Blood folate level needed for fully effective fortification in the prevention of neural tube defects
Objective Neural tube defects (NTDs) are a preventable folate deficiency disorder; increasing folic acid intake through food fortification increases serum and red blood cell folate and reduces the risk of an NTD pregnancy. There is controversy over the blood folate level needed to achieve the full preventive effect because of discrepant study conclusions. Methods Results from two published studies were used to determine the relationship between serum folate and NTD risk which was compared with the observed result in a randomised trial of folic acid that increased serum folate from 5 ng/mL to 44 ng/mL among women who took a 4 mg daily periconceptional folic acid supplement. Results Both studies showed a proportional (logarithmic) relationship between serum folate and NTD risk without evidence of a folate threshold above which there is no further NTD risk reduction. The suggestion of a threshold is due to the incorrect interpretation of the folate-NTD risk association when plotted on ari
