The study – published in Pediatrics – examined the incidence of childhood cancer before and after folic acid fortification became mandated in the USA. The research team, led by Dr Kimberly Johnson from the University of Minnesota, found the incidence of certain childhood cancers has decreased since folic acid fortification was introduced in the USA in 1998.
"We found that Wilms' tumor rates increased from 1986 to 1997 and decreased thereafter, which is an interesting finding since the downward change in the trend coincides exactly with folic acid fortification," said Johnson.
"Primitive neuroectodermal tumors (PNET) rates increased from 1986 to 1993 and decreased thereafter,” she added. “This change in the trend does not coincide exactly with folic acid fortification, but does coincide nicely with the 1992 recommendation for women of childbearing age to consume 400 micrograms of folic acid daily."
Johnson said further research is needed before the results can be confirmed, and in order to “rule out any other explanations."
Folic acid intake before and during early pregnancy ensures that the fetus does not develop the neural tube defect – commonly known as spina bifida. Women of child-bearing age need sufficient body stores of folate before conception to prevent folate-sensitive neural tube defects (NTDs), which make up 20% to 60%of all NTDs.
Because of this, merely recommending folic acid supplementation before conception has been found to be an unsuitable strategy – mainly due to the fact that many pregnancies are unplanned, and the average time until the first antenatal visit is 9 weeks – meaning neural tube defects may have already occurred before this time.
As such mandatory fortification of staple foods with folic acid began in the USA in 1998; since then over 50 countries around the world have followed suit in adopting a fortification strategy.
However, Johnson noted that one concern countries face as they are deciding whether or not to fortify foods to reduce neural tube defects in newborns is the possibility that fortification may cause unintended harm, such as causing new cancers or pre-cancerous lesions.
"Here, we are showing that folic acid fortification does not appear to be increasing rates of childhood cancers, which is good news," she says.
Johnson and her team used data from the 1986-2008 National Cancer Institute's Surveillance, Epidemiology, and End Results Program (SEER) – which has collected information on cancer cases in various areas of the U.S. since 1973.
The study involved 8,829 children, from birth to age four, diagnosed with cancer.
"Declines in Wilms' tumors and PNETs in children were detected by multiple analyses of the data," said Johnson. "Importantly, the reduced rates of Wilms' tumors also were found in a smaller study conducted in Ontario, Canada, that was published in 2011.”