Research Uncovers Ketogenic Diet's Mechanism in Epilepsy

A study by Washington University School of Medicine researchers has identified how a ketogenic diet reduces seizures in epilepsy patients. The diet, which is high in fat and extremely low in carbohydrates, has been observed for decades to reduce seizures in some individuals with epilepsy, but its precise mechanism was previously not understood.

The research, conducted in mice, indicates that the diet causes physical changes in brain cells, affecting how they communicate with one another. This effect dampens the strength of signals between neurons, potentially explaining how the diet mitigates the overactive electrical signaling characteristic of epileptic seizures. The study was published in Cell Reports.

Dietary Impact on Brain Function

The ketogenic diet is commonly used in children with epilepsy whose seizures do not respond to standard medications. For the diet to be effective, up to 90% of a patient's daily calories must come from high-fat sources. With strict adherence, the diet has been shown to reduce seizures by approximately 50% in some patients.

This high-fat, carbohydrate-restricted regimen prompts the liver to generate chemical compounds called ketones. Neurons in the brain then metabolize these ketones as fuel, in the absence of glucose, which is typically their primary energy source. Adherence to the strict dietary regimen is crucial, as even slight deviations can eliminate its benefits.

Cellular and Synaptic Changes Identified

Researchers, including Ghazaleh Ashrafi, Gabor Egervari, and Vitaly A. Klyachko, studied mice maintained on a high-fat pellet diet. They investigated changes in genetic activity within the hippocampus, a brain region often associated with seizure origin. Their analysis revealed hundreds of alterations, many of which were linked to genes involved in the functioning of synapses, the points where brain cells transmit messages to each other.

Further measurements showed that excitatory signals—neurotransmitter chemicals prompting neighboring neurons to activate—were lowered, while inhibitory chemicals, which reduce neuronal responsiveness, increased. The overall effect was a reduction in the strength of communication within brain-cell circuits. Using high-powered microscopy, the team also observed that neurons from mice on the ketogenic diet possessed fewer vesicles containing excitatory chemical signals compared to neurons from mice on a normal diet. Vesicles are tiny packets within brain cells that release neurotransmitter signals.

Implications for Future Treatments

These findings could lead to new, less burdensome approaches for treating epilepsy. Ashrafi noted that a deeper understanding of the diet's mechanism offers new avenues for developing interventions that control seizures without requiring the extreme strictness of the diet itself.

Reproducing these specific cellular changes, potentially through medications or other therapies, could provide alternative strategies for epilepsy management.