<P> The requirement is 0.135 mg of folate per 100g of bread . </P> <P> In 2003, a Hospital for Sick Children, University of Toronto research group published findings showing the fortification of flour with folic acid in Canada has resulted in a dramatic decrease in neuroblastoma, an early and very dangerous cancer in young children . In 2009, further evidence from McGill University showed a 6.2% decrease per year in the birth prevalence of severe congenital heart defects . </P> <P> Folic acid used in fortified foods is a synthetic form called pteroylmonoglutamate . It is in its oxidized state and contains only one conjugated glutamate residue . Folic acid therefore enters via a different carrier system from naturally occurring folate, and this may have different effects on folate binding proteins and its transporters . Folic acid has a higher bioavailability than natural folates and are rapidly absorbed across the intestine; therefore, it is important to consider the Dietary Folate Equivalent (DFE) when calculating one's intake . Natural occurring folate is equal to 1 DFE;, however, 0.6 μg of folic acid is equal to 1 DFE . </P> <P> Folic acid food fortification became mandatory in Canada in 1998, with the fortification of 150 μg of folic acid per 100 grams of enriched flour and uncooked cereal grains . The purpose of fortification was to decrease the risk of neural tube defects in newborns . It is important to fortify grains because it is a widely eaten food and the neural tube closes in the first four weeks of gestation, often before many women even know they are pregnant . Canada's fortification program has been successful with a decrease of neural tube defects by 19% since its introduction . A seven - province study from 1993 to 2002 showed a reduction of 46% in the overall rate of neural tube defects after folic acid fortification was introduced in Canada . The fortification program was estimated to raise a person's folic acid intake level by 70--130 μg / day; however, an increase of almost double that amount was actually observed . This could be from the fact that many foods are over fortified by 160--175% the predicted value . In addition, much of the elder population take supplements that adds 400 μg to their daily folic acid intake . This is a concern because 70--80% of the population have detectable levels of unmetabolized folic acid in their blood and high intakes can accelerate the growth of preneoplastic lesions . It is still unknown the amount of folic acid supplementation that might cause harm . </P>

Where is folic acid absorbed in the body