Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women

Norsworthy, Brooke K; Skeaff, C. Murray; Adank, Charlotte; Green, Timothy

doi:10.1038/sj.ejcn.1601843

Cited by 44 publications

(43 citation statements)

References 17 publications

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“…The increases and patterns attained in serum and red blood cell folate by both folic acid dosage regimens in the present trial are in line with previous studies (22)(23)(24) , but direct comparisons on absolute values cannot be made because of differences in laboratory procedures. However, in 2001 Martinez et al (23) carried out a supplementation trial with a weekly dosage of 5 mg folic acid among non-pregnant women of childbearing age in Nuevo León, Mexico, using similar laboratory tests.…”

Section: Discussionsupporting

confidence: 90%

Effect of different dosage and administration schedules of folic acid on blood folate levels in a population of Honduran women of reproductive age

Rosenthal

Milla²,

Flores

et al. 2008

Public Health Nutr.

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Background: Observational studies and clinical trials have shown conclusive evidence that periconceptional folic acid supplementation prevents up to 70 % of neural tube defects (NTD). The Honduran government wanted to implement a supplementation programme of folic acid but needed to assess the relative effects of two dosages of folic acid. Objective: To determine the effect of two dosages of folic acid on blood folate levels in Honduran female factory workers aged 18 to 49 years. Design: This was a randomized, double-blind control supplementation trial conducted in Choloma, Honduras. A total of 140 eligible women were randomly assigned to two dosage groups and followed up for 12 weeks. One group received a daily dosage of 1 mg folic acid and the other a once weekly dosage of 5 mg. Serum folate and red blood cell folate levels were determined by radioassay at baseline, 6 weeks and 12 weeks. Results: Serum folate levels increased from 6?3 (SE 0?2) to 14?9 (SE 0?6) ng/ml (P , 0?0001) in women assigned to the 1 mg/d group and from 6?9 (SE 0?3) to 10?1 (SE 0?4) ng/ml (P , 0?0001) in those assigned to the 5 mg/week group. Red blood cell folate concentrations also increased significantly in both groups, albeit more slowly. Educational level, age and BMI were not associated with the changes in serum and red blood cell folate levels during the supplementation period. However, a differential effect on serum folate levels by dosage group and time was observed. Conclusions: Although both folate supplementation regimens increased serum and red blood cell folate levels significantly among the women studied, blood folate levels that are considered to be protective of NTD were reached faster with the daily dosage of 1 mg folic acid.

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Section: Discussionsupporting

confidence: 90%

Effect of different dosage and administration schedules of folic acid on blood folate levels in a population of Honduran women of reproductive age

Rosenthal

Milla²,

Flores

et al. 2008

Public Health Nutr.

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“…European guidelines regarding FA supplementation do not currently feature an explicit recommendation concerning the required duration of FA supplementation preconceptionally. This suggests that there is a need to update our national and European FA guidelines to include a recommendation on the ideal timing of FA preconceptionally, in view of the recent kinetic studies in this area (7)(8)(9)(10) . This message should be incorporated into renewed public health campaigns in this area to enhance the clinical effectiveness of periconceptional FA supplementation.…”

Section: Public Health Nutritionmentioning

confidence: 99%

“…The questionnaire also included questions about the dose and brand name of FA used and compliance with the established minimum duration of supplementation for optimal NTD prevention (i.e. 12 weeks of preconceptional FA (8)(9)(10) ).…”

Section: Folic Acid Questionnairementioning

confidence: 99%

“…Scientific evidence suggests that the risk of NTD is substantially attenuated at red-blood-cell (RBC) folate concentrations of 906-1000 nmol/l (6,7) . In recent kinetic studies, it has been shown that it takes 12 weeks of daily supplementation with 400 µg FA to achieve these levels of RBC folate at which NTD prevention is optimised (8)(9)(10) . Irish studies suggest that 19-44 % of women take FA preconceptionally (11)(12)(13)(14) .…”

mentioning

confidence: 99%

“…Given the limited Irish data describing the duration of periconceptional FA supplementation and the rising incidence of NTD in Ireland, examination of the duration of periconceptional FA supplementation is important. Kinetic studies have shown that those who consumed 400 µg FA/d reached an RBC folate concentration associated with optimally reduced risk of NTD after 3 to 6 months (7)(8)(9) . Therefore, it is important to establish whether or not women who take FA preconceptionally are doing so for the required duration to optimise NTD prevention.…”

mentioning

confidence: 99%

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Duration of periconceptional folic acid supplementation in women booking for antenatal care

Cawley¹,

Mullaney²,

Kennedy³

et al. 2016

Public Health Nutr.

