Our review update included data from four new randomised studies of the ketogenic diet. Although none were blinded, some were of good quality. These studies suggest that in children, the ketogenic diet results in short to medium term benefits in seizure control, the effects of which are comparable to modern antiepileptic drugs. However, one study of long term outcome reports a high attrition rate for the diet. This would suggest that many children find the diet difficult to tolerate. The main reasons for drop-outs in the included studies included gastrointestinal side effects and dislike for the diet.
We found just three studies on the use of the diet in adults and none of these were randomised. There has been less research involving other diets. We found one randomised study of reasonable quality of the Atkins diet. This study showed similar benefits in seizure control with a less restrictive diet.
For those with medically intractable epilepsy or those in whom surgery is unsuitable, a ketogenic diet could improve seizure control, but tolerability is poor. One observational study suggested that the Atkins diet may have a similar effect on seizure control, but this requires more investigation.
The ketogenic diet: a review of the experience at Connecticut Children's Medical Center.
We undertook a retrospective analysis of epilepsy patients referred and treated for more than 6 months with the ketogenic diet during 1994-1999 at Connecticut Children's Medical Center. Outcome measures included antiepileptic drug number, seizure frequency, electroencephalogram background/paroxysmal activity, and adverse effects at 6 months and 1 year on the ketogenic diet. The final cohort included 24 of 48 referred patients (mean age, 6.5 years; range = 1-15 years of age). The etiology of epilepsy was equally divided between idiopathic and cryptogenic epilepsy and symptomatic epilepsy. Intention to treat analysis revealed that 35% (17 of 48) achieved more than 50% reduction in seizure frequency, and 8.5% (four of 48) were seizure-free by 6 months. A sustained 50% or greater reduction at 1 year was observed in 23% (11 of 48), and the same 8.5% (four of 48) remained seizure-free. None of these improvements were statistically related to age (P = 0.97), sex (P = 0.78), or epilepsy etiology (P = 0.80). The number of antiepileptic drugs used per patient decreased. Electroencephalogram at 1 year demonstrated an improvement in background in 31% (five of 16 patients) and a reduction in paroxysmal features in 37.5% (6 of 16 patients). Most adverse effects were mild, self-limited, and occurred early. Hyperuricemia (more than 6 mg/dL) was more persistent in three patients.