Ketogenic diet
Up to 70% of people with epilepsy could have their seizures controlled with anti-epileptic drugs (AEDs). For some children who continue to have seizures, the ketogenic diet may help to reduce the number or severity of their seizures and can often have positive effects on behaviour. The diet is very specialised is carried out with the care, supervision and guidance of trained medical specialists.
What is the Ketogenic diet?
The ketogenic diet (KD) is a high fat, low carbohydrate, controlled protein diet that has been used since the 1920s for the treatment of epilepsy. The word ketogenic means that chemicals, called ketones, are made in the body (keto = ketone, genic = producing).
How does the diet work?
Usually the body uses glucose (a type of sugar) from carbohydrates (found in foods like sugar, bread or pasta) for its energy source. In the ketogenic diet the body’s energy source comes from using fats instead of glucose.
Ketones are made when the body uses fat for energy (this is called ‘ketosis’). For some people with epilepsy, this type of ketone-producing diet helps to prevent seizures.
Who is the diet suitable for?
The ketogenic diet may not work for every child but there are certain types of epilepsy that may respond better than others. Myoclonic astatic epilepsy, myoclonic jerks and generalised seizures tend to respond best. Although the diet can be used sucessfully with many different seizure types and epilepsy syndromes it is usually only considered when two types of suitable medication have been tried and not worked.
The diet is a medical treatment and must only be followed with the support of an experienced paediatrician (children’s doctor) and dietitian (food specialist). It can be adapted to all ethnic diets and is suitable for children who are allergic to dairy products (although this can limit the food choice). The dietitian will calculate the diet and try to include foods your child likes. If your child has feeding problems, is a fussy eater or has a medical condition where a high fat diet would cause problems, the diet may not be suitable.
What age range is the diet suitable for?
Usually the diet is suitable for children from 12 months old. However it can be used for younger babies in some specialist centres that offer more detailed monitoring.
What sort of food is eaten on the diet?
There are two types of the diet – the Classical diet and the Medium Chain Triglyceride (MCT) diet. The types of foods eaten are slightly different, but trials show that both diets are equally effective.
Classical diet
In this diet most of the fat eaten comes from cream, butter, oil and other naturally fatty foods. It includes very little carbohydrate and minimal protein. Each meal has the same balance of carbohydrate, protein and fat.
Medium Chain Triglyceride (MCT) diet
This diet allows for more carbohydrates and protein and so offers more variety. It includes some fat that occurs naturally in food, as well as some from a supplement of MCT oil or emulsion. This can be mixed into food or milk and is only available on prescription.
Research is also being carried out into the effects of two other diets for children and adults with difficult to control epilepsy: a different kind of atkins diet, known as the modified atkins diet (MAD) and a version of the low glycaemic index diet known as low glycaemic index treatment (LGIT). So far both these diets have shown some success in controlling seizures. Further information is available from Matthew's Friends.
Is this a healthy way for my child to eat?
To make sure the diet is nutritionally balanced, an experienced paediatric dietitian works out exactly how much of which foods your child can eat each day. The diet can be difficult to get used to and follow. To help with this, parents have individual recipes for their child, are given support on how to plan meals and are guided on which foods should be avoided. As the diet can be quite restrictive, the dietician will recommend any vitamin and mineral supplements that are needed.
How is my child’s health monitored?
Regular follow-ups with the dietician and paediatrician will monitor your child’s growth (height and weight), health, their epilepsy and if there is a need for any change in their anti-epileptic medication. If the diet is followed carefully, children do not usually become overweight.
You may be given a diary to record the number and type of seizures your child has while on the diet. As food can affect how we feel or act, you may be asked to note any changes in your child’s mood, alertness and overall behaviour. It usually takes at least three months to see whether the diet is effective. The length of time a child may be on the diet may vary, but if a child remains seizure free, it is usually stopped slowly after two years.
How is the diet monitored?
To check that the fat eaten is being used for energy, ketone levels are checked using urine or blood tests. The urine test uses a urine analysis stick, which is dipped into a container of your child’s urine. The blood test involves a small pin prick on the finger (similar to monitoring diabetes). You can decide with your child’s doctor which method to use.
Are there any side effects of the diet?
Constipation is common partly due to fat taking longer to breakdown than carbohydrates. Hunger, vomiting and lack of energy are also common, but side effects may decrease with time and can sometimes be avoided with careful monitoring.
Does the Ketogenic Diet work?
A clinical trial at Great Ormond Street Hospital in 2008 showed that the diet significantly reduced the number of seizures in some children whose seizures do not respond well to AEDs. After three months 40% of children who started the diet had the number of their seizures reduced by over half, and were able to reduce their medication. Although not all children had better seizure control, some had other benefits such as increased alertness, awareness and responsiveness.
How can my child start the diet?
There are a very limited number of centres in the UK that offer these dietary treatments. If you would like to look into the possibility of your child starting the diet you can discuss this with your GP or your child’s paediatrician.
Further information
Great Ormond Street Hospital (GOSH)
Type ‘ketogenic diet’ into the website search box.
Matthew’s Friends
Information and support for parents of children who are on or considering the diet for their child.
The Daisy Garland
Help and support for parents and families around the ketogenic diet, including a booklet about the diet.
Epilepsy Society is grateful to Liz Neal, registered dietitian at Matthew's Friends and the Institute of Child Health, for her guidance on this information.
© Epilepsy Society
Information produced in May 2011
