Fig. 2

Pathway analysis diagram generated manually using metabolites identified in the reviewed literature and the KEGG Pathway Database. Pale colored boxes represent metabolic pathways. Pathways are simplified for summary purposes. Increased metabolites found in reviewed studies are indicated by a thick red outline and decreased metabolites are indicated by a thick black dashed outline. Metabolites with conflicting results are indicated by a dark blue outline. An asterisk (*) was placed on each metabolite that was found in only one of the reviewed studies. All other highlighted metabolites without an asterisk were present in more than one reviewed study and encompass the fifteen ‘recurrent’ metabolites identified in this review