So to get things rolling again here, let's start with a study that looked at how a change in metabolism helped the human brain evolve, and this relates to mitochondrial energy production, ketogenesis, and the like, so read on!
We know that genes and the environment both influence the metabolic processes that determine an organism's ability to survive and thrive in its environment. To illustrate the importance of metabolism for human brain evolution and health, researchers use the example of lipid energy metabolism (i.e. the use of fat [lipid] to produce energy) and the advantages that this metabolic pathway provides for the brain during environmental energy shortage.
In modern humans, lipid energy metabolism is a regulated multiple organs that link triglycerides in fat tissue to the mitochondria of many tissues, including the brain. There are three important control points, each of which are suppressed by insulin.
- Lipid reserves in fat tissue are released by lipolysis (the breakdown of fats) during fasting and stress, producing fatty acids (FAs) that circulate in the blood and are taken up by cells.
- FA oxidation. Mitochondrial entry is controlled by carnitine palmitoyl transferase 1 (CPT1). Inside the mitochondria, FAs undergo beta oxidation and energy production in the tricarboxylic acid cycle (TCA, or otherwise known as the Krebs cycle) and respiratory chain.
- In liver mitochondria, the HMG-CoA pathway produces ketone bodies for the brain and other organs. Unlike most tissues, the brain does not capture and metabolize circulating FAs for energy production. However, the brain can use ketone bodies for energy.
Another shameless plug for my book, but I did discuss things like this, so if you find this type of stuff interesting...well, what are you waiting for?! :)
Source: Metabolism as a tool for understanding human brain evolution: Lipid energy metabolism as an example