Diet and Angelman Syndrome: Exploring the Benefits of a Ketogenic Diet

Quick Overview

In this talk, Heidi Pfeifer, a Ketogenic Dietitian, discusses the use of diet therapy, specifically the ketogenic diet, in the treatment of Angelman syndrome. She explains the history and science behind the diet, as well as the different variations such as the low glycemic index treatment. Pfeifer emphasizes the importance of individualized care and monitoring, and provides recommendations for supplements and food choices. She also addresses common questions and concerns, such as the use of exogenous ketones and managing lactose intolerance. Pfeifer concludes by highlighting the potential benefits of nutrition in preventing and managing seizures in Angelman syndrome.


Welcome to the Diet and Angelman Syndrome talk at the 2021 ASF Virtual Family Conference. I am Heidi Pfeifer, the Ketogenic Dietitian at the Center for Dietary Therapy of Epilepsy at the Mass General Hospital for Children. In this talk, I will provide an overview of the history, science, and implementation of the ketogenic diet for individuals with Angelman Syndrome.

The Concept of Diet

When we think of the word “diet,” it often evokes thoughts of restrictions and deprivation. However, I view diet as a therapeutic treatment or a medical nutrition therapy. In fact, Hippocrates, the father of medicine, believed that food could be medicine and medicine could be food. This perspective aligns with the concept of using diet as a treatment for various conditions, including epilepsy.

The History of the Ketogenic Diet

The ketogenic diet has a long history dating back to ancient times. Hippocrates himself wrote about modifying the diet to treat epilepsy, believing that it could purify the body. Over the years, various physicians and researchers have explored the use of fasting and dietary modifications to manage epilepsy. In the 1920s, the ketogenic diet gained recognition as a treatment for epilepsy, and its efficacy has remained consistent over the years.

The Classic Ketogenic Diet

The classic ketogenic diet is based on a specific ratio of fat to protein and carbohydrates. Meals are carefully calculated and weighed to ensure adherence to the ratio. This diet is highly restrictive and requires close monitoring. However, it has shown significant efficacy in reducing seizures, especially in intractable cases.

The Low Glycemic Index Treatment

The low glycemic index treatment (LGIT) is a type of ketogenic diet that offers a more liberalized approach. It focuses on limiting the quantity and types of carbohydrates consumed. This diet has shown positive outcomes in individuals with Angelman Syndrome, with a significant reduction in seizures and improved EEG results.

Implementing the Low Glycemic Index Treatment

The low glycemic index treatment can be implemented as an outpatient therapy. It involves consuming 40 to 60 grams of carbohydrates per day, balancing meals and snacks, and ensuring adequate vitamin and mineral supplementation. This diet provides approximately 10% of calories from carbohydrates, 30% from protein, and 60% from fat.

Monitoring and Adjusting the Diet

Regular monitoring is essential when following a ketogenic diet. This includes tracking growth, assessing nutrient levels, and adjusting calories as needed. It is crucial to work closely with a healthcare team to ensure the diet is safe and effective. Additionally, monitoring for side effects such as constipation and elevated lipid levels is important.

Supplements and Other Considerations

Supplementation is often necessary when following a ketogenic diet. Multivitamins are essential to ensure adequate nutrient intake. Other supplements, such as calcium and probiotics, may also be recommended. It is important to choose high-quality supplements and work with a healthcare professional to determine individual needs.


The ketogenic diet, specifically the low glycemic index treatment, has shown promising results in individuals with Angelman Syndrome. It can significantly reduce seizures and improve overall health. However, it is essential to work with a healthcare team to ensure proper implementation and monitoring. By carefully following the diet and making necessary adjustments, individuals with Angelman Syndrome can experience improved seizure control and overall well-being.

This talk is based on the Diet and Angelman Syndrome talk presented by Heidi Pfeifer at the 2021 ASF Virtual Family Conference.

Talk details

  • Title: Diet and Angelman syndrome
  • Author(s): Heidi Pfeifer
  • Author(s)’ affiliation: Massachusetts General Hospital
  • Publication date: 2021-08-12
  • Collection: 2021 ASF Virtual Family Conference