Fortification of flour likely to halve neural tube defects, says CDCBMJ 2000; 321 doi: https://doi.org/10.1136/bmj.321.7270.1176 (Published 11 November 2000) Cite this as: BMJ 2000;321:1176
Targets set by US health authorities to increase the folic acid intake among women have been exceeded. The Centers for Disease Control and Prevention (CDC) found in its 1999 national health and nutrition examination survey that the average level of folic acid in the blood of US women of childbearing age almost tripled, from 6.3 ng/ml to 16.2 ng/ml (14.3 nmol/l to 36.7 nmol/l) in five years.
The average red blood cell folate concentration, a better measure of long term folate status, increased from 181 ng/ml to 315 ng/ml. That level exceeded the CDC's goal of a 220 ng/ml average by the year 2010.
The study showed that the average level of folate in women aged 15 to 44 was double that found in women in a similar study conducted from 1988 to 1994.
This latest survey—of a nationally representative sample of the nation's civilian population not living in an institution—consisted of an interview in the home, as well as a standardised physical examination and laboratory tests. Serum and red blood cell folate levels were measured by the CDC's environmental health laboratory.
In 1996 the US Food and Drug Administration (FDA) had ordered that, to prevent neural tube defects, all enriched cereal grain products should be fortified with folic acid by January 1998 (BMJ 1999;318:1506). Food fortification was determined to be the best strategy for increasing blood folate levels, as the critical period for adequate intake of folic acid is in the first weeks of pregnancy before most women know that they are pregnant and begin taking vitamins (BMJ 1999;319:93).
“We're talking about a simple intervention here that can prevent up to half of those birth defects,” said Dr David Fleming, the CDC's deputy director for science and public health. He said that those disorders affect as many as 4000 newborn infants a year.
“Efforts to increase folate levels are working due to sound public health research and action,” said Jane Henney, the FDA's commissioner.