Table 2. Summary of the parameters of colonic metabolism and toxicity.
| NP diet | HP diet | LP diet | p-value | |
| Colonic metabolism | ||||
| Fecal parameters | ||||
| 15N (dose %) | 10.4 (8.3–18.1) | 10.6 (8.9–13.7) | 13.1 (10.7–22.7) | 0.059 |
| Total VOC | 59 (54–63) | 62 (55–65) | 59 (56–62) | 0.284 |
| Total SCFA (mg/L) | 309.3 (210.5–442.5) | 365.3 (256.2–555.4) | 378.5 (252.6–508.5) | 0.212 |
| Acetic acid (mg/L) | 217.8 (140.4–299.3) | 251.9 (148.2–378.4) | 261.3 (165.0–372.2) | 0.861 |
| Propionic acid (mg/L) | 48.7 (38.8–79.5) | 68.8 (46.6–89.0) | 55. 3 (44.5–86.0) | 0.522 |
| Butyric acid (mg/L) | 51.0 (22.5–60.6) | 42.3 (29.8–71.2) | 46.7 (34.8–64.0) | 0.705 |
| Total BCFA (mg/L) | 18.8 (14.8–35.5) | 29.2 (19.8–44.1) | 19.8 (35.4–14.5) | 0.091 |
| Isobutyric acid (mg/L) | 9.6 (7.0–16.6)a | 14.7 (10.2–20.5)b | 10.4 (7.7–18.3)ab | 0.022 |
| Isovaleric acid (mg/L) | 9.2 (7.5–17.8) | 12.7 (9.5–22.4) | 10.2 (8.1–15.8) | 0.074 |
| Dimethyl sulfide (µg/L) | 4.6 (3.4–6.5) | 4.6 (4.3–7.7) | 6.3 (4.9–14.4) | 0.204 |
| p-Cresol (mg/L) | 1.9 (1.5–2.3) | 2.3 (1.5–2.8) | 1.9 (1.7–2.3) | 0.246 |
| Total fecal output (g) | 227.6 (137.3–312.8) | 254.2 (196.9–319.5) | 216.4 (156.3–350.3) | 0.524 |
| Fecal dry weight (%) | 26.9 (25.3–30.8)a | 30.1 (28.2–33.4)b | 29.0 (24.4–31.3)ab | 0.017 |
| 3H-recovery (%) | 65.8 (45.4–84.0) | 65.2 (41.2–85.0) | 58.8 (47.2–77.2) | 0.985 |
| Urinary parameters | ||||
| 15N (dose %) | 35.5 (30.2–41.9) | 39.7 (31.7–47.2) | 36.5 (29.1–43.6) | 0.280 |
| p-Cresol (mg/24 h) | 32.1 (25.8–37.7)a | 45.8 (39.4–53.8)b | 33.7 (21.5–48.9)ab | 0.018 |
| Fecal water toxicity | ||||
| Genotoxicity (TL) | 99.1 (47.4–121.7) | 103.1 (49.6–123.8) | 109.4 (47.1–148.4) | 0.861 |
| Cytotoxicity (IC50) | 42.1 (25.5–49.4) | 27.1 (19.6–40.3) | 28.9 (25.7–50.3) | 0.165 |
All values are expressed as median (IQR) (n = 20). Parameters with different letters (a, b, c) in superscript were significantly different between the dietary interventions. Friedman and Wilcoxon tests were used to evaluate the results, except for urinary 15N and p-cresol, and fecal 15N. Due to missing values an unstructured linear mixed model was applied using treatment as fixed effect. P-values refer to Friedman tests.