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Selhub J, Miller JW, Troen AM, Mason JB, Jacques PF. Perspective: The High-Folate-Low-Vitamin B-12 Interaction Is a Novel Cause of Vitamin B-12 Depletion with a Specific Etiology-A Hypothesis. Adv Nutr 2021; 13:16-33. [PMID: 34634124 PMCID: PMC8803489 DOI: 10.1093/advances/nmab106] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/26/2021] [Accepted: 09/02/2021] [Indexed: 11/12/2022] Open
Abstract
Vitamin B-12 is a water-soluble vitamin that plays important roles in intermediary metabolism. Vitamin B-12 deficiency has many identifiable causes, including autoimmune and other gastrointestinal malabsorption disorders, dietary deficiency, and congenital defects in genes that are involved in vitamin B-12 trafficking and functions. Another putative cause of vitamin B-12 deficiency is the high-folate-low vitamin B-12 interaction, first suspected as the cause for observed relapse and exacerbation of the neurological symptoms in patients with pernicious anemia who were prescribed high oral doses of folic acid. We propose that this interaction is real and represents a novel cause of vitamin B-12 depletion with specific etiology. We hypothesize that excessive intake of folic acid depletes serum holotranscobalamin (holoTC), thereby decreasing active vitamin B-12 in the circulation and limiting its availability for tissues. This effect is specific for holoTC and does not affect holohaptocorrin, the inert form of serum vitamin B-12. Depletion of holoTC by folic acid in individuals with already low vitamin B-12 status further compromises the availability of vitamin B-12 coenzymes to their respective enzymes, and consequently a more pronounced state of biochemical deficiency. This hypothesis is drawn from evidence of observational and intervention studies of vitamin B-12-deficient patients and epidemiological cohorts. The evidence also suggests that, in a depleted state, vitamin B-12 is diverted to the hematopoietic system or the kidney. This most likely reflects a selective response of tissues expressing folate receptors with high affinity for unmetabolized folic acid (UMFA; e.g., hematopoietic progenitors and renal tubules) compared with those tissues (e.g., liver) that only express the reduced folate carrier, which is universally expressed but has poor affinity for UMFA. The biochemical and physiological mechanisms underlying this interaction require elucidation to clarify its potential public health significance.
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Affiliation(s)
| | | | - Aron M Troen
- School of Nutritional Sciences and Institute of Biochemistry Food Science and Nutrition, The Robert H Smith Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joel B Mason
- Tufts–USDA Human Nutrition Research Center on Aging, Boston, MA, USA
| | - Paul F Jacques
- Tufts–USDA Human Nutrition Research Center on Aging, Boston, MA, USA
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D'Souza SW, Copp AJ, Greene NDE, Glazier JD. Maternal Inositol Status and Neural Tube Defects: A Role for the Human Yolk Sac in Embryonic Inositol Delivery? Adv Nutr 2020; 12:212-222. [PMID: 32892218 PMCID: PMC7849949 DOI: 10.1093/advances/nmaa100] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/10/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022] Open
Abstract
Supplementation with myo-inositol during the periconceptional period of pregnancy may ameliorate the recurrence risk of having a fetus affected by a neural tube defect (NTD; e.g., spina bifida). This could be of particular importance in providing a means for preventing NTDs that are unresponsive to folic acid. This review highlights the characteristics of inositol and describes the role of myo-inositol in the prevention of NTDs in rodent studies and the evidence for its efficacy in reducing NTD risk in human pregnancy. The possible reduction in NTD risk by maternal myo-inositol implies functional and developmentally important maternal-embryonic inositol interrelationships and also suggests that embryonic uptake of myo-inositol is crucial for embryonic development. The establishment of active myo-inositol cellular uptake mechanisms in the embryonic stages of human pregnancy, when the neural tube is closing, is likely to be an important determinant of normal development. We draw attention to the generation of materno-fetal inositol concentration gradients and relationships, and outline a transport pathway by which myo-inositol may be delivered to the early developing human embryo. These considerations provide novel insights into the mechanisms that may underpin inositol's ability to confer embryonic developmental benefit.
