Nearly one third of patients with epilepsy have medically refractory seizures
or drug related adverse effects. Of these, only around 33% have a surgically resectable
focus. Dietary therapy is an effective alternative for children with refractory epilepsy,
which results in upto 30-40% reduction in seizure frequency. The common modes of
dietary therapy are ketogenic diet, modified Atkin’s diet and low glycemic index
treatment. Enzymes active in metabolism of ketone bodies in the brain are expressed
maximally in childhood and hence are useful in the pediatric population. Apart from
ketonemia, secondary changes in brain energy and neurotransmitter dynamics also play
a role in its antiepileptic effect. There are specific indications and contraindications for
dietary therapy in epilepsy. The classical ketogenic diet is composed of fat to
carbohydrate and protein ratio of 4:1 (in terms of weight in grams). Modified Atkins
diet is more liberal with restriction in the composition of carbohydrate to not more than
20 grams per day. Low glycemic index treatment allows carbohydrate upto 60 grams
per day using foods with glycemic index of less than 50. Various growth related,
metabolic and systemic side effects are reported with this form of therapy. Screening
prior to initiation and periodic surveillance on therapy is very important. Failure is
labelled only if there is no response even after 12 weeks of therapy. Currently, dietary
therapy is also being tried investigationally in other neurological conditions like
migraine, brain tumour and autism.
Keywords: Dietary therapy, drug refractory epilepsy, ketogenic diet, low
glycemic index treatment, modified Atkins diet.
