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Fenne KT, Clauss M, Schäfer Olstad D, Johansen EI, Jensen J. An Acute Bout of Endurance Exercise Does Not Prevent the Inhibitory Effect of Caffeine on Glucose Tolerance the following Morning. Nutrients 2023; 15:nu15081941. [PMID: 37111160 PMCID: PMC10143402 DOI: 10.3390/nu15081941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 03/29/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Caffeine reduces glucose tolerance, whereas exercise training improves glucose homeostasis. The aim of the present study was to investigate the effect of caffeine on glucose tolerance the morning after an acute bout of aerobic exercise. Methods: The study had a 2 × 2 factorial design. Oral glucose tolerance tests (OGTT) were performed after overnight fasting with/without caffeine and with/without exercise the evening before. Eight healthy young active males were included (Age 25.5 ± 1.5 years; 83.9 ± 9.0 kg; VO2max: 54.3 ± 7.0 mL·kg-1·min-1). The exercise session consisted of 30 min cycling at 71% of VO2max followed by four 5 min intervals at 84% with 3 min of cycling at 40% of VO2max between intervals. The exercise was performed at 17:00 h. Energy expenditure at each session was ~976 kcal. Lactate increased to ~8 mM during the exercise sessions. Participants arrived at the laboratory the following morning at 7.00 AM after an overnight fast. Resting blood samples were taken before blood pressure and heart rate variability (HRV) were measured. Caffeine (3 mg/kg bodyweight) or placebo (similar taste/flavor) was ingested, and blood samples, blood pressure and HRV were measured after 30 min. Next, the OGTTs were initiated (75 g glucose dissolved in 3 dL water) and blood was sampled. Blood pressure and HRV were measured during the OGTT. Caffeine increased the area under curve (AUC) for glucose independently of whether exercise was done the evening before (p = 0.03; Two-way ANOVA; Interaction: p = 0.835). Caffeine did not significantly increase AUC for C-peptides compared to placebo (p = 0.096), and C-peptide response was not influenced by exercise. The acute bout of exercise did not significantly improve glucose tolerance the following morning. Diastolic blood pressure during the OGTT was slightly higher after intake of caffeine, independent of whether exercise was performed the evening before or not. Neither caffeine nor exercise the evening before significantly influenced HRV. In conclusion, caffeine reduced glucose tolerance independently of whether endurance exercise was performed the evening before. The low dose of caffeine did not influence heart rate variability but increased diastolic blood pressure slightly.
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Affiliation(s)
- Karoline T Fenne
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Matthieu Clauss
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | | | - Egil I Johansen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
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Virgili J, Motitis P, Julal G, Mavrommatis Y, Pilic L. The impact of genetic variability on the relationship between caffeine and cardiometabolic outcomes: A systematic review. NUTR BULL 2023; 48:28-42. [PMID: 36842137 DOI: 10.1111/nbu.12606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 02/27/2023]
Abstract
The relationship between caffeine consumption and cardiometabolic health has been reported, however with heterogenous results. Discrepancies in study results may be due to inter-individual variability between study participants. This systematic review aimed to identify the impact of genetics on the relationship between caffeine consumption and cardiometabolic outcomes. Electronic databases (PubMed and EMBASE) were searched for studies published until July 2021. Selected studies were of both intervention and observational design and included (1) analysis of at least one of the selected cardiometabolic outcome (type 2 diabetes, glucose/insulin levels, cardiovascular disease [CVD], blood pressure [BP] or hypertension, and blood lipid and catecholamine levels), (2) adults aged 18-65 years, and (3) genetic analysis of individuals consuming caffeine. Seventeen studies were included: four randomised controlled trials and an interventional and quasi-experimental study, six population-based prospective cohort studies, three cross-sectional studies, and three case-control studies. CYP1A2 rs762551 and ADORA rs5751876 were associated with glucose response when caffeine was consumed with carbohydrates. CYP1A2 rs762551 moderated the association between coffee intake and hypertension. Moreover, ADORA2A rs5751876 and the ADRA2B I variants moderated the associations between caffeine and BP. Studies that investigated the effects of genetic variations on CVD and caffeine consumption reported equivocal findings (CYP1A2) or warrant replication (COMT, ADORA and TRIB1). Elucidating the extent to which these genes moderate the association between caffeine and cardiometabolic outcomes will enable caffeine consumption advice to be tailored to specific individuals to optimise health.
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Affiliation(s)
- Jessica Virgili
- Department of Health Science, Faculty of Sport, Allied Health and Performance Sciences, St Mary's University Twickenham, Twickenham, UK
| | - Petros Motitis
- Department of Health Science, Faculty of Sport, Allied Health and Performance Sciences, St Mary's University Twickenham, Twickenham, UK
| | - Gabrielle Julal
- Department of Health Science, Faculty of Sport, Allied Health and Performance Sciences, St Mary's University Twickenham, Twickenham, UK
| | - Yiannis Mavrommatis
- Department of Health Science, Faculty of Sport, Allied Health and Performance Sciences, St Mary's University Twickenham, Twickenham, UK
| | - Leta Pilic
- Department of Health Science, Faculty of Sport, Allied Health and Performance Sciences, St Mary's University Twickenham, Twickenham, UK
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Prado E, Magalhães-Neto A, Neto JR, Bassini A, Cameron LC. Caffeine decreases ammonemia in athletes using a ketogenic diet during prolonged exercise. Nutrition 2021; 91-92:111377. [PMID: 34273681 DOI: 10.1016/j.nut.2021.111377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 05/26/2021] [Accepted: 05/30/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES Both exercise and a ketogenic (low-carbohydrate) diet favor glycogen depletion and increase ammonemia, which can impair physical performance. Caffeine supplementation has been routinely used to improve exercise performance. Herein, the effect of xanthine was evaluated on ammonemia in cyclists who were placed on a ketogenic diet and engaged in prolonged exercise. METHODS Fourteen male cyclists followed a ketogenic diet for 2 d before and during the experimental trial. The cyclists were assigned to either the caffeine- (CEx; n = 7) or placebo-supplemented (LEx; n = 7) group. Blood samples were obtained during cycling and the recovery periods. RESULTS The CEx group showed a significant decrease (up to 25%) in blood ammonia at 60, 90, and 120 min after beginning exercise compared with the LEx group. A higher concentration of apparent blood urea was observed in the LEx group than in the CEx group at 60 to 90 min of exercise (~10%). In addition, a significant increase in blood glucose levels was evident at 30 min of exercise (~28%), and an increase in blood lactate levels was visible during the first 30 to 60 min of exercise (~80%) in the CEx group. CONCLUSIONS Our results suggest that the consumption of caffeine might attenuate the increase in ammonemia that occurs during exercise.