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Affiliation(s)
- Stephen W D'Souza
- Maternal and Fetal Health Research Centre, St. Mary's Hospital, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew J Copp
- Newlife Birth Defects Research Centre, Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Nicholas D E Greene
- Newlife Birth Defects Research Centre, Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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Clark RL. Animal Embryotoxicity Studies of Key Non-Artemisinin Antimalarials and Use in Women in the First Trimester. Birth Defects Res 2017. [DOI: 10.1002/bdr2.1035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Selhub J, Rosenberg IH. Excessive folic acid intake and relation to adverse health outcome. Biochimie 2016; 126:71-8. [DOI: 10.1016/j.biochi.2016.04.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 04/07/2016] [Indexed: 11/27/2022]
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Abstract
John Scott (1940-2013) was born in Dublin where he was to spend the rest of his career, both as an undergraduate and subsequently Professor of Biochemistry and Nutrition at Trinity College. His research with the talented group of scientists and clinicians that he led has had a substantial impact on our understanding of folate metabolism, mechanisms of its catabolism and deficiency. His research established the leading theory of folate involvement with vitamin B12 in the pathogenesis of vitamin B12 neuropathy. He helped to establish the normal daily intake of folate and the increased requirements needed either in food or as a supplement before and during pregnancy to prevent neural tube defects. He also suggested a dietary supplement of vitamin B12 before and during pregnancy to reduce the risk of neural tube defects. It would be an appropriate epitaph if fortification of food with folic acid became mandatory in the UK and Ireland, as it is in over 70 other countries.
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Affiliation(s)
- A Victor Hoffbrand
- Emeritus Professor of Haematology, University College London, London, UK; Honorary Consultant Haematologist, Royal Free Hospital, London, UK
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Youngblood ME, Williamson R, Bell KN, Johnson Q, Kancherla V, Oakley GP. 2012 Update on global prevention of folic acid-preventable spina bifida and anencephaly. ACTA ACUST UNITED AC 2013; 97:658-63. [DOI: 10.1002/bdra.23166] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Monica E. Youngblood
- Department of Behavioral Science and Health Education; Rollins School of Public Health of Emory University; Atlanta; Georgia
| | - Rebecca Williamson
- Department of Epidemiology; Rollins School of Public Health of Emory University; Atlanta; Georgia
| | - Karen N. Bell
- Department of Epidemiology; Rollins School of Public Health of Emory University; Atlanta; Georgia
| | - Quentin Johnson
- Training and Technical Support Group; Flour Fortification Initiative; Atlanta; Georgia
| | - Vijaya Kancherla
- Department of Epidemiology; Rollins School of Public Health of Emory University; Atlanta; Georgia
| | - Godfrey P. Oakley
- Department of Epidemiology; Rollins School of Public Health of Emory University; Atlanta; Georgia
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Bassuk AG, Muthuswamy LB, Boland R, Smith TL, Hulstrand AM, Northrup H, Hakeman M, Dierdorff JM, Yung CK, Long A, Brouillette RB, Au KS, Gurnett C, Houston DW, Cornell RA, Manak JR. Copy number variation analysis implicates the cell polarity gene glypican 5 as a human spina bifida candidate gene. Hum Mol Genet 2012; 22:1097-111. [PMID: 23223018 DOI: 10.1093/hmg/dds515] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Neural tube defects (NTDs) are common birth defects of complex etiology. Family and population-based studies have confirmed a genetic component to NTDs. However, despite more than three decades of research, the genes involved in human NTDs remain largely unknown. We tested the hypothesis that rare copy number variants (CNVs), especially de novo germline CNVs, are a significant risk factor for NTDs. We used array-based comparative genomic hybridization (aCGH) to identify rare CNVs in 128 Caucasian and 61 Hispanic patients with non-syndromic lumbar-sacral myelomeningocele. We also performed aCGH analysis on the parents of affected individuals with rare CNVs where parental DNA was available (42 sets). Among the eight de novo CNVs that we identified, three generated copy number changes of entire genes. One large heterozygous deletion removed 27 genes, including PAX3, a known spina bifida-associated gene. A second CNV altered genes (PGPD8, ZC3H6) for which little is known regarding function or expression. A third heterozygous deletion removed GPC5 and part of GPC6, genes encoding glypicans. Glypicans are proteoglycans that modulate the activity of morphogens such as Sonic Hedgehog (SHH) and bone morphogenetic proteins (BMPs), both of which have been implicated in NTDs. Additionally, glypicans function in the planar cell polarity (PCP) pathway, and several PCP genes have been associated with NTDs. Here, we show that GPC5 orthologs are expressed in the neural tube, and that inhibiting their expression in frog and fish embryos results in NTDs. These results implicate GPC5 as a gene required for normal neural tube development.
