measures in healthy volunteers. METHODS Eight healthy men (age 20.1 ± 0.4 years, body mass index 23.0 ± 0.9 kg/m2 ) attended a test day before and after a 7-day macronutrient- and energy-matched HGI or LGI diet, followed by a minimum 4-week wash-out period, and then returned to repeat the intervention with the alternative diet. During test days, participants consumed either an HGI or an LGI test meal corresponding to their diet week, and liver fat [ 1 H magnetic resonance spectroscopy (MRS)], glycogen ( 13 C MRS) and gastric content volume (MRI) were measured. Blood samples were obtained regularly throughout the test day to assess plasma glucose and insulin levels. RESULTS Plasma glucose and insulin peak values and area under the curve were significantly greater after the HGI test meal compared with the LGI test meal, as expected. Hepatic glycogen concentrations increased more after the HGI test meal ( P < .05) and peak levels were significantly greater after 7 days of HGI dietary intervention compared with those at the beginning of the intervention ( P < .05). Liver fat fractions increased significantly after the HGI dietary intervention compared with the LGI dietary intervention (two-way repeated-measures analysis of variance P ≤ .05). CONCLUSIONS Compared with an LGI diet, a 1-week HGI diet increased hepatic fat and glycogen stores. This may have important clinical relevance for dietary interventions in the prevention and management of non-alcoholic fatty liver disease.
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Type of infectious disease affects glucose metabolism and liver glycogen content in Surinamese children: malaria vs. pneumonia.
Zijlmans, W, Jitan, J, Ackermans, MT, Serlie, MJ, van Kempen, AA, Sauerwein, HP
Journal of pediatric endocrinology & metabolism : JPEM. 2013;(3-4):293-9
Abstract
BACKGROUND AND AIM Fasting is an important risk factor for hypoglycemia in children with malaria or pneumonia. Young children are more at risk because of impaired endogenous glucose production presumably due to smaller liver glycogen stores. The aim of this study was to measure the effect of a bolus of glucagon on glucose kinetics, as an indicator of glycogen content, in fasted children with malaria and pneumonia. METHODS After a 16-h controlled fast, plasma glucose concentration and endogenous glucose production were measured using [6,6-2H2]glucose in six children with severe malaria and 12 children with severe pneumonia who were 1-5 years of age before and after a bolus glucagon. RESULTS Basal glucose concentration and endogenous glucose production were higher in children with malaria, p=0.034 and p=0.010, respectively. After glucagon, the increase in the plasma glucose concentration was higher in children with malaria (52±26% vs. 31±23%, p=0.029). Also, the increase in glucose production was higher in children with malaria (106±42% vs. 70±52%, p=0.023). There were no differences in the fasting duration or duration of illness. CONCLUSIONS This is the first study to show infectious disease-related differences in the adaptation of glucose metabolism to fasting in young children. It was found that basal glucose concentration and endogenous glucose production were higher in children with malaria. The increase in plasma glucose concentration and endogenous glucose production in response to glucagon was higher in children with malaria, indicating smaller glycogen stores in children with pneumonia.
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Creatine supplementation does not affect human skeletal muscle glycogen content in the absence of prior exercise.
Sewell, DA, Robinson, TM, Greenhaff, PL
Journal of applied physiology (Bethesda, Md. : 1985). 2008;(2):508-12
Abstract
Due to the current lack of clarity, we examined whether 5 days of dietary creatine (Cr) supplementation per se can influence the glycogen content of human skeletal muscle. Six healthy male volunteers participated in the study, reporting to the laboratory on four occasions to exercise to the point of volitional exhaustion, each after 3 days of a controlled normal habitual dietary intake. After a familiarization visit, participants cycled to exhaustion in the absence of any supplementation (N), and then 2 wk later again they cycled to exhaustion after 5 days of supplementation with simple sugars (CHO). Finally, after a further 2 wk, they again cycled to exhaustion after 5 days of Cr supplementation. Muscle samples were taken at rest before exercise, at the time point of exhaustion in visit 1, and at subsequent visit time of exhaustion. There was a treatment effect on muscle total Cr content in Cr compared with N and CHO supplementation (P < 0.01). Resting muscle glycogen content was elevated above N following CHO (P < 0.05) but not after Cr. At exhaustion following N, glycogen content was no different from CHO and Cr measured at the same time point during exercise. Cr supplementation under conditions of controlled habitual dietary intake had no effect on muscle glycogen content at rest or after exhaustive exercise. We suggest that any Cr-associated increases in muscle glycogen storage are the result of an interaction between Cr supplementation and other mediators of muscle glycogen storage.
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Gender-specific usage of intramyocellular lipids and glycogen during exercise.
