Epilepsy, a common neurological disorder in both humans and dogs, is characterized by unpredictable recurrent seizures. The causes are diverse and complex, and many individuals, despite medication, do not achieve sufficient seizure control or experience unacceptable side effects. While humans often explore alternatives like dietary therapy or brain surgery, brain surgery is rarely an option for dogs. Although dietary approaches show potential benefits, there are no standard recommendations. This article explores the role of diet in managing canine epilepsy, drawing on case studies, research, and expert opinions.
Understanding Canine Epilepsy
Epilepsy is the most common neurologic disorder in dogs, mirroring its prevalence in humans. In both species, the etiology is diverse, complex, and often unknown. Approximately 50% of human and canine epileptic patients are diagnosed with idiopathic epilepsy (IE), with 30-40% of these cases resistant to treatment with antiepileptic drugs (AED).
What Happens During a Seizure?
Seizures occur due to abnormal electrical activity in the brain. The big, bad grand mal seizure is a generalized, convulsive seizure with widespread, excessive, abnormal electrical activity occurring in both sides of the brain. Focal seizures, as opposed to generalized seizures, happen when the abnormal electrical activity is localized to just one spot in the brain. This can look like a lot of different things. For example, “fly-biting” is a classic one, where the dog looks like they are seeing and repeatedly snapping at flies. A focal seizure might just be repeated twitching of an eyelid, lip or ear. There is not necessarily a loss of consciousness. These types of seizures usually don’t require treatment.
Causes of Seizures
Seizures can be caused by metabolic disorders like low blood sugar or low blood calcium, liver disease, liver shunts, kidney disease and others. These seizures are called reactive seizures. Some drugs can cause seizures by lowering the seizure threshold in the brain. Toxins can also cause seizures. This is part of the risk of things like dark chocolate, caffeine, the sugar substitute xylitol, anti-freeze, rat poison and liquor. Additionally, seizures can be caused by abnormalities in the brain itself. However, the most common cause of seizures is idiopathic epilepsy, which is a seizure condition of unknown origin. Idiopathic epilepsy usually starts between 6-months-old and 6-years-old. Dogs younger than 1-year-old are more likely to have a congenital defect, an intoxication or an infectious disease like canine distemper. Breed predilection toward epilepsy is another clue your veterinarian uses during diagnosis.
Drug-Resistant Epilepsy
Up to 30% of dogs with idiopathic epilepsy are classified as drug resistant; that is, they fail to achieve satisfactory seizure control after adequate trials of 2 or more tolerated and appropriately chosen and administered AEDs.
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The Role of Diet
Dietary factors can influence the disposition of AEDs in the body, thereby affecting efficacy. For example, bromide is excreted in the urine, competing with chloride for renal tubular reabsorption, such that alterations in chloride intake can affect serum bromide concentrations. A high-chloride diet leads to an increase in bromide excretion and lower serum concentration, while a low-chloride diet has the opposite effect. To avoid fluctuations in serum bromide concentrations, dogs’ daily diet, including treats, should be kept consistent.
Dietary Therapies for Canine Epilepsy
The Ketogenic Diet
The ketogenic diet, a high-fat, low-carbohydrate, and moderate-protein protocol, has been used to treat epilepsy for nearly 100 years in both children and adults. A “classic” formulation is 4:1 (fat : (protein + carbohydrate); prescribed typically to children). The ketogenic diet forces utilization of primarily ketone bodies rather than glucose for cell energy, and this metabolic therapy can be a highly effective protocol for stopping seizures, even those that are refractory to all available medications. Some children even remain seizure‐free after ceasing the dietary restrictions, and in recent decades less‐restrictive formulations that shift the macronutrient ratio and lower the glycemic index (low glycemic index therapy, LGIT) have also been shown to reduce seizures, even if the diet does not produce significant ketosis.
In humans, the ketogenic diet is an efficacious, alternative therapy for drug-resistant epilepsy. This high-fat, low-carbohydrate diet is designed to mimic the biochemical changes of fasting, which has long been recognized to influence seizure control. Its proposed anticonvulsant mechanisms include altered neuronal excitability via enhanced mitochondrial energy metabolism, changes in synaptic function, and inhibition of glutaminergic neurotransmission.
