The keto diet is well known for its effects on energy and weight loss. But do ketones have any positive effect on your brain?
These alternative fuel sources may provide neuroprotective activity, as well 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. Let’s dig into the research.
There’s a lot of debate around what type of fuel your brain prefers. You’ve likely heard the statement, “your brain runs on glucose,” but there’s more to the story than that.
Your brain can’t store fuel to be used for energy later; it can only take up what’s in the bloodstream at the moment. In this way, your brain is much less of a team player when it comes to sharing fuel among the cells of your body. It’s also pretty picky about the type of fuel it’ll take in.
For instance, your liver and muscle tissue are happy to go the extra step and break down amino acids or fatty acids as fuel. Your brain, however, has no time for all that. It will only take up fuel sources that are ready to go.
And what might these fuel sources be?
Glucose or ketones.
When Does Your Brain Use Glucose Vs. Ketones?
The conventional talk would say that your brain only uses ketones in an emergency situation when glucose is low, and your needy brain is calling for fuel. This has led a lot of people to assume that the best source of fuel for your brain is glucose.
However, the truth is that ketones can provide up to 70% of your brain’s energy needs, and they do so in a more efficient manner than glucose[*].
Of course, you’re probably thinking, “what about that other 30%?”
For the areas of your brain that can’t run on ketones, glucose can still provide energy even if you’re following a low-carbohydrate diet. This happens in three ways:
- Any carbohydrates you do eat (even if very little), can be sent to the brain as fuel
- Through a process called gluconeogenesis, where the amino acids either from your diet or from stored protein are converted to glucose.
- The fatty acids that you consume contain a compound called glycerol. Unlike the rest of the fatty acid chain, glycerol can be converted directly to glucose.
The Institute of Medicine even stated that “the lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed[*].”
With this in mind, a low-carb diet can provide efficient fuel to your entire brain, with some exciting benefits that glucose can’t claim.
The terms keto diet and low-carb diet are often used interchangeably. While both diets restrict carbs, there’s one crucial aspect that differentiates the two: keto restricts carbs to the point of enhanced ketone production.
Okay, so what does this mean?
Following a low-carb diet can mean you’re consuming anywhere below the average amount of carbs that people typically consume daily. This could be as high as 200 grams of carbs a day, or as low as zero carbs a day[*].
On a ketogenic diet, your carbohydrate goal, depending on your body, is somewhere around 50 grams to 25 grams a day.
Why So Much Carb Restriction?
If there’s an abundance of glucose available in your liver, muscles, or bloodstream, your body will carry on with business as usual.
However, when glucose stores become depleted, your hungry brain will start asking for some more readily available fuel. As mentioned above, your brain doesn’t store fuel, and it’s not interested in taking the time to breakdown fuel from nutrients in your bloodstream.
This lack of glucose, plus your brains need for fuel, causes your liver to start producing an alternative type of fuel from fat — ketones.
This biological adaptation allowed our hunter-gatherer ancestors to survive the long Winters of food scarcity. During these times, you may have gone weeks to months without readily available food.
By tapping into their fat stores for energy, our ancestors were able to make it through times of famine.
The process of creating ketones from fat is called ketogenesis, and produces three different types of ketones (also known as ketone bodies):
- Acetoacetate is the first ketone formed from the breakdown of fats. Acetoacetate is then converted to either beta-hydroxybutyrate (BHB), or acetone.
- Beta-hydroxybutyrate is the primary ketone used by your cells for fuel.
- Acetone is a side product of acetoacetate that breaks down very quickly. This is usually removed from your body rather quickly in your waste or breath.
How Ketones Benefit 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.
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 were not responding to medication and is still 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 keto 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[*].
#2 Alzheimer’s Disease
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.
This progressive brain disorder slowly destroys memory and cognitive skills, and may eventually prevent the patient from completing simple daily tasks.
There are a few different brain changes that take place in Alzheimer’s patients, including plaque formation, and loss of connection between nerve cells[*].
Ketones provide an alternative fuel for glucose, which led researchers to want to study the effects that ketones may have on Alzhemer’s patients. 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[*].
#3 Parkinson’s Disease
Parkinson’s is a neurodegenerative disease that’s caused by the death of nerve cells in the area of your brain that controls movement. 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 Parkinson’s[*].
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[*].
#4 Congenital Hyperinsulinism
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[*].
#5 Memory and Cognitive Function
Ketones provide an efficient source of fuel for your brain cells and may have a protective effect as well. This makes the ketogenic diet an interesting candidate for those that are struggling with memory loss.
Memory loss can happen due to neurological disease, aging, or even just prolonged times of stress.
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[*].
The improvement in brain function that ketones impart has also been shown in several animal studies.
In a rat study, diet-induced ketosis improved the cognitive function of the rats put through a maze, as well as an object recognition test[*].
#6 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[*].
#7 Migraine Headaches
Everyone gets headaches now and then, but migraine headaches are a whole other animal.
Unlike your standard tension headaches, migraines can cause severe throbbing or pulsing, leading you to feel nauseous and extremely sensitive to light and sound. What’s worse, they can last for hours to days at a time.
It’s suggested the hormonal or neurochemical changes may be responsible, but no known cause has been nailed down[*].
In a 2013 study, a group of researchers decided to see if the ketogenic diet would affect symptoms of migraine headaches. The volunteers we 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[*].
Before trying out a new diet, it’s always best to check with your healthcare provider first. This is especially true if you already have a health condition, or are taking medication.
The ketogenic diet may cause your blood lipid profile to change a bit. Kids following a ketogenic diet for epilepsy saw changes in their total cholesterol, triglycerides, and LDL cholesterol levels[*].
While the high-fat diet and heart disease myth has been adequately debunked at this point, individual biochemistry always needs to be taken into account.
Another side effect that can come along with starting the ketogenic diet is constipation. If you already have severe constipation, you definitely want to get guidance in starting the keto diet. Typically, however, adding more fiber and making sure you’re hydrated can resolve the constipation that accompanies keto.
Keto flu is another aspect of starting the keto diet that you should be aware of.
As your body adapts to using ketones for fuel instead of glucose, there is an uncomfortable transition period, often called “keto flu.” Your body needs to get on board that ketones are now your preferred fuel source, and it can take a week or two for the process to complete.
During this transition time, you may notice symptoms like:
- Brain fog
- Lack of concentration
- Sugar cravings
- Trouble with sleep
- Low energy
Don’t let these symptoms deter you; they will pass. For more information on keto flu, check out this blog post: Keto Flu: Why It Happens and How To Get Rid of It.
Ketones are an incredibly efficient and powerful source of energy. Unlike glucose, which can cause a cascade of hormonal issues, ketones provide clean fuel to your 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 potentially heal it as well.
Although more clinical trials need to be done, there’s a fair amount of evidence 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.
From its humble beginnings in the 1920s, to the ongoing research happening today, the ketogenic diet may be the most effective diet for brain health out there.
If you’re beginning the keto diet for the first time, there are some guidelines to be aware of.
First, you need to make sure you’re consuming the appropriate macronutrient ratio for your body to get into ketosis. Even just a few extra grams of carbs a day may keep you in glucose burning-mode, and prevent ketone production.
Second, eating a variety of foods is an essential part of the keto diet. You don’t have to stick with bacon and hamburgers; there’s a wide range of keto-friendly foods you can pick from.
Third, don’t be turned off by keto flu. This is just your body reacting to the transition, but once you’re adapted you’ll feel amazing. Just make sure to drink lots of water and supplement with some electrolytes during this time.
For more tips for starting the keto diet, check out the Ultimate Guide To Ketosis.