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Affiliation(s)
- Eduardo Prado
- Laboratory for Research in Physical Exercise and Metabolism, Federal University of Alagoas, Maceió, Brazil
| | - Aníbal Magalhães-Neto
- Biological and Health Sciences Institute, Federal University of Mato Grosso, Barra do Garças, Brazil
| | - José Rezende Neto
- Department of Pharmacy, Federal University of Sergipe, Lagarto, Brazil
| | - Adriana Bassini
- Laboratory of Protein Biochemistry, Federal University of State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiz-Claudio Cameron
- Laboratory of Protein Biochemistry, Federal University of State of Rio de Janeiro, Rio de Janeiro, Brazil.
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Ahmad SY, Friel J, Mackay D. The Effects of Non-Nutritive Artificial Sweeteners, Aspartame and Sucralose, on the Gut Microbiome in Healthy Adults: Secondary Outcomes of a Randomized Double-Blinded Crossover Clinical Trial. Nutrients 2020; 12:nu12113408. [PMID: 33171964 PMCID: PMC7694690 DOI: 10.3390/nu12113408] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/15/2022] Open
Abstract
Non-nutritive artificial sweeteners (NNSs) may have the ability to change the gut microbiota, which could potentially alter glucose metabolism. This study aimed to determine the effect of sucralose and aspartame consumption on gut microbiota composition using realistic doses of NNSs. Seventeen healthy participants between the ages of 18 and 45 years who had a body mass index (BMI) of 20–25 were selected. They undertook two 14-day treatment periods separated by a four-week washout period. The sweeteners consumed by each participant consisted of a standardized dose of 14% (0.425 g) of the acceptable daily intake (ADI) for aspartame and 20% (0.136 g) of the ADI for sucralose. Faecal samples collected before and after treatments were analysed for microbiome and short-chain fatty acids (SCFAs). There were no differences in the median relative proportions of the most abundant bacterial taxa (family and genus) before and after treatments with both NNSs. The microbiota community structure also did not show any obvious differences. There were no differences in faecal SCFAs following the consumption of the NNSs. These findings suggest that daily repeated consumption of pure aspartame or sucralose in doses reflective of typical high consumption have minimal effect on gut microbiota composition or SCFA production.
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Affiliation(s)
- Samar Y. Ahmad
- Richardson Centre for Functional Foods and Nutraceuticals, Department of Human Nutritional Sciences, University of Manitoba, 196 Innovation Drive, Winnipeg, MB R3T 2E1, Canada; (J.F.); (D.M.)
- Correspondence: ; Tel.: +96-599-782-245
| | - James Friel
- Richardson Centre for Functional Foods and Nutraceuticals, Department of Human Nutritional Sciences, University of Manitoba, 196 Innovation Drive, Winnipeg, MB R3T 2E1, Canada; (J.F.); (D.M.)
| | - Dylan Mackay
- Richardson Centre for Functional Foods and Nutraceuticals, Department of Human Nutritional Sciences, University of Manitoba, 196 Innovation Drive, Winnipeg, MB R3T 2E1, Canada; (J.F.); (D.M.)
- Department of Community Health Sciences, Rady Faculty of Health Sciences Winnipeg, University of Manitoba, MB R3T 6C5, Canada
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Silveira R, Andrade-Souza VA, Arcoverde L, Tomazini F, Sansonio A, Bishop DJ, Bertuzzi R, Lima-Silva AE. Caffeine Increases Work Done above Critical Power, but Not Anaerobic Work. Med Sci Sports Exerc 2018; 50:131-140. [PMID: 28832393 DOI: 10.1249/mss.0000000000001408] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The assumption that the curvature constant (W') of the power-duration relationship represents anaerobic work capacity is a controversial, unresolved question. We investigated if caffeine ingestion could increase total work done above critical power (CP), and if this would be accompanied by greater anaerobic energy expenditure and by an enhanced maintenance of maximal oxidative metabolic rate. METHODS Nine men (26.6 ± 5.3 yr, V˙O2max 40.6 ± 5.8 mL·kg·min) cycled until exhaustion at different exercise intensities on different days to determine the CP and W'. On separated days, participants cycled until exhaustion in the severe-intensity domain (136% ± 7% of CP) after ingesting either caffeine (5 mg·kg body mass) or a placebo. RESULTS Time to exhaustion was 34% longer with caffeine compared with placebo, and this was accompanied by a greater work done above CP (23.7 ± 5.7 vs 17.5 ± 3.6 kJ; 130% ± 30% vs 95% ± 14% of W', P < 0.01). Caffeine increased the aerobic energy expenditure (296.4 ± 91.0 vs 210.2 ± 71.9 kJ, P < 0.01), but not anaerobic lactic, anaerobic alactic, and total anaerobic (lactic + alactic) energy expenditure. The end values of heart rate and ventilation were higher with caffeine, but the V˙O2 end was similar between conditions and was not different from V˙O2max. Caffeine did not change time to reach V˙O2max but increased time maintained at V˙O2max (199.3 ± 105.9 vs 111.9 ± 87.1 s, P < 0.05). CONCLUSIONS Caffeine increased total work done above CP, but this was not associated with greater anaerobic work. Rather, this was associated with a higher tolerance to maintain exercise at maximal oxidative metabolic rate.
