<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03288064</url>
  </required_header>
  <id_info>
    <org_study_id>UTH2017AJCD</org_study_id>
    <nct_id>NCT03288064</nct_id>
  </id_info>
  <brief_title>Ergogenic and Antioxidant Effects of Corinthian Currant</brief_title>
  <official_title>Effects of Corinthian Currant Supplementation on Redox Status, Inflammatory Markers, and Performance During Prolonged Exercise</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>University of Thessaly</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>University of Thessaly</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      The purpose of the present study is to investigate the effect of pre-exercise supplementation&#xD;
      of Corinthian currant on metabolism, performance and blood redox status during, and after an&#xD;
      acute bout of prolonged exercise.&#xD;
&#xD;
      Methods: Eleven healthy male adults (18 - 45y) performed an acute bout of prolonged cycling&#xD;
      in a crossover fashion. Each bout consisted of a 90 min constant-intensity (70 - 75% VO2max)&#xD;
      submaximal glycogen depletion trial, followed by a time trial (TT) to exhaustion (95%&#xD;
      VO2max), with a wash out period of 2 weeks between bouts. During each experimental condition&#xD;
      and 30 min prior to exercise, participants consumed an isocaloric (1.5 g CHO/kg body mass)&#xD;
      amount of randomly assigned Corinthian currants, glucose drink, or water. Blood was drawn at&#xD;
      baseline, 30 min after the supplement consumption (pre-exercise) and at 30, 60, 90 min of&#xD;
      submaximal trial, after TT, and 1 h after the end of exercise (post TT), for the assessment&#xD;
      of metabolic changes and redox status alterations.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Aerobic exercise performance in events lasting more than one hour has been shown to improve&#xD;
      with pre- or/and during-exercise consumption of carbohydrates (CHO) and athletes or&#xD;
      recreationally exercised individuals are often advised to consume CHO before, and/or during&#xD;
      exercise. The improvement in performance with CHO supplementation is due to the maintenance&#xD;
      of blood glucose levels and the increased CHO availability for oxidation late in exercise&#xD;
      that may preserve muscle glycogen. Apparently based on the above mechanisms, the dietary&#xD;
      industry provides a wide variety of CHO supplements in different forms (sport drinks, sport&#xD;
      gels, CHO bars, sport jellybeans, sport chews). Athletes at all levels use these supplements&#xD;
      to optimize their performance during training or competitive events. However, these products&#xD;
      are processed, and often expensive, in contrast with other natural foods that may provide an&#xD;
      alternative for those preferring a healthier, though, equally effective choice.&#xD;
&#xD;
      Aerobic exercise and training relates with the production of reactive oxygen and nitrogen&#xD;
      species (RONS), as indicated by the changes in the concentration of several by-products&#xD;
      deriving from the oxidation of biomolecules, and the upregulation of antioxidant enzymes.&#xD;
      Although RONS in low to moderate quantities are essential for optimized exercise performance&#xD;
      and exercise-induced adaptations, yet, excessive production of RONS especially during&#xD;
      exhaustive exercise, promote contractile dysfunction, muscle weakness and fatigue, and&#xD;
      impaired recovery from exercise.Therefore, research has focused on nutritional strategies&#xD;
      aimed at reducing these effects. There is evidence that treating with antioxidants, protects&#xD;
      in part against free radicals-mediated damage in exercise. In regards with this prospective,&#xD;
      the supplementation of antioxidants is a very common strategy to minimize RONS production and&#xD;
      avoid the detrimental effects of oxidative stress in exercise. In the same way with CHO,&#xD;
      natural foods could also provide an alternative antioxidant source for those seeking a more&#xD;
      healthy option.&#xD;
&#xD;
      Corinthian currants or Corinthian raisins are small, dark purple colored, sun-dried vine&#xD;
      products, produced from a special type of black grape (Vitis Vinifera L., var. Apyrena) and&#xD;
      cultivated almost exclusively in the Southern of Greece. Corinthian currants are well known&#xD;
      for their potential health benefits. They consist a high source of complex CHO (32.5%&#xD;
      glucose, 32.1% fructose, 0.40% sucrose, 0.72% maltose), minerals (magnesium, iron, potassium,&#xD;
      phosphorus, zinc) and vitamins (ascorbic acid, pyridoxine, riboﬂavin and thiamin) necessary&#xD;
      for vitality, while they contain virtually no fat or cholesterol. Additionally, currants are&#xD;
      considered as dried fruits with low to moderate glycemic index despite their high&#xD;
      carbohydrate content. Therefore, Corinthian currant could be used as an alternative CHO&#xD;
      source during exercise and provide a natural and healthy choice, equally effective to other&#xD;
      commercial supplements on favorably affecting metabolism and/or improving performance.&#xD;
&#xD;
      Except for their high CHO content, Corinthian currants are also rich in polyphenols which are&#xD;
      free radicals scavenging compounds and provide them with antioxidant properties. The rich&#xD;
      antioxidant content renders Corinthian currant a potentially capable nutrient to boost an&#xD;
      individual's antioxidant status in response to prolonged aerobic exercise. However, no study&#xD;
      so far has addressed this potential role of Corinthian currants.&#xD;
&#xD;
      Therefore, the purpose of the present study was to investigate the effect of pre-exercise&#xD;
      supplementation of Corinthian currants on metabolism and performance, as well as redox status&#xD;
      in response to prolonged aerobic exercise. These responses were compared against glucose and&#xD;
      water.&#xD;
&#xD;
      Eleven healthy well-trained male (n = 9) and female (n = 2) adults (18 - 45y) participated in&#xD;
