Athletic PerformanceNCT03288064
Ergogenic and Antioxidant Effects of Corinthian Currant
A study testing Corinthian currant, Glucose drink and Water ingestion in people with Athletic Performance and Oxidative Stress, run by University of Thessaly at 1 site in Greece.
Trial summary
The purpose of the present study is to investigate the effect of pre-exercise supplementation of Corinthian currant on metabolism, performance and blood redox status during, and after an acute bout of prolonged exercise. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Athletic Performance, Oxidative Stress, Inflammation
- What is being tested?
- Corinthian currant, Glucose drink and Water ingestion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 11 participants
- Where
- 1 siteGreece
- Study dates
- 5 Feb 2017to 15 Sep 2017
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Normal BMI (18.5 - 24.99),absence of lower-limb musculoskeletal injury, absence of any metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max ≥ 40ml/kg/min at baseline testing).
Who cannot join
- Abnormal BMI (<18.5, ≥25), presence of lower-limb musculoskeletal injury, presence of any metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max < 40ml/kg/min at baseline testing).
Trial locations and contacts
1 site in 1 country.
Greece1 site
School of Physical Education and Sport Science, University of Thessaly
Trikala, Thessaly, 42100
About this study
Official title: Effects of Corinthian Currant Supplementation on Redox Status, Inflammatory Markers, and Performance During Prolonged Exercise
The purpose of the present study is to investigate the effect of pre-exercise supplementation of Corinthian currant on metabolism, performance and blood redox status during, and after an acute bout of prolonged exercise.
Methods: Eleven healthy male adults (18 - 45y) performed an acute bout of prolonged cycling in a crossover fashion. Each bout consisted of a 90 min constant-intensity (70 - 75% VO2max) submaximal glycogen depletion trial, followed by a time trial (TT) to exhaustion (95% VO2max), with a wash out period of 2 weeks between bouts. During each experimental condition and 30 min prior to exercise, participants consumed an isocaloric (1.5 g CHO/kg body mass) amount of randomly assigned Corinthian currants, glucose drink, or water. Blood was drawn at baseline, 30 min after the supplement consumption (pre-exercise) and at 30, 60, 90 min of submaximal trial, after TT, and 1 h after the end of exercise (post TT), for the assessment of metabolic changes and redox status alterations.
Read the detailed description
Aerobic exercise performance in events lasting more than one hour has been shown to improve with pre- or/and during-exercise consumption of carbohydrates (CHO) and athletes or recreationally exercised individuals are often advised to consume CHO before, and/or during exercise. The improvement in performance with CHO supplementation is due to the maintenance of blood glucose levels and the increased CHO availability for oxidation late in exercise that may preserve muscle glycogen. Apparently based on the above mechanisms, the dietary industry provides a wide variety of CHO supplements in different forms (sport drinks, sport gels, CHO bars, sport jellybeans, sport chews). Athletes at all levels use these supplements to optimize their performance during training or competitive events. However, these products are processed, and often expensive, in contrast with other natural foods that may provide an alternative for those preferring a healthier, though, equally effective choice.
Aerobic exercise and training relates with the production of reactive oxygen and nitrogen species (RONS), as indicated by the changes in the concentration of several by-products deriving from the oxidation of biomolecules, and the upregulation of antioxidant enzymes. Although RONS in low to moderate quantities are essential for optimized exercise performance and exercise-induced adaptations, yet, excessive production of RONS especially during exhaustive exercise, promote contractile dysfunction, muscle weakness and fatigue, and impaired recovery from exercise.Therefore, research has focused on nutritional strategies aimed at reducing these effects. There is evidence that treating with antioxidants, protects in part against free radicals-mediated damage in exercise. In regards with this prospective, the supplementation of antioxidants is a very common strategy to minimize RONS production and avoid the detrimental effects of oxidative stress in exercise. In the same way with CHO, natural foods could also provide an alternative antioxidant source for those seeking a more healthy option.
