(Reuters Health) - Corn masa flour and tortillas sold in U.S. grocery stores may not be fortified with folic acid, which means a government effort to help reduce birth defects among Hispanic babies may not be working as intended, a small study suggests.

Folic acid has long been linked to a lower risk of spina bifida and anencephaly, birth defects of the brain and spinal cord that can develop early in pregnancy, often before women know they have conceived. In 1996, the U.S. Food and Drug Administration (FDA) required all enriched cereal grains - but not corn masa flour - to be fortified with folic acid. Fortification of corn masa flour became permissible but not mandatory in 2016.

In December 2017, researchers analyzed corn masa and corn tortilla products in 11 grocery stores in northeast Atlanta that cater to Hispanic residents. Only two of 20 corn masa flour products, and none of the 21 soft corn tortilla products, were labeled as containing folic acid, the researchers report in JAMA.

“If what we found in the Atlanta market is true nationwide - and we think it is, because we tested national brands - this means folic acid is not reaching the intended population - that being many Hispanic people who consume foods made with corn masa flour,” said senior study author Dr. Godfrey Oakley Jr., director of the Center for Spina Bifida Prevention at the Emory University Rollins School of Public Health in Atlanta.

“This is needed to reduce the two-fold increase in occurrence of neural tube defects, such as anencephaly and spina bifida, in babies born to Hispanic mothers compared to other racial and ethnic groups in the U.S.,” Oakley said by email.

The best way for women to prevent these birth defects is to only buy grain products that contain folic acid, and to also take prenatal vitamins containing at least 400 micrograms of folic acid daily, whether or not they are planning pregnancy, Oakley advised.

“Taking prenatal vitamins after the pregnancy test comes out positive is too late to prevent neural tube defects,” Oakley said. “One has to have folic acid before pregnancy and in the first four weeks of pregnancy for preventing neural tube defects.”

Hispanic women are less likely than other women to take prenatal vitamins, and also less likely to consume enriched cereals that must contain folic acid, Oakley and colleagues note.

The study results suggest that voluntary regulations allowing fortification of corn masa flour and tortillas may not be having the desired impact of reducing birth defects, the study authors conclude.

The study wasn’t a controlled experiment designed to prove whether or how enriching corn masa flour and tortillas might directly alter the amount of folic acid women consume or impact their risk of having babies with birth defects. It’s also possible that products in Atlanta grocery stores might not reflect what shoppers would find in other parts of the country.

Still, the benefits of folic acid are clear, said Alina Flores, a scientist with the National Center on Birth Defects and Developmental Disabilities at the U.S. Centers for Disease Control and Prevention.

“Getting the recommended daily amount of folic acid can help reduce a woman’s risk of having a baby born with a neural tube defect,” Flores, who wasn’t involved in the study, said by email.

“Hispanic women remain at higher risk for having a neural tube defect-affected birth than non-Hispanic white or black women,” Flores added. “Adding folic acid to corn masa flour will provide an additional avenue by which Hispanic women can get the recommended 400 micrograms of folic acid.”

SOURCE: bit.ly/2OxEKnC JAMA, online October 16, 2018.