      the present cross over, randomized study. The participants visited the laboratory four times&#xD;
      in total. During their ﬁrst visit, anthropometric characteristics assessment and baseline&#xD;
      measurements were performed (body mass, standing height, percentage body fat, VO2max). Both&#xD;
      the protocol for the assessment of VO2max, and the exercise protocol were performed on a&#xD;
      cycle ergometer (Cycloergometer, Monark 834, ERGOMED C, Sweeden). During their second visit,&#xD;
      the participants were randomly assigned to either Corinthian currant (1.5 g CHO/kg BW), or&#xD;
      glucose drink (1.5 g CHO/kg BW), or water (6ml/kg BW) condition. After the assignment of the&#xD;
      experimental condition, the participants performed the exercise protocol which consisted of&#xD;
      90 min of submaximal (70 - 75% VO2max) cycling, followed by a near maximal (95% VO2max) time&#xD;
      trial to euxhastion. Fluid intake was kept constant at 7 ml/kg BW before the start of&#xD;
      exercise, 3 ml/kg BW every 20 min during the 90-min exercise bout and 7 ml/kg BW within 15&#xD;
      min after the end of exercise. During their third and fourth visits, the participants&#xD;
      repeated the experimental procedure after they had been assigned to one of the remaining two&#xD;
      conditions. Between the first, second and third visit, there was a wash out period of two&#xD;
      weeks. Blood samples were collected at baseline (before the CHO or water consumption), 30 min&#xD;
      after CHO or water consumption (pre-exercise) and at 30 min, 60 min, 90 min of submaximal&#xD;
      trial, after exhaustion (TT), and 1 h after the end of the exercise, for the assessment of&#xD;
      GSH, catalase, uric acid , TAC, and TBARS.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">February 5, 2017</start_date>
  <completion_date type="Actual">September 15, 2017</completion_date>
  <primary_completion_date type="Actual">June 30, 2017</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Crossover Assignment</intervention_model>
    <primary_purpose>Other</primary_purpose>
    <masking>None (Open Label)</masking>
  </study_design_info>
  <primary_outcome>
    <measure>Differences in time trial performance between conditions</measure>
    <time_frame>After the 90 min submaximal exercise trial</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in glucose concentration (GLU) between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in lactate concentration (LA) between conditions</measure>
    <time_frame>AAt baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in oxygen consumption (VO2) during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in carbon dioxide (CO2) during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in respiratory quotient (RQ) during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in ventilation (VE) during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in charbohydrates oxidation during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in fat oxidation changes during exercise between conditions</measure>
    <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</time_frame>
    <description>Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in complete blood count (CBC) due to exercise between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>Assessment of CBC was performed in an automated hematological analyzer (Mythic 18, Orphee SA, Geneva, Switzerland).</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in reduced glutathione (GSH) (μmol/g Hb) due to exercise between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in oxidized glutathione (GSSG) (μmol/g Hb) due to exercise between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in thiobarbituric acid-reactive substances, TBARS (μM) due to exercise between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Differences in protein carbonyls, (PC) (nmol/mg pr) due to exercise between conditions</measure>
    <time_frame>At baseline, pre-exercise, 30 min, 60 min, 90 min of submaximal exercise trial, after exhaustion, 1 h post exercise</time_frame>
    <description>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.</description>
  </primary_outcome>
  <number_of_arms>3</number_of_arms>
  <enrollment type="Actual">11</enrollment>
  <condition>Athletic Performance</condition>
  <condition>Oxidative Stress</condition>
  <condition>Inflammation</condition>
  <arm_group>
    <arm_group_label>Corinthian currant supplementation</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Corinthian currant supplementation: 1.5 g CHO/kg BW prior to exercise</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Glucose supplementation</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Glucose drink (Top Star 100, Esteriplas, Portugal) supplementation: 1.5 g CHO/kg BW prior to exercise</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Water ingestion</arm_group_label>
    <arm_group_type>Placebo Comparator</arm_group_type>
    <description>Water ingestion: 7 ml/kg BW prior to exercise</description>
  </arm_group>
  <intervention>
    <intervention_type>Dietary Supplement</intervention_type>
    <intervention_name>Corinthian currant</intervention_name>
    <description>Supplementation of 1.5 g CHO/kg BW in the form of Corinthian currant prior to exercise</description>
    <arm_group_label>Corinthian currant supplementation</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Dietary Supplement</intervention_type>
    <intervention_name>Glucose drink</intervention_name>
    <description>Supplementation of 1.5 g CHO/kg BW in the form of glucose drink prior to exercise</description>
    <arm_group_label>Glucose supplementation</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Dietary Supplement</intervention_type>
    <intervention_name>Water ingestion</intervention_name>
    <description>Supplementation of 7ml/kg BW prior to exercise</description>
    <arm_group_label>Water ingestion</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Normal BMI (18.5 - 24.99),absence of lower-limb musculoskeletal injury, absence of any&#xD;
             metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max ≥&#xD;
