The effect of the ketogenic diet on the developing skeleton.

The ketogenic diet (KD) is a medically supervised, high fat, low carbohydrate and restricted protein diet which has been used successfully in patients with refractory epilepsy. Only one published report has explored its effect on the skeleton. We postulated that the KD impairs skeletal health parameters in patients on the KD. Patients commenced on the KD were enrolled in a prospective, longitudinal study, with monitoring of Dual-energy X-ray absorptiometry (DXA) derived bone parameters including bone mineral content and density (BMD). Areal BMD was converted to bone mineral apparent density (BMAD) where possible. Biochemical parameters, including Vitamin D, and bone turnover markers, including osteocalcin, were assessed. Patients were stratified for level of mobility using the gross motor functional classification system (GMFCS). 29 patients were on the KD for a minimum of 6 months (range 0.5-6.5 years, mean 2.1 years). There was a trend towards a reduction in lumbar spine (LS) BMD Z score of 0.1562 (p=0.071) per year and 20 patients (68%) had a lower BMD Z score at the end of treatment. While less mobile patients had lower baseline Z scores, the rate of bone loss on the diet was greater in the more mobile patients (0.28 SD loss per year, p=0.026). Height adjustment of DXA data was possible for 13 patients, with a mean reduction in BMAD Z score of 0.19 SD. Only two patients sustained fractures. Mean urinary calcium-creatinine ratios were elevated (0.77), but only 1 patient developed renal calculi. Children on the KD exhibited differences in skeletal development that may be related to the diet. The changes were independent of height but appear to be exaggerated in patients who are ambulant. Clinicians should be aware of potential skeletal side effects and monitor bone health during KD treatment. Longer term follow up is required to determine adult/peak bone mass and fracture risk throughout life.

Efficacy of the ketogenic diet: which epilepsies respond?

We report the efficacy of the ketogenic diet in refractory epilepsies focusing on outcomes with regard to epilepsy syndromes and etiology in children and adults with refractory epilepsy. Sixty-four consecutive children and four adults were prospectively enrolled from 2002 to 2009; seven were excluded from analysis. The classical ketogenic diet was initiated on an inpatient basis with dietary ratios ranging from 2:1 to 4:1 fat to carbohydrate and protein. Patients were classified according to syndrome and etiology using the 1989 and more recent 2010 International League Against Epilepsy (ILAE) classification systems. Responders were defined as >50% reduction in seizure frequency compared to baseline. Syndromes included symptomatic generalized (52), genetic (idiopathic) generalized (7), and focal epilepsies (2) and etiologies included structural (24), genetic (18), and unknown (19). Twenty-nine (48%) of 61 patients were responders at 3 months. Two children became seizure-free: one with focal epilepsy of unknown etiology and another with refractory childhood absence epilepsy. Responsive syndromes included migrating partial epilepsy of infancy, childhood absence epilepsy, focal epilepsy, epilepsy with myoclonic-atonic seizures, and Dravet syndrome. Children with lissencephaly and hypoxic ischemic encephalopathy had surprisingly good responses. The ketogenic diet is an effective treatment for children and adults with refractory epilepsy. The response is predicted by type of epilepsy syndrome. Accurate characterization of the electroclinical syndrome is an important factor in decisions about timing of initiation of the ketogenic diet.

The ketogenic diet in refractory childhood epilepsy.

OBJECTIVE: To report the efficacy and tolerability of the ketogenic diet (KD) in refractory paediatric epilepsy. METHODS: Twenty-six consecutive children were treated with the classical KD from 1996 to 2001. The epilepsy syndromes included symptomatic generalized epilepsy (15), idiopathic generalized epilepsy (4), symptomatic partial epilepsy (1) and unclassified epilepsy (6). One child was lost to follow up. RESULTS: Median age at initiation of the KD was 6.1 years. Median duration of the treatment was 9 months. Twelve children (48%) were treated for >12 months; one still remains on the KD. Four children (16%) became seizure-free. Five children (20%) had 50-99% reduction in seizures, seven (28%) had <50% reduction in seizures and eight (36%) had no improvement. Age, seizure-type and aetiology did not predict response. The medications were decreased in 33% of the children. The KD was discontinued in 64% of the children because of poor efficacy and in 12% because of side-effects. Problems during initiation of the KD included asymptomatic hypoglycaemia (24%) and vomiting (12%). Later complications included poor growth (20%), hyperlipidaemia (16%), hypercalcuria (8%), hypocarnitaemia (8%), constipation (8%), pancreatitis (4%) and decreased bone density (4%). There were no deaths. A 3-month trial of the KD costs A3879 dollars. The first 12 months cost A7275 dollars with a cost of A4528 dollars each year, thereafter. CONCLUSIONS: The KD is an effective treatment for some children with refractory epilepsy, being generally well tolerated and rarely associated with side-effects. Response is not necessarily predicted by age, syndrome or aetiology. A prospective study of the KD is presently underway.