How Do Families of Children with GLUT1 Really Use Dietary Therapies? Results of a Large Survey

In July 2013, I had the honor of speaking at the GLUT1 Deficiency Foundation annual meeting for parents and caregivers in Houston, Texas. GLUT1 Deficiency Syndrome is a condition in which children have epilepsy, movement problems, and learning issues as a result of decreased brain glucose accumulation. The ketogenic diet is the gold standard treatment for this condition.

At this conference, I was asked to speak about the use of dietary therapies for this condition, and after giving an overview of the various diets and how to use them, discussed what we knew about using diets for GLUT1 deficiency syndrome.

Parents Questioned Common Beliefs

For many years, it has been often stated that children with GLUT1 Deficiency require the ketogenic diet as a fuel, and as such, require high ratios (4:1), need regular monitoring of blood ketones, and should stay on these diets indefinitely. What surprised me was how many parents came up to the microphone to make comments and ask questions that challenged these beliefs: Many were on lower ratios (or even the modified Atkins diet (MAD)), some had discussed stopping dietary therapies with their physicians (or had even stopped already), and ketone monitoring was extremely variable. Some of this surprising information was mentioned in a past article for Keto News after this meeting.

What was very clear to me back then was that more study was needed. Seeing the dozens of families at the conference asking questions and willing to participate in studies, I realized a great opportunity was possible at the next conference, slated to be held in Orlando in July 2015. Along with Mary Washington University undergraduate student Hannah Kass, we obtained approval to survey parents and caregivers at this conference. A 2-page survey was distributed and nearly all of the families present completed it. Ms. Glenna Steele and the Glut1 Deficiency Foundation supported this project and also emailed it to families who could not be in Orlando but wanted to help.

How did we do?

In all, 92 families filled out the survey (about half at the conference and half by email afterwards), which makes this the largest group of people on dietary therapy reported so far. Of the respondents, 90 families had tried a diet at some point, and the ages were varied (from 1 to 24 years old).

Important (and Surprising!) Points

1. Diets used were very variable! The classic ketogenic diet was being used by 59, with the MAD used by 29, MCT (medium chain triglyceride) ketogenic diet by 4, and the LGIT (low glycemic index treatment) by 2. Which ratio used was also variable 4:1 (n=16), 3.5:1 (n=2), 3:1 (n=20), 2.5:1 (n=1), 2:1 (n=13), and 1.5:1 (n=2).
2. Switching between diets was common – about 1 in 4 did this. There was no difference in outcomes between ratios or diets.
3. The diet worked REALLY well: nearly half were seizure-free (and 4 out of 5 had at least a greater than 90% reduction in seizures compared to before starting the diet). Also, 2 out of 3 were no longer taking seizure medications.
4. The kids who did best were younger: 8.2 vs. 11.6 years, suggesting that starting the diet sooner was better. We couldn’t prove that a delay from diagnosis to starting the diet was less likely to lead to seizure freedom, though. However, results strongly hint that earlier use of diets for GLUT1 is better.
5. The average duration of diet therapy was over 5 years (as long as 20 years in one person). 67% were unsure if they’d ever come off the diet, 24% never intend to stop, and 9% were planning to stop someday (or had already).

More Questions to Answer

The study clearly shows the amazing efficacy of dietary therapy for GLUT1 deficiency syndrome. It also shows that families are using various diets, switching between them, and at times stopping them too. There are many more questions that this survey raised. What is the real value of high blood ketosis? Can the diet be stopped? Are the alternative diets (e.g. modified Atkins diet) definitely equal in outcomes? What really happens to epilepsy in GLUT1 during puberty? Hopefully we’ll keep answering these questions!

Reference

Kass HR, Winesett SP, Bessone SK, Turner Z, Kossoff EH. Use of dietary therapies amongst patients with GLUT1 deficiency syndrome. Seizure 2016; in press.