Long-Term Effect of Combined Citrulline and Nitrate-Rich Beetroot Extract Supplementation

Study Overview
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Brief Summary
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Citrulline (CIT) and nitrate-rich beetroot extract (BEET) are widely studied ergogenic aids. However, both supplements have been studied in sort-term and isolated. To the best of the authors' knowledge, the effects of combining both supplements on exercise-induced muscle damage (EIMD) and hormone status have not been investigated to date. Therefore, the main purpose of this study was to determine the effect and degree of potentiation of the long-term (9 weeks) mixture of 3 g/day of CIT plus 2.1 g/day of BEET (300 mg/day of NIT) supplementation on EIMD markers (urea, creatinine, AST, ALT, GGT, LDH and CK) and anabolic/catabolic hormone status (testosterone, cortisol and Testosterone cortisol ratio (T/C)) in male trained triathletes. This study was a double-blind, placebo-controlled trial where participants (n = 32) were randomized into 4 different groups: placebo group (PLG; n = 8), CIT group (CITG; 3 g/day of CIT; n = 8), BEET group (BEETG; 2.1 g/day of BEET (300 mg/day of NIT) ; n = 8) and CIT-NIT group (CIT-BEETG; 3 g/day of CIT plus 2.1 g/day of BEET (300 mg/day of NIT); n = 8). Blood samples were collected from all participants at baseline (T1) and after 9 weeks of supplementation (T2).

Detailed Description
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Triathlon is an endurance sport in which athletes compete sequentially in swimming, cycling and running. Prolonged and strenuous training combined with insufficient recovery can produce muscular and metabolic stress, resulting in structural and functional damage to the musculoskeletal system leading to a fatigue status, which results in decreased athletic performance. As a consequence of this type of combined exercise, there are also alterations in biochemical markers of exercise-induced muscle damage (EIMD) as well as anabolic/catabolic hormones. Therefore, their analysis is useful in determining the balance between training loads and recovery. In this sense, it is essential to include different strategies to reduce or prevent EIMD, which delay or reduce muscle fatigue and improve sports performance. One of these strategies is the use of different ergogenic aids such as L-citrulline (CIT) and nitrates (NIT) which have been proposed as both substances produce an increase in nitric oxide (NO).

Official Title
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Long-term Effect of Combined Citrulline and Nitrate-rich Beetroot Extract Supplementation on Recovery Status in Trained Male Triathletes

Conditions
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Citrulline, Nitrate, Athletes

Intervention / Treatment
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* Dietary Supplement: Citrulline
* Dietary Supplement: Nitrate
* Dietary Supplement: Nitrate plus Citrulline
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males between 25 and 35 years old Triathletes With at least 5 years of experience Without any disease Non smokers Non drinkers of alcohol Not to take any other medications or stimulant substances during the study 2 weeks without taking other nutritional supplements Exclusion Criteria: Exclusion criteria: Men under 25 and over 35 years of age. Non triathletes Less than 5 years of experience With any disease Smokers Alcohol drinkers

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The main purpose of this study was to determine the effect and degree of potentiation of the long-term (9 weeks) mixture of 3 g/day of CM plus 2.1 g/day of BEET (300 mg/day of NIT) supplementation on EIMD markers (urea, creatinine, AST, ALT, GGT, LDH and CK) and anabolic/catabolic hormone status (testosterone (T), cortisol (C), and T/C) in male trained triathletes.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>8 subjects took 3 g/kg/day of placebo during 9 weeks | Dietary Supplement: Placebo<br>* 3 g/day during 9 weeks<br>* Other names: Cellulose;|
| Active Comparator: Nitrate<br>8 subjects took 3 g/kg/day of nitrate during 9 weeks | Dietary Supplement: Nitrate<br>* 300 mg/day during 9 weeks<br>|
| Active Comparator: Citrulline<br>8 subjects took 3 g/kg/day of citrulline during 9 weeks | Dietary Supplement: Citrulline<br>* 3 g/day during 9 weeks<br>|
| Active Comparator: Nitrate plus Citrulline<br>8 subjects took 3 g/kg/day of nitrate plus citrulline during 9 weeks | Dietary Supplement: Nitrate plus Citrulline<br>* 3 g/day of citrulline and 300 mg/day of nitrate during 9 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cortisol | μg/dL | 9 weeks | 
| Testosterone | ng/mL | 9 weeks | 
| Testosterone to cortisol ratio | ng/mL | 9 weeks | 
| Urea | mg/dl | 9 weeks | 
| Creatinine | mg/dl | 9 weeks | 
| AST | U/L | 9 weeks | 
| ALT | U/L | 9 weeks | 
| GGT | U/L | 9 weeks | 
| LDH | U/L | 9 weeks | 
| CK | U/L | 9 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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triathlon, performance, ergogenic aids, muscle fatigue, recovery, hormones