Corinthian currants or Corinthian raisins are small, dark purple colored, sun-dried vine products, produced from a special type of black grape (Vitis Vinifera L., var. Apyrena) and cultivated almost exclusively in the Southern of Greece. Corinthian currants are well known for their potential health benefits. They consist a high source of complex CHO (32.5% glucose, 32.1% fructose, 0.40% sucrose, 0.72% maltose), minerals (magnesium, iron, potassium, phosphorus, zinc) and vitamins (ascorbic acid, pyridoxine, riboflavin and thiamin) necessary for vitality, while they contain virtually no fat or cholesterol. Additionally, currants are considered as dried fruits with low to moderate glycemic index despite their high carbohydrate content. Therefore, Corinthian currant could be used as an alternative CHO source during exercise and provide a natural and healthy choice, equally effective to other commercial supplements on favorably affecting metabolism and/or improving performance.
Except for their high CHO content, Corinthian currants are also rich in polyphenols which are free radicals scavenging compounds and provide them with antioxidant properties. The rich antioxidant content renders Corinthian currant a potentially capable nutrient to boost an individual's antioxidant status in response to prolonged aerobic exercise. However, no study so far has addressed this potential role of Corinthian currants.
Therefore, the purpose of the present study was to investigate the effect of pre-exercise supplementation of Corinthian currants on metabolism and performance, as well as redox status in response to prolonged aerobic exercise. These responses were compared against glucose and water.
Eleven healthy well-trained male (n = 9) and female (n = 2) adults (18 - 45y) participated in the present cross over, randomized study. The participants visited the laboratory four times in total. During their first visit, anthropometric characteristics assessment and baseline measurements were performed (body mass, standing height, percentage body fat, VO2max). Both the protocol for the assessment of VO2max, and the exercise protocol were performed on a cycle ergometer (Cycloergometer, Monark 834, ERGOMED C, Sweeden). During their second visit, the participants were randomly assigned to either Corinthian currant (1.5 g CHO/kg BW), or glucose drink (1.5 g CHO/kg BW), or water (6ml/kg BW) condition. After the assignment of the experimental condition, the participants performed the exercise protocol which consisted of 90 min of submaximal (70 - 75% VO2max) cycling, followed by a near maximal (95% VO2max) time trial to euxhastion. Fluid intake was kept constant at 7 ml/kg BW before the start of exercise, 3 ml/kg BW every 20 min during the 90-min exercise bout and 7 ml/kg BW within 15 min after the end of exercise. During their third and fourth visits, the participants repeated the experimental procedure after they had been assigned to one of the remaining two conditions. Between the first, second and third visit, there was a wash out period of two weeks. Blood samples were collected at baseline (before the CHO or water consumption), 30 min after CHO or water consumption (pre-exercise) and at 30 min, 60 min, 90 min of submaximal trial, after exhaustion (TT), and 1 h after the end of the exercise, for the assessment of GSH, catalase, uric acid , TAC, and TBARS.
- Conditions
- Athletic Performance, Oxidative Stress, Inflammation
- Being tested
- Corinthian currant, Glucose drink, Water ingestion
- Keywords
- raisins, carbohydrates, antioxidant capacity, substrate oxidation, prolonged cycling
- Medical subject headings
- Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Corinthian currantDietary supplement
Supplementation of 1.5 g CHO/kg BW in the form of Corinthian currant prior to exercise
Glucose drinkDietary supplement
Supplementation of 1.5 g CHO/kg BW in the form of glucose drink prior to exercise
Water ingestionDietary supplement
Supplementation of 7ml/kg BW prior to exercise
| Study group | Role | What they receive |
|---|---|---|
| Corinthian currant supplementation | Experimental | Corinthian currant supplementation: 1.5 g CHO/kg BW prior to exercise Receives: Dietary Supplement: Corinthian currant |
| Glucose supplementation | Experimental | Glucose drink (Top Star 100, Esteriplas, Portugal) supplementation: 1.5 g CHO/kg BW prior to exercise Receives: Dietary Supplement: Glucose drink |
| Water ingestion | Placebo comparator | Water ingestion: 7 ml/kg BW prior to exercise Receives: Dietary Supplement: Water ingestion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Differences in time trial performance between conditions
Participants performed an exercise protocol on a cycloergometer (Cycloergometer, Monark 834, ERGOMED C, Sweeden) consisted of 90 min of cycling at 70% - 75% VO2max, followed by a time trial (TT) at 95% VO2max to exhaustion or until the participants could not maintain a pace above 60 rpm. Gas exchange was monitored for the first 15 min until the desired steady state is established (70% - 75% VO2max), and every 25 min for 5 min thereafter.
