Epilepsy is one of the most common nervous system disorders and affects millions of people including children worldwide. Epilepsy is diagnosed in a person who experiences recurrent, unprovoked seizures or convulsions.
These seizures or fits occur when cells in the brain called neurons fire off electrical impulses excessively, leading to a short-term arrest of normal brain function. The majority of seizures are convulsive, with one third of these beginning as generalized seizures and the other two thirds as focal seizures, which may progress to generalized seizures at a later stage. The remainder of seizures are non-convulsive, an example being the absence seizure, where a person’s consciousness is decreased for around 10 seconds.
Epilepsy is treated and controlled successfully with the use of antiepileptic medications. In some people, however, these medications fail to control seizures. Epilepsy is considered refractory to treatment when two or three anticonvulsant drugs have failed to prevent the occurrence of seizures and this occurs in around 20% to 30% of patients. In cases where medication fails, other treatment options include epilepsy surgery, vagus nerve stimulation and the ketogenic diet.
The ketogenic diet is a special diet designed to help children with epilepsy that fails to respond adequately to routine anti-epileptic medications. A typical ketogenic diet is high in fat and low in carbohydrates, while providing an adequate amount of protein.
This diet is termed ketogenic because it mimics the effects of fasting, which causes the body to produce ketones. During starvation, the body is forced to burn fats rather than carbohydrates. An increased blood level of ketone bodies is referred to as ketosis and several studies have shown that a ketogenic diet is associated with seizure reduction in children with epilepsy that is difficult to manage. When a person follows a normal diet, carbohydrates provide glucose as an energy source that supplies the brain. When the diet is too low in carbohydrates, the liver breaks down fats to produce fatty acids and ketones, which replace this glucose as the brain’s energy source.
The ketogenic diet contains adequate amounts of protein for body growth and repair and total calories in the diet are also sufficient to maintain a healthy weight for a given age and height.
Reviewed by Sally Robertson, BSc