CSF concentrations of the 20 compounds detected and/or quantified. Values shown are the descriptive statistics of the samples detected and quantified only.

Compound name	LOQ	Mean	SD	Median	IQR	% samples quantified (>LOQ)
Benzene diols and triols
2,3-Dihydroxybenzene-1-sulfate	1.58	3.8	0.15	3.8	0.2	100
2,6-Dihydroxybenzene-1-sulfate	1.58	2.2	0.27	2.1	0.1	100
Benzoic acids
3-Hydroxybenzoic acid	16.7	367	292	304	532	10.0
2,5-Dihydroxybenzoic acid	16.7	35.3	0.08	35.3	0.1	100
4-Methoxybenzoic acid-3-sulfate	8.43	18.8	0.44	18.8	0.4	100
Cinnamic acids
3′,4′-Dihydroxycinnamic acid	1.76	4.7	3.19	3.8	5.0	20.0
3′-Methoxycinnamic acid-4′-glucuronide	17.2	18.1	12.7	13.2	10.6	4.40
4′-Methoxycinnamic acid-3′-sulfate	8.06	12.9	0.04	12.8	0.0	100
5-O-Caffeoylquinic acid	1.67	3.2	0.06	3.2	0.0	100
4-O-Feruloylquinic acid	1.65	1.8	0.05	1.8	0.1	100
Phenylpropanoic acids
3-(2′,3′-Dihydroxyphenyl)propanoic acid	7.48	15.9	0.37	15.8	0.5	100
3-(3′-Methoxyphenyl)propanoic acid-4′-glucuronide	1.56	1.7	—	1.7	0.0	1.10
Flavan-3-ols
(−)-Epicatechin	8.34	8.5	0.38	8.5	0.4	100
(−)-Epicatechin-3′-sulfate	8.13	12.1	0.46	11.9	0.3	100
Flavonols
Quercetin-3′-sulfate	8.36	18.1	0.01	18.1	0.0	100
Quercetin-3′-glucuronide	1.73	4.5	0.05	4.5	0.0	100
Hydroxycoumarins
7,8-Dihydroxycoumarin	8.43	19.6	0.03	19.6	0.0	100
Methylxanthine alkaloids
1,3-Dimethylxanthine	17.0	65.2	63.0	43.9	57.5	43.3
3,7-Dimethylxanthine	8.30	348	197	333	262	96.7
1,3,7-Trimethylxanthine	17.4	1348	612	1313	661	97.8