Dissertation
The effect of macronutrient-induced ketosis on prefrontal cortex neural activity and cognition
Doctor of Philosophy (Ph.D.), Drexel University
Sep 2023
DOI:
https://doi.org/10.17918/00001802
Abstract
Cognitive functions are crucial for daily activities, social interactions, and independent living; unfortunately, a decline in cognitive abilities can occur in advanced age and diseases like Alzheimer's. The concurrent deficiency in the brain's glucose metabolism contributes to the ominous process of impaired cognition by partly causing a gap between the energy supply and demand needed by the brain. However, the metabolism of the body's alternative fuel, known as ketone bodies, remains stable and may rescue the brain from cognitive deterioration when they rise to supraphysiological levels (ketosis). This dissertation project aimed to investigate the acute influence of ketosis on the cognitive brain neurophysiology and activation to understand the contribution of ketone bodies to the cognitive brain energy flow that may contribute to cognitive benefits. With the use of a double-blind single-case experimental design of a young participant with 20 randomized data points spread between two food interventions, the results indicated that a food mix containing purified Medium Chain Triglycerides (MCT) successfully induced ketosis (>0.5 mmol/L) from basal 15-hour fasting levels. Also, compared to after prolonged fasting, data from a wearable functional near-infrared spectroscopy that detects hemoglobin oxygenation changes as a surrogate of brain activation have shown a significant decrease in oxygenated hemoglobin met with an increase in deoxygenated hemoglobin at the dorsolateral prefrontal cortex as a consequence of ketosis during the engagement in a demanding cognitive N-back test. This change was unique only under a ketosis state; the absence of ketosis in the fasting state and the comparative non-MCT food mix did not lead to the aforementioned neurophysiological changes and showed an increase in oxygenated hemoglobin and decrease in deoxygenated hemoglobin which is typical activation changes during cognitive tasking under usual physiological circumstances. Nevertheless, regardless of ketosis status, improvement in cognitive performance was not noted. From the results of this project herein, the enhancement of oxygen consumption during cognitive brain activation highlights the efficiency of ketone bodies in optimizing the brain's bioenergy cycle and promoting mitochondrial respiration, which may bear clinical significance later in life.
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Details
- Title
- The effect of macronutrient-induced ketosis on prefrontal cortex neural activity and cognition
- Creators
- Mansour Altayyar
- Contributors
- Jennifer Nasser (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- ix, 144 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Nutrition Sciences; College of Nursing and Health Professions; Drexel University
- Other Identifier
- 991021229715704721