The low-carb, high-fat keto diet is well known for its effects on energy and weight loss — thanks to ketones, the byproducts of fat breakdown. But do ketones have any impact on your brain? Research indicates that ketones may be able to improve your brain health by boosting mental clarity (*).
Ketones as an alternative fuel source provide neuroprotective benefits, helping to prevent diseases like Alzheimer’s and Parkinson’s, as well serving as optimal fuel for energy metabolism.
In fact, the effects of a high-fat diet on insulin and blood glucose alone may provide the ideal environment for brain health.
It’s time to question some long-held beliefs about what your brain and central nervous system needs for optimal function.
Read on to find out what happens when you switch from a high-carbohydrate Standard American Diet (SAD) to a ketogenic diet thriving on ketones.
So before we explore the effects ketones have on your brain, let’s get to know more about them first.
The typically SAD diet provides between 200–300 grams of carbohydrates every day. Your body breaks down the carbs you eat into glucose, which your cells use as their main source of fuel.
Whatever glucose doesn’t get used is then stored in your liver and muscle tissue as fat, which can lead to weight gain.
When you transition to a ketogenic diet, you’ll take away this sugary fuel source so your body will run on ketones instead.
So what are ketones and how does your brain use them?
Ketones — acetoacetate (AcAc), β-hydroxybutyrate (BHB), and acetone (Ace) — are made by your liver when your body goes into the metabolic state known as ketosis, which happens when you limit your daily carb intake to less than 30-50 grams per day (*).
As your body runs low on glucose, your insulin levels decrease, then your liver starts producing ketones by burning through its fat stores.
Your body can then use ketones instead of glucose to supply your cells with the energy they need to carry out their functions.
Ketone production is a normal physiologic process. In fact, your body produces a small amount of ketones constantly, and this increases during fasted states, such as during a full night’s sleep or when you’re hiking long distances without food (*).
Whether or not you’re on a keto diet, these ketone bodies make sure your brain and muscles function properly.
While the standard American diet (SAD) provides plenty of glucose for your brain, emerging research suggests that ketones may be a better, more efficient fuel source for your brain.
Ketones are more energy-efficient.
Ketone bodies improve the way your body produces energy, which results in feeling like you have more of it.
In a 2016 FASEB Journal article, scientists noted that rats on a keto diet had better scores on both physical and cognitive tests than those on carb-heavy, low ketone-body diets (*).
Ketones don’t have to be converted before being used.
Your brain has a protective feature known as the blood brain barrier that prevents certain materials in your blood from reaching your brain. One of these happens to be glucose (*).
Since your brain can’t absorb glucose, it has to wait around for your body to convert it into a usable form and then circulate throughout the rest of your body.
This may be one reason why you feel mentally drained after you chow down on a bunch of carbs.
Ketone bodies can be used as soon as your body starts producing them — no slumps, mental fogs, or afternoon crashes (*).
Ketones stop glucose uptake issues.
Eating too many carbs and an excess of glucose in your body has been linked with several medical conditions, including (*):
- Insulin resistance (*)
- Type 2 diabetes (*)
- Heart disease (*)
- Polycystic ovary syndrome (PCOS) (*)
Many people experience brain benefits by switching from an unhealthy high-carb diet to a keto diet.
Ketones display antioxidant qualities.
Studies show ketone bodies may have antioxidant properties to protect your brain cells from free radicals, oxidative stress and damage (*).
Ketones bring out the best in BDNF.
Brain-derived neurotrophic factor (BDNF) is a protein that supports specific neurons in your nervous system and boosts the production of new neurons and neural pathways.
Ketones have been found to nudge BDNF in positive directions for your brain when it comes to crucial areas of your learning, memory, and higher thinking.
Besides the physical and mental energy slumps you’ll experience on the carb and sugar roller coaster — if you have a hard time recalling tasks and staying focused, and feel out of it mentally, your neurotransmitters may be to blame.
Your brain has two main neurotransmitters: glutamate and GABA (*).
Glutamate helps you form new memories, learn complicated concepts, and gets your brain cells to communicate with each other.
Any time you text, talk or think, you can thank glutamate for helping. But every time it steps in, it gets really excited.
GABA should be able to control glutamate and slow its roll.
Because when glutamate makes your brain cells overly excited way too often, they stop working and eventually die.
This is what’s known as neurotoxicity, or something that’s deadly (i.e., toxic) to your brain cells.
Neurotoxicity has been linked to all sorts of brain issues: from migraines, strokes and depression to ALS, seizures and Alzheimer’s disease (*).
Having too much glutamate and not enough GABA to stop that excitement can also lead to brain fog and trouble concentrating, not to mention decreased social behavior and more anxiety.
Here’s the twist: glutamate doesn’t always have to increase out of control; it can actually turn into GABA.
Ketones allow your brain to more efficiently process that extra glutamate into GABA. If ketones increase GABA and decrease glutamate, you may have a better chance of preventing damage to your brain cells, avoiding cell death and improving your mental focus.
