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Mystery Birth Defect Cluster: Is Diet to Blame?

Image: A restaurant employee stacks corn tortillas.

A restaurant employee stacks corn tortillas. MARK LENNIHAN / AP file

A baffling cluster of birth defects in central Washington state is raising new questions about whether adding a vital nutrient to corn tortillas, tamales and other foods favored by Hispanic families could prevent such devastating problems in the first place.

Health officials still can’t say why 42 babies have been identified with so-called neural tube defects in the region since 2010, including 32 with a fatal condition in which they’re born missing parts of the brain and skull. Of those, more than half the mothers are Mexican-American.

But some advocates point to low levels of folic acid, a supplement proven to prevent such birth defects, and they’re questioning why it still isn’t required to be added to corn masa flour, a staple of Hispanic diets — the same way it’s been added to enriched wheat and rice products in the U.S. since 1998.

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Critics say a petition calling for folic acid fortification of corn masa has been pending at the Food and Drug Administration for more than two years.

“This is one area where we can definitively prevent a known birth defect,” said Cynthia Pellegrini, senior vice president for public policy for the March of Dimes Foundation, which led the 2012 petition.

Fortifying grain products with 140 micrograms of folic acid per 100 grams of flour has been lauded as one of the “10 great public health achievements” in the U.S., said Dr. Joe Sniezek, chief of the Prevention Research Branch at the Centers for Disease Control and Prevention.

“This is one area where we can definitively prevent a known birth defect.”

Neural tube defects like spina bifida and anencephaly occur in the early weeks of pregnancy, usually before a woman knows she’s expecting, and are caused when the tube that typically develops into the brain and spinal cord fails to close completely.

Cases of NTDs dropped 36 percent in the U.S. after mandatory fortification, preventing an estimated 10,000 neural tube defect-affected pregnancies between 1996 and 2006. Today, about 3,000 babies each year are born with the devastating and costly problems, the CDC says.

Still, Hispanic women are about 20 percent more likely than other women to have babies with those conditions, and they continue to have far lower levels of folic acid intake, either through diet or supplements, according to Heather Hamner, a health scientist with the CDC.

Fortifying corn masa to the same level as other grain products could boost folic acid intake by 20 percent in Hispanic women of childbearing age, driving down the number of birth defects.

“From the information and the data and the science, our models indicate that about 40 babies would be born without spina bifida and anencephaly each year,” Hamner said.

But moving forward with such a seemingly positive public health intervention is proving much harder than expected, experts said.

"Our models indicate that about 40 babies would be born without spina bifida and anencephaly each year."

When folic acid fortification was implemented, first as a recommendation in 1992 and then as a requirement in 1998, corn masa flour wasn’t widely consumed and the FDA didn’t include it in the list of affected grains, Hamner said.

Since then, the population of Hispanics in the U.S. has jumped from about 31 million in 1998, or 11.4 percent of the population, to 53 million in 2012, or 17 percent of the population, according to census data.

Corn masa consumption has climbed, too, with the Tortilla Industry Association estimating that Americans consume about 85 billion tortillas a year.

But the FDA can’t simply apply rules for wheat and rice products to corn, Pellegrini said. Instead, the agency is requiring extensive — and expensive — testing to determine the safety and stability of adding folic acid to corn masa flour. The trouble is, neither the March of Dimes nor its co-petitioners — the American Academy of Pediatrics, the Spina Bifida Association and others — has the deep pockets to fund the extensive testing.

“It was in the $1 million range and we didn’t have $1 million to spend on this,” she said.

But with the lifetime cost of caring for one child with spina bifida estimated at $729,000, some public health advocates say that fortifying corn masa should be only obvious.

“Why did we do it for rice and wheat cereal and we didn’t do it for this?” said Vickie Ybarra, a public health nurse who spent 10 years visiting the homes of Hispanic women in Yakima, Washington, one of three counties where the cluster of birth defects has been detected.

“Why did we do it for rice and wheat cereal and we didn’t do it for this?"

Folic acid needs to be ingested in the earliest weeks of pregnancy to have an effect on neural tube development, she noted. Doctors recommend that all women of child-bearing age take the supplement because half of all pregnancies are unintended.

“Most women don’t know they’re pregnant at that time,” Ybarra said. “It’s why fortification happened in the first place.”

Several other countries already allow fortification of corn masa products with folic acid, including Costa Rica, El Salvador and Mexico. FDA officials said they can’t comment on the status of the pending petition, but Pellegrini said the issue appears to be stalled for now.

“You can make the public health benefits argument until you’re blue in the face, but until you address their food safety questions, you’re not getting anywhere,” she said. “We don’t have a sense right now whether we’re close to signoff.”