Measured: After the 90 min submaximal exercise trial
Differences in glucose concentration (GLU) between conditions
Blood GLU concentration was assessed as a marker of human metabolism. Blood GLU concentration was estimated in a Clinical Chemistry Analyzer Z 1145 (Zafiropoulos Diagnostica, Athens, Greece) with commercially available kits (Zafiropoulos, Athens, Greece). Each sample is analyzed in duplicates.
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in lactate concentration (LA) between conditions
Blood LA concentration was assessed as a marker of human metabolism. Blood LA concentration was estimated in a Clinical Chemistry Analyzer Z 1145 (Zafiropoulos Diagnostica, Athens, Greece) with commercially available kits (Zafiropoulos, Athens, Greece). Each sample is analyzed in duplicates.
Measured: AAt baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in oxygen consumption (VO2) during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in carbon dioxide (CO2) during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in respiratory quotient (RQ) during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in ventilation (VE) during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in charbohydrates oxidation during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in fat oxidation changes during exercise between conditions
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Measured: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Differences in complete blood count (CBC) due to exercise between conditions
Assessment of CBC was performed in an automated hematological analyzer (Mythic 18, Orphee SA, Geneva, Switzerland).
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in reduced glutathione (GSH) (μmol/g Hb) due to exercise between conditions
GSH will be measured as a general index of oxidative stress. For GSH, 20 μL of erythrocyte lysate will be treated with 5% TCA mixed with 660 μL of 67 mM sodium potassium phosphate (pH 8.0) and 330 ΜL of 1 mM 5,5-dithiobis-2 nitrobenzoate. The samples will be incubated in the dark at room temperature for 45 min, and the absorbance will be read at 412 nm.
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in oxidized glutathione (GSSG) (μmol/g Hb) due to exercise between conditions
GSSG will be measured as a general index of oxidative stress. Blood collected will be treated with NEM. For the analysis, 50 μL of erythrocyte lysate will be treating with 5% TCA and neutralized up to pH 7.0-7.5. One microliter of 2-vinylpyridine will be added, and the samples will be incubated for 2 h. Sample will be treated with TCA and will be mixed with 600 μL of 143 mM sodium phosphate 100 ΜL of 3 mM NADPH, 100 ΜL of 10 mM 5,5-dithiobis-2-nitrobenzoate, and 194 μL of distilled water. After the addition of 1 μL of glutathione reductase, the change in absorbance at 412 nm will be read for 3 min.
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in thiobarbituric acid-reactive substances, TBARS (μM) due to exercise between conditions
TBARS will be measured as an index of lipid peroxidation. For TBARS determination, 100 μL of plasma will be mixed with 500 ΜL of 35% TCA and 500 μL of Tris-HCl (200 mM, pH 7.4) and will be incubated for 10 min at room temperature. One milliliter of 2 M Na2SO4 and 55 mM thiobarbituric acid solution will be added, and the samples will be incubated at 95O C for 45 min. The samples will be cooled on ice for 5 min and then will be vortexed after adding 1 mL of 70% TCA. The samples will be centrifuged at 15,000g for 3 min, and the absorbance of the supernatant will be read at 530 nm.
