The metabolism of 18 carbon (13 C) unsaturated fatty acids in healthy women
Bibliographic record
Abstract
The question of how dietary fat is partitioned between the pathways of energy production and storage underlies several chronic disorders such as obesity, non-insulin dependent diabetes mellitus and cardiovascular disease. The goal of the present study was to integrate lipid metabolism by following the routes of various dietary fatty acids through energy utilization, transport in circulation, incorporation in adipose tissue, and conversion to other fatty acids. Four 13C-labelled fatty acids—oleate (9 cis-18:1), α-linolenate (ALA, 18:3n-3), elaidate (9 trans-18:1) and linoleate (LA, 18:2n-6), were administered as a single oral bolus to six healthy women. Samples were collected over 168 h. 13C in breath CO 2 and in plasma triglycerides (TG), phospholipids (PL), cholesteryl esters (CE), and free fatty acids (FFA) were analysed using isotope ratio mass spectrometry and the area under the isotope enrichment curve was determined. Adipose tissue biopsies were obtained at 6 h, 24 h, and 168 h after dosing. Selective incorporation of tracer LA into plasma PL and CE occurred, accompanied by lower oxidation of 13C LA, as compared to elaidate, oleate and ALA. In plasma TG, enrichment was in the order of elaidate > oleate > ALA. Elaidate was a poor substrate for cholesterol esterification. Enrichment in the desaturated and elongated products of LA and ALA was observed, but in low amounts. Enrichment in adipose tissue was observed as early as +6 h after dosing with ALA, elaidate and LA, and was still present at 168 h. Individuals with higher LA levels in plasma PL oxidised more of 13C LA and elaidate, implicating a relationship of high LA feeding to increased fatty acid oxidation. Although elaidate was highly oxidised, it also incorporated the highest in TG and the lowest in CE, which may relate to its hyperlipidemic effect. LA, although less oxidised, was incorporated into plasma PL and CE to a greater extent, indicating a preference for lipid membrane incorporation rather than oxidation. These metabolic differences can ultimately lead to an explanation of the differential health effects of these dietary fatty acids.
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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".