Ketone Monoester Ingestion Lowers Cerebral Perfusion, But Does Not Impact Memory Performance, In Young Adults
Bibliographic record
Abstract
Infusion of the ketone body beta-hydroxybutyrate (β-OHB) may improve cognitive abilities, including memory function. This improvement may be achieved via enhanced cerebral blood flow (CBF). However, it is unknown whether a single dose of an exogenous oral ketone monoester (KME) supplement can reproduce these effects. PURPOSE: to test the hypothesis that KME ingestion will improve memory performance and enhance resting CBF. METHODS: Six adults have participated to date (age = 22.8 ± 2.6 years, BMI = 23.7 ± 2.7 kg/m2). Participants ingested 600 mg β-OHB/kg body mass of a KME supplement. Capillary β-OHB was measured via a ketone meter over a 2-hr period post-ingestion. Global CBF was assessed using duplex ultrasound of the internal carotid and vertebral arteries. Partial pressure of end-tidal CO2 (PETCO2) and ventilation were measured using a metabolic cart. Cognitive performance was assessed 30 min post-ingestion using the mnemonic similarity task (MST) on a computer, which assesses hippocampal-dependent memory. A one-way repeated measures ANOVA was computed to assess changes in CBF, PETCO2, and blood [β-OHB] over time. Memory performance was assessed via the lure discrimination index (LDI) and calculated as the difference between the probability of giving a “similar” response to lure items and the probability of giving a “similar” response to foil items on the MST. A paired-sample t-test was used to compare LDI between KME and a time-control condition for MST performance. RESULTS: KME ingestion increased blood [β-OHB] from baseline (0.18 ± 0.08 mM) to peak concentration (4.40 ± 0.90 mM; P = 0.002) occurring at 45 min post-ingestion. Contrary to our hypotheses, KME ingestion did not impact memory performance compared to a time-control condition (P = 0.378) and CBF decreased by 13 ± 9% (P = 0.017). This was likely due to hypocapnia-mediated cerebrovascular constriction (PETCO2 ∆-2.1 ± 0.7 mmHg; P = 0.079), because of ventilatory compensation to buffer pH disturbances by KME ingestion. CONCLUSIONS: KME ingestion lowered CBF over a 2-hr period and memory performance was not affected by KME. Establishing a KME dosing regimen that does not perturb PETCO2 may be important to reproduce the noted benefits of β-OHB infusion for CBF and cognitive performance. This study was supported by a NSERC Discovery Grant (#202103522 to J. Walsh).
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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".