Table 5.

Metabolites demonstrating >50% decreases or >twofold changes related to amino acid metabolism measured before and after a 4‐day, 51‐km cross‐country ski march

Subpathway	Biochemical name	Fold change (POST/PRE)
Histidine	3‐Methylhistidine	0.34
	N‐Acetyl‐3‐methylhistidinea	0.32
Phenylalanine and tyrosine	Gentisate	0.42
	Vanillic alcohol sulfate	2.29
Tryptophan	Indoleacetylglutamine	0.47
Branched‐chain amino acids	3‐Hydroxy‐2‐ethylpropionate	2.63
	Ethylmalonate	2.07
Methionine, cysteine, S‐adenosylmethionine, and taurine	S‐Methylmethionine	0.35
	Alpha‐ketobutyrate	3.14
	N‐Methyltaurine	0.36
	2‐Hydroxybutyrate/2‐hydroxyisobutyrate	3.23
Urea cycle; arginine and proline metabolism	2‐Oxoarginine a	0.43

Data are fold changes calculated using the mean for each time point. Repeated measures ANOVA (n = 24) used to examine main effect of time, diet, and their interaction on metabolites measure before (PRE) and after (POST) military training. P values were adjusted using the Benjamini–Hochberg correction (Q); main effect of time, Q < 0.10 for all. All diet by time interactions were not statistically significant (Q > 0.20). Metabolites in bold font are those with the strongest influence on prediction accuracy in the random forest analysis (see Fig. 1B).

^aCompounds that have not been officially confirmed based on a standard, but are identified with high confidence.