TABLE 2.

Metabolites that changed significantly (P < 0.05) in response to β-carotene supplementation in the ATBC Study¹

Metabolite	Chemical class	Number > LOD	Effect size2	P value
Threonine	Amino acid	200	−0.381	0.0067
1,5-Anhydroglucitol	Carbohydrate	200	−0.379	0.0071
Hippurate	Xenobiotics	200	0.363	0.0099
3-(3-Hydroxyphenyl) propionate	Nonstandard amino acid	158	0.357	0.0111
3-Hydroxyhippurate	Xenobiotics	198	0.351	0.0126
Dihydroferulic acid	Xenobiotics	77	0.350	0.0131
2-Hydroxyacetaminophen sulfate	Xenobiotics	24	0.334	0.0179
3,7-Dimethylurate	Xenobiotics	158	0.318	0.0240
5-Acetylamino-6-amino-3-methyluracil	Xenobiotics	196	0.318	0.0241
β-Sitosterol	Lipid	114	−0.314	0.0262
Xylose	Carbohydrate	174	−0.296	0.0358
1-Methylurate	Xenobiotics	200	0.294	0.0372
2-Hydroxyisobutyrate	Nonstandard amino acid	200	0.293	0.0378
10-Nonadecenoate (19:1n−9)	Lipid	200	0.285	0.0434
Catechol sulfate	Xenobiotics	200	0.283	0.0451
Cinnamoylglycine	Xenobiotics	185	0.280	0.0475
7-Ketodeoxycholate	Lipid	63	0.277	0.0498

¹ATBC, Alpha-Tocopherol, Beta-Carotene Cancer Prevention; LOD, limit of detection.

²Effect size denotes the change in metabolite level (expressed in number of SDs on the log scale) for the β-carotene arm compared with the no β-carotene arm. The effect sizes and P values were estimated by linear regression.