Children with epilepsy who maintain a carefully regulated diet of exclusively fatty foods may drastically reduce their seizures by changing the brain’s metabolic mechanisms.
Feeding epileptic children a high fat diet that would make Michelle Obama cringe sounds like it should compound a child’s health problems. In this case, however, two wrongs – seizures and an extremely fatty diet – may make a right. The ketogenic diet, a diet composed of extremely high fat foods, such as mayonnaise, heavy cream, bacon, and eggs, has been clinically shown to reduce seizures in epileptic children who cannot be helped by the standard anticonvulsant medications. Frank Lefevre and Naomi Aronson’s meta-analysis of available studies in the journal Pediatrics shows that, while only 16 percent of children who go on the diet have their seizures eliminated entirely, 56% of patients experienced a reduction of seizures greater than 50%. However, research on this promising alternative has been limited, and further studies must be done in order to establish the ketogenic diet as a mainstream treatment for pediatric epilepsy.
The term “epilepsy” refers to a group of disorders, diagnosed in about seven out of one hundred children, which cause disturbances in electrical signaling in the brain. The brain uses signaling chemicals, called neurotransmitters, to create electrical impulses and communicate with the rest of the nervous system. The brain’s electrical impulses usually fire at roughly 80 pulses per second, producing thoughts, feelings, and memories. A seizure occurs when these signals fire at upwards of 500 pulses per second. The excess electrical activity can be attributed to an abnormality in the brain’s wiring due to an excess of excitatory neurotransmitters or an abnormally low level of inhibitory neurotransmitters. Genetic mutations and predispositions usually cause these imbalances in children. Many patients with epilepsy have an abnormally active version of a gene that increases resistance to drugs; many patients seek alternative treatments. Other mutated genes that cause epilepsy encode metabolic enzymes that break down dietary proteins and carbohydrates.
The idea of treating epilepsy with dietary alterations is not a new one. In the fifth century BC, Hippocrates reported an epileptic man whose seizures were completely cured by abstinence from food or drink. Even Jesus advised epileptic children to banish their demons through prayer and fasting. Yet abstaining from all food or drink is not exactly a viable treatment option, as it can lead to hypoglycemia, and, when the patient follows the protocol diligently for an extended period of time, death by starvation.
The ketogenic diet, a diet rich in fatty foods, may seem to be the opposite of the starvation diet recommended by the ancients, but the mechanism through which it operates is the same as starvation. When the body is being starved, it does not receive carbohydrates and sugars that break down easily. Since there is no sugar in the blood, the body begins to burn its fat reserves. The breakdown of complex fat compounds into fatty acids produces a byproduct, ketones.
The mechanism the ketogenic diet uses to reduce seizure frequency is not definitively known. Some scientists believe that the change in pH that accompanies ketosis creates a sedative effect that prevents seizures. Others suggest that a change in the fluid electrolyte balance stopped the seizures, and still others think that changes in lipid concentrations stopped the erratic brain signals that prompt a seizure. The link between ketone blood concentrations and decreased seizure frequency was demonstrated by Peter Huttenlocher in the journal Pediatric Research. However, the anticonvulsant effect of the diet does not take place until several weeks after ketosis begins, indicating that the effect is not merely due to ketones in the blood, but a change in the brain’s overall metabolic processes, perhaps when the brain shifts to utilizing the ketone bodies as an energy source. The effect also increases over time, indicating that the anticonvulsant effect is correlated with the gradual decrease of glycogen stores in the blood, and the substitution of ketones for glycogen as an energy source.
The ketogenic diet is an increasingly mainstream treatment in pediatric epilepsy, but there are still significant drawbacks and disadvantages associated with the treatment. The diet is extremely difficult to maintain. Many children crave sweets, and this diet is extremely restrictive. The patients must consume food in a 4:1 or 3:1 ratio of fats to carbohydrates and proteins combined. Even one meal that strays from the ratio can completely negate the anticonvulsant effects.
While some studies have been done assessing the diet’s efficacy, few of them had any kind of control group, and most were just anecdotal case studies. The sample size in statistical studies is almost always small, due to the limited availability of eligible patients. The ketogenic diet is not really an alternative treatment, but a supplemental one, as anticonvulsant drugs are continued while on the diet. It has never been used for patients who responded well to anticonvulsants, and has always been used as a last resort. Therefore, it has never properly been compared to anticonvulsant drugs. The diet has also been tested only on a limited scale for adults. Children seem to respond better to the treatment due to their quicker metabolisms, allowing them to produce ketones faster.
While the ketogenic diet has not been shown to cause obesity or the cognitive deficits of anticonvulsant drugs, it has been shown to produce some side effects. Hypoglycemia can develop, leading to lethargy and stupor, and patients can suffer from acidosis, nausea, vomiting, high cholesterol, and even mitochondrial dysfunction.
For the many children who do not respond to anticonvulsants, the ketogenic diet may provide much needed relief from persistent seizures. Although the diet sounds extreme, and is exceedingly strict and difficult to maintain, the research that has been done to date has found some promising results. The studies that have been done have not been sufficient to show that the diet can substitute for anticonvulsants, and the exact mechanism that the diet uses is not yet known. However, with more controlled studies and a larger number of participants, the ketogenic diet may become a mainstream treatment for epilepsy.
This article was updated on 8/19/2011.