Long-Term Effect of Combined Citrulline and Nitrate-Rich Beetroot Extract Supplementation
Condition: Citrulline; Nitrate; Athletes
Study type: Interventional

Summary: 
      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: 
      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).
    

Intervention name(s): Citrulline; Nitrate; Nitrate plus Citrulline; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): 3 g/day during 9 weeks; 300 mg/day during 9 weeks; 3 g/day of citrulline and 300 mg/day of nitrate during 9 weeks; 3 g/day during 9 weeks
Other intervention name(s): Cellulose
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention 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 (Investigator)
Primary purpose: Other
Keywords: triathlon; performance; ergogenic aids; muscle fatigue; recovery; hormones