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Affiliation(s)
- Rodrigo Silveira
- 1Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitoria de Santo Antao, Pernambuco, BRAZIL; 2Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, AUSTRALIA; 3School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA; 4Endurance Performance Research Group (GEDAE-USP), School of Physical Education and Sport, University of São Paulo, Sao Paulo, BRAZIL; and 5Human Performance Research Group, Academic Department of Physical Education, Technological Federal University of Parana, Curitiba, Parana, BRAZIL
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Postprandial glycaemic and lipaemic responses to chronic coffee consumption may be modulated by CYP1A2 polymorphisms. Br J Nutr 2018; 119:792-800. [DOI: 10.1017/s0007114518000260] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractThere is much epidemiological evidence suggesting a reduced risk of development of type 2 diabetes (T2D) in habitual coffee drinkers, however to date there have been few longer-term interventions, directly examining the effects of coffee intake on glucose and lipid metabolism. Previous studies may be confounded by inter-individual variation in caffeine metabolism. Specifically, the rs762551 SNP in the CYP1A2 gene has been demonstrated to influence caffeine metabolism, with carriers of the C allele considered to be of a ‘slow’ metaboliser phenotype. This study investigated the effects of regular coffee intake on markers of glucose and lipid metabolism in coffee-naïve individuals, with novel analysis by rs762551 genotype. Participants were randomised to either a coffee group (n 19) who consumed four cups/d instant coffee for 12 weeks or a control group (n 8) who remained coffee/caffeine free. Venous blood samples were taken pre- and post-intervention. Primary analysis revealed no significant differences between groups. Analysis of the coffee group by genotype revealed several differences. Before coffee intake, the AC genotype (‘slow’ caffeine metabolisers, n 9) displayed higher baseline glucose and NEFA than the AA genotype (‘fast’ caffeine metabolisers, n 10, P<0·05). Post-intervention, reduced postprandial glycaemia and reduced NEFA suppression were observed in the AC genotype, with the opposite result observed in the AA genotype (P<0·05). These observed differences between genotypes warrant further investigation and indicate there may be no one-size-fits-all recommendation with regard to coffee drinking and T2D risk.
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Felippe LC, Ferreira GA, Learsi SK, Boari D, Bertuzzi R, Lima-Silva AE. Caffeine increases both total work performed above critical power and peripheral fatigue during a 4-km cycling time trial. J Appl Physiol (1985) 2018; 124:1491-1501. [PMID: 29470151 DOI: 10.1152/japplphysiol.00930.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The link between total work performed above critical power (CP) and peripheral muscle fatigue during self-paced exercise is unknown. We investigated the influence of caffeine on the total work done above CP during a 4-km cycling time trial (TT) and the subsequent consequence on the development of central and peripheral fatigue. Nine cyclists performed three constant-load exercise trials to determine CP and two 4-km TTs ~75 min after oral caffeine (5 mg/kg) or cellulose (placebo) ingestion. Neuromuscular functions were assessed before and 50 min after supplementation and 1 min after TT. Oral supplementation alone had no effect on neuromuscular function ( P > 0.05). Compared with placebo, caffeine increased mean power output (~4%, P = 0.01) and muscle recruitment (as inferred by EMG, ~17%, P = 0.01) and reduced the time to complete the TT (~2%, P = 0.01). Work performed above CP during the caffeine trial (16.7 ± 2.1 kJ) was significantly higher than during the placebo (14.7 ± 2.1 kJ, P = 0.01). End-exercise decline in quadriceps twitch force (pre- to postexercise decrease in twitch force at 1 and 10 Hz) was more pronounced after caffeine compared with placebo (121 ± 13 and 137 ± 14 N vs. 146 ± 13 and 156 ± 11 N; P < 0.05). There was no effect of caffeine on central fatigue. In conclusion, caffeine increases muscle recruitment, which enables greater work performed above CP and higher end-exercise peripheral locomotor muscle fatigue. NEW & NOTEWORTHY The link between total work done above critical power and peripheral fatigue during a self-paced, high-intensity exercise is unclear. This study revealed that caffeine ingestion increases muscle recruitment, which enables greater work done above critical power and a greater degree of end-exercise decline in quadriceps twitch force during a 4-km cycling time trial. These findings suggest that caffeine increases performance at the expense of greater locomotor muscle fatigue.
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Affiliation(s)
| | | | - Sara Kely Learsi
- Sport Science Research Group, Federal University of Pernambuco , Pernambuco , Brazil
| | - Daniel Boari
- Center of Engineering, Modeling, and Applied Social Science, Federal University of ABC , São Paulo , Brazil
| | - Romulo Bertuzzi
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo , São Paulo , Brazil
| | - Adriano Eduardo Lima-Silva
- Sport Science Research Group, Federal University of Pernambuco , Pernambuco , Brazil.,Human Performance Research Group, Technological Federal University of Parana, Parana, Brazil
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Arcoverde L, Silveira R, Tomazini F, Sansonio A, Bertuzzi R, Lima-Silva AE, Andrade-Souza VA. Effect of caffeine ingestion on anaerobic capacity quantified by different methods. PLoS One 2017; 12:e0179457. [PMID: 28617848 PMCID: PMC5472322 DOI: 10.1371/journal.pone.0179457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/29/2017] [Indexed: 11/18/2022] Open
Abstract
We investigated whether caffeine ingestion before submaximal exercise bouts would affect supramaximal oxygen demand and maximal accumulated oxygen deficit (MAOD), and if caffeine-induced improvement on the anaerobic capacity (AC) could be detected by different methods. Nine men took part in several submaximal and supramaximal exercise bouts one hour after ingesting caffeine (5 mg·kg-1) or placebo. The AC was estimated by MAOD, alternative MAOD, critical power, and gross efficiency methods. Caffeine had no effect on exercise endurance during the supramaximal bout (caffeine: 131.3 ± 21.9 and placebo: 130.8 ± 20.8 s, P = 0.80). Caffeine ingestion before submaximal trials did not affect supramaximal oxygen demand and MAOD compared to placebo (7.88 ± 1.56 L and 65.80 ± 16.06 kJ vs. 7.89 ± 1.30 L and 62.85 ± 13.67 kJ, P = 0.99). Additionally, MAOD was similar between caffeine and placebo when supramaximal oxygen demand was estimated without caffeine effects during submaximal bouts (67.02 ± 16.36 and 62.85 ± 13.67 kJ, P = 0.41) or when estimated by alternative MAOD (56.61 ± 8.49 and 56.87 ± 9.76 kJ, P = 0.91). The AC estimated by gross efficiency was also similar between caffeine and placebo (21.80 ± 3.09 and 20.94 ± 2.67 kJ, P = 0.15), but was lower in caffeine when estimated by critical power method (16.2 ± 2.6 vs. 19.3 ± 3.5 kJ, P = 0.03). In conclusion, caffeine ingestion before submaximal bouts did not affect supramaximal oxygen demand and consequently MAOD. Otherwise, caffeine seems to have no clear positive effect on AC.
