expert opinion

Fifteen years of fortifying with folic acid

March 1, 2012


Sarah Zimmerman, Flour Fortification Initiative, Atlanta, Georgia, USA

“All people need folic acid to produce and maintain new cells and decrease the risk of folate deficiency anemia. Women, in particular, need folic acid at least a month before conception and in the early days of pregnancy because the neural tube, which ultimately develops the child’s brain and spinal cord, forms within 28 days of conception. Fortified flour adds to the dietary intake of folic acid through staple foods, such as bread, tortillas, noodles, and pasta. Flour has been fortified with iron and some B vitamins since the 1940s, but adding folic acid to flour did not begin for another 50 years. In 1991, one study (1) unequivocally showed that folic acid can prevent neural tube defects (NTDs), such as spina bifida, anencephaly, and encephalocele. One of its conclusions was that public health measures should be taken to ensure that the diets of all women of childbearing age contain an adequate amount of folic acid.

Deciding how much folic acid to add to flour to prevent NTDs was a challenge in the early 1990s. Guatemala and El Salvador added folic acid to flour in 1992 to replace the naturally occurring vitamin lost in the milling process; however, the amounts added were not high enough to significantly impact the incidence of NTDs. In 1996, several Middle Eastern countries considered several public health strategies to improve general nutri-tion. With encouragement from international organizations, such as the World Health Organization (WHO), the United Nations Children’s Fund (UNICEF), and the Micronutrient Initiative (MI), fortifying flour with iron and folic acid was one of the interventions under consideration. To test the feasibility of flour fortification, Oman Flour Mills began fortifying flour on a trial basis; then the country decided to update its wheat flour standard to require folic acid at a minimum of 1.5 mg/kg. In the same year, the United States and Canada began to add folic acid to flour at rates of 1.4 and 1.5 mg/kg, achieving nationwide coverage at the end of 1997. In 2002, a number of Central American countries agreed to fortify with folic acid at a rate of 1.8 mg/kg. Globally recognized recommendations for adding folic acid to wheat flour were published in 2009 with levels ranging from 1 to 5 mg/kg based on a country’s consumption patterns (2).

The decrease in the incidence of NTDs attributable to flour fortification varies depending on the amount of folic acid added to flour and the NTD rate prior to fortification. It is estimated that more than 300,000 infants worldwide are affected by NTDs annually (3). Between 50 and 70% of NTDs may be prevented by a daily consumption of 400 μg folic acid at least one month prior to conception and in the early days of pregnancy (4). A 2008 study estimated that about 22,000 neural tube birth defects were prevented globally due to flour fortification (5). That figure represented 9% of the estimated cases of folic acid-preventable spina bifida and anencephaly. By 2010, more countries were fortifying flour and an estimated 28,066 birth defects were prevented, i.e. 13.8% of the total number of cases of folic acid-preventable spina bifida and anencephaly (6). Currently, 63 countries require flour fortification; 57 of them include folic acid in the fortification standard. These 57 countries reported a total of 34.2 million births in 2009. The precise number of how many NTDs can be prevented thanks to flour fortification is difficult to measure because many countries do not have a surveillance system for birth defects. In addition, the number of pregnancies terminated as a result of NTD diagnoses is often unavailable or is not taken into consideration by researchers. However, a few studies have estimated the number of NTDs prevented as a result of flour fortification. One example is the United States, where fortification of flour and breakfast cereals is credited with preventing 1,000 NTDs a year (7).

The most common NTD is spina bifida, which occurs when the spinal cord does not form correctly. In mild cases, the permanent loss of some sensation or movement occurs. Severe cases result in paralysis and varying degrees of the loss of bowel and bladder control. Some spina bifida symptoms can be treated with surgeries and therapy, but spina bifida cannot be cured. Caring for children with spina bifida can require multidisciplinary medical treatment, including surgeries, physical therapy, and continence care. Wellington Hospital in New Zealand found that a newborn with spina bifida had undergone surgeries costing US$569,000 before his second birthday (8). The hospital’s study also found that the direct surgery and hospital costs for six teenagers, starting from birth, was US$790,000 per individual. The ongoing cost of fortifying flour with iron, folic acid, and other B vitamins is between US$2 and US$3 per metric ton of flour. Some countries have compared the costs of fortification with the cost of spina bifida treatment and found that fortifying flour is far more economical. The USA, for example, reports annual fortification costs of approximately US$3 million. Direct medical costs averted are US$145 million per year. Consequently, US$48 are saved annually for every dollar spent on fortification (9).

Once a mill’s infrastructure is set up to fortify flour, it is cost effective to fortify flour with other nutrients in addition to folic acid. Flour is also routinely fortified with iron, thiamine, riboflavin, and niacin. Some countries add vitamin D, vitamin B12, vitamin A, and zinc to flour. The economic implications of fortifying with these additional nutrients are not included in the folic acid cost-benefit studies.”

Atlanta, 2011


  1. Wald N. et al. Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study. Lancet. 1991; 338:131–137.
  2. Recommendations on Wheat and Maize Flour Fortification Meeting Report: Interim Consensus Statement. Geneva:World Health Organization. April 2009.
  3. March of Dimes Global Report on Birth Defects: The Hidden Toll of Dying and Disabled Children. White Plains, New York: March of Dimes Birth Defects Foundation, 2006, Executive Summary 2.
  4. Facts About Folic Acid, Centers for Disease Control and Prevention. (
  5. Bell K. N. and Oakley G. P. Update on Prevention of Folic Acid-Preventable Spina Bifida and Anencephaly. Birth Defects Res A Clin Mol Teratol. 2009; 85:102–107.
  6. Youngblood M. E. et al. Global Update on the Prevention of Folic Acid-Preventable Spina Bifida and Anencephaly Cases. 2010. Unpublished data.
  7. Spina Bifida and Anencephaly Before and After Folic Acid Mandate – United States, 1995 – 1996 and 1999 – 2000. US Centers for Disease Control and Prevention. Morb Mortal Wkly Rep. 2004; 53(17):362–365.
  8. Newton K. $1M Cost Per Child Sparks Folate Call, The Dominion Post. (
  9. Grosse S. et al. Reevaluating the Benefits of Folic Acid Fortification in the United States: Economic Analysis, Regulation, and Public Health. Am J Public Health. 2005; 95:1917–1922.