May 10, 2000 -- While experts debate the pros and cons of folic acid-enriched foods, most agree that women who could become pregnant should be taking a supplement containing folic acid to reduce their chances of conceiving a child with spina bifida or other serious birth defects that can be caused by a deficiency of the compound.
Spina bifida, a birth defect in which the spinal cord does not fuse properly before birth, occurs in about one of every 1,000 births. These children may suffer brain damage from fluid that can collect in the brain, and may be unable to walk because of weakness in their legs.
Since Jan. 1, 1998, the FDA has required that certain grain products be fortified with folic acid to reduce the number of children born with these birth defects. It's too early to tell if there has been a benefit, however.
The decision requiring folic acid to be added to certain foods was controversial because some, including officials with the CDC, wanted a required level of folic acid that was four times higher than what was approved.
But at that time, some experts -- including James L. Mills, MD, chief of pediatric epidemiology at the National Institute of Child Health and Human Development -- warned about the impact of folic acid on people who may have a vitamin B-12 deficiency. Folic acid can mask the anemia or low blood counts associated with B-12 deficiency.
Now the debate has fired up anew. Mills wrote an article in the May 11 issue of The New England Journal of Medicine, arguing that the current levels of fortification should remain in place until more research is available.
Studies have shown a dramatic increase in the levels of folic acid in older adults who do not use supplements, and that some foods contain much more folic acid than their labels suggest, according to Mills.
He says that since folic acid fortification exposes 274 million people to folic acid to prevent only 2,000 potential birth defects per year, "it is surprising that public health officials have not demanded a higher standard of proof that the current level of fortification is safe and effective. Who will perform the studies to document the safety of fortification in children and the elderly?" writes Mills.
"Women should be cautioned that half of all pregnancies are unplanned and that folic acid must be taken before conception to be effective. Taking supplements is the safest and most effective way" to prevent the birth defects associated with folic acid deficiency," he concludes.
Mills tells WebMD he wrote the article because "there has been a lot of politicking to increase the amount [of folic acid]" in enriched flour. The dose for most women who could become pregnant is 400 mcg per day, and 4,000 mcg per day is recommended for women who have already had a child with a birth defect associated with low folic acid, Mills says.
The results of the current folic acid enrichment program are not expected to be available until sometime later this summer, says J. David Erickson, PhD, chief of the branch of birth defects and genetic diseases at the CDC.
"Our best guess at this was that you might see a 50% drop [in these birth defects]," Erickson says. "That would be our hope; that's what one would hope to achieve with fortification. The projections by the FDA at the time were that women would consume an extra 100 mcg a day [with fortification]. That is one-fourth the recommended amount."
Mills provoked an impassioned response from Godfrey Oakley, MD, who likened Mills' article to "yelling fire in a crowd." Until two years ago, Oakley was the director of the CDC's Division of Birth Defects and Developmental Disabilities.
"My view is that, from everything we know up this point, the amount of fortification is not enough," Oakley tells WebMD. "You would have to eat a loaf of bread" made with folic acid-fortified or enriched flour to reach the recommended level, says Oakley. He is currently a visiting professor of epidemiology at Emory University in Atlanta.
"What gets missed is [that] this is not about what is the dose at which you can start to see some protective effect," he says. "That is not what you are after. It is about what is the least dose that will give you the most protective effect. It takes 400 mcg to do the whole job. We should have no child with folic acid-preventable [birth] defects. I agree that until fortification is fixed, we need to be teaching as many women as we can ... to take a multivitamin." However, this is an ineffective solution, he notes, because "no more than 50% of women will take vitamin supplements."
While many will take them once they realize they are pregnant, it's too late by then. "This birth defect occurs before most women know they are pregnant," says Oakley.
Lynn B. Bailey, PhD, a professor of human nutrition at the University of Florida, reviewed Mills' article for WebMD, and she agrees with Mills that more research is needed. She served on the FDA panel that made the fortification recommendations and supports the March of Dimes recommendation that a woman capable of becoming pregnant consume 400 mcg of folic acid from foods or supplements daily.
"Folate is not widespread in the food supply," says Bailey. "It's really not enough to say, 'consume five servings of fruits and vegetables.'" But it can be found in larger concentrations in orange juice, green leafy vegetables, strawberries, beans, and nuts, she says.
- In 1998, the government required certain foods to be fortified with folic acid, because of its ability to prevent serious birth defects.
- While many women take supplements once they become pregnant, folic acid must be taken before conception to be effective.
- Some experts argue that the level of folic acid fortification is not high enough, while others say that there is not enough evidence that the current level is safe and effective.