The biggest switch from SAD to keto is replacing your normal carb intake with fat, which means you’ll be increasing your monounsaturated and polyunsaturated fat intake.
Science shows adding more essential fatty acids to your diet in the form of omega-3, a polyunsaturated fat, is so beneficial for your brain that many people are already taking supplements for it — most commonly in the form of fish oil (*).
A majority of your brain tissue is made of fatty acids. Though they’re essential for your brain and body to perform right, you can’t produce them on your own. That means you need to absorb these fatty acids from your food.
Studies show that high dietary intake of omega-3 fatty acids may help prevent age-related cognitive decline, dementia and Alzheimer’s disease (*).
In fact, when animals eat diets lacking omega-3s, the amount of DHA present in their brains starts to dwindle and they start having trouble learning and remembering things (*).
More importantly, you must have the right balance of omega-3 to omega-6 fatty acids.
While omega-3s reduce inflammation (and less inflammation leads to greater memory and cognitive performance), too many omega-6s can actually cause or increase inflammation.
Most Americans eat 15–25 times more omega-6s than omega-3s. The biggest culprits of excess omega-6 in the SAD are low-quality vegetable oils and processed foods using them.
When you’re on a keto diet, your omega-3 to omega-6 ratios usually stay balanced and between 1:1 and 1:4. That’s because you’re avoiding processed foods and turning to healthy fats such as:
- Coconut oil
- Olive oil
- Avocado oil
- Grass-fed butter
- Animal fats
And you’ll find brain-healthy omega 3s in keto-approved foods like:
- Grass-fed animal meat
- Fatty fish (i.e., salmon, tuna, mackerel, trout, herring and sardines)
- Seeds (chia, flax and hemp)
- Nuts (walnuts, pecans and macadamia)
We’re only just starting to understand the power of ketone bodies for the longevity and the health of our brains.
Research so far has shown promise in using ketones to prevent or treat neurological conditions like Alzheimer’s disease, Parkinson’s disease, and epilepsy.
Ketones and Alzheimer’s Disease
Alzheimer’s disease (AD) is the most common cause of dementia in the US (*). The cause of Alzheimer’s disease is still unknown. However, one of the earliest signs of this disease is the brain’s inability to use glucose for fuel properly.
People with type 2 diabetes are at an increased risk for developing AD, suggesting that insulin resistance in the brain may lead to the plaques associated with Alzheimer’s disease. This has led researchers to refer to Alzheimer’s disease (AD) as type 3 diabetes (* , *).
You may be able to think about Alzheimer’s disease as a disorder of the brain ‘going hungry’ because it can’t use enough glucose to meet its energy needs. However, the brain with Alzheimer’s can easily use ketones as a fuel, which can lead to significant improvements.
Ketogenic diets can potentially reduce impaired brain energy metabolism in AD, leading to improved cognition, daily function, and quality of life.
One recent randomized trial investigated the impact of a ketogenic diet in patients with AD for 12 weeks (*).
Researchers found that compared to a usual diet, those following a keto diet showed improvements in:
- Daily functioning
- Quality of life
- Blood glucose levels
- Cholesterol levels (increase in HDL, or good cholesterol)
In a randomized, double-blind, placebo-controlled study, 152 subjects with mild to moderate Alzheimer’s were given a ketone supplement for 90 days (*).
The study aimed to determine any benefits the ketones had on cognitive performance.
At the close of the study, the patients taking the ketones showed statistically significant improvement in a cognitive test as compared to the placebo group.
Although no exact mechanism could be determined for these improvements, the availability of brain-fuel was likely a component (*).
Ketones and Parkinson’s Disease
Parkinson’s is a neurodegenerative disease caused by the death of nerve cells in the area of your brain that controls movement — the basal ganglia. These brain cells normally produce the neurotransmitter dopamine, which is responsible for movement in your body.
Symptoms of Parkinson’s often show up as tremors, stiffness, slowness of movement, and impaired balance and coordination. Depression and other emotional changes can also accompany this disease (*).
Research on the treatment of Parkinson’s with the keto diet is still in its infancy, but one human pilot trial showed promise (*).
In a group of seven volunteers, five of the patients showed significant improvement in their Parkinson’s symptoms after 28 days on a ketogenic diet.
Researchers believe the benefits may be due to the ketones ability to bypass areas of the brain that are damaged. This would allow the ketones to reach cells that need the fuel for growth and repair (*).
Additionally, one 2021 review of the research suggested that a keto diet may help improve learning and memory for patients with Parkinson’s disease (*).
Ketones and Epilepsy
Epilepsy was the first health condition that was treated with a ketogenic diet way back in the 1920s. The diet was created as a way to help treat children that didn’t respond to medication and is still being used to this day by many epileptic patients (*).
The term epilepsy refers to a range of brain disorders that can be mild to very severe, marked by seizures.
