Following a ketogenic (high-fat, low-carb) diet may help reduce seizures and improve cognitive function in Lennox-Gastaut syndrome (LGS) patients with dysfunctional mitochondria, a small study from Korea suggests.

The researchers highlighted patients’ difficulties in sticking to the diet, due to eating problems and gastrointestinal issues. That suggests there’s a need for strategies to overcome these problems and prolong adherence.

The study, “Effective and safe diet therapies for Lennox-Gastaut syndrome with mitochondrial dysfunction,” was published in the journal Therapeutic Advances in Neurological Disorders.

Mitochondrial disease comprises a group of disorders caused by mitochondrial dysfunction, mainly affecting high energy-demand organs and tissues such as the brain, heart, and muscles.

Many patients have seizures, and previous studies have shown that LGS “accounts for a high proportion of epilepsies in mitochondrial diseases, and its prognosis is poor,” the researchers wrote.

The ketogenic diet is a high-fat, low-carbohydrate, limited-protein diet developed by physicians in the 1920s to treat epilepsy. While the exact mechanisms by which the diet helps reduce seizures remain poorly understood, several studies have supported its use as an add-on therapy to conventional anti-seizure medication in epileptic patients, including those with LGS.

Despite previous data showing that a ketogenic diet can reduce seizure rate and improve cognitive function in patients with either LGS or mitochondrial diseases, studies on its therapeutic effects in LGS patients with mitochondrial diseases remain scarce.

Researchers in Korea set out to evaluate the safety and effectiveness of a ketogenic diet in LGS patients with mitochondrial disease.

The retrospective study included 20 children (10 boys and 10 girls) with LGS and mitochondrial dysfunction, who were prescribed ketogenic diets between 2004 and 2014 at the Severance Hospital in Seoul.

The children experienced their first clinical manifestations at a median of 13 months, with seizures being the first symptoms in 80% of them. They were diagnosed with LGS at a median of 37 months (about 3 years) and with mitochondrial disease at 49 months (about 4 years).

Ketogenic diet therapy was initiated at a median of 4.6 years, when most of the children (80%) were having daily seizures, despite standard anti-seizure medication. A diet with a fat-to-nonfat ratio of 4:1 was prescribed to 16 children (80%). Due to tolerability concerns, a diet with a fat-to-nonfat ratio of 3:1 was prescribed to two children, and an even less strict diet, the modified Atkins diet (MAD), to two others.

The diet’s effectiveness was assessed through changes in patients’ seizure frequency, brain electric activity, and cognitive function before and after the diet. Side effects and rate of treatment adherence were used to evaluate the diet’s tolerability.

Results showed that the children followed the diet for a median of 13.5 months (range one to 24 months), with nine of them (45%) still on the diet after one year, and eight of them (40%) after two years.

One year after beginning the diet, 40%–50% of children showed therapeutic benefits in seizure frequency, brain electric activity, and cognitive function. The researchers noted that these rates were not inferior to those reported in previous studies of people with medication-resistant epilepsy.

One boy and one girl became seizure-free, and two boys achieved a 75% decline in seizure frequency nine months to two years after initiating the diet.

At one year, two boys and one girl showed a 50% drop in seizure frequency, which remained stable for one of the boys and lowered even further (90%) for the girl at two years; the other boy was no longer following the diet at the last follow-up. One girl had a 25% decline in seizure frequency after one year and a 50% drop after two years.

Nine children showed improvements in their brains’ electric activity at the end of the diet, and cognitive function was improved in all children after one year of diet and in 87.5% of them after two years.

Among the 16 children on the 4:1 ketogenic diet, four (25%) switched to the 3:1 ratio due to tolerability issues. Side effects were observed in 14 children, and poor tolerability to the diet was mainly caused by poor oral intake and gastrointestinal problems (vomiting and diarrhea).

“Although DTs [ketogenic diet therapies] may be efficacious, efforts to improve DT tolerability are critical, as poorly tolerated DTs cannot be sustained,” the researchers wrote.

While the findings suggest that a ketogenic diet is effective and feasible for LGS patients with mitochondrial disease, larger studies “that provide more conclusive evidence should be performed to optimize individualized treatment of this disease,” they wrote.