Targeted metabolomic and nutritional analyses of a variety of protein-rich whole-food sources

Protein-rich whole-food sources may possess, as yet, unidentified non-protein components with anabolic potential. Targeted metabolomics can be applied to investigate candidate small compounds, an analytical approach not yet taken within diverse protein-rich whole-foods. We used targeted GC-MS based metabolomic analyses to determine the abundance of a range of small molecules implicated in the regulation of postprandial protein anabolism within a variety of protein-rich whole-foods (whole egg, pork, salmon, lentils and mycoprotein) and a less nutrient dense, more isolated source (egg whites). We aimed to establish the small metabolite profile across these conventionally consumed dietary protein sources and to investigate how they differ between their raw and cooked forms. Heatmap and principal component (PCA) analyses were conducted to identify differences between sources and to assess the effect of cooking. From the metabolites identified, 22 out of 24 (in the raw form; 92%) and 23 out of 24 metabolites (in the cooked form; 96%) differed between foods and the number of metabolites that either increased or decreased with cooking varied across foods. PCA analyses revealed the top three metabolites responsible for the variance between food sources were succinic-, arachidonic-, and myristic acids. Large differences at the nutritional and metabolite level between food sources indicate the diverse range of additional components, other than protein, within a whole-food matrix. The identification of potential anabolic non-protein components within a range of whole-foods provides the necessary step to examine why certain whole-foods may provide a more (or less) robust anabolic stimulus within human studies.