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Affiliation(s)
- Lucyana Arcoverde
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - Rodrigo Silveira
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - Fabiano Tomazini
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - André Sansonio
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - Romulo Bertuzzi
- Endurance Performance Research Group, School of Physical Education and Sport, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Adriano Eduardo Lima-Silva
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- Human Performance Research Group, Technological Federal University of Parana, Parana, Brazil
| | - Victor Amorim Andrade-Souza
- Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
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Shearer J, Graham TE. Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal. Nutr Rev 2015; 72 Suppl 1:121-36. [PMID: 25293551 DOI: 10.1111/nure.12124] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.
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Affiliation(s)
- Jane Shearer
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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Christensen PM, Petersen MH, Friis SN, Bangsbo J. Caffeine, but not bicarbonate, improves 6 min maximal performance in elite rowers. Appl Physiol Nutr Metab 2014; 39:1058-63. [PMID: 24999004 DOI: 10.1139/apnm-2013-0577] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the ergogenic effects in a 6 min maximal performance test (PT) on 12 elite rowers: 6 open-weight (mean ± SD; 25 ± 1 years, and 92 ± 3 kg) and 6 light-weight (25 ± 3 years, and 73 ± 6 kg), following supplementation with caffeine (CAF), sodium bicarbonate (SB), and the combination of both, in a double-blind randomized placebo (PLA) controlled design. PT was executed on 4 occasions, on separate days within a week, and in a non-fasted state, with standardized training being performed the day before PT. Protocols were as follows: (i) CAF, 3 mg/kg, 45 min prior to PT + calcium as SB-PLA; (ii) SB, 0.3 g/kg, 75 min prior to PT + dextrose as CAF-PLA; (iii) CAF + SB; and (iv) PLA; CAF-PLA + SB-PLA. The total distance in the CAF (1878 ± 97 m) and CAF + SB (1877 ± 97 m) was longer than in the PLA (1865 ± 104 m; P < 0.05) and SB (1860 ± 96 m; P < 0.01). The mean power in CAF (400 ± 58 W) and CAF + SB (400 ± 58 W) was higher than the PLA (393 ± 61 W; P < 0.05) and SB (389 ± 57 W; P < 0.01). In CAF and CAF + SB, power was higher (P < 0.05) relative to PLA in the last half (4-6 min) of PT. Trials with CAF were more effective in light-weight rowers (1.0% ± 0.8% improvement in distance; P < 0.05) than in open-weight rowers (0.3% ± 0.8%; P > 0.05). No difference between interventions was observed for readiness and stomach comfort before PT and perceived exertion during PT. This study demonstrates that caffeine ingestion does improve performance in elite rowing. In contrast sodium bicarbonate does not appear to be ergogenic, but it does not abolish the ergogenic effect of caffeine.
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Affiliation(s)
- Peter M Christensen
- a Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 KBH Ø, Denmark
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Heinonen I, Kemppainen J, Kaskinoro K, Peltonen JE, Sipilä HT, Nuutila P, Knuuti J, Boushel R, Kalliokoski KK. Effects of adenosine, exercise, and moderate acute hypoxia on energy substrate utilization of human skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2011; 302:R385-90. [PMID: 22129615 DOI: 10.1152/ajpregu.00245.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucose metabolism increases in hypoxia and can be influenced by endogenous adenosine, but the role of adenosine for regulating glucose metabolism at rest or during exercise in hypoxia has not been elucidated in humans. We studied the effects of exogenous adenosine on human skeletal muscle glucose uptake and other blood energy substrates [free fatty acid (FFA) and lactate] by infusing adenosine into the femoral artery in nine healthy young men. The role of endogenous adenosine was studied by intra-arterial adenosine receptor inhibition (aminophylline) during dynamic one-leg knee extension exercise in normoxia and acute hypoxia corresponding to ∼3,400 m of altitude. Extraction and release of energy substrates were studied by arterial-to-venous (A-V) blood samples, and total uptake or release was determined by the product of A-V differences and muscle nutritive perfusion measured by positron emission tomography. The results showed that glucose uptake increased from a baseline value of 0.2 ± 0.2 to 2.0 ± 2.2 μmol·100 g(-1)·min(-1) during adenosine infusion (P < 0.05) at rest. Although acute hypoxia enhanced arterial FFA levels, it did not affect muscle substrate utilization at rest. During exercise, glucose uptake was higher (195%) during acute hypoxia compared with normoxia (P = 0.058), and aminophylline had no effect on energy substrate utilization during exercise, despite that arterial FFA levels were increased. In conclusion, exogenous adenosine at rest and acute moderate hypoxia during low-intensity knee-extension exercise increases skeletal muscle glucose uptake, but the increase in hypoxia appears not to be mediated by adenosine.
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Egawa T, Tsuda S, Ma X, Hamada T, Hayashi T. Caffeine modulates phosphorylation of insulin receptor substrate-1 and impairs insulin signal transduction in rat skeletal muscle. J Appl Physiol (1985) 2011; 111:1629-36. [PMID: 21940847 DOI: 10.1152/japplphysiol.00249.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caffeine decreases insulin sensitivity and insulin-stimulated glucose transport in skeletal muscle; however, the precise mechanism responsible for this deleterious effect is not understood fully. We investigated the effects of incubation with caffeine on insulin signaling in rat epitrochlearis muscle. Caffeine (≥1 mM, ≥15 min) suppressed insulin-stimulated insulin receptor substrate (IRS)-1 Tyr(612) phosphorylation in a dose- and time-dependent manner. These responses were associated with inhibition of the insulin-stimulated phosphorylation of phosphatidylinositol 3-kinase (PI3K) Tyr(458), Akt Ser(473), and glycogen synthase kinase-3β Ser(9) and with inhibition of insulin-stimulated 3-O-methyl-d-glucose (3MG) transport but not with inhibition of the phosphorylation of insulin receptor-β Tyr(1158/62/63). Furthermore, caffeine enhanced phosphorylation of IRS-1 Ser(307) and an IRS-1 Ser(307) kinase, inhibitor-κB kinase (IKK)-α/β Ser(176/180). Blockade of IKK/IRS-1 Ser(307) by caffeic acid ameliorated the caffeine-induced downregulation of IRS-1 Tyr(612) phosphorylation and 3MG transport. Caffeine also increased the phosphorylation of IRS-1 Ser(789) and an IRS-1 Ser(789) kinase, 5'-AMP-activated protein kinase (AMPK). However, inhibition of IRS-1 Ser(789) and AMPK phosphorylation by dantrolene did not rescue the caffeine-induced downregulation of IRS-1 Tyr(612) phosphorylation or 3MG transport. In addition, caffeine suppressed the phosphorylation of insulin-stimulated IRS-1 Ser(636/639) and upstream kinases, including the mammalian target of rapamycin and p70S6 kinase. Intravenous injection of caffeine at a physiological dose (5 mg/kg) in rats inhibited the phosphorylation of insulin-stimulated IRS-1 Tyr(612) and Akt Ser(473) in epitrochlearis muscle. Our results indicate that caffeine inhibits insulin signaling partly through the IKK/IRS-1 Ser(307) pathway, via a Ca(2+)- and AMPK-independent mechanism in skeletal muscle.
