Vitamin B9, or folic acid or folate, is a type of water-soluble vitamin, namely it dissolves in water like vitamin C, it is one of the 13 essential vitamins, together with the other vitamins of group B, A, C, D, E and K, and it cannot be synthesized directly by the body but must be taken through the diet or supplements (Greenberg et al, Rev Obstet Gynecol, 2011).
Folic acid, what it is used for
Folic acid plays a pivotal role in DNA replication, in the synthesis of proteins and neurotransmitters, such as dopamine, adrenaline and noradrenaline. Not only that, vitamin B9 participates in the formation of blood cells and is very important in pregnancy for the correct growth and development of the fetus by helping to prevent some congenital malformations, in particular those affecting the neural tube.
Folic acid, food sources
Natural sources of vitamin B9 are oranges, Brussels sprouts, legumes, such as beans, lentils and peas, egg yolks, leafy greens such as broccoli, lettuce and spinach, wheat germ, brewer's yeast, sweet potatoes, barley, rice, soy and liver (Khan et al, StatPearls Publishing, Jan 2019).
Folic acid, causes of deficiency, diet and cooking methods
Folic acid is not stored by the body and its deficiency can be caused by a diet low in food sources of vitamin B9, but it may also be caused by diseases and problems of intestinal malabsorption such as celiac disease, by a lack of vitamin B12 or by incorrect cooking methods (Khan et al, StatPearls Publishing, Jan 2019 - Fisher et al, Ital J Pediatr, Aug 2017). In particular, boiling spinach or broccoli makes you lose up to 50% of folic acid, while steaming these foods has proven to be protective and not associated with the loss of this vitamin. Folic acid of animal origin is more resistant and tends not to decrease with cooking. Other foods, such as potatoes, do not lose folic acid even after prolonged boiling, such as for 1 hour, or after the peel has been removed (McKillop et al, Br J Nutr, Dec 2002). A varied diet that includes raw leafy greens, citrus fruits and legumes is certainly a good way to avoid a lack of folic acid whose daily requirement for a healthy adult is 0.4 micrograms. However, there are particular conditions, such as pregnancy or the intention to program one, which require folic acid supplements to reach 0.6 micrograms per day (Folate, National Academies Press (US), 1998).