Human requirement of folacin
The adul t recommended dietary allowance for folacin is 400 mcg per day. Due to the increased needs of the fetus, the allowance for pregnancy was set at 800 mcg per day; 500 mcg is the RDA for lactation. The infant allowance is 35 mcg per day for the first 6 months and 45 mcg during the second half of the first year, at which time it is increased to 100 mcg per day until 4 years of age. The recommendation for folic acid from 4 to 6 years is 200 mcg per day; from 7 to 10 years it is 300 mcg per day. The adult recommendation (400 mcg) starts at 11 years of age and is continued throughout life for both sexes. Use of a folacin supplement is recommended during pregnancy to provide for the increased need.
Folate deficiency has been reported in women using oral contraceptive agents. However, the incidence appears to be relatively low, considering the large number of women using these drugS.Although several mechanisms have been implicated as causes of impaired folate utilization when oral contraceptive agents are used, the evidence for all of them remains equivocal. Similarly, increased folate requirement has not been conclusively demonstrated in persons treated with anticonvulsant drugs. 106 Patients receiving anticonvulsant therapy have significantly lower levels of folic acid in serum and cerebrospinal fluid than healthy people. Administration of folic acid to these patients causes the serum level of the anticonvulsant drug to fall. 107 In daily doses up to 15 mg, folic acid does not seem to interfere with the control of seizures, but it does have a convulsant effect at very high concentrations. In addition to pregnancy, increased need for folate has been clearly demonstrated only in hemolytic anemias and alcohol intoxication.The actual amount of folacin in foods that is available for absorption has not been well established. Therefore, the NRC-RDA has included a large margin of safety for this nutrient.
Because more than 100 mcg of folic acid per day may prevent anemia but not cure the neurologic symptoms of pernicious anemia, vitamin preparations that contain more than 100 mcg of folic acid cannot be sold without prescription.