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Affiliation(s)
- Tatsuro Egawa
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
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13
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Beaudoin MS, Robinson LE, Graham TE. An oral lipid challenge and acute intake of caffeinated coffee additively decrease glucose tolerance in healthy men. J Nutr 2011; 141:574-81. [PMID: 21346110 DOI: 10.3945/jn.110.132761] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Lipid-induced insulin resistance has been investigated primarily with i.v. infusions, and caffeine-induced insulin resistance, with alkaloid caffeine. The effects of orally consumed lipids and coffee have not been established and to our knowledge have never been simultaneously investigated. The goals of this study were to determine whether an oral lipid challenge and caffeinated coffee would disrupt glucose homeostasis and to characterize their respective incretin responses. It was hypothesized that oral ingestion of saturated lipids would impair glucose tolerance and that caffeinated coffee would further hinder glucose management. Ten young, healthy males participated in 5 trials in a randomized, cross-over design. At time 0 h, they underwent an oral fat tolerance test (OFTT: 1 g lipid/kg body weight) or consumed water, followed 5 h later by caffeinated (5 mg/kg) coffee, decaffeinated coffee, or water. At 6 h, volunteers underwent an oral glucose tolerance test (OGTT). Consumption of the OFTT increased glucose concentrations (P < 0.05) after a subsequent OGTT. At 7 h, caffeinated coffee produced the highest glucose concentrations (P < 0.05). Glucagon-like peptide-1 active (GLP-1a) and glucose-dependent insulinotropic polypeptide (GIP) were both increased for up to 6 h in all OFTT trials (P < 0.05). Compared to all other treatments, caffeinated and decaffeinated coffee produced higher GLP-1a response at 6.25 h (P < 0.05), whereas only caffeinated coffee increased GIP secretion (P < 0.05). These results show that oral consumption of lipids and caffeinated coffee can independently and additively decrease glucose tolerance. Incretin hormones could explain at least in part this impaired glucose homeostasis.
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Affiliation(s)
- Marie-Soleil Beaudoin
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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14
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Lane JD. Caffeine, Glucose Metabolism, and Type 2 Diabetes. JOURNAL OF CAFFEINE RESEARCH 2011. [DOI: 10.1089/jcr.2010.0007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- James D. Lane
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
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15
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Beaudoin MS, Graham TE. Methylxanthines and human health: epidemiological and experimental evidence. Handb Exp Pharmacol 2011:509-548. [PMID: 20859811 DOI: 10.1007/978-3-642-13443-2_21] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
When considering methylxanthines and human health, it must be recognized that in many countries most caffeine is consumed as coffee. This is further confounded by the fact that coffee contains many bioactive substances in addition to caffeine; it is rich in phenols (quinides, chlorogenic acid, and lactones) and also has diterpenes (fatty acid esters), potassium, niacin, magnesium, and the vitamin B(3) precursor trigonelline. There is a paradox as consumption of either caffeine or caffeinated coffee results in a marked insulin resistance and yet habitual coffee consumption has repeatedly been reported to markedly reduce the risk for type 2 diabetes. There is strong evidence that caffeine reduces insulin sensitivity in skeletal muscle and this may be due to a combination of direct antagonism of A(1) receptors and indirectly β-adrenergic stimulation as a result of increased sympathetic activity. Caffeine may also induce reduced hepatic glucose output. With the exception of bone mineral, there is little evidence that caffeine impacts negatively on other health issues. Coffee does not increase the risk of cardiovascular diseases or cancers and there is some evidence suggesting a positive relationship for the former and for some cancers, particularly hepatic cancer.
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Affiliation(s)
- Marie-Soleil Beaudoin
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada, N1G 2W1
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16
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Affiliation(s)
- Philip E Cryer
- Washington University School of Medicine, St. Louis, Missouri, USA.
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17
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Kolnes AJ, Ingvaldsen A, Bolling A, Stuenaes JT, Kreft M, Zorec R, Shepherd PR, Jensen J. Caffeine and theophylline block insulin-stimulated glucose uptake and PKB phosphorylation in rat skeletal muscles. Acta Physiol (Oxf) 2010; 200:65-74. [PMID: 20180783 DOI: 10.1111/j.1748-1716.2010.02103.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Caffeine and theophylline inhibit phosphatidylinositol 3-kinase (PI3-kinase) activity and insulin-stimulated protein kinase B (PKB) phosphorylation. Insulin-stimulated glucose uptake involves PI3-kinase/PKB, and the aim of the present study was to test the hypothesis that caffeine and theophylline inhibit insulin-stimulated glucose uptake in skeletal muscles. METHODS Rat epitrochlearis muscles and soleus strips were incubated with insulin and different concentrations of caffeine and theophylline for measurement of glucose uptake, force development and PKB phosphorylation. The effect of caffeine was also investigated in muscles stimulated electrically. RESULTS Caffeine and theophylline completely blocked insulin-stimulated glucose uptake in both soleus and epitrochlearis muscles at 10 mm. Furthermore, insulin-stimulated PKB Ser(473) and Thr(308) and GSK-3beta Ser(9) phosphorylation were blocked by caffeine and theophylline. Caffeine reduced and theophylline blocked insulin-stimulated glycogen synthase activation. Caffeine stimulates Ca(2+) release and force development increased rapidly to 10-20% of maximal tetanic contraction. Dantrolene (25 microm), a well-known inhibitor of Ca(2+)-release, prevented caffeine-induced force development, but caffeine inhibited insulin-stimulated glucose uptake in the presence of dantrolene. Contraction, like insulin, stimulates glucose uptake via translocation of glucose transporter-4 (GLUT4). Caffeine and theophylline reduced contraction-stimulated glucose uptake by about 50%, whereas contraction-stimulated glycogen breakdown was normal. CONCLUSION Caffeine and theophylline block insulin-stimulated glucose uptake independently of Ca(2+) release, and the likely mechanism is via blockade of insulin-stimulated PI3-kinase/PKB activation. Caffeine and theophylline also reduced contraction-stimulated glucose uptake, which occurs independently of PI3-kinase/PKB, and we hypothesize that caffeine and theophylline also inhibit glucose uptake in skeletal muscles via an additional and hitherto unknown molecule involved in GLUT4 translocation.
