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Changes in Blood Folate Concentrations in Response to Intake of Folic Acid – a Systematic Review and Meta‐analysis
Author(s) -
Crider Krista S,
Devine Owen,
Qi Yan Ping,
Yeung Lorriane,
Sekkarie Ahila,
Zaganjor Ibrahim,
Berry Robert J
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.802.29
Subject(s) - folic acid , medicine , folic acid supplementation , physiology , guideline , meta analysis , pathology
Background The threshold for optimal red bloodcell (RBC) folate concentration for the prevention of neural tube defects wasset at 400ng/ml (906 nmol/L) by the World Health Organization (WHO) in 2015. After countries determine the distribution of RBC folate concentrations among reproductive age women, it will be critical to know how much additional folic acid intake from either a supplement or a fortification program is needed to reach the optimal concentrations specified in the WHO guideline. It is currently recommended that women consume 400 micrograms (mcg) of folic acid a day either through a supplement, fortified foods, or both. Objective The objective of this project was to determine how much blood folate concentrations increase in response to increasing doses of folic acid after three months of intake (as when taking a supplement) and then again after intake at steady state (similar to fortification). Results To accomplish this we conducted a systematic review of the literature for studies that included a known dose of folic acid taken continuously for ≥28 days. We searched for publications in Medline, Embase, CINAHL, Cochrane Library, POPLINE, and ClinicalTrials.gov. Of the 13,682 abstracts reviewed, 516 were selected for full‐text review and data from 100 articles were abstracted. Using a Bayesian meta‐analytic approach, one‐compartment physiologically based pharmacokinetic(PBPK) models describing folate uptake and elimination were used to estimate the steady‐state concentrations of both serum and RBC folate levels at varying levels of folic acid supplementation. Preliminary estimates showed that at approximately 400 mcg folic acid/day, RBC folate concentration increased 85% [Uncertainty Interval:75%, 97%] at steady state (after more than about 30 weeks of intake). Conclusions These results suggest that at there commended intake of folic acid to prevent neural tube defects (400 mcg/day) at steady state, RBC folate concentrations almost double. Additional analyses are underway to determine the impact of different doses of folic acid on serum and RBC folate concentrations.