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Affiliation(s)
- Alexander G Bassuk
- Department of Pediatrics, University of Iowa Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Bell KN, Oakley GP. Update on prevention of folic acid-preventable spina bifida and anencephaly. ACTA ACUST UNITED AC 2009; 85:102-7. [PMID: 19067404 DOI: 10.1002/bdra.20504] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The number of countries fortifying wheat and maize flour with folic acid has increased in the past 2 years. Folic acid prevents most cases of spina bifida and anencephaly by raising serum folate levels among women capable of bearing children, as does encouraging women to consume folic acid supplements prior to pregnancy. METHODS The progress in preventing these serious birth defects can be measured by tracking the number of countries now fortifying and program coverage in each. Country estimates of the number of pregnancies affected by spina bifida and anencephaly are calculated using a prefortification birth prevalence baseline and estimates of the proportion prevented by wheat and maize flour fortified with folic acid. RESULTS Current fortification programs are preventing about 22,000, or 9% of the estimated folic acid-preventable spina bifida and anencephaly cases. This represents an annual global decrease of about 6,600 folic acid-preventable spina bifida and anencephaly cases since 2006. CONCLUSIONS The pace of preventing these serious birth defects can be accelerated if more countries require fortification of both wheat and maize flour and if regulators set fortification levels high enough to increase a woman's daily average consumption of folic acid to 400 mcg.
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Affiliation(s)
- Karen N Bell
- Department of Epidemiology, Rollins School of Public Health of Emory University, Gloucester, Massachusetts, USA
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Selhub J, Morris MS, Jacques PF, Rosenberg IH. Folate-vitamin B-12 interaction in relation to cognitive impairment, anemia, and biochemical indicators of vitamin B-12 deficiency. Am J Clin Nutr 2009; 89:702S-6S. [PMID: 19141696 PMCID: PMC2647758 DOI: 10.3945/ajcn.2008.26947c] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Previous reports on pernicious anemia treatment suggested that high folic acid intake adversely influences the natural history of vitamin B-12 deficiency, which affects many elderly individuals. However, experimental investigation of this hypothesis is unethical, and the few existing observational data are inconclusive. With the use of data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES), we evaluated the interaction between high serum folate and low vitamin B-12 status [ie, plasma vitamin B-12 < 148 pmol/L or methylmalonic acid (MMA) > 210 nmol/L] with respect to anemia and cognitive impairment. With subjects having both plasma folate < or = 59 nmol/L and normal vitamin B-12 status as the referent category, odds ratios for the prevalence of anemia compared with normal hemoglobin concentration and impaired compared with unimpaired cognitive function were 2.1 (95% CI: 1.1, 3.7) and 1.7 (95% CI: 1.01, 2.9), respectively, for those with low vitamin B-12 status but normal serum folate and 4.9 (95% CI: 2.3, 10.6) and 5.0 (95% CI: 2.7, 9.5), respectively, for those with low vitamin B-12 status and plasma folate >59 nmol/L. Among subjects with low vitamin B-12 status, mean circulating vitamin B-12 was 228 pmol/L for the normal-folate subgroup and 354 pmol/L for the high-folate subgroup. We subsequently showed increases in circulating homocysteine and MMA concentrations with increasing serum folate among NHANES participants with serum vitamin B-12 < 148 pmol/L, whereas the opposite trends occurred among subjects with serum vitamin B-12 > or = 148 pmol/L. These interactions, which were not seen in NHANES III before fortification, imply that, in vitamin B-12 deficiency, high folate status is associated with impaired activity of the 2 vitamin B-12-dependent enzymes, methionine synthase and MMA-coenzyme A mutase.
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Affiliation(s)
- Jacob Selhub
- Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
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Bar-Oz B, Koren G, Nguyen P, Kapur BM. Folate fortification and supplementation—Are we there yet? Reprod Toxicol 2008; 25:408-12. [DOI: 10.1016/j.reprotox.2008.04.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 04/01/2008] [Accepted: 04/24/2008] [Indexed: 11/30/2022]
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Increasing folate supplementation for selected groups of Canadian women. JOURNAL OF OBSTETRICS AND GYNAECOLOGY CANADA 2008; 29:992-996. [PMID: 18053385 DOI: 10.1016/s1701-2163(16)32690-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
After review of current evidence related to the potential risks and benefits of folic acid supplementation, we conclude that unless clinicians can be assured that pregnant women will reliably use prenatal vitamin supplements containing 0.8-1.1 mg of folate, the prenatal vitamin supplements should be combined with 5 mg of folate.
