Published in:
01-04-2013 | Original Contribution
Effects of l-arginine supplementation on blood flow, oxidative stress status and exercise responses in young adults with uncomplicated type I diabetes
Authors:
Ana Paula Trussardi Fayh, Mauricio Krause, Josianne Rodrigues-Krause, Jerri Luiz Ribeiro, Jorge Pinto Ribeiro, Rogério Friedman, José Cláudio Fonseca Moreira, Alvaro Reischak-Oliveira
Published in:
European Journal of Nutrition
|
Issue 3/2013
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Abstract
Background and aims
Vascular disease is the principal cause of death and disability in patients with diabetes, and endothelial dysfunction seems to be the major cause in its pathogenesis. Since l-arginine levels are diminished in conditions such as type 1 and type 2 diabetes, in this work we aimed to verify the effects of l-arginine supplementation (7 g/day) over the endothelial function and oxidative stress markers in young male adults with uncomplicated type 1 diabetes. We also investigated the influences of l-arginine administration on vascular/oxidative stress responses to an acute bout of exercise.
Methods
Ten young adult male subjects with uncomplicated type 1 diabetes and twenty matched controls volunteered for this study. We analysed the influence of l-arginine supplementation (7 g/day during 1 week) over lower limb blood flow (using a venous occlusion plethysmography technique), oxidative stress marker (TBARS, Carbonyls), anti-oxidant parameters (uric acid and TRAP) and total tNOx in rest conditions and after a single bout of submaximal exercise (VO2 at 10 % below the second ventilatory threshold). Data described as mean ± standard error (SE). Alpha level was P < 0.05.
Results
Glycaemic control parameters were altered in type 1 diabetic subjects, such as HbA1c (5.5 ± 0.03 vs. 8.3 ± 0.4 %) and fasted glycaemia (94.8 ± 1.4 vs. 183 ± 19 mg/dL). Oxidative stress/damage markers (carbonyls and TBARS) were increased in the diabetic group, while uric acid was decreased. Rest lower limb blood flow was lower in type 1 diabetic subjects than in healthy controls (3.53 ± 0.35 vs. 2.66 ± 0.3 ml 100 ml−¹ min−¹). l-Arginine supplementation completely recovered basal blood flow to normal levels in type 1 diabetics’ subjects (2.66 ± 0.3 to 4.74 ± 0.86 ml 100 ml−¹ min−¹) but did not interfere in any parameter of redox state or exercise.
Conclusion
Our findings highlight the importance of l-arginine for the improvement of vascular function in subjects with diabetes, indicating that l-arginine supplementation could be an essential tool for the treatment for the disease complications, at least in non-complicated diabetes. However, based on our data, it is not possible to draw conclusions regarding the mechanisms by which l-arginine therapy is inducing improvements on cardiovascular function, but this important issue requires further investigations.