The Ketogenic Diet and Epilepsy

Epilepsy is one of the most common neurological disorders and is characterised by recurrent unprovoked seizures.  These seizures occur when there is a disruption of the normal brain activity that causes neurons to fire excessively and the sufferer can lose control of their muscles and senses, and even lose consciousness.  Because epilepsy can happen for a variety of reasons, there are classifications of epileptic syndromes and many of these syndromes become evident in childhood.

Epilepsy in children is usually treated with anticonvulsant drugs.  In most cases, the drugs are effective in controlling the symptoms but about 30% of patients don’t respond.  When antiepileptic medicines fail, other options include surgery, nerve stimulation and the ketogenic diet.

The ketogenic diet is a high-fat and low-carbohydrate diet that is used as a non-pharmacological therapy to treat epilepsy in children who have not responded to anticonvulsant drugs.  The diet was developed as a treatment for epilepsy in the 1920s and was widely used until the introduction of anticonvulsant drugs.  It is important that this diet is specifically prescribed by your doctor and carefully monitored by a dietician, because following this diet can be very complicated due to the constant monitoring of fats and carbohydrates according to the ketogenic ratio. This ratio of fat to carbohydrates and protein is around 4:1, but a more lenient regime of 3:1 can be used.

The ketogenic diet inhibits the intake of carbohydrates so that glucose – an important source of energy for the brain – is not readily available.  This forces the body to burn fats for fuel and the liver starts to convert fatty acids into ketone bodies to be used for energy.  The diet usually starts in the hospital with a 24 hour supervised fast to lead to a quicker onset of ketosis before a gradual introduction to the diet over several days.  There may be feelings of lethargy and tiredness during the first few days, and ongoing side effects like constipation and dehydration.

If the diet has been successful in controlling seizures after 2 years, your doctor may suggest gradually going off the diet over several months.  The epileptic child will still need to take anticonvulsant drugs, but in many situations the seizures are significantly more controllable.  In these cases, the family may choose to continue the ketogenic diet into the future.

It is still unclear as to why the ketogenic diet prevents or reduces seizures in children with certain epileptic syndromes, but it is believed that the ketones are responsible for the improved seizure control because ketones replace glucose as a source of energy for the brain.  Children that are put on the ketogenic diet continue to take seizure medication and a large portion of children see results within two weeks.  The studies show a 50% reduction in seizures and in some cases, the children become seizure-free.

There are a few criticisms about using the ketogenic diet as a treatment for epilepsy in children.  For instance, it needs to be followed precisely for maximum efficacy and one forbidden snack can bring the child’s macronutrient ratio outside of the ketogenic guidelines.  Following the diet can be particularly difficult if there are other children in the home that are on a ‘normal’ diet, or if the epileptic child has free access to the fridge or pantry.  Another problem with the diet is that it is not particularly balanced, which means that the epileptic child may be missing out on certain vitamins and minerals, particularly calcium, iron, folic acid and vitamin D.