Table 1. OPLS-DA coefficients and their variable importance in projection (VIP) for significantly changed metabolites in serum.

Metabolites			Multi-criteria assessment (MCA)c
No.	Names	δ 1H (ppm)	HFD vs. Normal			HFD+GAH vs. HFD
			Coefficient valued	VIP	p valuee	Coefficient valued	VIP	p valuee
Large macromolecules a
1	HDL	0.86 (m)	0.974	5.59	↑, <0.001	−0.777	5.18	↓, 0.001
2	LDL	0.88 (m)	0.953	4.06	↑, <0.001	−0.817	3.88	↓, 0.001
8	Lipid	1.28 (m)	0.857	4.00	↑, <0.001	−0.882	4.77	↓, <0.001
16	N-acetyl-glycoprotein	2.04 (s)	0.882	2.36	↑, <0.001	−0.840	2.50	↓, 0.001
17	O-acetyl-glycoprotein	2.14 (s)	−0.896	1.09	↓, <0.001	0.610	1.18	↑, 0.003
24	PUFA	2.75 (m)	0.985	2.93	↑, <0.001	−0.776	2.25	↓, 0.001
25	Albumin	3.02	−0.947	1.43	↓, <0.001	0.776	1.39	↑, 0.002
29	Phosphotidylcholine	3.23 (s)	0.904	4.52	↑, <0.001	−0.860	5.85	↓, <0.001
36	UFA	5.29 (m)	0.983	4.37	↑, <0.001	−0.838	3.93	↓, <0.001
Small molecules b
3	Isoleucine	1.01 (d)	−0.915	1.56	↓, <0.001	0.744	1.14	↑, 0.031
4	Leucine	0.97 (t)	−0.732	2.07	↓, 0.001	0.713	1.83	↑, 0.001
5	Valine	1.04 (d)	−0.755	2.10	↓, <0.001	0.628	1.61	↑, 0.010
6	Isobutyrate	1.14 (d)	−0.681	0.92	↓, 0.003	0.605	1.15	↑, 0.008
7	3-hydroxybutyrate	1.20 (d)	−0.507	2.18	–, 0.113	0.584	5.24	↑, 0.017
9	Lactate	4.11 (q)	−0.683	2.10	–, 0.285	0.601	2.77	–, 0.124
10	Alanine	1.48 (d)	−0.585	1.93	↓, 0.013	0.519	1.76	–, 0.067
11	Lysine	3.03 (t)	−0.815	1.19	↓, 0.001	0.791	1.87	↑, 0.001
12	Arginine	1.67 (m)	−0.701	0.98	↓, 0.003	0.711	0.99	↑, 0.003
13	Ornithine	3.06 (t)	−0.303	0.68	–, 0.254	0.742	1.28	↑, 0.005
14	Acetate	1.92 (s)	−0.742	1.83	↓, 0.003	0.568	1.17	–, 0.078
18	Glutamate	2.35 (t)	−0.843	1.21	↓, 0.003	0.834	1.45	↑, 0.006
19	Glutamine	2.45 (m)	−0.614	1.30	↓, <0.001	0.737	1.83	↑, 0.001
20	Acetoacetate	2.29 (s)	−0.591	1.23	–, 0.051	0.664	2.50	↑, 0.005
21	Pyruvate	2.37 (s)	−0.818	1.48	↓, <0.001	0.646	1.47	↑, 0.031
23	Citrate	2.53 (d)	−0.786	1.31	↓, <0.001	0.492	0.71	–, 0.136
32	Betaine	3.27 (s)	−0.774	2.87	↓, 0.001	0.623	2.21	–, 0.128
35	Glycine	3.56 (s)	−0.722	2.93	↓, 0.001	0.737	3.34	↑, 0.004
38	Tyrosine	6.90 (d)	−0.775	0.70	↓, <0.001	0.811	0.92	↑, 0.002
39	1-Methylhistidine	7.06 (s)	−0.760	0.69	↓, 0.001	0.779	0.65	↑, 0.003
40	Phenylalanine	7.33 (m)	−0.920	0.65	↓, <0.001	0.837	0.62	↑, 0.003

^aCoefficient values are calculated by LED-BPP coefficient-coded loadings plots.

^bCoefficient values are calculated by CPMG coefficient-coded loadings plots.

^cMulti-criteria assessment (MCA) was performed by followed criteria: 1. Coefficient value |r| >0.576, 2. VIP>1, 3. p value <0.05.

^dThe coefficients from the OPLS-DA results; positive and negative signs indicate positive and negative correlations in the concentrations of serum metabolites.

^eIndependent t test (two-tailed).

HDL: high-density lipoprotein; LDL: low-density lipoprotein; PUFA: Polyunsaturated fatty acids; UFA: unsaturated fatty acids.