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Liu S, West R, Randell E, Longerich L, O'Connor KS, Scott H, Crowley M, Lam A, Prabhakaran V, McCourt C. A comprehensive evaluation of food fortification with folic acid for the primary prevention of neural tube defects. BMC Pregnancy Childbirth 2004; 4:20. [PMID: 15450123 PMCID: PMC524178 DOI: 10.1186/1471-2393-4-20] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Accepted: 09/27/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND: Periconceptional use of vitamin supplements containing folic acid reduces the risk of a neural tube defect (NTD). In November 1998, food fortification with folic acid was mandated in Canada, as a public health strategy to increase the folic acid intake of all women of childbearing age. We undertook a comprehensive population based study in Newfoundland to assess the benefits and possible adverse effects of this intervention. METHODS: This study was carried out in women aged 19-44 years and in seniors from November 1997 to March 1998, and from November 2000 to March 2001. The evaluation was comprised of four components: I) Determination of rates of NTDs; II) Dietary assessment; III) Blood analysis; IV) Assessment of knowledge and use of folic acid supplements. RESULTS: The annual rates of NTDs in Newfoundland varied greatly between 1976 and 1997, with a mean rate of 3.40 per 1,000 births. There was no significant change in the average rates between 1991-93 and 1994-97 (relative risk [RR] 1.01, 95% confidence interval [CI] 0.76-1.34). The rates of NTDs fell by 78% (95% CI 65%-86%) after the implementation of folic acid fortification, from an average of 4.36 per 1,000 births during 1991-1997 to 0.96 per 1,000 births during 1998-2001 (RR 0.22, 95% CI 0.14-0.35). The average dietary intake of folic acid due to fortification was 70 μg/day in women aged 19-44 years and 74 μg/day in seniors. There were significant increases in serum and RBC folate levels for women and seniors after mandatory fortification. Among seniors, there were no significant changes in indices typical of vitamin B12 deficiencies, and no evidence of improved folate status masking haematological manifestations of vitamin B12 deficiency. The proportion of women aged 19-44 years taking a vitamin supplement containing folic acid increased from 17% to 28%. CONCLUSIONS: Based on these findings, mandatory food fortification in Canada should continue at the current levels. Public education regarding folic acid supplement use by women of childbearing age should also continue.
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Affiliation(s)
- Shiliang Liu
- Health Surveillance and Epidemiology Division, Centre for Healthy Human Development, PPHB, Health Canada, Ottawa, Ontario, Canada
| | - Roy West
- Division of Community Health, Faculty of Medicine, Memorial University, St. John's, Newfoundland and Labrador, Canada
| | - Edward Randell
- Health Sciences Centre and Division of Laboratory Medicine; Faculty of Medicine, Memorial University, St. John's, Newfoundland and Labrador, Canada
| | - Linda Longerich
- Division of Community Health, Faculty of Medicine, Memorial University, St. John's, Newfoundland and Labrador, Canada
| | - Kathleen Steel O'Connor
- Public Health Research, Education and Development Program, Kingston, Frontenac and Lennox & Addington Health Unit, Kingston, Ontario, Canada
| | - Helen Scott
- Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Marian Crowley
- Provincial Medical Genetics Program, Health Care Corporation of St. John's, St. John's, Newfoundland and Labrador, Canada
| | - Angeline Lam
- Health Sciences Centre and Division of Laboratory Medicine; Faculty of Medicine, Memorial University, St. John's, Newfoundland and Labrador, Canada
- Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Victor Prabhakaran
- London Health Sciences Centre & Department of Clinical Biochemistry, University of Western Ontario, London, Ontario, Canada
| | - Catherine McCourt
- Health Surveillance and Epidemiology Division, Centre for Healthy Human Development, PPHB, Health Canada, Ottawa, Ontario, Canada
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O'Donnell J, Perry DJ. Pharmacotherapy of hyperhomocysteinaemia in patients with thrombophilia. Expert Opin Pharmacother 2002; 3:1591-8. [PMID: 12437493 DOI: 10.1517/14656566.3.11.1591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Hyperhomocysteinaemia is often the result of inherited abnormalities of the enzymes involved in homocysteine metabolism or vitamin deficiencies (vitamins B12, B6 or folate) and is present in approximately 5% of the general population. High homocysteine levels in these individuals are associated with a significant increase in relative risk for both arterial and venous thromboembolic disease. Consequently, effective homocysteine-lowering therapeutic strategies have been extensively investigated. Folic acid represents the cornerstone of treatment. In daily doses of at least 0.4 mg, it effectively reduces homocysteine levels, even in non-folate-deficient patients. The addition of vitamins B12 and/or B6, to folic acid supplementation may provide a small further reduction in homocysteine levels in certain groups of patients. Renal impairment is an important cause of hyperhomocysteinaemia. Individuals with hyperhomocysteinaemia secondary to renal disease commonly require significantly higher doses of folic acid (5-40 mg) to achieve maximal therapeutic effect. The important question of whether effective homocysteine-lowering therapy translates into a reduction in vascular disease remains unknown but is being addressed in a series of ongoing prospective trials.
