Why Fortify? Prevent Neural Tube Defects
Grains are commonly fortified with folic acid (vitamin B9) to reduce the risk of neural tube defects such as spina bifida and anencephaly. These birth defects are permanently disabling or fatal. One meta-analysis showed that fortifying wheat flour with folic acid reduced the incidence of these birth defects by an average of 46%.
All people need folic acid to produce and maintain healthy cells. Women who might become pregnant need 400 micrograms of folic acid daily at least one month before conception and in the early stages of pregnancy. This can prevent the majority of neural tube defects (NTDs) .
Folic acid supplements are recommended for women who may become pregnant. Some women are not aware of this advice, and others forget to take supplements. Women who do not plan a pregnancy may not follow the recommendation.
A baby’s neural tube forms within the first four weeks of pregnancy. If women wait until they learn they are pregnant to take folic acid supplements, the baby’s neural tube may already be formed. Then it is too late for folic acid to have the protective effect.
The most common NTD is spina bifida in which the baby’s spine does not form correctly. In mild cases, permanent loss of some sensation or movement occurs. Severe cases include paralysis and varying degrees of loss of bowel and bladder control. Children born with spina bifida will undergo a lifetime of surgeries and face many health issues. Spina bifida cannot be cured. (The illustration below is courtesy of the US Centers for Disease Control and Prevention (CDC).
Another NTD is anencephaly in which the brain does not form properly. Pregnancies affected by anencephaly are often miscarried. Babies born with anencephaly die shortly after birth. A rare NTD is encephalocele in which part of the brain protrudes through the skull.
The March of Dimes estimates that more than 300,000 babies are born with an NTD every year for a global birth prevalence of 24/10,000 . Fortifying flour with folic acid is credited with preventing at least 38,417 of these birth defects a year or 105 a day. Only about one-third of the world’s flour from industrial mills is fortified, however, so this is only 15% of the NTDs that might be prevented . Countries which track birth defects generally find that their NTD prevalence drops to less than 10 per 10,000 live births after they begin fortifying flour with folic acid .
Some foods such as spinach and liver are rich in vitamin B9. However, the body does not absorb all of this; consequently it is virtually impossible to consume the equivalent of 400 micrograms of folic acid daily from unfortified foods. For example, to consume the equivalent of 400 micrograms of folic acid a day, a person would need to eat:
- four slices of beef liver or
- 14 cups of raw broccoli or
- 19 cups of raw green beans or
- 200 medium red apples 
By eating foods fortified with folic acid, women are more likely to consume adequate amounts of this essential nutrient.
Some people have been told to avoid folic acid because they have a variation of the MTHFR (methyltetrahydrofolate reductase) enzyme. However, these individuals simply process folic acid more slowly than those without the variation. See the CDC recommendation for people with the MTHFR variation to continue taking folic acid.
 Folic Acid Helps Prevent Neural Tube Defects; U.S. Centers for Disease Control and Prevention
 Global Report on Birth Defects, March of Dimes Birth Defects Foundation, 2006.
 Youngblood, Monica, et al. 2012 Update on Global Prevention of Folic Acid-Preventable Spina Bifida and Anencephaly. Birth Defects Research (Part A): Clinical and Molecular Teratology. September 2013.
 Zimmerman, Sarah. Fifteen Years of Fortifying With Folic Acid: Birth Defects are Reduced and Healthcare Expenses are Averted. Sight and Life. 25 (3) 2011:54-59.
 The Prevention of Neural Tube Defects and Folic Acid Fortification, Public Health Grand Rounds, U.S. Centers for Disease Control and Prevention, 18 February 2010. See slide 23 of PDF linked here.