Ketogenic diet in Sturge-Weber syndrome

The Ketogenic Diet  is a regime for managing epilepsy in children - a dietary alternative to anticonvulsant drugs - that has recently experienced a revival of interest.

Since the drug phenytoin appeared as a really effective anticonvulsant, some people might say that the Ketogenic Diet had fallen into disuse. The revival of interest has been largely due to an American film producer, Jim Abrahams, whose child had epilepsy and despite the efforts of eminent neurologists, no drug seemed to control the child`s seizures.

In his research Abrahams came upon the Ketogenic Diet, which no one had told him about, he introduced it to his child and was lucky enough to find an improvement. He then made a film, ...First Do No Harm, dramatising his own experiences.  However, it is important that you seek the help of a qualified dietician should you wish to try it and the following information has been supplied by Dr. R. Schwartz from the Central Middlesex Hospital in London.

The Ketogenic Diet
The Ketogenic Diet is a high fat, low protein, low carbohydrate diet designed to treat epilepsy in children. It has been used extensively throughout the world since the 1920s and has been shown to help in seizure control in many children.

The aim of the diet is to increase the daily intake of fat which may be achieved either by increasing the amount of animal fat such as cream, margarine, butter, or by taking special oils which are incorporated into the diet mixed with low fat milk. The protein (e.g. eggs, cheese, meat, fish) content of the diet is carefully controlled to ensure that the child receives adequate protein to enable normal growth. The remainder of the calories come from carbohydrates (e.g. sugar, bread, cakes, biscuits). The amounts of fat, protein and carbohydrate need to be calculated by a dietician so that the child does not receive more calories than they require each day and by carefully adhering to special formulae the child will grow normally and not become excessively fat. Also because the amount of fat is carefully controlled this will not be laid down in the blood vessels and body making a child at risk of later heart disease.

It is not clear how the diet work and it is possible that there are two separate mechanisms. When the fats are broken down they produce ketone bodies which are passed throughout the body and then are excreted in the urine. These can be tested very simply by dipping a special stick into the urine (or on to a nappy) to ensure that the child has become ketotic. It is thought that in some children these ketone bodies are actually working like antiepileptic (anti-fit) medicines. In these children the level of ketones is crucial and must be maintained to ensure good seizure control.

In other children, who take longer to respond to the diet, they appear to receive something that is deficient from their diet. Seizure control is often not obtained for about one month but then the effects are not so dependent on the ketone levels. It is impossible to predict into which group your child will fall. Not all children respond to the diet.

There are currently two main diets used in the United Kingdom. These are the Ketogenic Diet and the Modified Medium Chain Triglyceride Diet.

In the Classical Diet the child receives the majority of the fat in the form of cream, butter, oil and other naturally occurring fatty foods. The diet is calculated on meal exchanges so that each meal has the same balance of fat, protein and carbohydrate. The dietician would calculate these for you and would try and incorporate foods your child likes into the diet.

In the Modified Medium Chain Triglyceride Ketogenic Diet some of the fat comes from naturally occurring sources and some comes from medium chain triglyceride oil which is commercially available and can be prescribed by a doctor. This diet works on an exchange system which again will be explained to you in detail by your dietician.

Whilst on the diet it is necessary to take vitamin supplements and in small children mineral supplements, and the urine should be tested daily for ketones.

If your child is started on a Ketogenic Diet it is very important that it is followed very closely and the child does not receive any additional sugary foods or medicines as this reverses the effect of the diet.

In those children who respond to dietary therapy their antiepileptic medications are gradually reduced and in some cases can be discontinued. This would not occur until the child has been on the diet for at least a month.

The diets are very safe. Occasionally when they are first introduced the child complains of tummy ache or diarrhoea. As they become accustomed to the diet however this resolves. It is important that the child has an adequate fluid intake, to prevent kidney stone formation which has been reported in 3 or 4 children. It is also important that they receive the vitamin supplements. Because the calories and the amount of fat is carefully controlled and monitored there is no increased risk of heart disease. If the diet is strictly followed your child will not become fat.

Should you wish to undertake dietary therapy it is very important this is undertaken with the help of an expert dietician and the effects are carefully monitored. It is not possible to swap recipes with other families on the diet as each child's food intake is closely regulated and adapted to the individual child's needs, likes and dislikes.

The ketogenic diet can be used in any child except those who are unable to tolerate milk products. They can be adapted to all ethnic diets and if they work for your child they are associated with good seizure control and general well being.

Dr R Schwartz MBBS FRCPCH Central Middlesex Hospital