Estimated folate intakes: data updated to reflect food fortification, increased bioavailability, and dietary supplement use

Abstract

Background: There is a critical need to estimate dietary folate intakes for nutrition monitoring and food safety evaluations, but available intake data are seriously limited by several factors. Objective: Our objective was to update 2 national food consumption surveys to reflect folate intakes as a result of the recently initiated food fortification program and to correct folate intakes for the apparently higher bioavailability of synthetic folic acid (SFA; ie, folate added to foods or from dietary supplements) than of naturally occurring folate so as to express intakes as dietary folate equivalents. Design: It was not possible to chemically analyze foods, so adjustments were made to food-composition data by using information about food ingredients and characteristics. Total folate intakes were estimated for several sex and age groups by using the modified data coupled with dietary supplement use. Results: Within the limitations of the data, our findings suggested that 67-95% of the population met or surpassed the new estimated average requirement, depending on the sex and age group and survey. Nonetheless, some subgroups had estimated intakes below these standards. Estimated SFA intakes suggested that Ϸ15-25% of children aged 1-8 y, depending on the survey, had intakes above the newly established tolerable upper intake level. We estimated that 68-87% of females of childbearing age had SFA intakes below the recommended intake of 400 g/d, depending on the age group and survey. Conclusion: There is a need to explore ways to improve folate intakes in targeted subgroups, including females of childbearing age, while not putting other population groups at risk of excessive intakes.

Population-Level Changes in Folate Intake by Age, Gender, and Race/Ethnicity after Folic Acid Fortification

“…[27][28][29][30][31][32][33][34][35][36][37] Our results corroborate the findings from those studies and show that folate intake levels have increased for the average person by approximately 100 µg/day. However, our analysis also corrects for dietary intake data measurement error when estimating folate intake levels.…”

“…52 Given the uncertainty of the minimum effective dose of folate for preventing NTDs, the safety concerns for the elderly, and the magnitude of a national fortification mandate, there is great interest in evaluating folate intake and health outcomes after folic acid fortification. 24,30,31,[56][57][58] Although most of the FDA policy's focus has been on NTDs and masking anemia caused by vitamin B 12 deficiency, increased folate consumption is also believed to reduce the risk of coronary heart disease and colon cancer. It would help to better guide policy evaluation if future research could incorporate the existing epidemiological evidence on the relation of folate intake with myocardial infarctions and colon cancer, into an analysis that weighs the risks versus benefits of folic acid fortification on these multiple health outcomes.…”

Assessment of three levels of folic acid on serum folate and plasma homocysteine: a randomised placebo-controlled double-blind dietary intervention trial

“…When adjusted for methodological differences identified in folate assays (Gunter et al, 1996), the majority of women studied in the NHANES 1999 survey had red blood cell folate values in the range considered low risk for NTDs (Daly et al, 1995). Retrospective analyses of two nutrition surveys in the US suggest that recent fortification practices may have resulted in 15 -25% of children aged 1 -8 y exceeding the recommended tolerable upper intake for this age group (Lewis et al, 1999). Excessive intakes of folic acid are also of concern for those with low cobalamin status, particularly the elderly, who may be at risk for masking of pernicious anaemia and exacerbation of vitamin B 12 deficient neuropathy (Weir et al, 1999).…”

Folate fortification: potential impact on folate intake in an older population

“…We also used two models of universal fortification to determine potential folate intake, and to quantify possible associated benefits and risks. Additionally, folate is calculated using Dietary Folate Equivalents, which allow for the increased absorption of synthetic folic acid, as described and used in IOM (1998) and Lewis et al (1999).…”