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ObjectiveTo provide accurate estimates of the commencement time, duration and dosage of folic acid (FA) supplementation taken by Irish women in the periconceptional period. The study also aimed to establish the factors associated with optimal FA supplementation practices.DesignCross-sectional observational study. Women’s clinical and sociodemographic details were computerised. Maternal weight and height were measured before calculating BMI. Detailed FA supplementation questionnaires were completed under the supervision of a trained researcher.SettingA large university maternity hospital, Republic of Ireland, January 2014–April 2016.SubjectsWomen (n856) recruited at their convenience in the first trimester.ResultsWhile almost all of the women (97 %) were taking FA at enrolment, only one in four women took FA for at least 12 weeks preconceptionally (n208). Among the 44 % of women who were supplementing with FA preconceptionally, 44 % (162/370) reported taking FA for less than the 12 weeks required to achieve optimal red-blood-cell folate levels for prevention of neural tube defects. On multivariate analysis, only planned pregnancy and nulliparity were associated with taking FA for at least 12 weeks preconceptionally. Among women who only took FA postconceptionally, almost two-thirds commenced it after day 28 of their pregnancy when the neural tube had already closed.ConclusionsAs the timing of FA was suboptimal both before and after conception, we recommend that current national FA guidelines need to be reviewed.

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Effects and safety of periconceptional folate supplementation for preventing birth defects

De-Regil¹,

Fernández-Gaxiola²,

Dowswell³

et al. 2010

Cochrane Database of Systematic Reviews

233

101

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Background It has been reported that neural tube defects can be prevented with periconceptional folic acid supplementation. The effects of different doses, forms and schemes of folate supplementation for the prevention of other birth defects and maternal and infant outcomes are unclear. Objectives This review updates and expands a previous Cochrane Review assessing the effects of periconceptional supplementation with folic acid to reduce neural tube defects (NTDs). We examined whether folate supplementation before and during early pregnancy can reduce neural tube and other birth defects (including cleft palate) without causing adverse outcomes for mothers or babies. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (July 2010). Additionally, we searched the international clinical trials registry platform and contacted relevant organisations to identify ongoing and unpublished studies. Selection criteria We included all randomised or quasi-randomised trials evaluating the effect of periconceptional folate supplementation alone, or in combination with other vitamins and minerals, in women independent of age and parity. Data collection and analysis We assessed trials for methodological quality using the standard Cochrane criteria. Two authors independently assessed the trials for inclusion, one author extracted data and a second checked for accuracy. Main results Five trials involving 6105 women (1949 with a history of a pregnancy affected by a NTD and 4156 with no history of NTDs) were included. Overall, the results are consistent in showing a protective effect of daily folic acid supplementation (alone or in combination with other vitamins and minerals) in preventing NTDs compared with no interventions/placebo or vitamins and minerals without folic acid (risk ratio (RR) 0.28, 95% confidence interval (CI) 0.15 to 0.52). Only one study assessed the incidence of NTDs and the effect was not statistically significant (RR 0.08, 95% CI 0.00 to 1.33) although no events were found in the group that received folic acid. Folic acid had a significant protective effect for reoccurrence (RR 0.32, 95% CI 0.17 to 0.60). There is no statistically significant evidence of any effects on prevention of cleft palate, cleft lip, congenital cardiovascular defects, miscarriages or any other birth defects. There were no included trials assessing the effects of this intervention on maternal blood folate or anaemia at term. We found no evidence of short-term side effects. Authors’ conclusions Folic acid, alone or in combination with vitamins and minerals, prevents NTDs but does not have a clear effect on other birth defects.

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Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women

Cited by 44 publications

References 17 publications

Effect of different dosage and administration schedules of folic acid on blood folate levels in a population of Honduran women of reproductive age

Effect of different dosage and administration schedules of folic acid on blood folate levels in a population of Honduran women of reproductive age

Duration of periconceptional folic acid supplementation in women booking for antenatal care

Effects and safety of periconceptional folate supplementation for preventing birth defects

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