Nutr Res Pract.  2007 Sep;1(3):163-174.

Folate during reproduction: the Canadian experience with folic acid fortification

• Lindzon G
• O'Connor D

Abstract

Folate has received international attention regarding its role in the risk-reduction of birth defects, specifically neural tube defects (NTDs). In 1998, health officials in Canada, like the United States, mandated the addition of folic acid to white flour and select grain products to increase the folate intake of reproductive-aged women. Subsequent to this initiative there has been an increase in blood folate concentrations in Canada and a 50% reduction in NTDs. Many countries, including Korea, have not mandated folic acid fortification of their food supply. Reasons vary but often include concern over the masking of vitamin B12 deficiency, a belief that folate intakes among womenare adequate, low priority relative to other domestic issues, and the philosophy that individuals have the right not to consume supplemental folic acid if they so choose. Prior to folic acid fortification of the food supply in Canada, the folate intakes of women were low, and their blood folate concentrations while not sufficiently low to produce overt signs of folate deficiency (eg. anemia) were inconsistent with a level known to reduce the risk of an NTD-affected pregnancy. The purpose of this article is to describe the role of folate during the periconceptional period, pregnancy, and during lactation. The rationale for, and history of recommending folic acid-containing supplements during the periconceptional period and pregnancy is described as is folic acid fortification of the food supply. The impact of folic acid fortification in Canada is discussed, and unresolved issues associated with this policy described. While the incidence of NTDs in Canada pre-folic acid fortification were seemingly higherthan that of Korea today, blood folate levels of Korean women are strikingly similar. We will briefly explore these parallels in an attempt to understand whether folic acid fortification of the food supply in Korea might be worth consideration

Keyword

Folic acid; fortification; periconceptional period; pregnancy; lactation

MeSH Terms

Canada
Edible Grain
Congenital Abnormalities
Female
Flour
Folic Acid*
Food Supply
Humans
Incidence
Korea
Lactation
Masks
Neural Tube Defects
Philosophy
Pregnancy
Reproduction*
United States
Vitamin B 12 Deficiency
Folic Acid

Figure

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  Fig. 1 The chemical structure of folic acid or pterolylmonoglutamic acid. Other folate forms are denoted by the "R"-substitutions found in the box.

• 

  Fig. 2 Simplified diagram of intracellular folate metabolism involving DNA biosynthesis and methylation. THF, tetrahydrofolate; MTHFR, methylenetetrahydrofolate; SAM, S-adenosylmethionine; SAH, S-adenosylhomocysteine; CpG, Cytosine-guanine dinucleotide sequence; CH3 , methyl group; DNMT(1, 3a, 3b), DNA methyltransferases; MTR, methionine synthase; MTRR, methionine synthase reductase; TS, Thymidylate synthase; DHFR, dihydrofolate reductase; dUMP, deoxyuridine monophosphate; dTMP, deoxythymidine monophosphate; SHMT, serine hydroxymethyltransferase; CBS, cystathionine β-synthase [diagram modified with permission (Kim, 2004a; Sohn et al., 2004)]

• 

  Fig. 3 Quarterly prevalence of open neural tube defects(upper), spina bifida(middle), and anencephaly (lower) before and after (vertical dashed lines) folic acid food fortification. [reprinted with permission (Ray et al., 2002a)]

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  Fig. 4 Rates of neural tube defects before and after fortification in regions with mandatory folic acid fortification. Numbers include livebirths, stillbirths, prenatally diagnosed cases and elective abortions (Chile with livebirths and stillbirths only ,USA with surveillance programmes with and without prenatal assessment) (reprinted with permission). [diagram modified with permission (Eichholzer et al., 2006)]

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