Ketones are small molecules your liver makes from fats. They have featured in popular diets recently, but they first drew attention in the 1920s when clinicians found that some children with epilepsy recovered on the zero-sugar ketogenic diet, but nobody knew why.
"The brain ordinarily loves to work on sugar," said Joseph LaManna, Professor of Physiology and Biophysics at the Case Western Reserve School of Medicine. "But if ketones are available, the brain uses those first."
LaManna was studying how glucose, or sugar, gets into the brain from blood when he realized he actually had a clue for why the ketogenic diet worked.
"There’s this thing called a glucose transporter at the blood-brain barrier, and its job is to take glucose on one side and bring it into the brain," he said. "What we wondered was whether or not the infants having seizures had a problem getting glucose into their brain. And it later turned that they’re missing half of their transporters."
Suddenly LaManna and his colleagues had an actual, chemical explanation.
"It’s really supply and demand. Even though they don't quite have enough glucose, they have plenty if they have the ketones. And these kids, if they’re not treated they’re going to have developmental disabilities for their whole life. But if you put them on ketones, it’s like night and day.