Assessing a Panel of Biomarkers in Plasma Reflecting Dietary Intakes: Data From a Large Randomized Controlled Trial

Specific metabolites detected in human biofluid after the ingestion of food have been proposed as objective markers of dietary intake, yet their evaluation across diverse dietary settings remains limited. This study sought to build a panel of biomarkers of food intake (BFI) representing major food groups and compared their plasma concentrations with self-reported dietary intakes during a randomized three-arm trial. Interventions were of delivered groceries either high in fiber or unsaturated fats, or no groceries for 12 weeks. Plasma samples from 245 adults (mean age: 63.4 ± 9.5 years) were analyzed pre- and post-dietary intervention. Gas chromatography-mass spectrometry detected 104 known food-related metabolites. Pre-intervention, modest Spearman's rank correlation coefficients were observed for red meat (1-methylhistidine ρ = 0.13; urea ρ = 0.19), fish (anserine ρ = 0.24; 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid and docosahexaenoic acid ρ = 0.13), fruit (ascorbic acid, hippuric acid, 4-coumaric acid, linoleic acid ρ = 0.14-0.17), and legumes (pipecolic acid ρ = 0.16-0.19) using 4-day food dairy data. Post-intervention, additional modest correlations were observed between biomarkers and self-reported dietary intakes. We identified over 40 plasma metabolites associated with specific foods or food groups, supporting their use in a multimarker panel for objective dietary assessment. No biomarkers were identified for vegetables, dairy, and chocolate, highlighting key gaps for future research to understand and validate BFI for their broader application.