Circulating concentrations of biomarkers and metabolites related to vitamin status, One-carbon and the Kynurenine pathways in U.S., Nordic, Asian and Australian Populations

Background: Circulating concentrations of biomarkers related to vitamin status vary by factors such as diet, fortification and supplement use. Published biomarker concentrations are also influenced by variation across laboratories, which complicates comparison of results from different studies.

Objective: To robustly and comprehensively assess differences in biomarkers related to vitamin status across geographic regions.

Design: The present work is a cross-sectional study that investigated 38 biomarkers related to vitamin status, one-carbon- and tryptophan metabolism, in serum/plasma from 5314 healthy controls, representing 20 cohorts recruited from the United States (U.S.), Nordic countries, Asia and Australia, participating in the Lung Cancer Cohort Consortium (LC3). All samples were analysed in a centralized laboratory.

Results: Circulating concentrations of riboflavin, pyridoxal 5'-phosphate, folate, vitamin B12, all-trans retinol, 25-OH vitamin D, and ∝-tocopherol, as well as combined vitamin scores based on these nutrients, showed that the general B-vitamin level was highest in the U.S., and that the B-vitamins and lipid soluble vitamins were low in Asians. Conversely, circulating concentrations of metabolites inversely related to B-vitamin status in the one-carbon and kynurenine pathway, were high amongst Asians. The high B-vitamin level in the U.S. appears to be driven mainly by multivitamin supplement users.

Conclusions: The observed differences likely reflect variation in the intake of vitamins, and in particular the widespread multivitamin supplement use in the U.S. The results provide valuable information on differences in biomarker concentrations in populations across continents.