Oxidant-Antioxidant Capacity of Dietary Guanidinoacetic Acid.
OBJECTIVE
Guanidinoacetic acid (GAA) is an experimental nutritional additive under the functional group amino acids and derivatives, yet its use in human nutrition is hindered by limited data on GAA safety. In this double blind, placebo-controlled pilot study, we evaluated the effects of dietary GAA (3 g/day) administered for 2 weeks on the oxidant-antioxidant system in healthy men.


METHODS
Twelve healthy men (age 22.3 ± 2.1 years) were recruited for blood sampling at baseline (day 0) and at the end of the intervention period (day 14). Fasting venous blood samples were assessed for plasma total antioxidant capacity, superoxide dismutase (SOD), glutathione peroxidase, total oxidant status and malondialdehyde.


RESULTS
Fasting plasma SOD increased significantly from before to after administration in GAA-supplemented participants (91.4 ± 19.6 vs. 122.8 ± 25.9 ng/ml; p = 0.04). Other markers of oxidant-antioxidant system were not affected by the placebo or GAA intervention (p > 0.05).


CONCLUSIONS
Oral GAA did not impact the cumulative action of antioxidants present in plasma, yet its SOD-boosting capacity might be considered beneficial when GAA is used as a dietary supplement. Further studies are needed to reveal the direct effects of GAA ingestion on markers of lipid and protein oxidation and on DNA damage.
Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia.
Sergej M
SM
Ostojic
Marko D
MD
Stojanovic
Guillermo
G
Olcina
D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005979:Glutathione Peroxidase / Q000097:blood; D005998:Glycine / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D009752:Nutritional Status; D016877:Oxidants / Q000378:metabolism*; D010084:Oxidation-Reduction; D010865:Pilot Projects; D013482:Superoxide Dismutase / Q000097:blood; D055815:Young Adult
D000975:Antioxidants; D016877:Oxidants; D008315:Malondialdehyde; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; C004946:glycocyamine; D005998:Glycine