The US Food and Drug Administration has approved folic acid fortification of corn masa flour. The approval allows manufacturers to voluntarily add up to 0.7 milligrams of folic acid per pound of corn masa flour, consistent with the levels of certain other enriched cereal grains.

Folic acid, a synthetic form of folate, is a B vitamin that when taken by a pregnant woman may help prevent neural tube defects, which are birth defects affecting the brain, spine, and spinal cord. Pregnant women with folate deficiency have a higher risk of giving birth to infants affected with neural tube defects.

Corn masa flour, sometimes called masa (Spanish for dough), is produced by cooking corn in alkali and then grinding it. Corn masa flour is a staple food for many Latin Americans including individuals of Mexican and Central American descent in the United States. It can be used to make foods such as tortillas, tortilla chips, tamales, taco shells, and corn chips.

Currently, manufacturers may use folic acid as an optional ingredient at specified levels in breakfast cereals and certain other foods, such as infant formula and medical foods, so that it is easier for people to get enough folic acid in their diets. Additionally, folic acid must be added to certain enriched grains and enriched grain products like breads, rolls, noodles and pasta. The March of Dimes Foundation, the American Academy of Pediatrics, and others submitted a food additive petition in 2012 to request the extension of voluntary fortification to corn masa flour to increase the folic acid intake for US women of childbearing age who regularly consume products made from corn masa flour as a staple in their diet.   

"Increased consumption of folic acid in enriched flour has been helpful in reducing the incidence of neural tube defects in the general population," said Susan Mayne, Ph.D., director of the FDA's Center for Food Safety and Applied Nutrition. "Our analysis shows that adding folic acid to corn masa flour will help increase the consumption of folic acid by women who consume this flour as a staple in their diet."

The FDA may approve the use of a food additive only after conducting a scientific safety review of the information provided in the petition to ensure that the additive is safe for the general population. With regard to folic acid, the FDA evaluated the projected human dietary exposure, toxicological data, and other relevant information, including whether folic acid remained stable in corn masa flour.