Folic acid fortification above mandated levels results in a low prevalence of folate inadequacy among Canadians

Abstract

Understanding folate intakes after folic acid fortification of the food supply will help to establish dietary and supplement recommendations that balance health benefits and risks. The objectives were to estimate the prevalence of folate inadequacy (POFI) and intakes above the Tolerable Upper Intake Level (UL) among Canadians and to estimate the supplemental dose that, with diet, provides reproductive-aged women with 400 μg folic acid/d to prevent neural tube defects. Twenty-four-hour recall and supplement (prior 30 d) data from the 2004 Canadian Community Health Survey (n = 35,107) were used to calculate the POFI and intakes above the UL with and without adjustment for fortification overages. POFI was also estimated by risk factors thought to be related to low folate intake. The Software for Intake Distribution Evaluation (SIDE program; Department of Statistics and Center for Agricultural and Rural Development, Iowa State University) was used to estimate usual dietary intakes in all analyses. Except for women aged >70 y, POFI was <20% after adjustment for fortification overages. For children aged <14 y, POFI approached zero, even when supplement use was excluded. POFI among adults was unaffected by supplement use, except for women aged >70 y. Only 18% of reproductive-aged women consumed 400 μg folic acid/d from diet and supplements. Modeling showed that supplements containing 325-700 μg folic acid would provide adult women with 400 μg/d but not more than the UL. Diabetes was associated with POFI. Innovative strategies are needed to ensure that the subgroups of Canadians who could still benefit from improved folate intake are targeted. Consideration should be given to removing folic acid from supplements designed for young children and men.