Which nutrient is critical preconception to prevent neural tube defects?

• A. Vitamin D.
• B. Calcium.
• C. Iron.
• D. Folic acid (folate).

Answer: (D)

Preventing neural tube defects hinges on adequate folate status before conception and in the earliest weeks of pregnancy. Folate, or folic acid from supplements, provides the one-carbon units needed for DNA synthesis and rapid cell division. The neural tube closes very early in development—often before a woman realizes she’s pregnant—so having sufficient folate beforehand helps ensure proper closure. Because of this critical timing, preconception folic acid supplementation is recommended: about 400 micrograms daily for those planning a pregnancy, with higher doses (around 4 milligrams) for individuals with prior neural tube defects or other risk factors. Folate can come from fortified foods and leafy greens, but supplements help guarantee adequate intake during that vulnerable window. Other nutrients like vitamin D, calcium, and iron are important for overall health, but they aren’t specifically linked to preventing neural tube defects.