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Affiliation(s)
- James O'Donnell
- Katherine Dormandy Haemophilia Centre and Haemostasis Unit, Department of Haematology, Royal Free Hospital School of Medicine, Pond Street, London NW3 2QG, UK
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Langley-Evans SC, Langley-Evans AJ. Use of folic acid supplements in the first trimester of pregnancy. THE JOURNAL OF THE ROYAL SOCIETY FOR THE PROMOTION OF HEALTH 2002; 122:181-6. [PMID: 12391833 DOI: 10.1177/146642400212200315] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Folic acid supplementation in the periconceptual period is known to reduce the risk of neural tube defects. High dose supplementation prevents a high proportion of recurrent defects, whilst low doses reduce the risk of first occurrences. The Department of Health advises all women considering pregnancy to take folate supplements for 12 weeks prior to conception and in the first trimester of pregnancy. Surveys of the British population indicate that the uptake of this advice is poor. The aim of the present study was to evaluate the uptake of advice in a group of Northampton women between January and June 2001. A total of 301 Caucasian women were recruited through an antenatal dating scan clinic. The women were aged between 16 and 42 years and completed a questionnaire concerning nutritional supplements prior to and during pregnancy and a five-day food diary, which was used to estimate dietary folate intakes. Of the women 67% consumed folate-containing supplements in the first trimester of pregnancy and 43% reported taking folate before becoming pregnant. Women under the age of 21 years were less likely to take folate supplements than women over the age of 21 years (p = 0.007), as were smokers (p < 0.001) and women from lower social classes. Mean folate intakes, including supplements, were 511 +/- 17 micrograms per day and unsupplemented dietary intakes were 237 +/- 5 micrograms per day. Of the women interviewed, 24.5% had folate intakes below the reference nutrient intake for pregnancy (300 micrograms per day). The data supports the assertion that neural tube defects are more likely to be prevented through the fortification of staple foods than through supplementation, but highlights the fact that young women from poor social backgrounds may still require close monitoring and support.
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Affiliation(s)
- Simon C Langley-Evans
- Department of Nutritional Biochemistry, University of Nottingham, Loughborough LE12 5RD, England.
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Reisch HS, Flynn MAT. Folic acid and the prevention of neural tube defects (NTDs). Challenges and recommendations for public health. Canadian Journal of Public Health 2002. [PMID: 12154525 DOI: 10.1007/bf03405011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To outline specific challenges facing public health in Canada that need to be addressed to ensure that all women of childbearing years can attain optimal folate status for prevention of NTDs. METHODS The new Dietary Reference Intake (DRI) for folate was examined in terms of the literature on the effective form of the vitamin, the level of folic acid provided by the Canadian food supply and the folic acid content of available supplements. FINDINGS There are six major challenges facing public health in Canada on this issue. These include confusion among health professionals and the general public on the effective form of the vitamin, requirements, and the necessity of taking supplements. Further obstacles to ensuring optimal folate status in all women of childbearing age in Canada include the limited amounts of folic acid that are currently permitted in foods and the difficulties involved in identifying the amount of folic acid provided in these foods in relation to needs. INTERPRETATION These challenges must be addressed to enable women in Canada to make an informed choice about folic acid. This has the potential to prevent up to 70% of the 300 births affected by NTDs each year.
