Folate is the natural source of vitamin B9 found in a variety of foods, most often, in leafy green vegetables, dried beans, and peas. When it is used as an additive in foods, generally in bread, grains or breakfast cereal, or when it is taken as a supplement, it is called folic acid.eans and peas are good sources of folate. Pregnant women are advised to take folic acid supplements to reduce the risk of birth defects. Curly endive, which contains folate. Folate supplements are water-soluble.