True Ileal Amino Acid Digestibility of Human Foods Classified According to Food Type as Determined in the Growing Pig.
Level 5 - mechanism / opinion, no new human data
Animal model (pig) experimental study for estimating human nutrient parameters.
PubMed 40812478 · doi:10.1016/j.tjnut.2025.08.004
What was done
Researchers measured the true ileal digestibility (TID) of amino acids (AA) across 97 human foods in 3 laboratories using female growing pigs (25–100 kg, n ≥ 6 per diet). Pigs were fed experimental diets for 7 days in a Youden Square design, and ileal digesta were collected through a T-cannula on days 6 and 7. Basal endogenous AA losses were quantified using a protein-free diet. Foods, diets, and digesta were assayed for nitrogen, individual AA, reactive lysine, titanium (indigestible marker), and dry matter to compare variation across food categories.
What was found
Mean AA TID spanned from 0.247 (apples) to 0.988 (beef tenderloin). Food categories with median AA TID above 0.90 included dairy, eggs, fish/seafood, isolates/concentrates, meat, nuts, plant-based burgers, soy products, and wheat products. Categories with median AA TID under 0.80 were baked products, fruit, pulses/seeds, wheat bran cereal, yeast, and zein. Variation between foods within categories was lowest in fish and seafood (1% unit spread), dairy (3% units), and eggs (5% units), but highest in grains (18% units), vegetables (16% units), seeds (14% units), and fruit (12% units).
Why it matters
This study provides a multi-laboratory reference database of true ileal amino acid digestibility across 97 human foods, supplying data needed to calculate Digestible Indispensable Amino Acid Scores (DIAAS).
Limits
Measurements were conducted in growing female pigs rather than humans. Total animal sample size is not stated beyond n ≥ 6 per food. Foods were tested individually rather than as complex mixed meals, which may not capture full meal-matrix effects on digestion.
Cited by
- supports Based on the Digestible Indispensable Amino Acid Score (DIAAS), animal protein possesses the highest protein digestibility and protein quality found in nature.