Low-Carb, High-Fat Diets Effective for Adult Epilepsy

Pauline Anderson

December 16, 2014

SEATTLE, Washington — Cutting down on daily consumption of carbohydrates and boosting fat intake can result in a seizure control rate matching that of antiepileptic drugs in some difficult-to-treat adults with epilepsy, emerging research suggests.

More than 40% of patients who are following diets with varying ratios of fat to carbs and protein — including the low-glycemic-index diet (LGID) and the modified Atkins diet (MAD) — had their seizures reduced by at least half, new studies found.

Researchers reported on results of these studies here at the American Epilepsy Society (AES) 68th Annual Meeting.

The LGID refers to a nutrition plan that assigns a number to carbohydrate-containing foods according to how much these foods increase blood sugar. The MAD is a version of the low-carbohydrate weight-loss diet promoted by Robert Atkins, the premise of which is that it forces the body to stop metabolizing glucose as energy and to convert fat into energy. The modified version is not aimed at weight loss but rather at seizure control.

The main difference between these diets is the daily carbohydrate target: 10 to 20 g for the LGID, depending in part on whether the patient is a child or adult, and 40 to 60 g for the MAD.

Another diet — the ketogenic diet — was until recently tested mostly in children and is now gaining interest for use in adults. It's a very-high-fat diet, typically with a 4-to-1 ratio of fat to protein and carbohydrates.

It's unclear exactly how exactly these diets work to decrease seizure activity, although there are many theories, including ones that point to neurotransmitters as the likely mechanism. In any case, it appears that the brain needs energy from glucose to create a seizure.

In one study, researchers at the epilepsy center at Rush University Medical Center in Chicago, Illinois, reviewed medical records of 34 adult patients with intractable epilepsy, mostly women, with a mean age of 38 years. Of these, 79% followed the MAD and 21% followed the LGID.

Overall, 44% of the patients reported at least a 50% improvement in seizure frequency. Of these responders, 80% were on the MAD and 20% on the LGID.

"This is very similar [to], if not better than, the efficacy of antiepilepsy drugs," commented Antoaneta Balabanov, MD, from Rush University.

Quality of life was improved in 79% of the patients overall. This included not only 93% of responders but, importantly, 68% of the nonresponders, said Dr Balabanov.

Improved qualify of life can be as important as seizure control, or even more so, she said. "Going from having 5 seizures every 6 months down to 3 seizures is not going to let you drive, and it's not going to let you do lot of things you like to do, but if your mood improves, if you're thinking more clearly, if your memory problems improve — and these are all those things are very common in epilepsy patients — these quality-of-life issues will make even more of a difference in your life than the seizure control itself."

Feel Better

Dr Balabanov reported that when patients come in for follow-up they often comment that even though they still have seizures they "feel so much better on this diet."

Adverse effects in the study included a 5% weight loss in 56% of all patients, constipation in 18%, and a total cholesterol level of more than 200 mg/dL in 35%.

The diets are "very well tolerated," commented Dr Balabanov. "That's a big selling point for us because not only does the diet help control seizures and make you feel better but you don't have the side effects of antiepileptic drugs," which can include weight gain and drowsiness.

The choice of diet is based on many factors, including seizure type and intractability, but also on individual choices and preferences. Dr Balabanov stressed that adherence is important in these patients.

People following these diets are encouraged to get their carbs from high-fiber foods, which could also be high-fat foods (such has nuts and seeds), although foods high in saturated fats aren't restricted, according to Kelly Roehl, RD, a dietitian involved in the study. "In fact, we encourage patients to eat lots of butter and coconut oil, both of which are completely saturated fat for the most part."

Clinicians should educate all epileptic patients — not just those in whom prior drug therapy has failed — about the possible benefits of these diets, said Dr Balabanov. "We proved that the diet works for medically intractable patients, but it is our strong belief that the dietary treatment should be discussed with every patient who walks into the epilepsy clinic."

Patients following the diet may be able to reduce the number of medications they take and thus improve their quality of life, she said.

The second study was carried out by Mackenzie Cervenka, MD, assistant professor, neurology, and other researchers at the Adult Epilepsy Diet Center at Johns Hopkins Hospital, Baltimore, Maryland. They followed 100 refractory patients, defined as those who had tried two or more drugs, continued to have seizures, and were naive to diet therapy for up to 4 years.

The study found that at 1 month, 55% of the study group responded to the MAD (greater than 50% seizure reduction), with that rate dipping to about 40% at 3 months, Dr Cervenka reported.

At 3 years, the seizure freedom rate was 8%, "which is comparable to a third or fourth antiseizure medication," noted Dr Cervenka. She added that these patients had been on an average of 7 drugs before trying the MAD, and some had also undergone surgery.

"I would argue that these were 'super' refractory drug-resistant patients, so to have a responder rate and to achieve a seizure freedom rate that high was very encouraging," said Dr Cervenka.

By about 2 years, all the patients who were not responders had stopped the diet. "That wasn't a surprise to us," said Dr Cervenka. "Patients that didn't see a definite improvement ended up stopping the diet."

But what surprised her and her colleagues was that of the patients who stopped, one third were actually seizure-free. "We thought seizure freedom would motivate more patients to stay on the diet."

Most of those who stopped the diet found it too restrictive. There were also adverse effects, including constipation, increased seizures, weight loss, and hyperlipidemia. Weight loss occurred in about a third of the patients, and although this might be a desired effect for obese patients, it was unwanted for some of the intellectually disabled patients in the study who had a low body mass index before beginning the study. Many of these patients had strong food preferences, which also made it difficult for them to stick with the diet, said Dr Cervenka.

One question surrounding these higher-fat nutrition plans is the effect on lipid levels. A recent study suggested that although low-density lipoprotein and total cholesterol increased significantly in the first 3 months after start of the MAD, the levels improved and by 1 year and were similar to those at baseline.

Dr Cervenka cited one example of a man with Lennox-Gastaut syndrome who has been following the ketogenic diet since 1980. "We started ordering screening studies on him when he came to the center and his lipid levels were absolutely normal; he's in perfect health and is seizure free on the ketogenic diet."

Dr Balabanov and Dr Cervenka have disclosed no relevant financial relationships.

American Epilepsy Society 68th Annual Meeting. Poster 2.205 Presented Sunday, December 7, 2014; Platform session B.07 Presented Monday, December 8, 2014.

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