             40ml/kg/min at baseline testing).&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Abnormal BMI (&lt;18.5, ≥25), presence of lower-limb musculoskeletal injury, presence of&#xD;
             any metabolic disease, no drug/supplement consumption, and aerobic fitness (VO2max &lt;&#xD;
             40ml/kg/min at baseline testing).&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>18 Years</minimum_age>
    <maximum_age>45 Years</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Athanasios Z Jamurtas, Professor</last_name>
    <role>Study Chair</role>
    <affiliation>University of Thessaly</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>School of Physical Education and Sport Science, University of Thessaly</name>
      <address>
        <city>Trikala</city>
        <state>Thessaly</state>
        <zip>42100</zip>
        <country>Greece</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>Greece</country>
  </location_countries>
  <results_reference>
    <citation>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.</citation>
    <PMID>11090571</PMID>
  </results_reference>
  <results_reference>
    <citation>Jeukendrup 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.</citation>
    <PMID>21346333</PMID>
  </results_reference>
  <results_reference>
    <citation>Chiou 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.</citation>
    <PMID>24176327</PMID>
  </results_reference>
  <results_reference>
    <citation>Too 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.</citation>
    <PMID>22704463</PMID>
  </results_reference>
  <verification_date>October 2017</verification_date>
  <study_first_submitted>September 17, 2017</study_first_submitted>
  <study_first_submitted_qc>September 17, 2017</study_first_submitted_qc>
  <study_first_posted type="Actual">September 19, 2017</study_first_posted>
  <last_update_submitted>October 16, 2017</last_update_submitted>
  <last_update_submitted_qc>October 16, 2017</last_update_submitted_qc>
  <last_update_posted type="Actual">October 18, 2017</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>University of Thessaly</investigator_affiliation>
    <investigator_full_name>Athanasios Z. Jamurtas</investigator_full_name>
    <investigator_title>Professor</investigator_title>
  </responsible_party>
  <keyword>raisins</keyword>
  <keyword>carbohydrates</keyword>
  <keyword>antioxidant capacity</keyword>
  <keyword>substrate oxidation</keyword>
  <keyword>prolonged cycling</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Inflammation</mesh_term>
  </condition_browse>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03288064
org study id: UTH2017AJCD
nct id: NCT03288064
lead sponsor: 
has dmc: No
is fda regulated drug: No
is fda regulated device: No
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.
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.
allocation: Randomized
intervention model: Crossover Assignment
primary purpose: Other
masking: None (Open Label)
measure: Differences in time trial performance between conditions
time frame: After the 90 min submaximal exercise trial
description: 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.
measure: 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
description: 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.
measure: 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
description: 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.
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Cardiorespiratory changes were recorded throughout the entire exercise. Gas exchange was monitored using a gas analyzer (CareFusion, Viasis, Yorba Linda, USA).
measure: 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
description: Assessment of CBC was performed in an automated hematological analyzer (Mythic 18, Orphee SA, Geneva, Switzerland).
measure: 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
description: 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.
measure: 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
description: 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.
measure: 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
description: 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.
measure: 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
description: 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.
arm group label: Corinthian currant supplementation
arm group type: Experimental
description: Corinthian currant supplementation: 1.5 g CHO/kg BW prior to exercise
arm group label: Glucose supplementation
arm group type: Experimental
description: Glucose drink (Top Star 100, Esteriplas, Portugal) supplementation: 1.5 g CHO/kg BW prior to exercise
arm group label: Water ingestion
arm group type: Placebo Comparator
description: Water ingestion: 7 ml/kg BW prior to exercise
intervention type: Dietary Supplement
intervention name: Corinthian currant
description: Supplementation of 1.5 g CHO/kg BW in the form of Corinthian currant prior to exercise
arm group label: Corinthian currant supplementation
intervention type: Dietary Supplement
intervention name: Glucose drink
description: Supplementation of 1.5 g CHO/kg BW in the form of glucose drink prior to exercise
arm group label: Glucose supplementation
intervention type: Dietary Supplement
intervention name: Water ingestion
description: Supplementation of 7ml/kg BW prior to exercise
arm group label: Water ingestion
criteria: 
gender: All
minimum age: 18 Years
maximum age: 45 Years
healthy volunteers: Accepts Healthy Volunteers
last name: Athanasios Z Jamurtas, Professor
role: Study Chair
affiliation: University of Thessaly
facility: 
country: Greece
citation: 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.
PMID: 11090571
citation: Jeukendrup 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.
PMID: 21346333
citation: Chiou 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.
PMID: 24176327
citation: Too 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.
PMID: 22704463
responsible party type: Principal Investigator
investigator affiliation: University of Thessaly
investigator full name: Athanasios Z. Jamurtas
investigator title: Professor
mesh term: Inflammation