Ketogenic diet

  • What is the ketogenic diet?

    The ketogenic diet is a strict, medically supervised diet that may be used as a treatment option for some children with epilepsy.   It is a very high fat, very low carbohydrate and moderate protein diet that ensures the body will burn fat instead of carbohydrate for energy.  Burning fat for energy produces "ketones", and for some children having a very high level of ketones in their blood helps to reduce seizure activity.  The mechanisms which it does this by are not fully understood. 

    The ketogenic diet is not a "natural therapy".  Less is known about the beneficial and adverse effects of the ketogenic diet than other treatment options for epilepsy such as antiepileptic medications, surgery and the vagal nerve stimulator.

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    Who is the diet for?

    The ketogenic diet is most frequently used for children with poorly controlled seizures. Assessment by a paediatric neurologist, experienced in epilepsy and ketogenic diet management works the best. There is emerging evidence to support its use in young children with severe myoclonic epilepsy of infancy, myoclonic astatic epilespy, Lennox Gastaux Syndrome, infantile spasms and uncontrolled absence seizures. It is also the treatment option of choice for children with Glucose Transporter 1 Deficiency syndrome.

    In our Program, only children with severe epilepsy which has not responded to medication, and who are not suitable for surgery, are considered for the ketogenic diet.  Our Program allows for only one child per month to be admitted for the ketogenic diet, due to limited resources.

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    What is involved prior to commencing the ketogenic diet?

    Initial assessment

    All children and families require a referral from their neurologist or paediatrician to the ketogenic diet clinic for assessment of their suitability.  At this visit families will be seen by a paediatric neurologist, dietitian and epilepsy nurse specialist who are experienced in the implementation and monitoring of the ketogenic diet. If the child is felt to be suitable and the family wish to proceed they will attend a second education session.

    Education

    Families are informed about the ketogenic diet before embarking on this form of treatment. Information is given in the form of written material and formal "one on one" discussions.  Areas covered include:

    • aims of the diet,
    • how the diet works,
    • the advantages and disadvantages of the diet,
    • how the diet is calculated,
    • examples of the types of meals a child would eat on the diet,
    • duration of diet,
    • admission process and
    • ongoing management at home.

    If a joint decision by the Ketogenic Diet Team and the family is made to proceed with the diet, a hospital admission is scheduled.

    Seizures

    Frequency and type of seizures must be documented for one month prior to commencing the ketogenic diet and throughout the course of the diet. The neurologist will review medications before the diet is commenced, changing syrup medications to tablet form, due to their high sugar content.

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    What happens during the admission for the ketogenic diet?

    All children who are to commence the diet are admitted to hospital for a 4-5 day stay. Usually, the admission is from Monday to Thursday. Admission is initially to Cockatoo Ward and then families may move to Parent Accommodation.

    Nutrition

    The aim of the diet is to induce ketosis. Children will be given a ketogenic formula called Ketocal®. The child is also encouraged to drink water throughout this time.   If ketosis is being established and the ketogenic formula tolerated, food is introduced after a 48 hour period until the calculated ratio and energy level is reached. The dietitian calculates all energy requirements and grades the fat ratio up slowly.  

    Tests

    Baseline blood, urine and radiological investigations are performed on admission. Throughout the hospital admission blood sugar levels are monitored to ensure that they do not become too low. To do this, finger prick blood tests are performed every 6 hours and may be required more frequently if sugar levels do drop too low. Low blood sugars are treated with a high sugar drink.  Likewise, blood ketones levels are also monitored 6 hourly and urinary ketone levels are tested at least twice daily. Special dipsticks (Keto-stixs™) indicate ketone levels and this form of monitoring will continue at home.  The child is weighed at the beginning and end of the admission to monitor for weight losses or gains.

    Medications

    All medications continue as normal. Medications will be given in tablet or capsule form.

    Activity

    All children are encouraged to maintain normal levels of activity and are not confined to bed. Play therapists and teachers become involved with families during the admission. Seizures are monitored by parents and staff.

    Parental Involvement

    Parents are encouraged to participate in all aspects of their child's care throughout the hospital stay as this is considered part of the education process. If the child is tolerating the diet and the family feel comfortable with the diet by day 3, they move from Cockatoo Ward to the Parent Accommodation located within the hospital. Contact with the Ketogenic Diet Team is maintained through this time until discharge on day 4-5. Regular education sessions occur with the dietitian and epilepsy nurse coordinator to ensure families will be able to manage at home.

    What happens after discharge home?

    Twice daily urine ketone monitoring and regular weights need to be recorded. Based on this, fine tuning of the diet, especially for the first few weeks at home, is required. Close contact with the dietitian, epilepsy nurse and neurologist is maintained throughout this time. Appointments will be made for formal outpatient review after one, two, three and six months, but more frequently if required. Routine blood tests will continue to be taken at regular intervals.

    Trial Period

    A trial period of at least 3 months is needed to assess whether the ketogenic diet is having beneficial effects on the child's seizures. Antiepileptic medications should continue unchanged through this period, unless otherwise advised by the neurologist. If there is a significant reduction in seizures, the diet is maintained in most cases for approximately 18 months to 2 years. Medications may be reduced or withdrawn during this period. If after the 3 month trial period there is no significant improvement in the child's seizures, the diet is not tolerated, or the diet is judged too difficult to manage, a joint decision between the family and the ketogenic diet team will be made to determine whether the diet should be ceased.

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    Does it work?

