How Much Folate Is in Canadian Fortified Products 10 Years after Mandated Fortification?
Shakur, Yaseer A., Rogenstein, Carly, Hartman-Craven, Brenda, Tarasuk, Valerie, O'Connor, Deborah L., Canadian Journal of Public Health
Objective: In 1998, the Canadian government mandated folic acid fortification of white flour and enriched grain products to lower the prevalence of neural tube defects. There is now growing concern over the potential harmful effects of too much folic acid on some segments of the population. Given that the actual amount of folate in Canadian foods is unknown, the objective of this study was to measure the folate content in selected fortified foods.
Methods: Using data from the 2001 Food Expenditure Survey and the ACNielsen Company, 95 of the most commonly purchased folic acid-fortified foods in Canada were identified. Folate concentrations in these foods were determined using tri-enzyme digestion followed by microbiological assay. Analyzed values were compared to those in the Canadian Nutrient File (2007b, CNF) and to label values.
Results: The analyzed folate content of foods was, on average, 151% ± 63 of the CNF values. Analyzed values as a percent of CNF values ranged from 116% in the "rolls and buns" category to 188% in "ready-to-eat cereals". Analyzed values were higher than label values for "breads", "rolls and buns" and "ready-to-eat cereals" (141%, 118% and 237%, respectively [p<0.05]).
Conclusions: Ten years after folic acid fortification of the food supply, neither the CNF nor label values accurately reflect actual amounts of folate in foods. Further, overage differences by food category hinder the development of future strategies designed to strike the right balance between health benefits and risks; monitoring of fortified foods for their nutrient content is required.
Key words: Folic acid; Canada; food supply; fortified foods
La traduction du résumé se trouve à la fin de l'article. Can J Public Health 2009;100(4):281-84.
Mots clés : acide folique, Canada, approvisionnement alimentaire, aliments enrichis
Folate, a B-vitamin, is necessary for proper neural tube development, which occurs early after conception when most women are still unaware they are pregnant.1 In light of this, women of child-bearing age are encouraged to consume a supplement containing folic acid (a synthetic form of folate); however, Canadian data suggest only 57.7% of women report taking folic acid during the peri-conceptional period.2 Therefore in 1998, the Canadian government mandated folic acid fortification of all white flour and enriched pasta to 150µg/100g and 200µg/100g, respectively, to increase daily intake by 100µg.3
Since folic acid fortification has become mandatory, the incidence of neural tube defects (NTDs) has declined in Canada by approximately 50%,4 with improvements in blood folate indices5,6 and folate intake.6 Given the apparent success with this intervention, there have been calls to raise the levels of folic acid fortification in Canada to further reduce the incidence of folate-dependent NTDs.7,8 In addition to this, suboptimal intakes of folate have been associated with other congenital defects (cleft lip and palate), vascular disease, neuropsychiatric disorders, and cancer.1
However, a growing body of literature suggests that consuming high levels of folic acid may have several negative consequences beyond the masking and progression of vitamin B12 deficiency,1 including cancer progression,9,10 and reduced natural killer cell cytotoxicity.11 In one recent study, a combination of high folate levels and low vitamin B12 status has been associated with increased cognitive impairment in seniors;12 in another recently published study, the same combination in pregnant women was associated with increased insulin resistance and higher central adiposity in their children.13
When evaluating the current Canadian situation, the arguments on either side of the "how much folic acid should be added to the food supply?" debate are hampered by a lack of understanding of how much folate is actually in the foods we eat. In the early years after mandated fortification, analysis of folate in foods indicated actual levels were twice that mandated in the United States (US). …