TUESDAY, Sept. 6, 2005 (HealthDay News) -- Folic acid fortification of foods, mandated since 1998 in the United States, continues to help reduce the incidence of severe birth defects such as spina bifida, researchers report.
The study, which appears in the September issue of Pediatrics, included a look at the effects of the B vitamin on children born to black and Hispanic women.
"We wanted to see if all racial and ethnic groups are having decreases, or is it only, for example, in one group?" explained study co-author Dr. Sonja Rasmussen, a clinical geneticist with the U.S. Centers for Disease Control and Prevention.
Her team analyzed data from 21 population-based birth defect surveillance systems. They examined trends in neural tube defects -- serious malformations such as spina bifida, a leading cause of childhood paralysis, and anencephaly, a condition in which parts of the brain and skull cap are missing. Both can be prevented through maternal intake during pregnancy of folate, which is thought to be important to embryonic development.
Looking at the years 1995 to 2002, the team divided births into pre-fortification, optional- and mandatory-fortification periods, and then evaluated associations between maternal folate levels and birth defects.
The study included data on 4,468 cases of spina bifida and 2,625 cases of anencephaly.
The CDC team concluded that folic acid fortification accounted for a 36 percent decline in the birth defects among the Hispanic population, and 34 percent in the non-Hispanic white population. The decline among blacks was not significant.
Before fortification, about 4,000 pregnancies annually were affected by neural tube defects, according to the March of Dimes. Now, about 1,000 fewer babies a year develop one of these conditions.
But some experts believe the fortification level, while helpful, needs to be set higher. In an editorial accompanying the study, Dr. Godfrey Oakley Jr., of the CDC, says the U.S. Food and Drug Administration should at least double the amount of folic acid required in enriched grain foods, currently set at 140 micrograms per 100 grams of grains.
The March of Dimes is also calling for higher fortification levels, said Dr. Jennifer Howse, president of the organization. She called the decline found in the Rasmussen study "very significant," but thinks higher levels of fortification are needed.
In a note of caution, however, Dr. Tsunenobu Tamura, author of a second Pediatrics study on folate status and child development, said more study is needed before that recommendation should be enacted.
"We should be extremely careful in increasing the fortification level because we do not know the consequences of high-dose fortification," said Tamura, a professor of nutrition science at the University of Alabama at Birmingham.
In his study, Tamura's team evaluated the maternal blood folate levels of black women at 19, 26 and 37 weeks of pregnancy. They then evaluated the neurological development of 355 of the women's children at 5 years of age using memory, motor skills and other tests.
"The mothers' folate nutritional status during pregnancy does not appear to affect psychomotor development of the children at 5 years of age," he said.
Still, he said, he believes it's crucial that women get adequate folate during pregnancy.
Women of childbearing age are advised to take in 400 micrograms a day of folate, which can be obtained through vitamin pills or foods such as leafy green vegetables and citrus fruits.
To learn more about folic acid and birth defects, visit the March of Dimes.