Zehnder, M, Ith, M, Kreis, R, Saris, W, Boutellier, U, Boesch, C
Medicine and science in sports and exercise. 2005;(9):1517-24
Abstract
PURPOSE Gender-specific differences in substrate utilization during exercise have been reported, typically such that women rely more on fat than men. This study investigated whether gender differences exist in the utilization of intramyocellular lipids (IMCL) and glycogen. METHODS IMCL and glycogen, as well as total fat and carbohydrate (CHO) oxidation were measured in nine males and nine females before, during, and after an endurance exercise. The trained subjects exercised on a bicycle ergometer at 50% maximal workload for 3 h. IMCL and glycogen were determined in the thigh by magnetic resonance spectroscopy. Oxygen uptake (VO(2)) and carbon dioxide production were determined by open circuit spirometry to calculate total fat and CHO oxidation. Relative power output, percent of maximum heart rate, VO(2peak), and respiratory exchange ratio were the same. RESULTS Average fat oxidation was the same, whereas CHO oxidation was significantly higher in males compared with females. The relative contribution of these fuels to total energy used were similar in males and females. Males and females depleted IMCL and glycogen significantly (P < 0.001) during the 3-h exercise. IMCL levels at rest (P < 0.05) and its depletion during exercise (P < 0.001) were significantly higher in males compared with females, whereas glycogen was stored and used in the same range by both genders. CONCLUSION During this 3-h exercise, energy supplies from fat and CHO were similar in both genders, and males as well as females reduced their IMCL stores significantly. The larger contribution of IMCL during exercise in males compared with females could either be a result of gender-specific substrate selection, or different long-term training habit.
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Failure to repeatedly supercompensate muscle glycogen stores in highly trained men.
McInerney, P, Lessard, SJ, Burke, LM, Coffey, VG, Lo Giudice, SL, Southgate, RJ, Hawley, JA
Medicine and science in sports and exercise. 2005;(3):404-11
Abstract
PURPOSE It is not known whether it is possible to repeatedly supercompensate muscle glycogen stores after exhaustive exercise bouts undertaken within several days. METHODS We evaluated the effect of repeated exercise-diet manipulation on muscle glycogen and triacylglycerol (IMTG) metabolism and exercise capacity in six well-trained subjects who completed an intermittent, exhaustive cycling protocol (EX) on three occasions separated by 48 h (i.e., days 1, 3, and 5) in a 5-d period. Twenty-four hours before day 1, subjects consumed a moderate (6 g.kg)-carbohydrate (CHO) diet, followed by 5 d of a high (12 g.kg.d)-CHO diet. Muscle biopsies were taken at rest, immediately post-EX on days 1, 3, and 5, and after 3 h of recovery on days 1 and 3. RESULTS Compared with day 1, resting muscle [glycogen] was elevated on day 3 but not day 5 (435+/-57 vs 713+/-60 vs 409+/-40 mmol.kg, P<0.001). [IMTG] was reduced by 28% (P<0.05) after EX on day 1, but post-EX levels on days 3 and 5 were similar to rest. EX was enhanced on days 3 and 5 compared with day 1 (31.9+/-2.5 and 35.4+/-3.8 vs 24.1+/-1.4 kJ.kg, P<0.05). Glycogen synthase activity at rest and immediately post-EX was similar between trials. Additionally, the rates of muscle glycogen accumulation were similar during the 3-h recovery period on days 1 and 3. CONCLUSION We show that well-trained men cannot repeatedly supercompensate muscle [glycogen] after glycogen-depleting exercise and 2 d of a high-CHO diet, suggesting that the mechanisms responsible for glycogen accumulation are attenuated as a consequence of successive days of glycogen-depleting exercise.
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Muscle glycogen content in type 2 diabetes mellitus.
He, J, Kelley, DE
American journal of physiology. Endocrinology and metabolism. 2004;(5):E1002-7
Abstract
Muscle contains the largest reservoir of glycogen (Glyc), a depot that is closely regulated and with influence on insulin sensitivity. The current study examines muscle Glyc in type 2 diabetes mellitus (T2DM) and obesity and with respect to muscle fiber type, intramyocellular lipid content (IMCL), and mitochondrial function (oxidative enzyme activity; OX-Enz). There is increasing interest in the relation of IMCL and mitochondrial dysfunction with insulin resistance (IR), yet the association with muscle Glyc has not been examined with regard to these parameters. Using a quantitative histological approach specific to muscle fiber types, we assessed muscle Glyc, IMCL, and OX-Enz in vastus lateralis obtained by percutaneous biopsy in lean nondiabetic (L; n = 16), obese nondiabetic (Ob; n = 15), and T2DM volunteers (n = 14). Insulin sensitivity was estimated using homeostasis model assessment (HOMA)-IR. Muscle Glyc was reduced in T2DM, a deficit evident for type IIa fibers, yet minor in types I and IIb fibers. Low Glyc in T2DM correlated with fasting hyperglycemia. Also, in T2DM and Ob, there was significantly higher IMCL and lower OX-Enz in all fiber types. The IMCL-to-OX-Enz ratio, especially for type I fibers, correlated strongly with IR. Similarly, a Glyc-to-OX-Enz ratio correlated with IR, particularly for type IIb fibers. This ratio tended to be higher in Ob and T2DM. In summary, there is decreased muscle Glyc in T2DM yet a disproportional Glyc-to-OX-Enz relationship that is related to IR, although not as robustly as the IMCL-to-OX-Enz ratio.