How Ketogenic Diets Work
Brain tissue consumes a large amount of energy in proportion to volume, largely to sustain the electric charge of neurons. The brain derives most of its energy from oxygen-dependent glucose metabolism, which provides a substrate for ATP. Ketones (e.g., β-hydroxybutyrate and acetoacetate) provide an important alternative brain energy source, especially in starvation where they provide up to 60% of the requirement.
Medium-Chain Triglycerides (MCTs)
The medium-chain triglyceride (MCT) diet substitutes medium-chain fatty acids for a portion of the long-chain fatty acids in the classic ketogenic diet.
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Triglycerides are comprised of three fatty acid (FA) carbon (C) chains and a “backbone” of glycerol. The attributes of fats are due to the carbon chain length and the degree of hydrogen saturation. Less hydrogens means more double C:C bonds, resulting in mono (one double bond) or polyunsaturated fats (PUFAs). Triglycerides with long-chain fatty acids (LCFA) usually have 16 to 22 carbons, medium-chain triglycerides (MCTs) have 6 to 12 carbons, and short-chain fatty acids have less than 6 carbons. The most useful medium-chain fatty acids (MCFA) appear to be octanoic acid (C8; caprylic acid) and decanoic acid (C10; capric acid). Unlike LCFA, MCFAs are oxidized in brain astrocytes and provide a glucose-sparing effect.
MCT oils are typically a mixture of saturated triglycerides, C8:0 (65-75%) and C10:0 (23-35%), with 1-4% of C6:0 and C12:0. Coconut and palm kernel oils are used for the commercial extraction of MCT. Coconut oil contains about 65% MCFA. MCT oils contain few essential fatty acids and should not be the sole dietary fat. MCTs are metabolized by the liver into ketone bodies, even without starvation. MCTs provide more ketones/calories than LCFA triglycerides. Ketones readily cross the blood-brain barrier.
MCTs and Seizure Control
A more promising diet, based on MCTs, improved seizure control in the majority of cases in two placebo-controlled studies. MCTs have a higher ketogenic yield, which can improve brain metabolism. Furthermore, valproic acid-an anti-epileptic drug (AED)-is an MCT; its metabolites and other MCTs might have a similar anti-epileptic effect. There is now robust evidence that decanoic acid has anti-seizure effects, with a ground-breaking study revealing its mechanism of action. Thus, the effect on the AMPA receptor may be the main mechanism of action for an MCT diet. Another interesting potential mechanism is decanoic acid regulating mitochondrial proliferation and, therefore, protecting against mitochondrial dysfunction, which can be seen with intense seizure activity.
Research on MCT Diets
An MCT-enriched diet was tested in a 6-month prospective, randomized, double-blinded, placebo-controlled crossover study in chronically AED-treated dogs with IE. The dogs were randomised to either the MCT or placebo diet and switched to the other diet after 3 months. The overall seizure frequency was significantly reduced by 13% on the MCT diet in comparison to placebo diet; 71% of dogs showed a reduction in seizure frequency, 48% of dogs showed a 50% or greater reduction in seizure frequency, and 14% of dogs achieved cessation of seizures. The MCT diet resulted in significant elevation of blood β-hydroxybutyrate concentrations in comparison to the placebo diet.
Homemade Diets
In some cases, homemade diets have been used to manage canine epilepsy. These diets often involve reducing or controlling carbohydrate content. Two case studies detail the effects of homemade diets prepared for dogs with uncontrolled epileptic seizures and/or toxic side effects of medication. These included a high‐fat “ketogenic” diet and a partial “whole food” diet. Both dogs experienced fewer seizures and side effects when eating these modified diets compared to when they were administered antiepileptic drugs, including complete cessation of seizures for extended periods.
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Case Study 1: Bo
Bo, a 12-year-old mixed-breed dog with refractory seizures, experienced a remarkable improvement when switched to a high-fat diet. He received a diet with a ratio of 1.07:1 (fat: (carbohydrate + protein), approximating the ratio of the typical modified Atkins diet (1:1) prescribed to adult humans. Bo initially continued on phenobarbital and was reported to be seizure-free for 33 weeks following the switch to this dietary treatment. Although his diet may have produced significant ketosis (changes in urine or blood ketones are not available), significant ketosis may not be necessary in all cases.
