UNTARGETED METABOLIC PROFILING BY MEANS OF UHPLC-QTOF/MS FOR THE IDENTIFICATION OF MEAT AND DAIRY PRODUCTS INTAKE BIOMARKERS

Abstract

Meat intake has been associated with positive as well as negative health outcomes. Meat is essential from a nutritional point of view but, on the other hand, has been associated with increased risk of several diseases. However, a causal relation between meat consumption and negative health outcomes is still controversial. In order to shed light on this issue, a reliable method for assessment of meat intake is needed. Meat intake has often been assessed using very imprecise methods. Dietary biomarkers measured in biological fluids by means of untargeted metabolomics have been proposed as a possible way to find objective biomarkers for measurement of the actual intake of specific foods. A meat intake marker should be able to differentiate meat consumption from that of other protein-rich foods, such as dairy products. For this purpose, a randomized, controlled, cross-over single meal study was conducted on 17 subjects to collect urine samples at several time points after the ingestion of red meat or dairy product based meals. An ultra-high-performance-liquid chromatograph coupled via an electrospray source to a Q-TOF mass spectrometer was used for the separation and metabolic profiling of the urine samples. Data were analyzed and group differences compared by both univariate and multivariate data analysis and results combined. As a result, 37 compounds were found to be highly important for discriminating the two diets; in particular 20 markers were higher after the dairy-based meal, while 17 markers were higher after the meat-based meal. These markers were fragmented and tentatively identified. Some of them were synthesized to allow confirmation of their identity. Combinations of these markers should be further validated as meat or dairy product intake biomarkers.