    The ketogenic diet does not control seizures in all children.  In fact , only a relatively small proportion of children benefit significantly from the ketogenic diet. A recent randomised controlled trial from the United Kingdom found that 38% of children had a substantial (>50%) reduction in seizures and 9% had a >90% reduction in seizures (Neale et al). An analysis of studies describing use of the Diet from 1990 until 2005 found that approximately 15% of children became seizure free and 33% had more than 50% reduction in seizures (Kune et al).

    This roughly equates to 1 in 3 children having a significant reduction in seizures, 1 in 3 having only a slight improvement in seizures, and 1 in 3 having no improvement in seizures.

    Some centres around the world report up to 50% of their patients having a significant improvement with the diet, however, it should be noted that patient selection and reporting differ between centres.

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    What does it look like?

    Meals and snacks are produced to meet energy requirements for normal growth and development.  The meal pattern is designed to mimic the child's usual meal pattern. Meals appear small because of the high fat content. As the diet is nutritionally inadequate daily vitamin and mineral supplements are necessary.

    Below is a range of meals suitable for children of different ages.

     KD Meal Example

    Ketocal®

    Egg and cheese salad

    Puree zuchini and chicken

    Fruit selection

    Chicken stir fry

    Egg omlette

    Egg and bacon quiche

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    What is required at home?

    equipment for ketogenic dietEquipment essential for home includes:

    • electronic weigh scales which measure accurately to 1 gram
    • vitamin and mineral supplements
    • urine testing strips (ketodiastix)
    • ketogenic diet computer program (excel spreadsheet)
    • numerous plastic containers
    • freezer bags for food storage
    • small spatula
    • food labels 

    The ketogenic diet must be strictly followed at all times. Children attending play group, kindergarten, school and social occasions should have ketogenic diet meals arranged for them and all carers and teachers must be fully informed of the diet. Some families initially find planning and preparing the diet time consuming, but with practice this becomes easier and faster. Shopping practices may change, but costs are comparable to normal household budgets. The initial outlay for necessary equipment may be a cost factor.

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    What problems can arise?

    Loss of ketosis may occur in some children on the ketogenic diet due to:

    • the child is given food that is not on the diet or they are secretly eating extra food   
    • incorrect calculation or preparation of food 
    • the child is unwell 
    • incorrect nutritional content documented on food product labels

    Constipation can occur because of the small amount of food and fibre consumed.

    Weight loss or gain.

    Height slowing 

    Inappropriate food related behaviours such as refusal of certain foods, stress in house associated with change of diet.

    Compliance of children may be an issue especially in some social circumstances.

    Long term side effects are monitored for and may include:

    • Renal stones have been described in 5-8% of children.
    • Susceptibility to infections
    • Thinning of the bones
    • Routine blood tests have been reported as showing low protein, anaemia and high cholesterol, but the significance of this, especially in relation to cardio/vascular disease, is unknown.

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    Commonly asked questions?

    We recommend that any questions specific to your child or treatment be discussed directly with your Neurologist or an Epilepsy Nurse Specialist in the Neurology Department.

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    Links

    The following sites may be useful for further general information regarding the ketogenic diet.

    • The Epilepsy Foundation of Victoria. This site has other informative links, access to ordering books, often relevant articles and a good general epilepsy site.
      http://www.epinet.org.au

    • Johns Hopkins Epilepsy Centre
      www.hopkinsmedicine.org

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    References

    1. Kossoff EH, et.al.  Optimal Clinical Management of Children Receiving the Ketogenic Diet:   Recommendations of the International Ketogenic Diet Study Group.  Epilepsia, Epub 24 Sept 2008. 
    2. Freeman JM, Kossoff EH, Freeman JB, Kelly MT.  The Ketogenic Diet: A Treatment for Children and Others with Epilepsy. 4th edn.  New York: Demos Publishing, 2007. 
    3. KeeneDL. A Systematic Review of the Use of the Ketogenic Diet in Childhood Epilepsy.  Ped. Neurol. 2006; 35: 1-5.
    4. Neal EG, Chaffe HM, Schwatrz RH, Lawson M, Edwards N, Fitzsimmons G, Whitney A, Cross JH.  The Ketogenic Diet for the Treatment of Childhood Epilepsy: A Randomised Control Trial.  Lancet Neuro. 2008; 7:500-506.
    5. Freeman JM et al. The efficacy of the ketogenic diet-1998: a prospective evaluation of intervention in 150 children. Pediatrics. 102(6): 1358-63,1998 Dec. [PubMed]
    6. Hemingway C et al. The Ketogenic Diet: A 3- to 6- year follow-up of a 150 children enrolled prospectively. Pediatrics 108(4):898-905, 2001 Oct. [PubMed]
    7. Vining EP et al. A multicenter study of the efficacy of the ketogenic diet. Archives of Neurology. 55(11):1433-7, 1998 Nov. [PubMed]
    8. Kinsman SL et al. Efficacy of the Ketogenic Diet for intractable seizure disorders: review of 58 cases. Epilepsia 33(6):1132-1136, 1992 [PubMed]
    9. Sirven J et al. The ketogenic diet for intractable epilepsy in adults: preliminary results. Epilepsia. 40(12):1721-6, 1999 Dec. [PubMed
    10. Ballaban-Gil K et al. Complications of the ketogenic diet. Epilepsia. 39(7):744-8, 1998 Jul. [PubMed
    11. Lefevre F, Aronson N. Ketogenic Diet for the Treatment of Refractory Epilepsy in Children: A Systematic Review of Efficacy. Paediatrics. 2000 Apr;105(4):E46 [PubMed
    12. The Ketogenic Diet: A Treatment for children and others with epilepsy (4th Ed.) by  Freeman, Kossof, Freeman & Kelly. ISBN: 1-932603-18-2 This book can be purchased or borrowed from the Epilepsy Foundation of Victoria library.