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Affiliation(s)
- Heidi S Reisch
- Health Promotion & Disease Prevention, Healthy Communities, Calgary Health Region, Calgary, AB
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Olney RS, Mulinare J. Trends in neural tube defect prevalence, folic acid fortification, and vitamin supplement use. Semin Perinatol 2002; 26:277-85. [PMID: 12211618 DOI: 10.1053/sper.2002.34773] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this review, the authors analyze international trends in rates of neural tube defects (NTDs) during the past three decades. Population-based data sources include the Metropolitan Atlanta Congenital Defects Program and other US birth defects surveillance programs in the National Birth Defects Prevention Network, the International Clearinghouse for Birth Defects Monitoring Systems, and US and Canadian vital records. To analyze trends in vitamin consumption, we review data from the US National Health and Nutrition Examination Surveys and international surveys of multivitamin use. We discuss the role of factors associated with historic and continuing declines in NTD rates in most countries. These factors include the introduction and increased utilization of prenatal diagnosis, recommendations for multivitamin use in women of childbearing age, and population-wide increases in blood folate levels that have occurred since food fortification was mandated. We also discuss research needs for further NTD prevention. This is a US government work. There are no restrictions on its use.
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Affiliation(s)
- Richard S Olney
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA 30341-3724, USA.
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Williams LJ, Mai CT, Edmonds LD, Shaw GM, Kirby RS, Hobbs CA, Sever LE, Miller LA, Meaney FJ, Levitt M. Prevalence of spina bifida and anencephaly during the transition to mandatory folic acid fortification in the United States. TERATOLOGY 2002; 66:33-9. [PMID: 12115778 DOI: 10.1002/tera.10060] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND In 1992, the United States Public Health Service recommended that all women of childbearing age consume 400 microg of folic acid daily. The Food and Drug Administration authorized the addition of synthetic folic acid to grain products in March 1996 with mandatory compliance by January 1998. The impact of these public health policies on the prevalence of neural tube defects needs to be evaluated. We sought to determine the prevalences of spina bifida and anencephaly during the transition to mandatory folic acid fortification. METHODS Twenty-four population-based surveillance systems were used to identify 5,630 cases of spina bifida and anencephaly from 1995-99. Cases were divided into three temporal categories depending on whether neural tube development occurred before folic acid fortification (January 1995 to December 1996), during optional fortification (January 1997 to September 1998), or during mandatory fortification (October 1998 to December 1999). Prevalences for each defect were calculated for each time period. Data were also stratified by programs that did and did not ascertain prenatally diagnosed cases. RESULTS The prevalence of spina bifida decreased 31% (prevalence ratio [PR] = 0.69, 95% confidence interval [CI] = 0.63-0.74) from the pre- to the mandatory fortification period and the prevalence of anencephaly decreased 16% (PR = 0.84, 95% CI = 0.75-0.95). Stratification by prenatal ascertainment did not alter results for spina bifida but did impact anencephaly trends. CONCLUSIONS The decline in the prevalence of spina bifida was temporally associated with folic acid fortification of US grain supplies. The temporal association between fortification and the prevalence of anencephaly is unclear.
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Affiliation(s)
- Laura J Williams
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
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Abstract
The purpose of this article is to describe the etiology of neural tube defects (NTDs) and the role of folic acid in their prevention. NTDs are all too common and devastating outcomes of many pregnancies. The brain and spinal cord malformations that develop during gestation in the NTD-affected pregnancies are expressed through various anomalies. Estimates by the Centers for Disease Control and Prevention (CDC) for 1995 reported over 4,000 occurrences of NTDs in the United States alone. Research has demonstrated that the preconception and prenatal addition of folic acid can greatly reduce the incidence of NTDs. Recent advances in genetic studies have increased awareness of the important role of folic acid in preventing NTDs. Identification of a genetic marker will allow for specific treatment of those women at high risk for NTDs. Despite recommendations from the CDC for folic acid supplementation, there is insufficient awareness of these guidelines by both the public and by healthcare providers. A National campaign to promote awareness of the role of folic acid in the prevention of NTDs has been initiated, and has been successful at reducing NTDs's by 19%. Nurses can be instrumental in the dissemination of information not only to women of childbearing age, but also to other nurses and physicians.
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Affiliation(s)
- Susan M Hasenau
- Wayne State University, College of Nursing, Detroit, MI 48202, USA.
