December 17, 2009 (Boston, Massachusetts) - The ketogenic diet can be so effective in epilepsy that those who use it routinely say it should be considered first line. Specialists here at the American Epilepsy Society 63rd Annual Scientific Conference debated the mechanism of seizure control and discussed the diet's potential as a first-line therapy.
"Neurologists and scientists are way beyond just proving the ketogenic diet works," session coordinator Eric Kossoff, MD, from Johns Hopkins in Baltimore, Maryland, told Medscape Neurology.
"Many clinical ketogenic diet experts realize that the ketogenic diet works so well that perhaps we should be using it before epilepsy becomes so difficult to control that families become angry it wasn't tried earlier," he said.
The high-fat, low-carbohydrate diet provides just enough protein for body growth and repair and sufficient calories to maintain a healthy weight. The classic ketogenic diet contains a 4:1 ratio of fat to combined protein and carbohydrate.
This is typically achieved by excluding high-carbohydrate foods, such as starchy fruits and vegetables, bread, pasta, grains, and sugar, while increasing foods high in fat, such as cream and butter.
With so few carbohydrates, the liver converts fat into fatty acids and ketone bodies. These ketone bodies pass into the brain and replace glucose as an energy source. Elevated levels of ketone bodies in the blood lead to a process known as ketosis.
Another type of ketogenic diet, called medium-chain triglyceride (MCT) diet, uses less fat and more carbohydrates and protein. The MCT diet is thought to be even more ketogenic.
"There is an ongoing debate on whether it's the high fat content affecting seizure control vs reduced carbohydrate," Dr. Kossoff said. "Most scientists and neurologists are becoming skeptical that it's ketosis, which is what the diet was initially named after."
The mechanism of seizure control is unknown, but debating during a special interest group meeting, experts suggested that extra fat and carbohydrate restriction are probably both playing a role.Multiple Mechanisms Likely
Stephane Auvin, MD, from Hôpital Robert Debre in Paris, France, said there is a lack of evidence showing the ketosis triggered by fewer carbohydrates is having an anticonvulsant effect. He points out that a modified Atkins diet does not initiate significant ketosis and yet can also reduce seizures.
"We are in an interesting situation where we have a cure, but we still have to figure out how it works," Carl Stafstrom, MD, from the University of Wisconsin in Madison, presented at the meeting.
"We know that fasting decreases seizures and the diet mimics starvation by forcing the body to burn fats rather than carbohydrates," he said. "It probably is a mixed mechanism involving both fats and carbohydrates.We have a cure, but we still have to figure out how it works.
Speaker Elizabeth Donner, MD, from the Hospital for Sick Children in Toronto, Ontario, Canada, argued at the meeting that the ketogenic diet is effective and should be considered first line - especially in GLUT1 deficiency syndrome, pyruvate dehydrogenase deficiency, and infantile spasms.
"Antiepileptic drugs do bad things to children," Dr. Donner said, naming a long list of adverse effects - many serious and some involving cognitive impairment. "In some cases, antiepileptic drugs can even make seizures worse," she said.
Dr. Donner suggested that since the ketogenic diet works quickly, it makes sense to try it first line. She pointed to a study led by Dr. Kossoff of 118 children with a high rate of seizure reduction. The median time to first improvement was just 5 days, and 84% of children had fewer seizures. In the end, 75% of children improved in 14 days (Epilepsia. 2008;49:329-333).More Study Needed
Speaker Douglas Nordli, MD, from the Children's Memorial Hospital in Chicago, Illinois, agreed that the ketogenic diet can be used first line in patients with GLUT1 or pyruvate dehydrogenase deficiency. However, he argues that there is limited evidence confirming the benefits of the diet in other areas.
Dr. Nordli says it is not easy for dieticians and families to start a ketogenic diet emergently, and so he will continue to try 1 or 2 medications first.
"The diet is not completely innocuous," he added, noting that it can be especially dangerous for patients with underlying metabolic defects.
"We would do a disservice to the ketogenic diet to propose it first line without sufficient prospective comparative data," Dr. Nordli said. "Articles showing a probable beneficial effect are not the same as comparative superiority to existing agents."The speakers have disclosed no relevant financial relationships.
American Epilepsy Society (AES) 63rd Annual Scientific Conference: Special Interest Group Meeting on the Ketogenic Diet. December 8, 2009.