Objectives: Folate and the metabolically related B vitamins are an important priority throughout life, but few studies have examined their status through childhood and adolescence. The aims of the current study were to investigate age, gender, and lifestyle factors as determinants of folate, related B-vitamin status, and homocysteine concentrations among British children and adolescents and to propose age-specific reference ranges for these biomarkers, which, at present, are unavailable.
Participants and methods: Data from the National Dietary and Nutritional Survey of 2127 young people aged 4 to 18 years were accessed to provide a representative sample of British children. All of the subjects who provided a blood sample for homocysteine concentrations were included in the current study (n = 840). Of these, laboratory biomarkers of folate (serum and red cell folate: n = 832 and 774, respectively), vitamin B(12) (n = 828), vitamin B(6) (n = 770), and riboflavin (n = 839) were also examined.
Results: The biomarker status of all 4 of the relevant B vitamins decreased significantly with age. Correspondingly, homocysteine concentrations progressively increased, with median values of 5.6, 6.3, and 7.9 mumol/L for children aged 4 to 10 years, 11 to 14 years, and 15 to 18 years, respectively, and were higher in boys compared with girls (15-18 years only). Independent of age and gender, fortified breakfast cereal intake (consumed by 89% of the sample) was associated with significantly higher B-vitamin status and lower homocysteine concentrations.
Conclusions: It is not generally appreciated that the well-established progressive increase in homocysteine from 4 to 18 years reflects decreases in the biomarker status of all 4 metabolically related B vitamins. We suggest age-specific laboratory reference ranges for homocysteine and related B-vitamin concentrations for potential use within a pediatric setting.