What is the Low Glycemic Index Treatment (LGIT)?
The LGIT is a special high fat diet similar to the ketogenic diet that is used for difficult to treat seizures. It focuses on both the type of carbohydrate, low glycemic index, as well as the amount of carbohydrate based on portion sizes and household measurements. The glycemic index (GI) is a measure of the effect of carbohydrates on blood sugar levels. When carbohydrates are digested, they release glucose into the bloodstream. Carbohydrates that digest rapidly have a high GI. Carbohydrates that are digested slowly have a low GI. Foods are rated based on their GI values ranging from zero to 100. The LGIT includes foods that have a GI of 50 or lower. In addition to the GI, the digestion of a carbohydrate food is slowed by foods that are eaten at the same time that contain either fat or fiber. Therefore, meals are balanced with sources of fat, protein and a low glycemic index carbohydrate.
Who developed this diet?
The LGIT was developed in 2002 by Dr. Elizabeth Thiele and dietician Heidi Pfeifer at Massachusetts General Hospital in Boston, MA. They wanted to offer an option of a more liberal diet in addition to the classic ketogenic diet to their patients. The first publication of the treatment's efficacy was reported in 2005.
How effective is the diet at controlling or eliminating seizures?
In the most recent publication looking at the efficacy, safety and tolerability of those patients treated with the LGIT, after 6 months, 34% had a >90% reduction, 20% had 50-90% reduction, 20% had <50 % reduction and 26% had no change or increase in seizures. Although the LGIT is less restrictive than the ketogenic diet, about ¼ of families who have used this treatment report that it is too difficult to follow long-term.
How different is it from the other diets?
The LGIT allows for an increased intake of carbohydrates, with a typical goal of 40-60 grams per day. Food quantities are not weighed out to the gram, but are based on portion sizes. Because it is based on portion instead of exact measurement, patients are able to live a more flexible lifestyle that includes eating at restaurants. Foods that are the basis for the ketogenic diet and are high in fat, such as heavy cream and high fat meats (bacon, sausage, hot dogs and eggs) are also included in the LGIT. However, on the LGIT the percentage of calories from fat is approximately 60%, compared with up to 90% on the ketogenic diet. Initial findings indicate that it is an effective treatment for individuals with either generalized or partial onset seizures. Seizures were reduced in a majority of patients using the LGIT. Some of these individuals achieved seizure freedom, and many were able to reduce their use of anticonvulsant medications.
How is the LGIT diet designed?
A calorie level is determined by a dietician for each child based on their age, activity level and current calorie intake. The dietician devises nutrition goals that meet the required fat, protein and carbohydrate for each meal. A typical meal includes a carbohydrate source such as small amount of fruit or vegetable, and/ or low glycemic carbohydrate bread or pasta, a protein rich food such as meat, fish, poultry or cheese, and a source of fat such as heavy cream and butter or vegetable oil. Since the LGIT limits the carbohydrates that are consumed vitamin and mineral intake is decreased and therefore supplements are recommended based on individual needs to prevent a nutritional deficiency.
How do you begin the LGIT diet?
The diet is started under the guidance of a dietician and neurologist familiar with the use of dietary therapy of epilepsy. The education and initiation is done following an outpatient visit. Depending on the patient it can be gradually introduced or goals can be started on day one. Since the LGIT is not intended to place the individual into a metabolic state of ketosis, it is less likely to cause problems like low blood sugar or nausea. The LGIT is flexible as long as carbohydrate intake is restricted to target levels and the overall diet meets caloric needs.
To ensure that no untoward side effects are seen while on the treatment, follow up visits are scheduled one month after initiation and then every three months thereafter. During these visits, height and weight as well as blood tests are obtained to carefully monitor each individual. A registered dietitian with experience in treating patients with intractable epilepsy assesses individuals to make sure all nutrition requirements are met while on the treatment. Like with any anticonvulsant treatment, if seizure freedom is achieved, physicians and patients can discuss the pros and cons of weaning off of the treatment.
Some children have demonstrated positive weight reduction while on the LGIT. There has also been an increase in risk of acidosis while initiating the LGIT. Acidosis is a blood condition in which the bicarbonate concentration is below normal; symptoms include lethargy, nausea, vomiting and headache and acidosis is diagnosed with a simple blood test. This can be treated with supplementation of a bicarbonate solution without affecting treatment efficacy of the LGIT. It is recommended that all carbohydrates be consumed together with fats and protein to further reduce glycemic index. Due to the dietary changes, multivitamin and mineral supplementation as well as calcium supplementation is required while on the LGIT to reduce the risk of deficiencies.
Can the diet be used for children with feeding tubes?
The LGIT is not used for children who receive 100% of their nutrition through tube feedings. They are initiated on the ketogenic diet as the special ketogenic formulas are designed for this purpose and are optimal for individuals with feeding tubes. These formulas are based on the ratio system (4:1, 3:1) and are considered low glycemic due to their low-carbohydrate, high-fat composition.
Are there any special tests that are needed before starting the diet?
There are blood tests that may be needed to determine if the diet is safe for your child. These include metabolic tests to rule-out fatty acid disorders or a carnitine deficiency. Laboratory surveillance is recommended during LGIT similar to the ketogenic diet and are done at baseline and their follow up clinic visits at intervals of 1 month post diet initiation and then every three months.
To hear a personal experience of the use of the LGIT, copy and paste this link into your browser, then click on Rose. http://www.massgeneral.org/childhoodepilepsy/
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