Newswise — A new study by researchers at The Medical College of Wisconsin and Children's Hospital of Wisconsin has shown that the highly regimented ketogenic diet, a high-fat nutritional therapy used to limit seizures, requires long-term medical management and strong parental commitment to achieve both sufficient nutrition and improved seizure control in children.
The study, by Mary L. Zupanc, M.D., professor of pediatrics and medical director of the pediatric epilepsy program, and Beth Zupec-Kania, R.D., C.D., appeared in the Nov. 4, 2008, issue of Epilepsia. Their approach to the diet includes a thorough diet history and metabolic assessment of the child, long-term seizure, nutrition, and medical monitoring, and vitamin/mineral supplementation.
"This diet cannot be tried by parents without close medical management and follow-up," cautions Dr. Zupanc. "It requires careful metabolic monitoring and precise supplementation of missing nutrients."
Their approach has been effective, as seen in an as yet unpublished study of 43 patients at Children's Hospital, between the ages of twelve months and 15 years. Of these children who started on the ketogenic diet between 2002 and 2006, half had a greater than 90 percent reduction in seizure frequency. The majority of the children who responded to the diet had either a severe form of childhood epilepsy called Lennox-Gastaut syndrome or symptomatic generalized epilepsy. Their brain activity, as measured by electro encephalograms also improved significantly, paralleling the dramatic changes in seizure control.
"Lack of compliance or of consistent medical monitoring can lead to poor growth, impaired nutrition and seizure recurrence," says Dr. Zupanc. "There has to be careful monitoring and consistent communication between the dietitian and the physician managing the diet. Metabolic screening should be performed after the first month and every three months afterward. The family should keep a detailed seizure diary. Growth and weight parameters require ongoing monitoring, as do side effects such as lethargy or nausea, which may indicate a hidden metabolic defect."
The carbohydrate-restricted ketogenic diet also requires strong parental support, according to Zupec-Kania. "Fat comprises between 80 and 90 percent of the diet's calories and is provided by foods such as whipping cream, butter and vegetable oils. The remaining calories are allocated to essential protein requirements from meat and fish, and secondarily to low-carbohydrate vegetables and fruit," she says. "The elimination of carbohydrate-rich foods such as simple sugars, bread, pasta, cereals grains and milk makes this diet difficult for many patients to follow."
While the mechanism of seizure control by the ketogenic diet is not fully understood, the diet forces the body to accumulate large amounts of compounds such as acetone and acetoacidic acid, produced by the oxidation of fatty acids. The diet also restricts the intake of micronutrients such as vitamin D, calcium and phosphorous, which may already be low in those on long-term anti-epileptic drug therapy.