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Affiliation(s)
- A J Kolnes
- Department of Physiology, National Institute of Occupational Health, Oslo, Norway
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18
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Consumption of caffeinated coffee and a high carbohydrate meal affects postprandial metabolism of a subsequent oral glucose tolerance test in young, healthy males. Br J Nutr 2009; 103:833-41. [DOI: 10.1017/s0007114509992406] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Caffeine and caffeinated coffee (CC) elicit acute insulin insensitivity when ingested before a carbohydrate load. The effects of CC on glucose tolerance and insulin sensitivity when co-ingested with a high carbohydrate meal and on postprandial metabolism of a subsequent (second) carbohydrate load have not been studied. In a randomised, crossover design, ten healthy males ingested either CC (5 mg caffeine/kg body weight), decaffeinated coffee (DC) or water (W; equal volume) co-ingested with a high glycaemic index cereal followed 3 h later by a 75 g oral glucose tolerance test. After the initial meal, insulin area under the curve (AUC) and insulin sensitivity index did not differ between treatments, although glucose AUC for CC (107 (sem 18) mmol/l × 3 h) and DC (74 (sem 15) mmol/l × 3 h) was greater than W ( − 0·2 (sem 29) mmol/l × 3 h, P < 0·05). After the second carbohydrate load, insulin AUC for CC was 49 % and 57 % greater (P < 0·01) than for DC and W, respectively. Despite the greater insulin response, glucose AUC for CC (217 (sem 24) mmol/l × 2 h) was greater than both DC (126 (sem 11) mmol/l × 2 h, P = 0·01) and W (55 (sem 34) mmol/l × 2 h, P < 0·001). Insulin sensitivity index after the second meal was lower after CC (8·2 (sem 0·9)) compared with both DC (12·4 (sem 1·2), P < 0·01) and W (13·4 (sem 1·4), P < 0·001). Co-ingestion of CC with one meal resulted in insulin insensitivity during the postprandial phase of a second meal in the absence of further CC ingestion. Thus, CC may play a role in daily glycaemic management.
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19
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Acute Caffeine Ingestion and Glucose Tolerance in Women With or Without Gestational Diabetes Mellitus. JOURNAL OF OBSTETRICS AND GYNAECOLOGY CANADA 2009; 31:304-312. [DOI: 10.1016/s1701-2163(16)34147-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Graham TE, Battram DS, Dela F, El-Sohemy A, Thong FSL. Does caffeine alter muscle carbohydrate and fat metabolism during exercise? Appl Physiol Nutr Metab 2009; 33:1311-8. [PMID: 19088793 DOI: 10.1139/h08-129] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine, an adenosine receptor antagonist, has been studied for decades as a putative ergogenic aid. In the past 2 decades, the information has overwhelmingly demonstrated that it indeed is a powerful ergogenic aid, and frequently theories have been proposed that this is due to alterations in fat and carbohydrate metabolism. While caffeine certainly mobilizes fatty acids from adipose tissue, rarely have measures of the respiratory exchange ratio indicated an increase in fat oxidation. However, this is a difficult measure to perform accurately during exercise, and small changes could be physiologically important. The few studies examining human muscle metabolism directly have also supported the fact that there is no change in fat or carbohydrate metabolism, but these usually have had a small sample size. We combined the data from muscle biopsy analyses of several similar studies to generate a sample size of 16-44, depending on the measure. We examined muscle glycogen, citrate, acetyl-CoA, glucose-6-phosphate, and cyclic adenosine monophosphate (cAMP) in resting samples and in those obtained after 10-15 min of exercise at 70%-85% maximal oxygen consumption. Exercise decreased (p < 0.05) glycogen and increased (p < 0.05) citrate, acetyl-CoA, and glucose-6-phosphate. The only effects of caffeine were to increase (p < 0.05) citrate in resting muscle and cAMP in exercise. There is very little evidence to support the hypothesis that caffeine has ergogenic effects as a result of enhanced fat oxidation. Individuals may, however, respond differently to the effects of caffeine, and there is growing evidence that this could be explained by common genetic variations.
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Affiliation(s)
- Terry E Graham
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G2W1, Canada.
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21
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Tunnicliffe JM, Shearer J. Coffee, glucose homeostasis, and insulin resistance: physiological mechanisms and mediators. Appl Physiol Nutr Metab 2009; 33:1290-300. [PMID: 19088791 DOI: 10.1139/h08-123] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Epidemiological studies show coffee consumption to be correlated to large risk reductions in the prevalence of type 2 diabetes (T2D). Such correlations are seen with decaffeinated and caffeinated coffee, and occur regardless of gender, method of brewing, or geography. They also exist despite clear evidence showing that caffeine causes acute postprandial hyperglycemia and lower whole-body insulin sensitivity. As the beneficial effects of coffee consumption exist for both decaffeinated and caffeinated coffee, a component of coffee other than caffeine must be responsible. This review examines the specific coffee compounds responsible for coffee's effects on T2D, and their potential physiological mechanisms of action. Being plant-derived, coffee contains many beneficial compounds found in fruits and vegetables, including antioxidants. In fact, coffee is the largest source of dietary antioxidants in industrialized nations. When green coffee is roasted at high temperatures, Maillard reactions create a number of unique compounds. Roasting causes a portion of the antioxidant, chlorogenic acid, to be transformed into quinides, compounds known to alter blood glucose levels. Coffee consumption may also mediate levels of gut peptides (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), hormones intimately involved in the regulation of satiety and insulin secretion. Finally, coffee may have prebiotic-like properties, altering gut flora and ultimately digestion. In summary, it is evident that a better understanding of the role of coffee in the development and prevention of T2D has the potential to uncover novel therapeutic targets and nutraceutical formulations for the disease.
