Today, research on the ketogenic diet is being published at a rate never seen before and over the last 20 years, hundreds of studies have shown remarkably similar results.
Evidence in children
Research shows that just over half of children on the ketogenic diet will have 50% or more improvement in seizures at 3 months. About a third of children will have over 90% improvement in seizures and over one in ten children will become seizure free. When dietary therapy is effective in controlling seizures, anti-epileptic drugs can sometimes be reduced or even stopped entirely. Many parents also report improved development and behaviour.
The efficacy of the ketogenic diet seems to remain with time, and many children continue to have seizure control even after the ketogenic diet is stopped.
There are some specific epilepsy syndromes and situations where the ketogenic diet appears to work better:
- Glucose transporter protein I (GLUT-I deficiency)
- Pyruvate dehydrogenase (PDH) deficiency
- Myoclonic-astatic epilepsy (Doose syndrome)
- Tuberous sclerosis complex
- Rett syndrome
- Severe myoclonic epilepsy of infancy (Dravet syndrome)
- Lennox-Gastaut syndrome
- Infantile spasms (West syndrome)
Several new epilepsy conditions have recently shown benefit with the ketogenic diet, including refractory status epilepticus, FIRES (fever-induced refractory epilepsy syndrome), childhood absence epilepsy and Sturge-Weber syndrome.
Evidence in adults
Despite the promising response rates observed in children treated with the ketogenic diet, there are limited studies in adults. However, there is a growing interest worldwide to use the ketogenic diet to manage adults with drug-resistant epilepsy, which may see more studies conducted within this population.
It has been suggested that the main barrier to starting the ketogenic diet in adults is the perception that many would find it difficult to comply with the dietary restrictions and the possibility of side effects.
Efficacy rates of the ketogenic diet are slightly lower in adults, but are still considered comparable to the effectiveness rates of children. Studies show 30-40% of adults will have 50% or more improvement in seizures at 3 months, although fewer than 10% will have 90% improvement in seizure reduction or seizure freedom.
- Morandi G, et al. A bibliometric study of scientific literature on the dietary therapies for epilepsy in Scopus. Nutritional Neurosciences. 2014 Mar 17.
- Kossof EH and Wang HS. Dietary therapies for epilepsy. Biomed J. 2013; 36: 2-8.
- Freeman JM et al. The efficacy of the ketogenic diet-1998: a prospective evaluation of intervention in 150 children. Pediatrics. 1998; 102(6) :1358-63.
- Kossoff EH, Pyzik PL, McGrogan JR, et al. Impact of early versus late anticonvulsant reduction after ketogenic diet initiation. Epilepsy and Behav. 2004; 5: 499-502.
- Gilbert DL, Pyzik PL, Vining EP, et al. Medication cost reduction in children on the ketogenic diet: data from a prospective study. J Child Neurol. 1999; 14: 469-471.
- Schoeler NE and Cross JH. Ketogenic dietary therapies in adults with epilepsy: a practical guide. Pract Neurol. 2016 Feb 23.