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Differences in protein carbonyls, (PC) (nmol/mg pr) due to exercise between conditions
Changes in Protein carbonyls, PC (nmol/mg pr) Carbonyls will be measured as an index of protein oxidation. Protein carbonyls will be determined adding 50 μL of 20% TCA to 50 μL of plasma. Samples will be incubated in the dark at room temperature for 1 hour. The supernatant will be discarded, and 1 mL of 10% TCA will be added. The supernatant will be discarded, and 1 mL of ethanol-ethyl acetate will be added and centrifuged. The supernatant will be discarded, and 1 mL of 5 M urea will be added, vortexed, and incubated at 37C for 15 min. The samples will be centrifuged at 15,000g for 3 min at 4C, and the absorbance will be read at 375 nm.
Measured: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Sep 2017
- Study start5 Feb 2017
- Primary completion30 Jun 2017
- Study completion15 Sep 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Athletic PerformanceStudies of the same condition, open and under way.
- More trials run by University of ThessalyThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Thessaly
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Athanasios Z. Jamurtas, University of Thessaly
- Investigators
- Athanasios Z Jamurtas, Professor, Study chair, University of Thessaly
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03288064
- Sponsor's protocol ID
- UTH2017AJCD
- Status last verified
- Oct 2017
- First submitted
- 17 Sep 2017
- Last updated
- 18 Oct 2017
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Febbraio MA, Chiu A, Angus DJ, Arkinstall MJ, Hawley JA. Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance. J Appl Physiol (1985). 2000 Dec;89(6):2220-6. doi: 10.1152/jappl.2000.89.6.2220.
PubMed 11090571Jeukendrup AE, Killer SC. The myths surrounding pre-exercise carbohydrate feeding. Ann Nutr Metab. 2010;57 Suppl 2:18-25. doi: 10.1159/000322698. Epub 2011 Feb 22.
PubMed 21346333Chiou A, Panagopoulou EA, Gatzali F, De Marchi S, Karathanos VT. Anthocyanins content and antioxidant capacity of Corinthian currants (Vitis vinifera L., var. Apyrena). Food Chem. 2014 Mar 1;146:157-65. doi: 10.1016/j.foodchem.2013.09.062. Epub 2013 Sep 19.
PubMed 24176327Too BW, Cicai S, Hockett KR, Applegate E, Davis BA, Casazza GA. Natural versus commercial carbohydrate supplementation and endurance running performance. J Int Soc Sports Nutr. 2012 Jun 15;9(1):27. doi: 10.1186/1550-2783-9-27.
PubMed 22704463
Study at a glance
From the registry record, last updated by the sponsor on 18 Oct 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Corinthian Currant Supplementation on Redox Status, Inflammatory Markers, and Performance During Prolonged Exercise
- ClinicalTrials.gov ID
- NCT03288064
- Acronym / sponsor ID
- UTH2017AJCD
- Conditions
- Athletic Performance, Oxidative Stress, Inflammation
- Keywords
- raisins, carbohydrates, antioxidant capacity, substrate oxidation, prolonged cycling
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- University of ThessalyUniversity, hospital or other
- Study start
- 5 Feb 2017 (actual)
- Primary completion
- 30 Jun 2017 (actual)
- Study completion
- 15 Sep 2017 (actual)
- First posted
- 19 Sep 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the present study is to investigate the effect of pre-exercise supplementation of Corinthian currant on metabolism, performance and blood redox status during, and after an acute bout of prolonged exercise.
Methods: Eleven healthy male adults (18 - 45y) performed an acute bout of prolonged cycling in a crossover fashion. Each bout consisted of a 90 min constant-intensity (70 - 75% VO2max) submaximal glycogen depletion trial, followed by a time trial (TT) to exhaustion (95% VO2max), with a wash out period of 2 weeks between bouts. During each experimental condition and 30 min prior to exercise, participants consumed an isocaloric (1.5 g CHO/kg body mass) amount of randomly assigned Corinthian currants, glucose drink, or water. Blood was drawn at baseline, 30 min after the supplement consumption (pre-exercise) and at 30, 60, 90 min of submaximal trial, after TT, and 1 h after the end of exercise (post TT), for the assessment of metabolic changes and redox status alterations.
