The Ketogenic Diet in Epilepsy
Can a ketogenic diet really aid those suffering from epilepsy?
A diet that can help to prevent seizures and improve quality of life, sounds to good to be true. But, the ketogenic diet (KD) offers a lot of potential, not only for weight loss aspects but also for medical conditions such as epilepsy, cancer, chronic inflammatory disorders etc. The KD is a high fat, adequate protein and low carbohydrate diet. The hallmark of the KD is the production of ketone bodies by the liver which becomes the brain’s primary source of energy. The KD has been applied in individuals with refractory or also known as drug-resistant epilepsy since the 1920s. The diet was discovered by the observation of decreased seizure frequency during episodes of fasting. In 1921, Dr. Wilder at Mayo clinic suggested the KD for the long-term management of epilepsy. In terms of this suggestion, it was stated that the benefits of fasting could be recreated through the implementation of a KD. Additionally, the KD could be sustained for a much longer period as it compensates for the clear disadvantages associated with a prolonged period of fasting.
The use of the diet was restricted to very young children and strictly impaired individuals as it was considered a last resort therapy, due to its severe dietary restrictions, unpalatability and limited access to ketogenic diet centres. Nevertheless, currently, the KD is a well-established nonpharmacologic treatment for childhood refractory epilepsy. Today, there are established KD clinics worldwide with dietitians trained and experienced in the KD. But the question remains: when should someone be referred to such a clinic or dietitian, to initiate the KD? It is recommended to implement the KD after two trials of anti-seizure medication has failed to alleviate the frequency and/or the severity of seizures .
Initial anti-seizure drug (as standalone therapy) control seizures in approximately half of patients with newly diagnosed epilepsy . The remaining half of the patients, normally those suffering from drug-resistant/refractory/intractable epilepsy, may benefit from the KD. Systemic reviews of KD therapies in children with refractory epilepsy suggest that 33 - 56% of children achieve ≥50% seizure reduction and approximately 16% achieve seizure freedom . Keep in mind that the KD is the treatment of choice for GLUT1 deficiency syndrome and pyruvate dehydrogenase deficiency (PDHD), which are two distinct disorders of brain energy metabolism . Some KD therapies, for example, the classical KD, may be too restrictive for adults suffering from refractory epilepsy and for those refusing pharmacological treatment, and is associated with decreased compliance. However, with the development of less restrictive diets such as the Modified Atkins Diet (MAD), Medium-Chain Triglyceride (MCT) Diet, and the Low Glycaemic Index Treatment (LGIT), the diet is associated with increased compliance in adults . Therefore, the KD can be used safely in the adult and adolescent population, with a response rate similar to those seen in children .
Traditionally, the long chain triglyceride (LCT) diet was used, but recently, it has appeared that the medium chain triglyceride (MCT) diet is more effective and palatable . This is primarily as a result of the unique metabolism of MCT oils and the higher ketone yield per gram as MCT oils bypass normal absorptive pathways and as such are metabolized faster . The increased ketogenic potential results in the patients having lower dietary fat demands, thereby allowing for a greater intake of protein and carbohydrates which are associated with increased compliance .
The KD is characterized by ratios between total fats and the sum of the carbohydrates and proteins. The ratio is calculated based on the total grams of fat to the total grams of protein and carbohydrates combined. Up until recently, the 4:1 ratio or also known as the classical KD (CKD) has been the most commonly used therapeutic ratio. The modified Atkins or modified ketogenic diet (MAD/MKD) has a ratio of 2:1. These diets are less restrictive, compared to the CKD and are most likely to be used in infants, adolescents, and adults.
The LGIT relates to a ratio of approximately 1:1 compared to the CKD, with emphasis on the consumption of low glycaemic index (GI) foods (GI of <50), as well as a low glycaemic load. The LGIT is not normally recommended in those suffering from refractory epilepsy, as the diet does allow for a greater intake of carbohydrates, however, the LGIT is a healthier option for those wanting to follow a KD for weight loss. Reason being, the LGIT still allows for an intake of fruits, vegetables and high-fibre foods. Therefore, the LGIT is rarely associated with vitamin or mineral deficiencies, constipation, nausea or other side effects that may be associated with a strict CKD.
The KD and variants thereof has shown promising results in those (from infancy to adulthood) suffering from refractory epilepsy and should be recommended by medical professionals after two trials of anti-seizure medication has proven to be unsuccessful. The KD should be monitored by an experienced medical professional in order to encourage the benefits and prevent the side effects. In practice I have life changing results when the KD is applied in individuals with epilepsy. From children who can live and grow up without the challenges associated with frequent seizures and even adults who can finally get a driver’s licence because their seizures are properly controlled. The KD is considered to be both a medical therapy, requiring medical supervision, as well as a dietary option for healthy individuals.
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