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Affiliation(s)
- Jasmine M Tunnicliffe
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Faculty of Kinesiology, University of Calgary, AB T2N4N1, Canada.
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Tunnicliffe JM, Erdman KA, Reimer RA, Lun V, Shearer J. Consumption of dietary caffeine and coffee in physically active populations: physiological interactions. Appl Physiol Nutr Metab 2008; 33:1301-10. [DOI: 10.1139/h08-124] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine is a proven ergogenic aid, increasing athletic performance, endurance, and mental chronometry at doses as low as 1–3 mg·kg–1. As coffee is a readily available and commonly ingested form of caffeine, the two are often equated. However, coffee also contains hundreds of other biologically active compounds, many of which are metabolically distinct from caffeine. The purpose of this review was to examine the prevalence of coffee and (or) caffeine consumption among elite Canadian athletes, and to delineate the effects of coffee and caffeine on physical activity, weight maintenance, performance, and metabolism. A total of 270 self-reported 3-day food records were examined for caffeine intake from athletes registered with Canadian Sport Centres in 2005 and 2006. Athletes ranged in age from 16–45 years, and competed in 38 different sports. Results showed that 30% of athletes ingested >1 mg·kg–1·day–1 from a variety of sources. Average daily intake was 0.85 ± 13 mg·kg–1. Caffeine intake was not correlated with any 1 sport; the 10 highest caffeine users were athletes from 9 different sports, including skill, endurance, and power sports. No differences were noted for average caffeine ingestion between summer and winter sports. High caffeine intakes corresponded to coffee ingestion, with the 25 highest individual intakes (193–895 mg·day–1) from coffee drinkers. In summary, it can be concluded that the majority of high-level Canadian athletes consume dietary caffeine primarily in the form of coffee. However, levels consumed are insufficient to elicit performance enhancement. Potential detrimental effects of caffeine consumption on exercise performance include gastric upset, withdrawal, sleep disturbance, and interactions with other dietary supplements.
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Affiliation(s)
- Jasmine M. Tunnicliffe
- Roger Jackson Center for Health and Wellness, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Sports Medicine Center, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kelly Anne Erdman
- Roger Jackson Center for Health and Wellness, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Sports Medicine Center, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Raylene A. Reimer
- Roger Jackson Center for Health and Wellness, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Sports Medicine Center, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Victor Lun
- Roger Jackson Center for Health and Wellness, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Sports Medicine Center, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jane Shearer
- Roger Jackson Center for Health and Wellness, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Sports Medicine Center, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
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MacKenzie T, Comi R, Sluss P, Keisari R, Manwar S, Kim J, Larson R, Baron JA. Metabolic and hormonal effects of caffeine: randomized, double-blind, placebo-controlled crossover trial. Metabolism 2007; 56:1694-8. [PMID: 17998023 DOI: 10.1016/j.metabol.2007.07.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 07/16/2007] [Indexed: 11/28/2022]
Abstract
In short-term studies, caffeine has been shown to increase insulin levels, reduce insulin sensitivity, and increase cortisol levels. However, epidemiological studies have indicated that long-term consumption of beverages containing caffeine such as coffee and green tea is associated with a reduced risk of type 2 diabetes mellitus. There is a paucity of randomized studies addressing the metabolic and hormonal effects of consuming caffeine over periods of more than 1 day. We evaluated the effect of oral intake of 200 mg of caffeine taken twice a day for 7 days on glucose metabolism, as well as on serum cortisol, dehydroepiandrosterone (DHEA), and androstenedione, and on nighttime salivary melatonin. A double-blind, randomized, placebo-controlled crossover study with periods of 7 days and washouts of 5 days comparing caffeine with placebo capsules was conducted. Participants were 16 healthy adults aged 18 to 22 years with a history of caffeine consumption. Blood samples from each subject were assayed for glucose, insulin, serum cortisol, DHEA, and androstenedione on the eighth day of each period after an overnight fast. Nighttime salivary melatonin was also measured. Insulin levels were significantly higher (by 1.80 microU/mL; 95% confidence interval, 0.33-3.28) after caffeine intake than after placebo. The homeostasis model assessment index of insulin sensitivity was reduced by 35% (95% confidence interval, 7%-62%) by caffeine. There were no differences in glucose, DHEA, androstenedione, and melatonin between treatment periods. This study provides evidence that daily caffeine intake reduces insulin sensitivity; the effect persists for at least a week and is evident up to 12 hours after administration.
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Affiliation(s)
- Todd MacKenzie
- Department of Medicine, Dartmouth Medical School, Hanover, NH 03755, USA.
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Dekker MJ, Gusba JE, Robinson LE, Graham TE. Glucose homeostasis remains altered by acute caffeine ingestion following 2 weeks of daily caffeine consumption in previously non-caffeine-consuming males. Br J Nutr 2007; 98:556-62. [PMID: 17524180 DOI: 10.1017/s0007114507730738] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Acute caffeine ingestion increases serum NEFA and plasma adrenaline and decreases insulin sensitivity. Although frequently suggested, it is not known if a tolerance to these alterations in glucose homeostasis is developed in habitual caffeine consumers. Our objective was to determine whether acute caffeine ingestion continued to alter insulin, glucose, NEFA and adrenaline during an oral glucose tolerance test (OGTT) following 14 d of caffeine consumption. Twelve caffeine-naive young males underwent four OGTTs over a 4-week period. Subjects ingested a gelatin-filled placebo (PLA) capsule on the first trial day and 5 mg caffeine/kg body weight on the remaining three trial days (day 0, day 7, day 14) before a 2 h OGTT. Following day 0 and day 7, subjects were given six dosages of 5 mg caffeine/kg to consume per d between trials. Serum insulin and blood glucose area under the curve (AUC) were significantly elevated (P < 0·05) v. PLA on day 0 (36 and 103 %, respectively) and were not different from PLA on day 7. On day 14, insulin AUC was 29 % greater than PLA (P < 0·05), and glucose was greater (P < 0·05) during the first hour, although the 50 % elevation in glucose AUC was not different from PLA. Before the OGTT, caffeine resulted in greater (P < 0·05) serum NEFA and plasma adrenaline concentrations in all three caffeine trials, but both NEFA and adrenaline concentrations were decreased (P < 0·05) on day 14 v. day 0. Although 14 d of caffeine consumption by previously caffeine-naive subjects reduced its impact on glucose homeostasis, carbohydrate metabolism remained disrupted.
