Table 1.
True ileal and fecal digestibility in humans. Interindividual variability is represented by the coefficient of variation (CV)
| Protein source | Reference | True digestibility (%) | |||
|---|---|---|---|---|---|
| n | Mean | SD | CV | ||
| Ileal digestibility | |||||
| Animal protein | |||||
| Skimmed milk pasteurised | [231] | 5 | 95.5 | 0.9 | 0.9 |
| Protein milk alone | [232] | 7 | 94.8 | 1.6 | 1.7 |
| Protein milk with fat | [232] | 9 | 94.5 | 3.0 | 3.2 |
| Protein milk with sucrose | [232] | 9 | 94.6 | 1.5 | 1.6 |
| Intact casein | [233] | 6 | 94.1 | 1.5 | 1.5 |
| Hydrolysed casein | [233] | 5 | 92.3 | 1.3 | 1.4 |
| Bovine meat, cooked at 55 °C, 5 min | [234] | 8 | 94.1 | 2.0 | 2.1 |
| Bovine meat, cooked at 90 °C, 30 min | [234] | 8 | 90.1 | 5.9 | 6.6 |
| Egg protein, raw | [19] | 5 | 51.3 | 21.9 | 42.7 |
| Egg protein, cooked | [19] | 5 | 90.9 | 1.8 | 2.0 |
| Plant protein | 0.0 | ||||
| Wheat toast (15N gluten) | [235] | 9 | 90.3 | 4.3 | 4.8 |
| Soy protein isolate | [236] | 11 | 91.8 | 1.9 | 2.1 |
| Soy protein isolate with sucrose | [236] | 10 | 90.9 | 2.2 | 2.4 |
| Pea flour (Pisum Sativum, Solara cultivar) | [237] | 7 | 89.4 | 1.1 | 1.2 |
| Pea globulins (Pisum Sativum, Baccara cultivar) | [238] | 9 | 94.0 | 2.5 | 2.7 |
| Pea globulins + albumins (Pisum Sativum, Baccara cultivar) | [238] | 8 | 89.9 | 4.0 | 4.4 |
| Lupin flour (Lupinus Albus, cultivar Arès) | [239] | 7 | 91.0 | 3.0 | 3.3 |
| Rapeseed isolate (Brassica Napus L., Goeland cultivar) | [20] | 7 | 84.0 | 8.8 | 10.5 |
| Fecal digestibility | |||||
| Animal protein | |||||
| Egg | [240] | – | 97.0 | 3.0 | 3.1 |
| Egg, spray‐dried | [241] | 5 | 92.2 | 1.6 | 1.7 |
| Milk, cottage cheese | [241] | 4 | 99.1 | 1.8 | 1.8 |
| Milk, cheese | [240] | – | 95.0 | 3.0 | 3.2 |
| Tuna, canned | [241] | 4 | 89.9 | 1.0 | 1.1 |
| Meat, fish | [240] | – | 94.0 | 6.0 | 6.4 |
| Plant protein | |||||
| Maize | [240] | – | 85.0 | 4.0 | 4.7 |
| Rice, polished | [240] | – | 88.0 | 5.0 | 5.7 |
| Wheat, whole | [240] | – | 86.0 | 4.0 | 4.7 |
| Wheat, refined | [240] | – | 96.0 | 7.0 | 7.3 |
| Wheat gluten | [241] | 4 | 93.8 | 3.0 | 3.2 |
| Oatmeal | [240] | – | 86.0 | 7.0 | 8.1 |
| Soy flour | [240] | – | 86.0 | 7.0 | 8.1 |
| Soy isolate | [241] | 4 | 94.8 | 4.4 | 4.6 |
| Peanut flour | [241] | 4 | 90.8 | 2.0 | 2.2 |
| Mixed protein source | |||||
| Low fiber control diet | [242] | 7 | 95.1 | 1.5 | 1.6 |
| High fiber diet (coarse whole meal rye bread) | [242] | 7 | 90.7 | 1.4 | 1.5 |
| High fiber diet (fine whole meal rye bread) | [242] | 7 | 90.8 | 2.2 | 2.4 |
All ileal studies used 15N‐labelled protein sources ingested by healthy adults equipped by a naso‐ileal tube, except when noted.
Ileal digesta were collected in ileostomy patients.
True fecal digestibility was estimated by correcting apparent digestibility with a constant value of obligatory endogenous losses (9–12 mg N kg–1 body weight d–1).