Table 2.

Biological function of lipid classes included in Table 1.

Class	Biological Function	Reference
SM	SM facilitates formation of lateral membrane domains and has a strong interaction with cholesterol. SM has a varied and vast biological influence including but not limited to; regulation of endocytosis and receptor-mediated ligand uptake, ion channel and G-protein coupled receptor function, protein sorting, and functioning as receptor molecules for various bacterial toxins, and for non-bacterial pore-forming toxins.	76
ChE	ChE is the inactive form of cholesterol and it is primarily used for transport of cholesterol to organs or to act as a biologically inert storage of excess cholesterol by the addition of fatty acids to the hydroxyl group results in less polarity making the lipid ‘inert’	71
TG	TGs are the main form of fat recorded in humans and are present across many species. They are found in the blood and act as an energy supply for the body in addition to being stored as body fat when excess is present.	77,78

The top 10 lipids with most significantly changing relative intensity in sex:age interaction were lipid sub-species of three lipid classes; SM (sphingomyelin, ChE (cholesterol ester) and TG (triglyceride).