Validation of Existing Methods for Determining Protein and Amino Acid Requirements
Bibliographic record
Abstract
The validity of protein and amino acid (AA) requirement estimates obtained using the minimally invasive 1-day indicator amino acid oxidation (IAAO) method have been questioned. Critics argue that there is no evidence linking 1-day IAAO-derived protein requirements to beneficial health outcomes in humans. Another concern is that the 1-day IAAO protocol is too short, potentially leading to inaccurate estimates of AA requirements due to incomplete adaptation. To address these concerns, this thesis conducted the following research: 1) a randomized cross-over trial measuring erythrocyte glutathione (GSH) kinetics in healthy adults receiving graded proteins intakes (0.6 to 1.5 gkg-1d-1) for 3 days; 2) a scoping review on adaptation and AA oxidation methods, identifying knowledge gaps to inform the planning of study 3 and; 3) a repeated measures design using IAAO to determine whether 1, 3, or 7 days of adaptation to experimental diets altered the threonine requirement in adult men. The first study found that a protein intake of 1.0 gkg-1d-1 (95% CI= 0.63, 1.39) maximized GSH fractional synthesis rates in healthy adults. The scoping review indicated that adaptation periods exceeding 7 days violate the conditions of successful adaptation, but further research is needed to directly compare 1-day and 7-day adaptations in AA requirement studies. This led to the purpose of study 3. In study 3, the mean threonine requirements (95% CI) for days 1, 3, and 7 were 10.5 (5.7, 15.9), 10.6 (7.5, 13.7), and 12.1 (9.2, 15.0 mgkg-1d-1), respectively. These requirements were not statistically different. In healthy young adults, maximum antioxidant synthesis was achieved at a protein intake of 1.0gkg-1d-1, which closely aligns with the 1-day IAAO-derived requirement of 0.93 gkg-1d-1. This suggests that 1-day IAAO-derived protein requirements are indeed reflective of favourable health outcomes. Furthermore, the short 1-day IAAO protocol allows for reliable estimation of AA requirements, as it was not different from those obtained after 3 or 7 days of adaptation. Overall, the 1-day IAAO method proves suitable for studying protein and AA requirements in humans. Moreover, its minimally invasive nature makes it particularly appropriate for investigating the nutritional needs of vulnerable populations that have been scarcely studied.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.096 | 0.162 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.003 |
| Bibliometrics | 0.006 | 0.006 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.006 | 0.003 |
| Open science | 0.005 | 0.004 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.004 | 0.004 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".