Hormonal response to L-arginine supplementation in physically active individuals

  • Davi Vieira Teixeira da Silva
  • Carlos Adam Conte-Junior
  • Vânia Margaret Flosi Paschoalin
  • Thiago de Silveira Alvares Federal University of Rio de Janeiro
Keywords: Nutritional supplements, amino acids, insulin, growth hormone, exercise performance.

Abstract

Background: Nutritional supplements based on the amino acid L-arginine have been hypothesized to improve exercise performance by increasing levels of insulin and growth hormone (GH). Changes of these parameters in response to L-arginine supplementation may clarify the mechanisms underlying its putative physiological effects on physical performance.

Objective: The aim of the study was to evaluate the effect of L-arginine supplementation on serum insulin, GH, Growth Factor Insulin-like (IGF-1), and cortisol in response to exercise. Exercise performance was also evaluated.

Design: Fifteen trained runners were divided into groups supplemented with 6 g of L-arginine (ARG) or placebo (PLA). Blood samples were collected before supplementation (T0), immediately after the first exercise session (T1), after the second exercise session (T2), and after 20 min of rest (T3). The exercise consisted of two bouts of 5 km time-trial running test.

Results: There was a significant increase in serum GH (T0: 3.28±0.95 vs. 3.21±0.5 ng/mL; T1: 4.35±0.23 vs. 4.17±90.13 ng/mL; T2: 4.22±0.25 vs. 4.17±0.09 ng/mL; T3: 4.14±0.29 vs. 4.13±0.18 ng/mL) and cortisol (T0: 198.71953.77 vs. 207.57±69.51 nmol/L; T1: 458.16±116.12 vs. 433.26±101.77 nmol/L; T2: 454.61±125.21 vs. 431.88±74.82 nmol/L; T3: 311.14±102.91 vs. 362.26±110.42 nmol/L) after T1, T2, and T3, with no significant difference between the ARGand PLA groups, respectively. There was also no significant difference observed in the variables of IGF-1, insulin, and total running time between the ARG and PLA groups.

Conclusions: The supplementation of L-arginine did not appear to stimulate the production of insulin, GH, and IGF-1 and, thus, provided no benefit in hormonal response or exercise performance in trained runners.

Keywords: nutritional supplements; amino acids; insulin; growth hormone; exercise performance

(Published: 25 March 2014)

Citation: Food & Nutrition Research 2014, 58: 22569 - http://dx.doi.org/10.3402/fnr.v58.22569

 

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Published
2014-03-25
How to Cite
Teixeira da Silva, D. V., Conte-Junior, C. A., Paschoalin, V. M. F., & Alvares, T. de S. (2014). Hormonal response to L-arginine supplementation in physically active individuals. Food & Nutrition Research. https://doi.org/10.3402/fnr.v58.22569
Section
Original Articles

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