1. Folic acid causes higher prevalence of detectable unmetabolized folic acid in serum than B-complex: a randomized trial.
- Author
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Obeid, Rima, Kirsch, Susanne, Dilmann, Sarah, Klein, Cosima, Eckert, Rudolf, Geisel, Jürgen, and Herrmann, Wolfgang
- Subjects
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FOLIC acid metabolism , *GERIATRIC nutrition , *CHI-squared test , *DIETARY supplements , *FOLIC acid , *GLUTAMIC acid , *PROBABILITY theory , *REGRESSION analysis , *STATISTICAL sampling , *STATISTICAL hypothesis testing , *STATISTICS , *VITAMIN B complex , *VITAMIN B12 , *VITAMIN B6 , *HOMOCYSTEINE , *STATISTICAL power analysis , *DATA analysis , *STATISTICAL significance , *RANDOMIZED controlled trials , *BLIND experiment , *DATA analysis software , *DESCRIPTIVE statistics , *NUTRITIONAL status , *MANN Whitney U Test , *OLD age - Abstract
Purpose: Unmetabolized folic acid (UMFA) is common in serum of elderly individuals receiving folic acid (FA)-fortified foods or supplements. We studied the effect of supplementing FA or B-complex on serum concentrations of (6 S)-5-methyltetrahydropteroylglutamate [(6S)-5-CH-HPte] and UMFA in elderly people and explored factors associated with detectable UMFA post-supplementation. Methods: This is a randomized single-blind non-controlled trial on 58 elderly people using daily 400 µg FA ( n = 31) or 400 µg FA, 10 µg cyanocob(III)alamin and 8 mg pyridoxine ( n = 27) for a median of 23 days. Main outcome includes changes in concentrations of serum (6S)-5-CH-HPte and UMFA. Results: Total homocysteine declined by a median of 1.6 ( p = 0.074) in the FA and 1.3 µmol/L ( p = 0.009) in the B-complex arms ( p = 0.66 between the arms). Serum (6S)-5-CH-HPte significantly ( p < 0.001 vs. baseline) increased by a median of 9.2 and 6.5 nmol/L in the FA and B-complex groups, respectively ( p = 0.152 between the groups). Compared to FA, B-complex reduced cystathionine and caused lower post-intervention serum UMFA, percentage of UMFA to (6S)-5-CH-HPte and prevalence of UMFA ≥ 0.21 nmol/L. Higher serum cystathionine and whole-blood folate predicted higher post-intervention serum UMFA. Conclusions: FA caused higher UMFA as compared to B-complex. Pyridoxine appears to improve folate recycling. Data on serum UMFA should be interpreted in relation to other vitamins involved in folate metabolism. Serum UMFA is suggested to play a sensory role through which the cell recognizes FA available for metabolism via dihydrofolate reductase. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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