Medium-chain triglyceride (MCT) ketogenic diet therapy for epilepsy

What is the medium-chain triglyceride diet?

The medium-chain triglyceride (MCT) diet is a form of ketogenic diet therapy for epilepsy, intended to help control a child’s seizures.

Ketosis happens when the body burns fat instead of carbohydrates for energy, producing ketones that the brain can use as a source of energy. Unlike the classic ketogenic diet, the MCT diet includes a supplement called MCT oil, which contains fatty acids called medium-chain triglycerides. These fatty acids are more "ketogenic" than the fatty acids usually found in butter and oil. This means that children treated with the MCT diet can eat a wider range of food, including more carbohydrates, and still be in a state of ketosis.

What are the benefits of the MCT diet?

The MCT diet has been shown to be as effective in controlling seizures as the traditional classic ketogenic diet. Although ketogenic diet therapy does not work for every child, this therapy has been shown to reduce seizures in many children. In some children, it may eliminate seizures altogether.

Compared with the classic ketogenic diet, the MCT diet allows more carbohydrates, larger portion sizes, more fruits and vegetables, less fat and a wider range of food. For these reasons, it can be useful for children with regular to large appetites. Children taking the MCT diet are also less likely to have low blood sugar, constipation, and poor growth. Their ratio of "good" high-density lipoprotein (HDL) cholesterol to "bad" low-density lipoprotein (LDL) cholesterol also tends to be better than with the classic ketogenic diet.

It takes time to build up the necessary amount of MCT oil in your child’s diet to achieve ketosis, so it may take a few months to determine whether the diet will be effective. If the MCT diet is successful in controlling seizures, there is not a maximum amount of time that this treatment can be used. It is always used under the guidance and monitoring of your child's health-care team.

Limitations and side effects of the MCT diet

• MCT oil is expensive, which is a barrier for some families.
• Few dietitians are trained to use the MCT diet, so it may not be available in your health-care setting.
• In some studies, the MCT diet has been associated with side effects such as diarrhea, vomiting, bloating and cramps. Other studies have found that these side effects can be reduced by increasing the amount of MCT oil in the diet slowly.
  
• Like with all ketogenic diet therapies, children need to take specific vitamin and mineral supplements. Your child's ketogenic diet therapy team will advise you on these.
• The MCT diet should not be used by children who take valproate, as there have been some reports that the combination causes liver failure. Ask your child's doctor to explain all possible side effects, what you should watch for and what action you should take for each one.

Points to consider before trying the MCT diet

• More foods are allowed with the MCT diet than with the classic ketogenic diet, but the MCT diet is still very restrictive. The diet controls the type of food and the quantity of food. Some children may feel isolated at school because they cannot eat "normal" food.
• The MCT diet may have additional financial costs (i.e. cost of buying additional or different food, MCT oil, supplements and equipment) that are a barrier for some families.
• The diet will not work unless it is followed carefully, and some children are unable or unwilling to follow it.
• It can be time-consuming and tedious to prepare meals and snacks. This usually becomes easier as families adapt to the new routine.
• It might not work for some children, no matter how closely they follow the diet.
• It is not safe for children with certain metabolic disorders, such as fatty acid oxidation defects.
• The diet has some potentially serious medical side effects. Children must be followed closely by a doctor during treatment with the diet.

Starting the MCT diet

Before starting the MCT diet, your child will need to be seen in a ketogenic diet clinic for a full evaluation by the ketogenic diet therapy team members. Your child will need a physical examination, with measurement of their height and weight and a number of blood and urine tests. The team will also ask for a diet history for your child, including:

• What they eat at home
• What they do and do not like to eat
• How much they eat
• Whether you see any problems feeding them the diet
• Whether your family has any cultural or religious food restrictions

The MCT diet is usually started in the hospital. Your child will be admitted to hospital for up to 4 days.

As your child begins the diet, ketones will appear in the blood and urine. These will be measured at regular intervals. Your child's glucose (blood) sugar will also be measured.

The MCT oil is gradually introduced over 2 days so your child’s body can get used to the change in food. Your child will be given "ketogenic shakes" containing milk, sugar, MCT oil and protein powder, and then move to solid foods if this goes well. Your child will also take vitamin and mineral supplements.

While in the hospital, your child will be closely monitored with urine and blood tests, and your child will be watched for any side effects such as diarrhea or vomiting, dehydration, low blood sugar or lethargy (little to no energy).

Learning to use the MCT diet

The ketogenic diet therapy team will teach you how to administer the diet. A dietitian will explain how to plan menus, what food to use, how to read nutrition labels, how to prepare the food, quantities, feeding times and side effects to watch for. They will explain where to buy MCT oil and how to use it. They will give you vitamin and mineral supplements that your child will need and explain where to buy more.

They will also help you deal with problems you may encounter while your child is on the diet, including illness, hunger, refusing food, low blood sugar and high or low ketones.

A nurse will teach you on how to measure your child's blood sugar and urinary ketones and how to keep track of their body weight, fluid intake and seizure activity.

After about 3-4 days in the hospital, once the diet is established, there are no complications, and you have been taught how to continue with the diet at home, your child will be discharged from the hospital. The team will explain what to do if you have any questions once you have left the hospital.

Using the MCT diet at home

Following the diet closely is very important to ensure your child has given it the best chance to work and to see if it can control your child's seizures. It may take several months of treatment with the diet to see if it reduces your child's seizures. However, straying from the diet, for example by having a couple of cookies, can have an almost immediate negative effect. If you find the diet too restrictive, speak to your dietitian and doctor to discuss ways to alter it to make it easier to use. Changes to the diet could mean changes to food content, quantity or scheduling.

Follow up appointments for MCT diet therapy

Children treated with the MCT diet require frequent monitoring by their ketogenic diet therapy team. They are seen by the ketogenic diet therapy team in clinic 1 month after going home and then every 3 to 6 months,

Check-ups will include measurements of weight and height, review of urine and blood tests, discussion of your child’s seizures and side effects of the diet, and a medical examination.

Between appointments, you will need to keep track of your child's seizure activity, urinary ketone levels, blood sugar levels, fluid intake and body weight. Record this information in a diary or your phone so that you can bring it with you to your child’s next clinic appointment.

Because your child is growing, the diet may need to be adjusted periodically to give them enough energy. If there are no side effects, the amount of MCT oil in your child’s diet will be gradually increased for better seizure control.

Some medications, including over-the-counter cough and cold medicines and intravenous (IV) fluids, have sugar (carbohydrates) in them. The team will explain how to avoid using any medications with carbohydrates. Tell all doctors and pharmacists involved with your child’s care that your child is treated with the MCT diet.

Discontinuing the MCT diet

If the diet has kept seizures well under control for several years, your child may be slowly taken off the MCT diet with guidance from their doctor. Alternatively, if the diet is not working or you find it too restrictive, the diet may be slowly discontinued, or your child’s ketogenic diet therapy team may suggest switching to a different diet. If the diet continues to work well for your child’s seizures and your child has no negative side effects, the diet can be continued for longer. Some children will transition to adult health care with the ketogenic diet therapy.

The MCT diet should not be stopped abruptly, as this may trigger seizures. It is usually slowly discontinued, by giving 10 per cent less MCT oil every month and gradually increasing the amount of carbohydrate. Your child may be told to avoid sweets and junk food, even after stopping the diet. Your child's ketogenic diet therapy team will work with you to discontinue the diet.