Abstract
Background: Reliable nutritional assessment is key for understanding diet-health interactions. Current dietary assessment is self-reported, and us such prone to a range of bias. Objective markers, such as the quantification of diet-related metabolites in human tissue may prove a more reliable of dietary assessment and reduce participant burden.
Research Objective: To compare the accuracy of known metabolite makers of dietary intake (objective) with current dietary assessment methods (self-reported) against known amounts of foods consumed under observation.
Methods: We conducted a randomised crossover feeding study of three interventions (one standardisation day followed by a feeding day of known foods consumed under observation). Each feeding day differed by which food groups were provided or entirely absent. Participants provided 24-hour urine samples, 24-hour recalls and fasted blood samples on all six days. Known metabolite markers of dietary intake (approximately 70) were identified in blood and urine using LC-MSqToF, and semi-quantified with a known standard. Twenty-four hour urine sodium content was also measured as the current best known objective marker of dietary intake.
Results and Progress: Twenty-four participants (74% female) commenced the study, with 21 (88%) completing all three interventions. Mean energy intake on feeding days (11720 kJ (2943.01)) was higher than self-reported energy intake on standardisation days (9243.57 kJ (3582.92)). Meals were well tolerated, with mean intakes of 9.8 serve whole grains, 2.4 serves fish, 3.1 serves dairy, 5.6 serves chicken, 8.2 serves legumes, 3.1 serves fruit, 3.9 serves red meat, 1.7 serves nuts and seeds, and 13.4 serves vegetables on their respective feeding days. The three feeding days provided clearly identifiable clusters when assessing the overall metabolic profile. The relative correlations between self-reported intakes and individual metabolite concentrations reflecting specific foods or food groups with the known dietary intakes from feeding days will be presented at the conference.