Detailed description
Aerobic exercise performance in events lasting more than one hour has been shown to improve with pre- or/and during-exercise consumption of carbohydrates (CHO) and athletes or recreationally exercised individuals are often advised to consume CHO before, and/or during exercise. The improvement in performance with CHO supplementation is due to the maintenance of blood glucose levels and the increased CHO availability for oxidation late in exercise that may preserve muscle glycogen. Apparently based on the above mechanisms, the dietary industry provides a wide variety of CHO supplements in different forms (sport drinks, sport gels, CHO bars, sport jellybeans, sport chews). Athletes at all levels use these supplements to optimize their performance during training or competitive events. However, these products are processed, and often expensive, in contrast with other natural foods that may provide an alternative for those preferring a healthier, though, equally effective choice.
Aerobic exercise and training relates with the production of reactive oxygen and nitrogen species (RONS), as indicated by the changes in the concentration of several by-products deriving from the oxidation of biomolecules, and the upregulation of antioxidant enzymes. Although RONS in low to moderate quantities are essential for optimized exercise performance and exercise-induced adaptations, yet, excessive production of RONS especially during exhaustive exercise, promote contractile dysfunction, muscle weakness and fatigue, and impaired recovery from exercise.Therefore, research has focused on nutritional strategies aimed at reducing these effects. There is evidence that treating with antioxidants, protects in part against free radicals-mediated damage in exercise. In regards with this prospective, the supplementation of antioxidants is a very common strategy to minimize RONS production and avoid the detrimental effects of oxidative stress in exercise. In the same way with CHO, natural foods could also provide an alternative antioxidant source for those seeking a more healthy option.
Corinthian currants or Corinthian raisins are small, dark purple colored, sun-dried vine products, produced from a special type of black grape (Vitis Vinifera L., var. Apyrena) and cultivated almost exclusively in the Southern of Greece. Corinthian currants are well known for their potential health benefits. They consist a high source of complex CHO (32.5% glucose, 32.1% fructose, 0.40% sucrose, 0.72% maltose), minerals (magnesium, iron, potassium, phosphorus, zinc) and vitamins (ascorbic acid, pyridoxine, riboflavin and thiamin) necessary for vitality, while they contain virtually no fat or cholesterol. Additionally, currants are considered as dried fruits with low to moderate glycemic index despite their high carbohydrate content. Therefore, Corinthian currant could be used as an alternative CHO source during exercise and provide a natural and healthy choice, equally effective to other commercial supplements on favorably affecting metabolism and/or improving performance.
Except for their high CHO content, Corinthian currants are also rich in polyphenols which are free radicals scavenging compounds and provide them with antioxidant properties. The rich antioxidant content renders Corinthian currant a potentially capable nutrient to boost an individual's antioxidant status in response to prolonged aerobic exercise. However, no study so far has addressed this potential role of Corinthian currants.
Therefore, the purpose of the present study was to investigate the effect of pre-exercise supplementation of Corinthian currants on metabolism and performance, as well as redox status in response to prolonged aerobic exercise. These responses were compared against glucose and water.
