December 7, 1998
Researchers at the Johns Hopkins Children's Center have long-term evidence that a 70-year-old, unconventional diet helps many epileptic children, especially those who don't respond to modern medicines.
Results of a prospective study of 150 children with difficult-to-control epilepsy are reported in the December issue of Pediatrics. Children on the ketogenic diet were followed for a year or longer. More than half of patients experienced a 50 percent or greater reduction in the number of seizures. A quarter realized a 90 percent improvement.
Multiple uncontrolled retrospective studies at many institutions during several decades reported the effectiveness of the ketogenic diet, but this study is the first to test the diet's efficacy, the authors say.
"Our study shows that despite new and improved anticonvulsant medications on the market, the ketogenic diet is still a viable option for children with difficult-to-manage epilepsy," says John M. Freeman, M.D., principle investigator of the study and professor of pediatric neurology at the Johns Hopkins Children's Center.
The ketogenic diet was originally developed at Johns Hopkins and the Mayo Clinic in the 1920s to curb seizures in epilepsy patients before the advent of modern anti-convulsant medications. It requires exact and careful measurements of all food. The high-fat and low-carbohydrate staples of the diet result in a condition called ketosis. Ketosis occurs when the body burns the fat supplied by the diet since there is a limited amount of glucose to burn. Ketones, the products left after fat is burned, build up in the blood and inhibit seizures, although exactly how is still unknown.
Epilepsy, which stems from erratic surges in the brain's electrical rhythms, affects some 2.5 million people. Almost 20 percent of children have hard-to-control seizures that interfere with their quality of life.
At the start of the Hopkins study, children had an average of 410 seizures per month and had received no relief after attempting treatment with an average of six anticonvulsant medications. At one year, 55 percent of the original patients remained on the diet, and 27 percent had a greater than 90 percent decrease in seizure frequency.
"Occasionally, children who have uncontrollable seizures go on the diet, remain seizure-free for two years, and stay that way even when they have stopped the diet, never having to take more medication," says Freeman. "Something is healed. If we knew what and how it healed, then we might know what causes epilepsy."
According to Freeman, however, the ketogenic diet should not be the first-line treatment for children with epilepsy. Seventy percent of epileptic children can gain control of their seizures with one medication. For those whose seizures don't respond to medications, the diet is a very effective alternative. Freeman cautions that the diet only should be used under very controlled circumstances with the appropriate medical and nutritional supervision. For example, patients usually are admitted to the hospital for several days to start the diet.
"The diet is an increasingly acceptable approach to management of childhood epilepsy," explains Dr. Freeman. "The key to better management of epilepsy is understanding how this diet controls or sometimes cures epilepsy. With such understanding, perhaps less difficult approaches to seizure control can be developed."
Other investigators are Eileen P.G. Vining, M.D.; Diana J. Pillas, B.A.; Paula L. Pyzik, B.A.; Jane C. Casey, R.N., L.C.S.W.; and Millicent T. Kelly, R.D., L.D.
Children who have more than 20 seizures per day and who have not previously been treated with the diet may be eligible for an NIH-funded study. For more information, contact Diana Pillas at 410-955-9100.