Title |
Folic acid causes higher prevalence of detectable unmetabolized folic acid in serum than B-complex: a randomized trial
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Published in |
European Journal of Nutrition, May 2015
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DOI | 10.1007/s00394-015-0916-z |
Pubmed ID | |
Authors |
Rima Obeid, Susanne H. Kirsch, Sarah Dilmann, Cosima Klein, Rudolf Eckert, Jürgen Geisel, Wolfgang Herrmann |
Abstract |
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 (6S)-5-methyltetrahydropteroylglutamate [(6S)-5-CH3-H4Pte] and UMFA in elderly people and explored factors associated with detectable UMFA post-supplementation. 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-CH3-H4Pte and UMFA. 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-CH3-H4Pte 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-CH3-H4Pte and prevalence of UMFA ≥ 0.21 nmol/L. Higher serum cystathionine and whole-blood folate predicted higher post-intervention serum UMFA. 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. |
X Demographics
Geographical breakdown
Country | Count | As % |
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United States | 1 | 25% |
Comoros | 1 | 25% |
Australia | 1 | 25% |
Unknown | 1 | 25% |
Demographic breakdown
Type | Count | As % |
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Practitioners (doctors, other healthcare professionals) | 2 | 50% |
Members of the public | 1 | 25% |
Scientists | 1 | 25% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
Canada | 1 | 2% |
Unknown | 52 | 98% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Bachelor | 8 | 15% |
Student > Ph. D. Student | 6 | 11% |
Student > Master | 5 | 9% |
Student > Doctoral Student | 4 | 8% |
Researcher | 4 | 8% |
Other | 12 | 23% |
Unknown | 14 | 26% |
Readers by discipline | Count | As % |
---|---|---|
Medicine and Dentistry | 13 | 25% |
Agricultural and Biological Sciences | 12 | 23% |
Nursing and Health Professions | 8 | 15% |
Immunology and Microbiology | 2 | 4% |
Biochemistry, Genetics and Molecular Biology | 2 | 4% |
Other | 2 | 4% |
Unknown | 14 | 26% |