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Dose-response effects of oral guanidinoacetic acid on serum creatine, homocysteine and B vitamins levels.
- Source :
-
European Journal of Nutrition . Dec2014, Vol. 53 Issue 8, p1637-1643. 7p. 2 Charts, 2 Graphs. - Publication Year :
- 2014
-
Abstract
- Purpose: Guanidinoacetic acid (GAA) is an intermediate in the biosynthesis of creatine (Cr), yet its use in human nutrition is limited due to a lack of a clear understanding of its' dose-response effect. Thus, the purpose of this study was to investigate the effect of three different dosages of GAA (1.2, 2.4 and 4.8 g/day) administered for 6 weeks on serum and urinary variables related to GAA metabolism. Methods: Forty-eight healthy volunteers participated in the randomized, placebo-controlled, double-blind, repeated-measure study. At baseline, after 1, 2, 4 and 6 weeks, participants provided both fasting blood samples and 24-h urine. Results: GAA intervention significantly increased serum and urinary GAA, Cr and creatinine as compared to placebo ( P < 0.05). Differences were found for serum GAA and Cr responses between the three GAA dosages, with high-dose GAA resulting in a greater increase ( P < 0.05) in the plasma concentration of both variables as compared to other GAA dosages. In GAA groups, fasting plasma total homocysteine (T-Hcy) increased by 3.5 μmol/L on average at post-administration, yet no dose-response differences were found between trials. Serum B vitamins were not affected by either placebo or GAA intervention ( P > 0.05). Conclusion: Results indicate that low-to-high dosages of exogenous GAA can increase serum concentrations of Cr and T-Hcy while not depleting the B vitamins pool available for remethylation of homocysteine. Clinical trial registration: ClinicalTrials.gov, identification number NCT01133899. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ANALYSIS of variance
*ANTHROPOMETRY
*CREATINE
*DIETARY supplements
*DOSE-effect relationship in pharmacology
*NUTRITIONAL assessment
*PROBABILITY theory
*PRODRUGS
*QUESTIONNAIRES
*RESEARCH funding
*STATISTICAL sampling
*STATISTICS
*VITAMIN B complex
*HOMOCYSTEINE
*STATISTICAL power analysis
*DATA analysis
*STATISTICAL significance
*RANDOMIZED controlled trials
*PRE-tests & post-tests
*BLIND experiment
*FOOD diaries
*DESCRIPTIVE statistics
Subjects
Details
- Language :
- English
- ISSN :
- 14366207
- Volume :
- 53
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- European Journal of Nutrition
- Publication Type :
- Academic Journal
- Accession number :
- 99620621
- Full Text :
- https://doi.org/10.1007/s00394-014-0669-0