Table 1. Fecal organic acid and short chain fatty acid concentration of twins discordant and concordant for BMI.

Component	Lower BMI siblings (n=16) (mean±s.d.e)	Higher BMI siblings (n=16) (mean±s.d.e.)	P-value	Controls (n=32) (mean±s.d.e.)
Acetate	56.44±6.38	74.41±9.04	0.252	56.97±6.49
Butyrate	13.76±1.59	25.12±3.51	0.013	16.40±1.90
Iso-butyrate	0.23±0.14	1.15±0.33	0.067	1.09±0.29
Malate	10.56±2.60	25.71±8.3	0.403	11.81±2.84
Propionate	16.82±1.76	25.25±4.04	0.193	15.86±1.42
Succinate	0.64±0.35	0.03±0.03	0.178	1.41±1.21
Valerate	1.47±0.30	3.43±0.62	0.006	2.00±0.30

Abbreviation: BMI, body mass index.

Citrate, lactate, fumarate and formate were not detected. Statistical testing of between the concentrations of lower BMI sibling and higher BMI sibling groups was performed with paired dependent two-group Wilcoxon signed rank tests and P-values are reported (significant P-values are in bold).