南美洲国家也有添加。似乎男女需要叶酸水平不一，女多吃点有益，男不宜过多，有增加癌症风险的可能

Changes in NTD rates by sex in Chile, Argentina and Venezuela (1990–2013).

NTD: neural tube defect; FAF: folic acid fortification; Neural tube defects rates (per 10,000 births) for females (dashed orange line), and males (full blue line). Rates estimated by multivariate regression models adjusted by hospital.

PLoS One. 2018; 13(3): e0193127.

Published online 2018 Mar 14. doi: 10.1371/journal.pone.0193127