The Study
In vitro DIAAS of Swiss soybean cultivars using the INFOGEST model: Increase in protein quality from soybean to soymilk and tofu.
This study tested how well your body might digest soybeans, soymilk, and tofu — but only in a test tube, not in a real person. It tells us how the food breaks down in the lab, not whether it actually helps people grow strong or stay healthy.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists tested how well kids' bodies can use protein from different soy foods — boiled soybeans, soy milk, and tofu — using a lab model that mimics digestion.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 56 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Tofu and soy milk are much better than plain soybeans at delivering usable protein for young children — but the iron and zinc in them might not be absorbed well.
- 2Cooked soybeans: 52–63% protein digestible; soy milk: 84–91%; tofu: 95–98%.
- 3Protein quality score: soybeans <60 (low), soy milk and tofu 78–91 (good).
- 4Iron and zinc are present but blocked by phytic acid.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Food research international
Year
2024
Authors
Laila Hammer, Diego Moretti, C. Bétrix, Pabiraa Kandiah, Agostino Pellegri, Lychou Abbühl-Eng, R. Portmann, L. Egger
Related Content
Claims (6)
Tofu contains all essential amino acids in better proportions than most plant proteins, but the body absorbs fewer of those amino acids from tofu than from eggs, meat, or dairy.
For children aged 0.5 to 3 years, processed soy products like soymilk and tofu provide better amino acid adequacy than cooked soybeans, as measured by the DIAAS method under in vitro conditions.
Soymilk and tofu have higher amino acid scores than cooked soybeans in laboratory tests, meaning they provide more usable protein for human nutrition after traditional processing.
When soybeans are processed into soymilk and tofu, the amount of protein that can be broken down into amino acids during simulated digestion increases significantly compared to cooked soybeans.
Soy foods contain iron and zinc, but high levels of phytic acid relative to these minerals reduce their absorption in laboratory tests.
Laboratory tests show that soymilk and tofu have protein quality comparable to animal-based foods, but these tests do not measure how well humans digest or use that protein.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.