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Abstract
BACKGROUND Folic acid is known to prevent neural-tube defects (NTDs) but the size of the effect for a given dose is unclear. We aimed to quantify such an effect. METHODS We used published data from 13 studies of folic acid supplementation on serum folate concentrations and results from a large cohort study of the risk of NTDs according to serum folate, to measure the preventive effect of specified increases in intake of folic acid. FINDINGS Serum folate concentrations increase by 0.94 ng/mL (95% CI 0.77-1.10) for every 0.1 mg/day increase in folic acid intake in women aged 20-35 years, and about double that in people aged 40-65. Every doubling of serum folate concentration roughly halves the risk of an NTD. These two effects can be combined to predict the reduction in risk according to intake of extra folic acid and background serum folate concentration. Such results predict that the preventive effect is greater in women with low serum folate than in those with higher concentrations. The results have also been used to predict direct observations from large randomised trials and the effect of food fortification. From a typical western background serum folate of 5 ng/mL, about 0.2 mg/day (the US level of folic acid fortification) would be expected to reduce NTDs by about 20%; a similar effect can be expected from the current British recommendation (0.24 mg/day). An increase of 0.4 mg/day would reduce risk by about 36%, of 1 mg/day by 57%, and taking a 5-mg tablet daily would reduce risk by about 85%. INTERPRETATION Folic acid fortification levels should be increased. Additionally women planning a pregnancy should take 5 mg folic acid tablets daily, instead of the 0.4 mg dose presently recommended.
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Affiliation(s)
- N J Wald
- Department of Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, Barts, Charterhouse Square, London, UK.
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Choumenkovitch SF, Jacques PF, Nadeau MR, Wilson PW, Rosenberg IH, Selhub J. Folic acid fortification increases red blood cell folate concentrations in the Framingham study. J Nutr 2001; 131:3277-80. [PMID: 11739880 DOI: 10.1093/jn/131.12.3277] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In 1996 the Food and Drug Administration (FDA) issued a regulation to take effect in January 1998 that all enriched cereal grain products include 140 microg of folic acid/100 g. The present cross-sectional study was undertaken to assess the effect of this fortification on RBC folate concentrations in the Framingham Offspring Cohort. Among those who did not take B-vitamin supplements, we compared RBC folate in 561 individuals who were examined before implementation of the FDA mandatory folic acid fortification (not exposed) vs. 354 individuals who were examined after implementation of fortification (exposed). We calculated the prevalence of deficient (<160 microg/L, 362.6 nmol/L) and acceptable (>200 microg/L, 453.2 nmol/L) RBC folate concentrations in both groups. Those exposed to folic acid fortification had a mean RBC folate of 450.0 microg/L (1019.7 nmol/L), a value 38% higher than the mean RBC folate of 325.3 microg/L (737.1 nmol/L) in those who were not exposed to fortification (P < 0.001). The prevalence of individuals with deficient RBC folate was 4.9% in the group not exposed to fortification compared with 1.9% in the group exposed to fortification (P < 0.02), and the prevalence of individuals with acceptable RBC folate was 87.0% in the group not exposed to fortification compared with 96.1% in the group exposed to fortification (P < 0.001). Similar results were seen in individuals who used supplements containing B-vitamins. The results of this study showed that in this cohort, the introduction of folic acid fortification significantly improved folate nutritional status measured as RBC folate.
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Affiliation(s)
- S F Choumenkovitch
- Vitamin Metabolism and Aging Laboratory, and Epidemiology Program, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA
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Sen S, Manzoor A, Deviasumathy M, Newton C. Maternal knowledge, attitude and practice regarding folic acid intake during the periconceptional period. Public Health Nutr 2001; 4:909-12. [PMID: 11527515 DOI: 10.1079/phn2001123] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To study the knowledge, attitude and practice of pregnant women regarding periconceptional folic acid (FA) intake. DESIGN Questionnaire-based prospective study. SETTING Antenatal clinic of a District General Hospital. SUBJECTS Three-hundred pregnant women in an antenatal clinic. RESULTS Nearly all (298/300) had heard of FA. A majority (275/300, 91%) knew that FA could prevent neural tube defects, and married women those with higher education those of Social Classes 1-3 and women over 30 years of age were more likely to be thus aware. Knowledge about the correct timing of FA intake was seen in 76% and was more likely in those with higher education married women and women age over 30 years Intake of FA in the periconceptional period was seen in 134/300 (44.6%) women and was most likely in the married, Social Classes 1-3, women with higher education (all P<0.001), non-smokers women with a planned pregnancy and women aged 30 years and over CONCLUSIONS The knowledge of the correct timing of FA intake was present in only 76%. Less than half (44.6%) had taken FA in the periconceptional period, and this was far more common in the more 'privileged' classes. Low socio-economic status, age less than 30 years, lower educational status and unplanned pregnancy were high risk factors for not taking FA. The challenge to the medical profession for targeting this group cannot be over-emphasised.