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Regulation of metabolic genes in human skeletal muscle by short-term exercise and diet manipulation.
Arkinstall, MJ, Tunstall, RJ, Cameron-Smith, D, Hawley, JA
American journal of physiology. Endocrinology and metabolism. 2004;(1):E25-31
Abstract
Changes in dietary macronutrient intake alter muscle and blood substrate availability and are important for regulating gene expression. However, few studies have examined the effects of diet manipulation on gene expression in human skeletal muscle. The aim of this study was to quantify the extent to which altering substrate availability impacts on subsequent mRNA abundance of a subset of carbohydrate (CHO)- and fat-related genes. Seven subjects consumed either a low- (LOW; 0.7 g/kg body mass CHO) or high- (HIGH; 10 g/kg body mass CHO) CHO diet for 48 h after performing an exhaustive exercise bout to deplete muscle glycogen stores. After intervention, resting muscle and blood samples were taken. Muscle was analyzed for the gene abundances of GLUT4, glycogenin, pyruvate dehydrogenase kinase-4 (PDK-4), fatty acid translocase (FAT/CD36), carnitine palmitoyltransferase I (CPT I), hormone-sensitive lipase (HSL), beta-hydroxyacyl-CoA dehydrogenase (beta-HAD), and uncoupling binding protein-3 (UCP3), and blood samples for glucose, insulin, and free fatty acid (FFA) concentrations. Glycogen-depleting exercise and HIGH-CHO resulted in a 300% increase in muscle glycogen content (P < 0.001) relative to the LOW-CHO condition. FFA concentrations were twofold higher after LOW- vs. HIGH-CHO (P < 0.05). The exercise-diet manipulation exerted a significant effect on transcription of all carbohydrate-related genes, with an increase in GLUT4 and glycogenin mRNA abundance and a reduction in PDK-4 transcription after HIGH-CHO (all P < 0.05). FAT/CD36 (P < 0.05) and UCP3 (P < 0.01) gene transcriptions were increased following LOW-CHO. We conclude that 1) there was a rapid capacity for a short-term exercise and diet intervention to exert coordinated changes in the mRNA transcription of metabolic related genes, and 2) genes involved in glucose regulation are increased following a high-carbohydrate diet.
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Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans.
Battram, DS, Shearer, J, Robinson, D, Graham, TE
Journal of applied physiology (Bethesda, Md. : 1985). 2004;(3):943-50
Abstract
The purpose of this study was to examine the effects of caffeine (Caf) ingestion on pro- (PG) and macroglycogen (MG) resynthesis in 10 healthy men. Subjects completed two trials, consisting of a glycogen-depleting exercise, while ingesting either Caf or placebo capsules. Throughout recovery, biopsies were taken at 0 (exhaustion), 30, 120, and 300 min, and 75 g of carbohydrate were ingested at 0, 60, 120, 180, and 240 min. Whereas Caf ingestion resulted in a higher blood glucose concentration and decreased glycogen synthase fractional velocity (P
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Skeletal muscle glycogen concentration and metabolic responses following a high glycaemic carbohydrate breakfast.
Chryssanthopoulos, C, Williams, C, Nowitz, A, Bogdanis, G
Journal of sports sciences. 2004;(11-12):1065-71
Abstract
The purpose of this study was to examine the influence of a carbohydrate-rich meal on post-prandial metabolic responses and skeletal muscle glycogen concentration. After an overnight fast, eight male recreational/club endurance runners ingested a carbohydrate (CHO) meal (2.5 g CHO x kg(-1) body mass) and biopsies were obtained from the vastus lateralis muscle before and 3 h after the meal. Ingestion of the meal resulted in a 10.6 +/- 2.5% (P < 0.05) increase in muscle glycogen concentration (pre-meal vs post-meal: 314.0 +/- 33.9 vs 347.3 +/- 31.3 mmol x kg(-1) dry weight). Three hours after ingestion, mean serum insulin concentrations had not returned to pre-feeding values (0 min vs 180 min: 45 +/- 4 vs 143 +/- 21 pmol x l(-1)). On a separate occasion, six similar individuals ingested the meal or fasted for a further 3 h during which time expired air samples were collected to estimate the amount of carbohydrate oxidized over the 3 h post-prandial period. It was estimated that about 20% of the carbohydrate consumed was converted into muscle glycogen, and about 12 % was oxidized. We conclude that a meal providing 2.5 g CHO x kg(-1) body mass can increase muscle glycogen stores 3 h after ingestion. However, an estimated 67% of the carbohydrate ingested was unaccounted for and this may have been stored as liver glycogen and/or still be in the gastrointestinal tract.