Eleven healthy well-trained male (n = 9) and female (n = 2) adults (18 - 45y) participated in the present cross over, randomized study. The participants visited the laboratory four times in total. During their first visit, anthropometric characteristics assessment and baseline measurements were performed (body mass, standing height, percentage body fat, VO2max). Both the protocol for the assessment of VO2max, and the exercise protocol were performed on a cycle ergometer (Cycloergometer, Monark 834, ERGOMED C, Sweeden). During their second visit, the participants were randomly assigned to either Corinthian currant (1.5 g CHO/kg BW), or glucose drink (1.5 g CHO/kg BW), or water (6ml/kg BW) condition. After the assignment of the experimental condition, the participants performed the exercise protocol which consisted of 90 min of submaximal (70 - 75% VO2max) cycling, followed by a near maximal (95% VO2max) time trial to euxhastion. Fluid intake was kept constant at 7 ml/kg BW before the start of exercise, 3 ml/kg BW every 20 min during the 90-min exercise bout and 7 ml/kg BW within 15 min after the end of exercise. During their third and fourth visits, the participants repeated the experimental procedure after they had been assigned to one of the remaining two conditions. Between the first, second and third visit, there was a wash out period of two weeks. Blood samples were collected at baseline (before the CHO or water consumption), 30 min after CHO or water consumption (pre-exercise) and at 30 min, 60 min, 90 min of submaximal trial, after exhaustion (TT), and 1 h after the end of the exercise, for the assessment of GSH, catalase, uric acid , TAC, and TBARS.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Corinthian currant supplementation | Experimental | Dietary Supplement: Corinthian currantCorinthian currant supplementation: 1.5 g CHO/kg BW prior to exercise |
| Glucose supplementation | Experimental | Dietary Supplement: Glucose drinkGlucose drink (Top Star 100, Esteriplas, Portugal) supplementation: 1.5 g CHO/kg BW prior to exercise |
| Water ingestion | Placebo comparator | Dietary Supplement: Water ingestionWater ingestion: 7 ml/kg BW prior to exercise |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Normal BMI (18.5 - 24.99),absence of lower-limb musculoskeletal injury, absence of any metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max ≥ 40ml/kg/min at baseline testing).
Key exclusion criteria (1 listed)
- Abnormal BMI (<18.5, ≥25), presence of lower-limb musculoskeletal injury, presence of any metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max < 40ml/kg/min at baseline testing).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Corinthian currantSupplementation of 1.5 g CHO/kg BW in the form of Corinthian currant prior to exercise | Dietary supplement | Corinthian currant supplementation |
| Glucose drinkSupplementation of 1.5 g CHO/kg BW in the form of glucose drink prior to exercise | Dietary supplement | Glucose supplementation |
| Water ingestionSupplementation of 7ml/kg BW prior to exercise | Dietary supplement | Water ingestion |
Primary outcome
Differences in time trial performance between conditions
Time frame: After the 90 min submaximal exercise trial
Participants performed an exercise protocol on a cycloergometer (Cycloergometer, Monark 834, ERGOMED C, Sweeden) consisted of 90 min of cycling at 70% - 75% VO2max, followed by a time trial (TT) at 95% VO2max to exhaustion or until the participants could not maintain a pace above 60 rpm. Gas exchange was monitored for the first 15 min until the desired steady state is established (70% - 75% VO2max), and every 25 min for 5 min thereafter.
Differences in glucose concentration (GLU) between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Blood GLU concentration was assessed as a marker of human metabolism. Blood GLU concentration was estimated in a Clinical Chemistry Analyzer Z 1145 (Zafiropoulos Diagnostica, Athens, Greece) with commercially available kits (Zafiropoulos, Athens, Greece). Each sample is analyzed in duplicates.
Differences in lactate concentration (LA) between conditions
Time frame: AAt baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Blood LA concentration was assessed as a marker of human metabolism. Blood LA concentration was estimated in a Clinical Chemistry Analyzer Z 1145 (Zafiropoulos Diagnostica, Athens, Greece) with commercially available kits (Zafiropoulos, Athens, Greece). Each sample is analyzed in duplicates.
Differences in oxygen consumption (VO2) during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in carbon dioxide (CO2) during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in respiratory quotient (RQ) during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in ventilation (VE) during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in charbohydrates oxidation during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in fat oxidation changes during exercise between conditions
Time frame: During the first 15 min of submaximal exercise trial until the desired steady state of VO2 (70% - 75%) was established, and every 25 min for 5 min thereafter
Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
Differences in complete blood count (CBC) due to exercise between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Assessment of CBC was performed in an automated hematological analyzer (Mythic 18, Orphee SA, Geneva, Switzerland).
Differences in reduced glutathione (GSH) (μmol/g Hb) due to exercise between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
GSH will be measured as a general index of oxidative stress. For GSH, 20 μL of erythrocyte lysate will be treated with 5% TCA mixed with 660 μL of 67 mM sodium potassium phosphate (pH 8.0) and 330 ΜL of 1 mM 5,5-dithiobis-2 nitrobenzoate. The samples will be incubated in the dark at room temperature for 45 min, and the absorbance will be read at 412 nm.
