Even though the brain makes up only 2 percent of a person’s body weight, it consumes 20 percent of the body’s oxygen and 25 percent of the glucose. That makes the brain one of the most intensely metabolic organs in the body. In fact, it never rests, even during deep sleep or under anesthesia.

Until recently it was believed that the only fuel the brain could use was glucose, and that when glucose levels fell significantly, brain function was impaired. But it’s now known that the brain can utilize other fuels — in particular the ketone BHB.

BHB results in more efficient production of ATP energy molecules than dietary lipids or carbohydrates, and it enters the brain without difficulty. Ketones, especially BHB, are very effective for treating uncontrolled epilepsy and several neurodegenerative diseases.

In older studies, radical dietary-induced ketosis (severe carbohydrate fasting) was used to control epilepsy. But these days, it’s understood that ketone supplements can replace more radical methods and prevent many of the complications associated with ketogenic diets.

With most neurological conditions, including aging, there is increased free radical generation and lipid peroxidation in the brain. This especially includes a process called immunoexcitotoxicity. The ability of ketones to substantially reduce free radical generation plays a major role in their ability to protect the brain.

Under conditions of long-term brain inflammation and lipid peroxidation, mitochondria in brain cells are damaged, preventing the brain from generating the energy it requires. Ketones not only reduce inflammation and lipid peroxidation, they also stimulate mitochondrial function and increase the number of mitochondria within brain cells and glia — a process called biogenesis. That makes the brain work much more efficiently.

Impairment of energy-producing enzymes within the brain cell mitochondria (especially a component called complex I) is linked to many neurodegenerative diseases, especially Alzheimer’s and Parkinson’s diseases. With Parkinson’s, abnormalities and poor functioning of complex I occur very early in the course of the disease.