Abstract
The function of folate, in its various co-factor forms, is in mediating one-carbon metabolism, a network of pathways involving the transfer and utilization of single-carbon units, including methylene, forminino, methyl, methenyl, and formyl groups. Folate is thus essential for key biological functions, including the biosynthesis of DNA, serine and glycine metabolism, and methionine synthesis. Folate, in the form of 5‑methyltetrahydrofolate, along with vitamin B12 (as methylcobalamin), is required for the synthesis of methionine from homocysteine, and in turn the generation of S‑adenosylmethionine, a methyl group donor used in numerous reactions, including the methylation of DNA, RNA, proteins, and phospholipids. Clinical deficiency of folate is manifested as megaloblastic anemia, characterized by abnormal cell replication in the hematopoietic system, megaloblasts in the bone marrow and macrocytes in the peripheral blood. The megaloblastic anemia of folate deficiency is identical to that of vitamin B12 deficiency, and specific biomarker testing is essential to provide a differential diagnosis. Folate-related anemia occurs commonly in pregnant and lactating women in low- and middle-income countries. Clinical folate deficiency is less common in high-income countries, but subclinical deficiency is widespread, especially in women of reproductive age and in the presence of certain diseases and drugs. Notably, maternal folate nutrition before and in early pregnancy plays a critical role in fetal development, with conclusive scientific evidence that folic acid supplementation in early pregnancy protects against the occurrence of neural tube defects. Serum and red blood cell (RBC) folate are the biomarkers used to assess folate status, whilst plasma homocysteine provides a functional indictor of status.
Original language | English |
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Title of host publication | Principles of Nutritional Assessment |
Editors | Rosalind Gibson |
Publisher | Oxford University Press (OUP) |
Chapter | 22a |
Edition | 3rd |
Publication status | Published (in print/issue) - Mar 2022 |