Table 3.

Metabolite species reported to be positively and negatively associated with CRF

Metabolite super classes	Metabolite species	Studies reporting associations with CRF
		Positive	Negative
Lipids and lipid-like molecules	Nervonic acid	[41]	[45]
	Vitamin A	[41]	[45]
	CE(20:4)	[41]	[45]
	CE(22:4)	[41]	[40]
Organic acids and derivatives	Pyroglutamic acid	[47]	[41]
	Histidine	[45]	[47]
	Methionine	[40]	[47]
	Cinnamoylglycine	[41]	[45]
	Phenylalanine	[52]	[41]
	Serine	[45]	[40]
	Tyrosine	[52]	[41, 47]
Organic oxygen compounds	1,5-Anhydroglucitol	[45]	[47]
	Kynurenine	[45]	[47]
Organoheterocyclic compounds	C-Glycosyltryptophan	[45]	[41]

CE cholesterol ester, CRF cardiorespiratory fitness