Dietary Intake and Biomarkers of Folate and Cobalamin Status in Norwegian Preschool Children: The FINS-KIDS Study

Abstract

<jats:title>ABSTRACT</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Folate and cobalamin (vitamin B-12) are essential for growth and development. However, few population-based studies have investigated B-vitamin status in children.</jats:p> </jats:sec> <jats:sec> <jats:title>Objectives</jats:title> <jats:p>This study aimed to assess biomarkers of folate and vitamin B-12 status and to explore their dietary determinants in healthy Norwegian children.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Using baseline data obtained from a randomized controlled trial on the effect of fish intake on neurodevelopment in children aged 4–6 y, we measured the plasma concentrations of folate, cobalamin, total plasma homocysteine (tHcy), and methylmalonic acid (MMA). Food-frequency questionnaires (FFQs) were used to assess dietary intake. We used unadjusted and multiple linear regression models to explore the determinants of biomarker concentrations.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The median (IQR) of plasma folate (n = 197) and plasma cobalamin (n = 195) concentrations were 15.2 (12.2–21.1) nmol/L and 785 (632–905) pmol/L, respectively. Plasma folate concentrations of &amp;lt;10 nmol/L were observed in 13% of the children. No child had a cobalamin concentration &amp;lt;148 pmol/L. Two children were identified with elevated plasma MMA concentrations (&amp;gt;0.26 μmol/L) and 8 children had elevated tHcy concentrations (&amp;gt;6.5 μmol/L). Plasma folate concentration was inversely correlated with tHcy (ρ = −0.24, P &amp;lt; 0.001); we found no correlation between tHcy and cobalamin (ρ = −0.075, P = 0.30). Children who consumed vitamin supplements had 51% higher plasma folate concentrations (P &amp;lt; 0.0001) than those who did not. Consumption of red meat for dinner more than twice a week was associated with 23% lower plasma folate (P &amp;lt; 0.01). No other significant associations between dietary intake and the biomarkers were observed.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The Norwegian preschool children from this cohort had adequate vitamin B-12 status. Poor folate status was common and associated with elevated tHcy. The implications of poor folate status during childhood should be a prioritized research question. This trial was registered at ClinicalTrials.gov as NCT02331667.</jats:p> </jats:sec>

Folate and Cobalamin Serum Levels in Healthy Children and Adolescents and Their Association with Age, Sex, BMI and Socioeconomic Status

“…As mentioned, overall, our cobalamin values compared well to previous findings, although values were 25–40% higher for some age groups [ 10 , 13 ] and, notably, 20–50% lower during infancy [ 6 , 12 , 13 , 15 , 16 , 17 ]. On the basis of data from an US adult population, the WHO defines cobalamin deficiency as a plasma cobalamin concentration (<150 pmol/L) for all ages [ 3 ].…”

“…As stated in the Results section, there was great variability of measurements not only between ages but also within each age group. In our study, folate values exceeded previously reported concentrations by 18%-60%, especially in teenagers [7,10,11,13,[15][16][17]. In contrast, only two previous studies found substantially higher folate values for some age groups [14,16].…”

“…In the current study, folate levels < 10 nmol/L were observed in merely 1.3% of cases ( n = 53), a low prevalence compared to other studies. For instance, in Norway, 5.8% of two-year-old [ 11 ] and 13.2% of four- to six-year-old children [ 15 ] presented with levels below the cut-off, while in this study no child aged ≤ 6 years had folate levels < 10 nmol/L. Similarly, 6% of 6-to 15-year-old Greeks had levels below 7.7 nmol/L [ 12 ], compared to 0.1% ( n = 2) of children of the same age in the current study.…”

“…Thus, if we apply the WHO-recommended cut-off, 10% of infants would be categorized as cobalamin-deficient. By comparison, in the aforementioned Norwegian study, none of the children between 4–6 years of age had levels < 148 pmol/L [ 15 ], which ties well with this sample, where no children in the same age range presented with levels < 148 pmol/L. Similar to folate, the 2.5th percentile for cobalamin in both children aged ≤ 1 year and 16.5- to 18-year-old females was below the proposed cut-off.…”

“…The transferability of these reference values to pediatric populations in Europe is therefore limited. While several studies have been carried out on folate and cobalamin status in European children [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], only four focused on reference values for healthy children and/or adolescents ( Table S1 ) [ 6 , 7 , 8 , 9 ]. At present, to the best of the authors’ knowledge, no single study exists which is not limited by age range, small sample size, or the publication of only mean/median values for broad age groups.…”