The term 'megaloblastic' refers to a particular abnormality in bone marrow hemopoiesis, and can only be diagnosed definitively after a bone marrow examination. Its presence can be strongly suspected by finding oval macrocytes and hypersegmented neutrophils in the peripheral blood. The relationship between dietary folate intake and hyperhomocysteinemia 10. The prevention of neural tube defects using folate supplements Biochemical Introduction Folates act as 1-carbon unit carriers and are needed for synthesising both DNA and RNA, as well as the conversion of homocysteine to methionine. Vitamin B 12 is required also for converting homocysteine to methionine, and for one other known reaction in humans, the isomerisation of methylmalonic acid.
Folate deficiency affects DNA synthesis in all mitotic tissues.
Vitamin B 12 also causes abnormal DNA synthesis. Effects of deficiency Folate and vitamin B 12 deficiency both produce an identical megaloblastic anaemia, with marked ineffective erythropoiesis. They may also cause a sore tongue, and affect the gut mucosa. Dietary Folate and its absorption Folates are present in most vegetables, especially green leafy ones, and in liver and meat. They are degraded by prolonged boiling.