Sulphur Amino Acid Requirements and Metabolism in Healthy Adults ≥60 Years
Bibliographic record
Abstract
Current protein and indispensable amino acid (AA) recommendations for older adults are based on young adult data. The protein requirement based on nitrogen balance studies is lower than our indicator amino acid oxidation (IAAO) derived estimate in older adults. Physiological studies suggest that protein intakes similar to our IAAO-derived estimates result in better physiological outcomes. Glutathione (GSH) is a functional marker of cellular antioxidant capacity, and its synthesis rate depends on protein and sulphur AA (SAA) intakes. Recommendations for increased plant-protein consumption necessitate determining the indispensable AA needs directly in older adults, particularly the SAA, which are limiting in plant proteins. The goal of the current thesis was to assess the protein and SAA requirements of healthy adults 360 years by 1) measuring GSH synthesis as a functional marker of protein adequacy using a precursor-product method; 2) deriving the total SAA (methionine devoid of cysteine) requirement and 3) the minimum methionine (methionine with excess cysteine) requirement using the IAAO method. GSH fractional synthesis rate (FSR) was maximized at a protein intake of 0.96 g·kg-1·d-1 (95% CI: 0.74,1.18). Total SAA requirements for older males and females were 26.2 and 17.1 mg×kg- 1×d-1 respectively, which were statistically different (Difference in 95% CI: 9.1 ± 8.85). The minimum methionine requirement for older males and females was 5.1 mg×kg-1×d-1 (95% CI: 3.67, 6.53). Our lab's IAAO protein requirement estimates in healthy adults 360 years are comparable to the level of protein intake that maximized GSH synthesis. This suggests that the IAAO method measures a protein requirement higher than that needed for nitrogen balance. Additionally, considering the observed sex and age effect of total SAA requirement, young adults indispensable AA requirements do not apply to older adults. Therefore, all remaining indispensable AA requirements of older adults should be urgently assessed to properly assess the effectiveness of dietary intakes and plant-based diets to meet their specific needs.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".