Case Study 2: Dante
Dante, a husky, started having regular seizures at 8 years of age. He experienced severe side effects from phenobarbital treatment. After stopping the medication and instituting a dietary change that reduced commercial food consumption, added whole food components, and eliminated any additional carbohydrates and treats, his behavior improved immediately, and his tonic-clonic seizures resolved. Within 1 month of starting the new dietary protocol, the frequent myoclonic jerks also resolved completely.
Based on calculated macronutrient composition, this diet was not high in fat, not a ketogenic ratio, and not significantly lower in carbohydrates. It was, however, a more controlled diet with a high proportion of whole food components. Components were adjusted according to availability, and the owners indicated that gravy was added occasionally. Case 2 also provides an unexpected positive control of the relationship between diet and seizures: rare seizures occurred exclusively after well‐intentioned family members fed him a carbohydrate‐laden treat with a high glycemic index, for example, pizza crust.
Practical Dietary Recommendations
High-Quality Protein: Diets should be at least 60% real meat, cooked at low temperatures and freshly prepared. High-quality protein sources such as lean meats or fish are essential for dogs with epilepsy, providing the necessary amino acids for optimal health without triggering seizures. Sources such as chicken, lean beef, or fish like salmon provide essential amino acids without unnecessary fillers.
Low-Glycemic Index Foods: Incorporating low-glycemic index foods like sweet potatoes and whole grains can help provide vitamins and minerals/ aid digestion while ensuring your dog's blood sugar levels don't spike.
Omega-3 Fatty Acids: Foods rich in omega-3s, like fatty fish (salmon, mackerel, sardines), flaxseed, and chia seeds, support brain health and have anti-inflammatory effects.
Limited Ingredient Diets: For dogs with food sensitivities, limited-ingredient diets can help minimise the risk of dietary triggers for seizures.
Avoid Harmful Chemicals and Additives: Chemicals and additives in dog food, such as artificial colours, flavours, and preservatives, can also have various negative effects on canine health. For dogs with epilepsy, it's particularly important to avoid ingredients that could act as neurological triggers.
Considerations for Diet Changes
For dogs with seizures, any diet change should be carefully considered and will likely be different for each dog based on their underlying conditions. Of special note, if your dog receives the seizure medication potassium bromide, it is very important to not make quick changes to your dog’s diet or treats as changes in the chloride levels of different foods can change how the medication works in the body. For healthy dogs, we recommend at least a week to transition to any new food. For dogs on potassium bromide, the amount of time needed for transition will depend on the severity and frequency of their seizure condition and how significant of a change in chloride content there will be between the new and old diet.
The Gut Microbiota and Epilepsy
Significant evidence points towards a relationship between gut microbiota and epilepsy, and that the KD can alter this microbiota and reduce seizure frequency. A study examined the effects of a MCT diet administered for one month on the fecal microbiota in dogs with IE and non-epileptic beagles. The diet reduced Actinobacteria in all dogs while reducing seizure frequency in epileptic ones. Different baseline microbiota patterns were found in dogs with drug-sensitive epilepsy (DSE) and dogs with drug-refractory epilepsy (DRE). The baseline microbiota pattern of dogs with DSE was similar to that of non-epileptic dogs. In them, the MCT diet decreased the relative abundance of bacteria from the Firmicutes phylum and increased that of the Bacteroidetes and Fusobacteria phylum. The opposite effect was found in dogs with DRE.
Other Important Factors
What to Do During a Seizure
If a dog is having a seizure, first, make sure you both stay safe. To keep your dog safe from injury, remove any items near them that are breakable or that may fall on them. Avoid your dog’s mouth so you don’t get bitten.
When to Seek Veterinary Help
“Status epilepticus is an ongoing seizure that doesn’t self-resolve, typically considered more than five minutes. If a dog is in status epilepticus for too long, they could die. A general rule is to start antiepileptic drugs if there is more than one seizure a month,” Most veterinary professionals think that if a dog is seizing as much as once a month, it’s interfering too much with their quality of life and yours. Starting anticonvulsant therapy will likely be recommended in this case.