In an epileptic patient, the normal wiring of the brain activity becomes disturbed. This can lead to muscle spasms, strange sensations, convulsions, or even loss of consciousness (*).
There certainly aren’t many dietary protocols in the medical community that have lasted 100 years, but the outcome of the keto diet for epileptic children is pretty impressive.
The acute anticonvulsant effects of the diet provide around 50% decrease in seizures in the first six months for half the children that try this protocol. Even more impressive, one-third of the children on this protocol experienced a 90% decrease in seizures (*).
Memory and cognitive functioning
Ketones serve as an efficient source of fuel for your brain cells, in addition to being protective. This makes the ketogenic diet an interesting candidate for those that are struggling with memory loss.
After following a very low carbohydrate diet for 6-12 weeks, older adults at risk for Alzheimer’s disease showed improvements in memory (*).
When adults experiencing mild cognitive impairment were put on a ketogenic diet, they showed improved verbal memory performance in just six weeks. The anti-inflammatory effect of ketones may have played a role, along with the enhanced availability of energy that they provide.
Either way, the researchers reported a direct correlation between the improvement of memory and the levels of ketones (*).
Congenital hyperinsulinism (CHI) is a condition where people make too much insulin, the hormone responsible for regulating blood sugar. These high levels of insulin result in frequent episodes of low blood sugar resulting in lethargy and irritability.
Repeated episodes, however, can cause much more severe effects like seizures, vision loss, intellectual disability, coma or brain damage (*).
Since ketones don’t instigate the release of insulin, they may provide an alternative energy source for patients struggling from CHI.
In one pilot study, a patient with CHI was put on a ketogenic diet for two years. Within six months, the patient saw improvements in psychological development along with a complete resolution of epilepctic episodes (*).
Traumatic Brain Injury
Traumatic brain injury (TBI) is any injury to the head that disrupts to the normal function of your brain (*).
Nutrition is an essential component to the recovery of TBI, and hyperglycemia (too much blood sugar) may worsen the neurological outcome.
In a study on 20 patients with a severe head injury, a carbohydrate-free diet provided caloric needs for the patients to recover without inducing hyperglycemia (*).
Unlike standard tension headaches, migraines can cause severe throbbing or pulsing, making you feel nauseous and extremely sensitive to light and sound. Migraines can last for hours to days at a time.
In a 2013 study, a group of researchers decided to see if the ketogenic diet would affect symptoms of migraine headaches. The volunteers were put on either a low-carb diet (not producing significant ketones) or a ketogenic diet.
After one month, the volunteers were re-evaluated for their migraine symptoms and medication use. The keto group, and not the low-carb group, reported significant reductions in migraine attacks, with 90% feeling relief from the new diet.
Researchers theorize that one way that ketones may alleviate the symptoms of migraines is through their anti-inflammatory activity (*).
Researchers in one 2019 study suggested that the keto diet and the ketones it produces shows great promise in preventing migraine headaches (*).
Ketones are an incredibly efficient and powerful source of energy. Unlike excess glucose, which can cause a cascade of issues, ketones provide clean fuel to your brain.
- They efficiently cross the blood-brain barrier (BBB).
- They produce more usable energy for your brain than glucose.
- They’ve been shown to protect neurons (brain cells) from damage.
- They may have an antioxidant effect in the brain.
One of the common issues associated with neurological disease is an inability to use glucose properly. Ketones provide an alternative source of nutrients to not only fuel your brain but also potentially heal it.
There’s a fair amount of evidence showing that ketones provide both anti-inflammatory and antioxidant benefits to your brain. In addition, ketones may be able to bypass damaged areas of the brain and support tissues in need of repair.
That said, the ketogenic diet may be a highly effective approach for brain health.
Are ketones good for the brain?
Your body produces and uses ketones for fuel instead of glucose on the keto diet.
Research suggests that ketones may be a better, more efficient fuel source for your brain and may also provide antioxidant and anti-inflammatory properties which can enhance memory and cognition.
Ketones may also help prevent neurodegenerative diseases like Alzheimer’s and Parkinson’s.
What brain diseases does ketosis help with?
The keto diet has been recognized as an effective treatment for some people with epilepsy. New research also suggests that it can benefit those with Alzheimer’s disease, Parkinson’s disease, congenital hyperinsulinism, and migraine headaches.
Do ketones cause brain damage?
Ketones do not cause brain damage. Ketones are produced from the fat that you eat, or from your body’s stored fat. When following a keto diet, ketones are used to meet up to 70% of your brain’s energy needs.
In fact, research shows that ketones may provide neuroprotective benefits for your brain which may help people with Alzheimer’s disease, Parkinson’s disease, and other neurological conditions.
Swaminathan S et al. Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study: prospective cohort study. 2021 February 3
Gustafson D et al. Dietary fatty acids and risk of Alzheimer’s disease and related dementias: Observations from the Washington Heights-Hamilton Heights-Inwood Columbia Aging Project (WHICAP). 2020 July 27