Final answer:
Folic acid is essential to prevent neural tube defects, which can occur during the first trimester of pregnancy. Consuming at least 400 µg/day of folate is recommended for women who might become pregnant to ensure proper neural tube development.
Step-by-step explanation:
Folic acid is vitally important in preventing neural tube defects, which can occur during pregnancy. Neural tube defects, including conditions like spina bifida and anencephaly, take place when the neural tube does not close completely. The critical period for neural tube development and closure is during the early stages of pregnancy, specifically the first trimester, when many women might not even be aware they are pregnant yet.
To prevent such birth defects, the Food and Nutrition Board of the Institute of Medicine recommends that all women who might become pregnant consume at least 400 µg/day of folate from supplements or fortified foods. This is because folic acid, or vitamin B9, is essential for the proper development of the neural tube. Insufficient folic acid intake can lead to serious birth defects that affect the brain and spinal cord.
Therefore, the correct answer to the question "Folic acid is important to take to prevent neural tube defects, which occurs during:" is a) First trimester.