Correlation analysis of metabolomics to lipidomics in obese_PN vs obese_No_PN groups. Spearman correlation was performed between metabolites (along the vertical y axis) and lipids (along the horizontal x axis) in the obese_PN vs obese_No_PN comparisons. Heat map shows significant correlations (adjusted P < .05) for positive (red, strongest with the value of 1) and negative (blue, strongest with the value of –1) correlations. A cluster of positive correlations occurs between CERs, DCERs, and SMs with 2-hydroxynervonate, β-hydroxyisovalerate, and 2-hydroxymyristate, which are negatively correlated with other lipid species. Additionally, CERs, DCERs, and SMs positively correlate with α-ketobutyrate and 2-hydroxybutyrate/2-hydroxyisobutyrate, which are negatively correlated with phospholipids (PCs, PEs), CEs, and LPEs. CE, cholesterol ester; CER, ceramide; DCER, dihydroceramide; FFA, free fatty acid; LCER, lactosylceramide; LPE, lysophosphatidylethanolamine; PC, phosphatidylcholine; PE, phosphatidylethanolamines; SM, sphingomyelin; TAG, triacylglycerol.