Food fortification and nutrient supplementation are important strategies to address micronutrient deficiencies. Mandatory folic acid fortification was implemented in Canada and the U.S. in 1998 to reduce the incidence of neural tube defects (NTD). However, the actual amount of folic acid added to foods has not been reported in Canada. We analyzed 95 fortified foods and found that there is 50% more folate in foods than that reported in food composition tables, which are primarily based on minimum mandated fortification levels. We then determined if these observed folate overages impacted the prevalence of dietary folate inadequacy or intakes above the Tolerable Upper Intake Level (UL). Using data from the 2004 nationally-representative Canadian Community Health Survey (CCHS) 2.2 (n = 35,107), adjusted for folate overages, we found a low prevalence of folate inadequacy in Canada post-fortification. However, few women 14-50y consumed 400µg/d of synthetic folic acid, an amount associated with maximal protection against an NTD. Conversely, we also showed that use of folic acid-containing supplements led to intakes >UL in the general population. To develop a tool that would help clinicians identify women with red blood cell (RBC) folate concentrations that were not maximally protective against an NTD (<906nmol/L), we used data from the nationally-representative U.S. National Health and Nutrition Examination Survey 2003-2006 to define risk factors of RBC folate <906nmol/L. We found that 35% of American women 19-45y had RBC folate <906nmol/L. Younger age, low dietary folate intake, not consuming supplemental folic acid, smoking, and being African-American were associated with increased risk of RBC folate <906nmol/L. Given our observations of a low prevalence of folate inadequacy and folic acid supplement use leading to intakes >UL, we used CCHS 2.2 data to compare the diets of supplement users and non-users in terms of inadequacy and intakes >UL for other nutrients. We showed that the prevalence of inadequacy was low for most nutrients, and from diet alone, supplement users were not at increased risk of inadequacy compared to non-users. Furthermore, inclusion of supplements led to intakes >UL above 10% for vitamins A, C, niacin, folic acid, and iron, zinc and magnesium.

Food fortification and nutrient supplementation are important strategies to address micronutrient deficiencies. Mandatory folic acid fortification was implemented in Canada and the U.S. in 1998 to reduce the incidence of neural tube defects (NTD). However, the actual amount of folic acid added to foods has not been reported in Canada. We analyzed 95 fortified foods and found that there is 50% more folate in foods than that reported in food composition tables, which are primarily based on minimum mandated fortification levels. We then determined if these observed folate overages impacted the prevalence of dietary folate inadequacy or intakes above the Tolerable Upper Intake Level (UL). Using data from the 2004 nationally-representative Canadian Community Health Survey (CCHS) 2.2 (n = 35,107), adjusted for folate overages, we found a low prevalence of folate inadequacy in Canada post-fortification. However, few women 14-50y consumed 400µg/d of synthetic folic acid, an amount associated with maximal protection against an NTD. Conversely, we also showed that use of folic acid-containing supplements led to intakes >UL in the general population. To develop a tool that would help clinicians identify women with red blood cell (RBC) folate concentrations that were not maximally protective against an NTD (<906nmol/L), we used data from the nationally-representative U.S. National Health and Nutrition Examination Survey 2003-2006 to define risk factors of RBC folate <906nmol/L. We found that 35% of American women 19-45y had RBC folate <906nmol/L. Younger age, low dietary folate intake, not consuming supplemental folic acid, smoking, and being African-American were associated with increased risk of RBC folate <906nmol/L. Given our observations of a low prevalence of folate inadequacy and folic acid supplement use leading to intakes >UL, we used CCHS 2.2 data to compare the diets of supplement users and non-users in terms of inadequacy and intakes >UL for other nutrients. We showed that the prevalence of inadequacy was low for most nutrients, and from diet alone, supplement users were not at increased risk of inadequacy compared to non-users. Furthermore, inclusion of supplements led to intakes >UL above 10% for vitamins A, C, niacin, folic acid, and iron, zinc and magnesium.

Background: There has been a concern regarding the masking of vitamin B-12 deficiency in the post-fortification period (after January 1, 1998). Objective: The objective of this study was to investigate the potential masking of vitamin B-12 deficiency by comparing the proportion of individuals with low serum B-12 without macrocytosis between pre- and post-fortification periods using data from the National Health and Nutrition Examination Survey (NHANES). Methods: The study included 7242 individuals from NHANES III (pre-fortification group) and combined NHANES 1999-2000, 2001-2002, 2003-2004, 2005-2006 (post-fortification group). Vitamin B-12 deficiency and macrocytosis were defined as having <148 pmol/L of serum vitamin B-12 and mean corpuscular volume (MCV) of>98 fL, respectively. A multivariate logistic regression was performed to estimate the likelihood of being low serum B-12 without macrocytosis in the post-fortification period in relation to the pre-fortification period. Results: Between pre- and post-fortification periods, there was no significant difference in the proportion of individuals with low serum vitamin B-12 without macrocytosis. However, odds of having low serum vitamin B-12 without macrocytosis in the post fortification era increased in men (OR=2.65, 1.24-5.65), non-Hispanic blacks (OR=3.12, 1.04-9.35), Non-smokers (OR=4.63, 1.90-11.27), and those aged 55 and older (OR=2.183, 1.01-4.74) compared their respective counterparts in the pre-fortification period. Conclusions: No significant difference in the proportion of individuals with vitamin B-12 deficiency without macrocytosiss was seen between the pre and post-fortification periods suggesting no making of vitamin B-12 deficiency. In the post-fortification period, serum folate was found to be a predictor of the masking effect. The impact of increased folic acid intake in the post-fortification period needs to be evaluated on a periodic basis especially, in non-target population.