Differences in erythrocyte folate concentrations in older adults reached steady-state within one year in a two-year, controlled, 1 mg/d folate supplementation trial.
J Nutr
; 142(9): 1633-7, 2012 Sep.
Article
em En
| MEDLINE
| ID: mdl-22810981
ABSTRACT
Daily supplementation with folate increases erythrocyte folate concentrations; however, the time to reach steady-state concentrations has not been empirically demonstrated. Previous predictions of time to steady state or time to 90% steady-state concentration, based on modeling changes in erythrocyte folate during short-term trials, range widely from 40 to 86 wk. We sought to determine the time to steady-state erythrocyte folate concentrations following the initiation of daily folate supplementation using data collected from a 2-y, double-blind, placebo-controlled, randomized trial involving 276 participants aged 65 y or older. The daily supplement contained 1 mg of folate. Erythrocyte folate concentrations were measured, using a microbiological assay, at baseline and at 6, 12, 18, and 24 mo. The mean plasma and erythrocyte folate concentrations in the folate-supplemented group were higher than in the placebo group at 6, 12, 18, and 24 mo (P < 0.001). Adjusted for baseline differences, the difference in erythrocyte folate concentrations between the folate and placebo group at 6 mo was 1.78 µmol/L (95% CI 1.62-1.95 µmol/L). The difference increased significantly to 2.02 µmol/L (95% CI 1.85-2.18 µmol/L) at 12 mo. This difference (between the folate and placebo groups) did not significantly change after a further year of folate supplementation; at 18 mo, it was 2.09 µmol/L (95% CI 1.92-2.27 µmol/L) and at 24 mo it was 1.98 µmol/L (95% CI 1.18-2.15 µmol/L). Twelve months of daily folate supplementation with 1 mg is sufficient time to cause erythrocyte folate concentrations to reach a new steady state.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Complexo Vitamínico B
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Eritrócitos
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Ácido Fólico
Tipo de estudo:
Clinical_trials
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Prognostic_studies
Limite:
Aged
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Aged80
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Female
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Humans
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Male
Idioma:
En
Revista:
J Nutr
Ano de publicação:
2012
Tipo de documento:
Article