Abstract
BACKGROUND: Alkylresorcinols are a well-established biomarker for whole-grain intake. There is evidence suggesting that total plasma alkylresorcinol concentration may also be used as a biomarker for gluten intake in adults. OBJECTIVES: The aim of this study was to evaluate if total alkylresorcinol concentration is a valid biomarker for gluten intake in young children. METHODS: Nonfasting plasma alkylresorcinol concentrations were analyzed by normal-phase ultrahigh-pressure liquid chromatography-tandem mass spectrometry in 65 children aged 18 mo included in a randomized controlled trial. The intervention group was following a gluten-free diet (n = 21, 31.3%), whereas the diet was unrestricted in the control group (n = 44, 65.7%). Alkylresorcinol concentrations in the 65 children were validated against simultaneously collected 3-d food records estimating total gluten intake. RESULTS: Gluten intake in controls was median 5.8 grams/d (IQR: 2.8-9.4, max 17.1) compared with 0.0 g/d (IQR: 0.0-0.0, max 0.7, P < 0.001) in the intervention group. In the control group, wheat accounted for mean 85% (SD: 0.1) of the gluten intake. The intervention group had lower alkylresorcinol levels (median: 7.2 nmol/L; IQR: 4.0-10.5) compared with controls (median: 269; IQR: 116-505 nmol/L, P < 0.001). The correlation between alkylresorcinol concentrations and gluten intake was ρ = 0.68 (P < 0.001). Alkylresorcinol concentrations increased by 35.7% [95% confidence interval (CI): 25.9, 46.2, P < 0.001] for every g/d increase of gluten intake. The Cohen's weighted kappa between quartiles of alkylresorcinol and gluten intake was 0.73 (95% CI: 0.59, 0.86). CONCLUSIONS: Alkylresorcinol concentrations increased with gluten intake in young nonfasting children. The findings suggest that alkylresorcinol concentrations may be a useful biomarker for gluten intake in young children. This trial was registered at clinicaltrials.gov as NCT03562221.