This month on Epilepsy Explained, we focus on dietary therapies for epilepsy with Dr. Mackenzie Cervenka, Medical Director of the Johns Hopkins Adult Epilepsy Diet Center and Monitoring Unit. In “Dietary Therapies Explained”, Dr. Cervenka answers the following questions.
0:15 What is the ketogenic diet?
1:52 Why does it help some people reduce their seizures?
3:02 Are there other diets that can help people with epilepsy?
5:02 Can diet therapy replace epilepsy medications?
5:44 When should someone consider dietary therapy for epilepsy and who should be consulted?
7:22 Are there certain epilepsy syndromes or seizure types that respond well to dietary therapy?
9:44 How long does it take to determine if a diet is working to reduce seizures?
10:48 Do patients have to stay on a diet for the rest of their lives?
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Video Transcript
What is the ketogenic diet?
The ketogenic diet is a high-fat, low-carbohydrate diet. The idea behind the ketogenic diet is that if you eat lots of fat, your body will break down that fat in your liver into what are called ketone bodies. Ketone bodies can actually be absorbed from your liver into your bloodstream and then from your bloodstream into your brain and are used as a fuel source. If you lower the intake of carbohydrates, then you actually lower your glucose levels in your body and you’ll be using that fat, those ketone bodies as the primary fuel source for your brain, and that can actually lower seizures in people with epilepsy in some circumstances.
And that is what is called the ketogenic diet. Now for the management of people with epilepsy, we actually use the term ketogenic diet therapies, and the reason that we use that term ketogenic diet therapies is because with epilepsy, we are using this diet as a treatment. You may have heard about this diet used for weight loss or for other conditions, but really we are focusing on the diet as a treatment for epilepsy, and we really want to make sure that it’s being used under medical supervision.
Why does the ketogenic diet help some people reduce their seizures?
There are a lot of theories about why the ketogenic diet helps with reducing seizures. We actually really don’t know why the ketogenic diet reduces seizures. We have lots of ideas that come from basic science research in animals. Some of these theories and some of these ideas come from comparing the ketogenic diet to different anti-seizure medications. And what has been shown is that the diet can work similarly to individual anti-seizure medications, but aren’t the same as any particular anti-seizure medication. Some other things that we know the diet can do are reducing inflammation, changing mitochondrial function, and even changing the bacteria in the gut in ways that can reduce seizures. So these are just some examples of how the diet works, but really we don’t know, and we suspect that over time we’re going to find even more ways that the diet works to control seizures.
Are there other diets that can help people with epilepsy?
There are other diets that have been studied for managing seizures in people with epilepsy. One of these diets is called the low glycemic index diet, and this has been studied particularly in individuals with a very specific type of epilepsy called Angelman syndrome. And what the low glycemic index diet is, is it is a diet where you pick out certain types of foods that have what are called a low glycemic index. What that means is that that food, when you eat, it increases your glucose level very slowly. A food that has a high glycemic index will actually increase your glucose very quickly.
So an example is a food like white bread or Coca-Cola because it’s made with just pure processed sugar, it’s going to have a glycemic index of a hundred, which is the highest that it can possibly be. A food like hummus, which is digested very slowly and only increases glucose slightly, will have a much lower glycemic index. So people on this type of diet, this very special diet, will actually only pick from foods that have a low glycemic index to control their seizures, and that’s thought to be one way in which a diet can help with reducing seizures in this particular type of epilepsy.
Intermittent fasting is another dietary intervention that has been looked at in managing epilepsy in certain individuals. It has even been compared to the ketogenic diet to see if it can be more beneficial. And interestingly in animals, it seems to work for some types of epilepsy and not others and in different types than the ketogenic diet does. So this is a promising diet that may potentially be used for the management of epilepsy in the future as well.
Can diet therapy replace epilepsy medications?
It is currently not recommended to use diet therapy to replace epilepsy medications. The reason for this is diet therapy has not been studied as monotherapy or as the only therapy for the treatment of epilepsy. It has been studied in combination with other treatments such as anti-seizure medications, such as neurostimulation devices, epilepsy surgery, but not as the only therapy for epilepsy by itself. So right now, providers can’t recommend it as monotherapy.
When should someone consider dietary therapy for epilepsy and who should be consulted?
