Evaluation of safe utilization of l-threonine for supplementation in healthy adults: a randomized double blind controlled trial
Bibliographic record
Abstract
L-threonine is used in dietary supplements and nutritional products ingested by healthy consumers. The objective of this study was to determine in a randomized double blind controlled clinical trial the safety and tolerability of L-threonine used as graded doses in supplements for 4 weeks. Healthy male adults (age 42.9) ingested randomly placebo or different doses of L-threonine (0, 3, 6, 9, 12 g/day) for 4 weeks using a crossover design. At the end of supplementation period, the subjects visited the clinic for medical examination, anthropometric parameter measurements, blood sampling for biochemical tests including amino acid concentrations in plasma, measurement of blood pressure and heart rate, and dietary intake evaluation. Adverse events were recorded all along the trial. None of the anthropometric parameters measured, dietary intake and the biochemical parameters were affected by L-threonine supplementation except a non-specific minor increase in plasma aspartate amino transferase and creatine kinase which was measured in the group supplemented with 9 g L-threonine per day but not with the 12 g per day dose. Also, the concentration of L-threonine as well as the concentration of its metabolite L-2-amino butylate were found to be increased in plasma after supplementation with 6, 9, 12 g/day L-threonine. The moderate and mild adverse events were found to occur at random. All symptoms disappeared during the supplementation period despite continuous L-threonine supplementation. These results of this study indicate a no-observed-adverse-effect-level (NOAEL) value for L-threonine to be 12 g/day in healthy adult males. This study was registered at jRCT as jRCT1050230137.
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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 | 0.004 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".