Leeks are an excellent source of vitamins that are essential for optimum health. Their leafy stems indeed contain several vital vitamins such as pyridoxine, folic acid, niacin, riboflavin, and thiamin in the right proportions. 100 g fresh stalks provide 64 µg of folates. Folic acid is essential for DNA synthesis and cell division. Their adequate levels in the diet during pregnancy can help prevent neural tube defects in newborn babies.