A reasonable time to consider dietary therapy would be if you’ve tried two appropriate anti-seizure medications for your type of epilepsy, and the seizures have continued. Now, if you are a candidate for epilepsy surgery, that would be the most appropriate next step because we do know that epilepsy surgery is more likely to cure the seizures than starting dietary therapy. However, not everyone is ready for epilepsy surgery when they are a candidate to start that therapy or to consider epilepsy surgery, and so dietary therapy may be appropriate at that point. So when you’re considering things like neurostimulation devices, clinical trials, additional anti-seizure medications, dietary therapy may be appropriate at that point as well. The person to discuss this with would be your neurologist, the person that is treating your epilepsy. That person may be familiar with dietary therapy and could help you with that process and how to get started. If they’re not familiar with dietary therapy, then they could refer you to a dedicated center that has a specialist who has experience with dietary therapy and most importantly, that also works with a dietician or a nutritionist who has expertise in dietary treatments.
Are there certain epilepsy syndromes or seizure types that respond well to dietary therapy?
There are certain epilepsy syndromes and seizure types where we have found that diet therapy is particularly effective. Dietary therapy is the gold standard for a rare condition called glucose transporter type one deficiency syndrome. The reason for this is that patients that have this condition cannot transport glucose across the blood brain barrier and use that as a fuel source for the brain. Their body just is not able to do that properly, and so ketogenic diets in particular can actually provide an alternate fuel source for the brain through ketone bodies, and so that is why ketogenic diet is thought to be the gold standard. Some other conditions include Rett syndrome, tuberous sclerosis, infantile spasms, Doose syndrome, Dravet syndrome, Lennox-Gastaut syndrome, juvenile myoclonic epilepsy, and that’s just to name a few among many other.
In general, patients that have generalized epilepsy may respond better than patients that have focal epilepsy. However, we have seen that individuals with focal epilepsy can respond to dietary treatments as well. With regards to individuals that should avoid dietary treatments. An important thing to note is that anyone who has a condition where eating more fat could exacerbate their medical condition, meaning if it could make it worse, they should avoid these types of dietary treatments. So there are a number of rare metabolic and genetic disorders where eating a high-fat diet could actually make those conditions worse. In addition to that, if you have porphyria, if you have acute liver failure or if you have pancreatitis, you want to avoid these types of diets. Another thing is we really do not know if these diets are safe in pregnancy or not. So if you’re considering becoming pregnant, if you’re a person with epilepsy who is considering becoming pregnant, this might not be the right idea for you.
How long does it take to determine if a diet is working to reduce seizures?
To figure out whether or not a diet is working to reduce seizures is kind of similar to figuring out whether any other treatment is helping to reduce seizures. It really depends on how often you’re having seizures. So for instance, if you’re someone who has 10 seizures the day and you start a diet therapy and you notice that the next day you might have five seizures the day after that you might have three seizures, then that could give you a hint that the diet is starting to work. However, if you’re someone who only has a seizure once every one week or two weeks, or maybe even once a month, it might take you a month or two to realize, well, hey, actually I’m having fewer seizures now. Typically, what we recommend is trying to stick to a ketogenic diet for at least three months to really make a decision about whether or not the diet is working for you.
Do patients have to stay on a diet for the rest of their lives?
Some patients may stay on a ketogenic diet therapy for the rest of their lives while others may not. It really depends on the seizure type, the epilepsy syndrome, and the cause for their seizures. In children, sometimes they can outgrow their seizures and just like their medications, they may not need to stay on a ketogenic diet or any type of dietary therapy lifelong. And typically after two years that treatment is sort of reevaluated and children are taken off of the diet. One of the reasons for that is that in children, because a ketogenic diet is not only low in carbohydrates but it’s low in protein, it can actually cause the children to have slow growth.
And so having them start to increase their protein after they’ve been on the diet for two years can help them catch up with their growth. And so if they need to be on it lifelong, that can really be an advantage. Some adults decide that they want to be on a ketogenic diet longer than two years, particularly depending on their seizure type, their epilepsy syndrome, and the cause, and also some of the non-seizure benefits such as improved cognition, memory, quality of life, weight control, and other things that they have seen. In that case, we make sure to follow any potential long-term side effects to try to prevent these or address these if they occur.
