Folic acid is a water-soluble vitamin. folate (folate, folic acid) belongs to vitamin B9 and is a water-soluble vitamin. It is a general term for a class of compounds with similar chemical structures. The importance of folic acid in the diet has gradually been recognized, especially its role in preventing birth defects, cardiovascular diseases, tumors and neurodegenerative diseases, which has made it an important micronutrient.