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Affiliation(s)
- Mark J Dekker
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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25
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Battram DS, Graham TE, Dela F. Caffeine's impairment of insulin-mediated glucose disposal cannot be solely attributed to adrenaline in humans. J Physiol 2007; 583:1069-77. [PMID: 17656440 PMCID: PMC2277186 DOI: 10.1113/jphysiol.2007.130526] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Caffeine (CAF) impedes insulin-mediated glucose disposal (IMGD) and increases plasma adrenaline concentrations ([ADR]; 0.6 nm). While the antagonism of ADR abolishes the CAF effect, infusion of ADR (0.75 nm) has no effect on IMGD. We have now examined CAF and ADR in concert to determine whether or not they elicit an additive response on IMGD. We hypothesized that CAF + ADR would elicit a greater effect than either CAF or ADR alone (i.e. that CAF effects would not be solely attributed to ADR). Subjects (n = 8) completed four trials in a randomized manner. An isoglycaemic-hyperinsulinaemic clamp was performed 30 min after the following treatments were administered: (1) placebo capsules and saline infusion ([ADR] = 0.29 nm) (PL trial), (2) CAF capsules (dose = 5 mg kg(-1)) and saline infusion ([ADR] = 0.62 nm) (CAF trial), (3) PL capsules and ADR infusion ([ADR] = 1.19 nm) (ADR trial), and (4) CAF capsules (dose = 5 mg kg(-1)) and ADR infusion ([ADR] = 0.93 nm) (CAF + ADR trial). As expected, CAF, ADR and CAF + ADR decreased (P <or= 0.05) IMGD compared to PL. CAF + ADR resulted in a more pronounced decrease in IMGD versus PL (42%) compared to CAF (26%) or ADR (24%) alone; however, the effect was not fully additive (P = 0.08). Furthermore, CAF decreased IMGD to a similar magnitude as ADR despite a 50% lower [ADR]. In summary, while ADR contributes to the CAF-induced impairment in IMGD, it is not solely responsible for caffeine's effects.
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Affiliation(s)
- D S Battram
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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Battram DS, Bugaresti J, Gusba J, Graham TE. Acute caffeine ingestion does not impair glucose tolerance in persons with tetraplegia. J Appl Physiol (1985) 2006; 102:374-81. [PMID: 17068214 DOI: 10.1152/japplphysiol.00901.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute caffeine (Caf) ingestion impairs glucose tolerance in able-bodied humans during an oral glucose tolerance test (OGTT). The mechanism responsible for this effect remains unclear, however, it is suggested to be due to the accompanying increase in epinephrine concentration. We examined whether or not Caf would elicit a glucose intolerance in persons with tetraplegia (TP) who do not exhibit an increased epinephrine response following Caf ingestion. All TP [n = 14; 9 incomplete (Inc) lesion, 5 complete (Com) lesion] completed two OGTT 1 h after consuming either gelatin (Pl) or Caf capsules (dose = 4 mg/kg). Blood samples were collected at baseline (time = 0 min), 1 h after capsule ingestion (time = 60 min), and every 30 min during the OGTT (time = 90-180 min). Glucose, insulin, proinsulin, and C-peptide responses were similar (P > 0.05) between treatments, demonstrating no effect of Caf on glucose tolerance. This lack of a Caf effect may be due to the low epinephrine concentration that remained unchanged (P > 0.05) throughout all experiments. Interestingly, the Com exhibited a 50% higher glucose response (P <or= 0.05) and a 46% (P > 0.05) lower insulin response (vs. Inc), suggesting a more pronounced glucose intolerance within this subgroup. Furthermore, nine TP (5 Com, 4 Inc) had glucose levels of >or= 7.8 mM at the end of the OGTT (time = 180 min), classifying them as glucose intolerant. In summary, acute Caf ingestion does not increase epinephrine concentration or impair glucose tolerance in TP.
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Affiliation(s)
- D S Battram
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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Battram DS, Arthur R, Weekes A, Graham TE. The glucose intolerance induced by caffeinated coffee ingestion is less pronounced than that due to alkaloid caffeine in men. J Nutr 2006; 136:1276-80. [PMID: 16614416 DOI: 10.1093/jn/136.5.1276] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Although acute alkaloid caffeine (CAF) ingestion results in an impaired glucose tolerance, chronic coffee (RCOF) ingestion decreases the risk of developing type 2 diabetes. This study examines the hypothesis that CAF ingestion impairs glucose tolerance to a greater extent than RCOF and that the ingestion of decaffeinated coffee (DECAF) results in a positive effect. Eleven healthy males underwent 4 double-blinded randomized trials. Each trial included the ingestion of either: 1) CAF in capsule form (4.45 mg/kg body weight), 2) RCOF (4.45 mg/kg body weight caffeine), 3) dextrose (placebo, PL) in capsule form, or 4) DECAF (equal in volume to the RCOF trial), followed 1-h later by a 2-h oral glucose tolerance test. Blood samples were collected at baseline (-30), 0 (time of treatment ingestion), 60 (initiation of oral glucose tolerance test), 75, 90, 120, 150, and 180 min. Area under the curve for glucose and insulin were higher (P < or = 0.05) following CAF than both PL and DECAF and, although a similar trend (P = 0.07) was observed following RCOF compared with DECAF, the effect was less pronounced. Interestingly, DECAF resulted in a 50% lower glucose response (P < or = 0.05) than PL, suggesting that the effects of PL and DECAF on glucose tolerance are not the same. These findings suggest that the effects of CAF and RCOF are not identical and may provide a partial explanation as to why acute CAF ingestion impairs glucose tolerance while chronic RCOF ingestion protects against type 2 diabetes.
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Affiliation(s)
- Danielle S Battram
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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