Seizure resistance is dependent upon age and calorie restriction in rats fed a ketogenic diet

The present study was designed to evaluate the effects of age on the efficacy of the ketogenic diet in suppressing seizures evoked by tail-vein infusion of pentylenetetrazole (PTZ). Male rats of various ages were divided into three groups and fed one of three diets: (1) a calorie-restricted ketogenic diet, (2) a calorie-restricted normal (rodent chow) diet, or (3) a normal diet, ad libitum. After animals had been on experimental or control diets for more than 20 days, seizure threshold and blood levels of beta-hydroxybutyrate (beta-OHB) were determined. Animals fed a ketogenic diet exhibited significant elevations in levels of beta-OHB and seizure resistance compared to animals fed either a calorie-restricted normal diet or a normal diet, ad libitum. The levels of beta-OHB and seizure resistance were greatest for young pups. A surprising finding was that young animals fed a calorie-restricted rodent chow diet exhibited a significantly increased resistance to seizures compared to those fed the same diet, ad libitum. Results presented here demonstrate that the ketogenic diet produces the highest levels of ketonemia and seizure threshold in young animals. Collectively, these data suggest that age and caloric restriction are important considerations for implementing the ketogenic diet. (C) 1999 Elsevier Science B.V. All rights reserved.