Objective

Ketogenic diets reduce seizures in children with drug-resistant epilepsy. Whether adults benefit from similar treatment has not been clarified. We therefore examined the efficacy of the modified Atkins diet in adults with drug-resistant focal epilepsy.

Methods

We performed a randomized clinical trial (RCT) with patients >16 years who had at least 3 seizures per month despite having tried at least 3 antiepileptic drugs. They were randomized to either 12 weeks on the modified Atkins diet (diet group) or habitual diet (control group). Primary endpoint was a change in seizure frequency from baseline to the intervention period, comparing those on diet with controls.

Results

We assigned 37 patients to the diet group and 38 to the control group. Nine of the patients in the diet group and 4 controls were excluded. Of those who completed the dietary intervention (n = 24), median seizure change was -1.0 (interquartile range [IQR] -13.7-8.8), while in the control group (n = 32) the median change was 4.5 (IQR -4.8-33.5). The median difference between the groups was -7.0 (95% confidence interval [CI] -37.0-3.0; P = .21). In the intention-to-treat analysis, the relative risk (RR) for achieving >50% seizure reduction was 1.8 (95% CI 0.3-10.2; P = .65), while for achieving >25% seizure reduction RR was 2.43 (95% CI 0.94-6.28; P = .06). We observed no serious adverse events.

Significance

In this RCT investigating the effect of an adjunctive modified Atkins diet on seizure frequency in adults with difficult-to-treat focal epilepsy, we found a significant reduction in seizure frequency in the diet group compared to the controls, but only for moderate benefit (>25% seizure reduction) among those who completed the intervention. However, seizure response varied considerably between individuals, perhaps negatively influenced by a drop in serum concentrations of antiepileptic drugs.