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Affiliation(s)
- S Sen
- Department of Paediatrics, Queen's Hospital, Burton, Belvedere Road, Burton on Trent, Staffordshire, DE13 0RB, UK.
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Abstract
Neural tube defects represent one of a limited number of congenital conditions for which primary prevention strategies are available. Despite strong clinical evidence to support the preventive effect of supplementary folic acid given prior to conception and continued throughout the first 12 weeks of pregnancy, there is limited recent epidemiological data to support the effectiveness of national folic acid supplementation programs. Whether folic acid fortification of staple foods will provide a more effective means of achieving further reductions in the prevalence rates for this condition remains open to question. Recent advances associating folic acid supplementation, hyperhomocysteinaemia and neural tube defects provide a new insight into the possible pathological mechanism of this and possibly other related congenital conditions.
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Affiliation(s)
- S A Ali
- Royal Free and University College School of Medicine, University of London
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Affiliation(s)
- L D Botto
- Birth Defects and Genetic Diseases Branch, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
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Abstract
OBJECTIVE To review the current literature on nutrition to provide a basis for counseling patients. DESIGN Literature review. RESULT(S) Studies on nutrition and nutritional supplements in women's health are found primarily in literature not typically read by reproductive endocrinologists and gynecologist/obstetricians. A surprising number of people do not receive the vitamins and minerals that they need. Soy and soy isoflavones should be considered an important part of the diet. CONCLUSION(S) A better understanding of nutrition and nutritional supplements may reduce or prevent illness, saving the health care system millions of dollars each year.
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Affiliation(s)
- M M Seibel
- Fertility Center of New England, Dedham, Massachusetts, USA.
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Cuskelly GJ, McNulty H, Scott JM. Fortification with low amounts of folic acid makes a significant difference in folate status in young women: implications for the prevention of neural tube defects. Am J Clin Nutr 1999; 70:234-9. [PMID: 10426700 DOI: 10.1093/ajcn.70.2.234] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Mandatory fortification of grain products with folic acid was introduced recently in the United States, a policy expected to result in a mean additional intake of 100 microgram/d. One way of predicting the effectiveness of this measure is to determine the effect of removing a similar amount of folic acid as fortified food from the diets of young women who had been electively exposed to chronic fortification. OBJECTIVE The objective was to examine the effect on folate status of foods fortified with low amounts of folic acid. DESIGN We investigated the changes in dietary intakes and in red blood cell and serum concentrations of folate in response to removing folic acid-fortified foods for 12 wk from the diets of women who reportedly consumed such foods at least once weekly (consumers). RESULTS Consumers (n = 21) had higher total folate intakes (P = 0.002) and red blood cell folate concentrations (P = 0.023) than nonconsumers (women who consumed folic acid-fortified foods less than once weekly; n = 30). Of greater interest, a 12-wk intervention involving the exclusion of these foods resulted in a decrease in folate intake of 78 +/- 56 microgram/d (P < 0.001), which was reflected in a significant reduction in red blood cell folate concentrations (P < 0.05). CONCLUSIONS Cessation of eating folic acid-fortified foods resulted in removing 78 microgram folic acid/d from the diet. Over 12 wk this resulted in a lowering of red blood cell folate concentrations by 111 nmol/L (49 microgram/L). This magnitude of change in folate status in women can be anticipated as a result of the new US fortification legislation and is predicted to have a significant, although not optimal, effect in preventing neural tube defects.
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Affiliation(s)
- G J Cuskelly
- Northern Ireland Centre for Diet and Health, University of Ulster, Coleraine, Northern Ireland, United Kingdom, and the Department of Biochemistry, Trinity College, Dublin, Ireland
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Kadir RA, Sabin C, Whitlow B, Brockbank E, Economides D. Neural tube defects and periconceptional folic acid in England and Wales: retrospective study. BMJ (CLINICAL RESEARCH ED.) 1999; 319:92-3. [PMID: 10398632 PMCID: PMC28158 DOI: 10.1136/bmj.319.7202.92] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- R A Kadir
- Department of Obstetrics and Gynaecology, Royal Free and University College Medical School, London NW3 2QG
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