Differences in oxidized glutathione (GSSG) (μmol/g Hb) due to exercise between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
GSSG will be measured as a general index of oxidative stress. Blood collected will be treated with NEM. For the analysis, 50 μL of erythrocyte lysate will be treating with 5% TCA and neutralized up to pH 7.0-7.5. One microliter of 2-vinylpyridine will be added, and the samples will be incubated for 2 h. Sample will be treated with TCA and will be mixed with 600 μL of 143 mM sodium phosphate 100 ΜL of 3 mM NADPH, 100 ΜL of 10 mM 5,5-dithiobis-2-nitrobenzoate, and 194 μL of distilled water. After the addition of 1 μL of glutathione reductase, the change in absorbance at 412 nm will be read for 3 min.
Differences in thiobarbituric acid-reactive substances, TBARS (μM) due to exercise between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
TBARS will be measured as an index of lipid peroxidation. For TBARS determination, 100 μL of plasma will be mixed with 500 ΜL of 35% TCA and 500 μL of Tris-HCl (200 mM, pH 7.4) and will be incubated for 10 min at room temperature. One milliliter of 2 M Na2SO4 and 55 mM thiobarbituric acid solution will be added, and the samples will be incubated at 95O C for 45 min. The samples will be cooled on ice for 5 min and then will be vortexed after adding 1 mL of 70% TCA. The samples will be centrifuged at 15,000g for 3 min, and the absorbance of the supernatant will be read at 530 nm.
Differences in protein carbonyls, (PC) (nmol/mg pr) due to exercise between conditions
Time frame: At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise
Changes in Protein carbonyls, PC (nmol/mg pr) Carbonyls will be measured as an index of protein oxidation. Protein carbonyls will be determined adding 50 μL of 20% TCA to 50 μL of plasma. Samples will be incubated in the dark at room temperature for 1 hour. The supernatant will be discarded, and 1 mL of 10% TCA will be added. The supernatant will be discarded, and 1 mL of ethanol-ethyl acetate will be added and centrifuged. The supernatant will be discarded, and 1 mL of 5 M urea will be added, vortexed, and incubated at 37C for 15 min. The samples will be centrifuged at 15,000g for 3 min at 4C, and the absorbance will be read at 375 nm.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Oct 2017.
- Results publication: PubMed 11090571Febbraio MA, Chiu A, Angus DJ, Arkinstall MJ, Hawley JA. Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance. J Appl Physiol (1985). 2000 Dec;89(6):2220-6. doi: 10.1152/jappl.2000.89.6.2220.
- Results publication: PubMed 21346333Jeukendrup AE, Killer SC. The myths surrounding pre-exercise carbohydrate feeding. Ann Nutr Metab. 2010;57 Suppl 2:18-25. doi: 10.1159/000322698. Epub 2011 Feb 22.
- Results publication: PubMed 24176327Chiou A, Panagopoulou EA, Gatzali F, De Marchi S, Karathanos VT. Anthocyanins content and antioxidant capacity of Corinthian currants (Vitis vinifera L., var. Apyrena). Food Chem. 2014 Mar 1;146:157-65. doi: 10.1016/j.foodchem.2013.09.062. Epub 2013 Sep 19.
- Results publication: PubMed 22704463Too BW, Cicai S, Hockett KR, Applegate E, Davis BA, Casazza GA. Natural versus commercial carbohydrate supplementation and endurance running performance. J Int Soc Sports Nutr. 2012 Jun 15;9(1):27. doi: 10.1186/1550-2783-9-27.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Athanasios Z Jamurtas, Professor study chair
University of Thessaly
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Corinthian currant, Glucose drink and Water ingestion in people with Athletic Performance and Oxidative Stress, run by University of Thessaly at 1 site in Greece.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Oct 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Greece. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Differences in time trial performance between conditions (time frame: After the 90 min submaximal exercise trial). The study lists 14 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03288064, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Oct 2017.