Could a Low-Carb Diet Reverse Aging in the Brain?

Plenty of attention has been paid to the ketogenic diet in recent years: Its supporters have touted its potential health benefits when it comes to weight loss, cardiovascular health and even brain health. A 2020 study explored this idea further when it comes to the brain, delving into whether a low-carb diet could potentially reverse, or at least slow down, aging in the brain.

The study, led by Stony Brook University professor Lilianne Mujica-Parodi, suggests that early signs of aging in the brain can be prevented by a low-carb diet, or what’s commonly referred to as the ketogenic diet — a low-carb, high-protein diet designed release ketones into the bloodstream for the body to use stored fat as its main source of energy, rather than blood sugar or glucose from carbohydrates. Once the body starts breaking down ketone molecules—a process called ketosis—it begins to run on the energy provided by fat, rather than glucose. The ketogenic diet needs to be pretty substantial with fats and proteins in order to be sustainable. It typically includes things like grass-fed meats, eggs, cheese, butter, oils and avocados, and almost entirely avoids common carbs like bread, wheat or rice.

While there is a great deal of evidence that diets full of healthy foods like vegetables and fish do reduce the risk of Alzheimer’s, studying diet and brain health is notoriously tough to get right, and in some ways, these 2020 findings contradict other research around ketogenic eating and brain health. This said, here’s what the researchers in the Stonybrook study found about the keto diet and brain health.

The effects of ketones on the brain

In the latest study, Mujica-Parodi and her team wanted to examine whether the effects of a low-carb diet could be seen in the brains of people who may be showing some early signs of aging, but who were presymptomatic.

First, the researchers found that aging in the brain, seen in the form of destabilized communication between brain regions, typically starts to set in when a person is in their late 40s, particularly around age 47. This tends to be associated with weaker cognition.

They identified brain network stability as a biomarker for aging, and found that having type 2 diabetes increased this destabilization of brain networks. They then tested how the brain’s network stability would respond to diet changes.

One group of participants was placed on a standard diet, which metabolizes glucose as its primary fuel. The second group was given a low-carb diet, meaning they were only eating things like meat or fish with salad—and no sugar, grains or starchy vegetables. In the low carb diet, the main fuel source was ketones.

The researchers found that the people who were metabolizing ketones on the low-carb diet saw increased brain activity and stabilized networks in brain regions.

“The bad news is that we see the first signs of brain aging much earlier than was previously thought,” Mujica-Parodi said in a news release.

“However, the good news is that we may be able to prevent or reverse these effects with diet,” she continued, “by exchanging glucose for ketones as fuel for neurons.”

Part of the power behind ketones, Mujica-Parodi argues, is that the brain eventually loses its ability to use glucose as fuel, something known as hypometabolism.

“Therefore, if we can increase the amount of energy available to the brain by using a different fuel, the hope is that we can restore the brain to more youthful functioning,” she said.

The medical consensus on the ketogenic diet is varied. Some experts note that it can be restrictive and possibly even dangerous for people with certain conditions, while other research has shown it may hold protective benefits when it comes to the brain and overall health.

In the Alzheimer’s research world, ketones are actually being explored for their potential as a therapeutic pathway for the disease. One recent study conducted by a researcher at the National Institute on Aging found that increasing the number of ketones in the body may help fight Alzheimer’s.

Diet, overall, has been examined in various studies to better understand how it’s linked to improved brain function and mental health. Some experts say that a healthy diet and exercise are some of the most effective interventions for preventing, or slowing down, the progression of neurodegenerative diseases.

Mujica-Parodi says her next steps are to examine brain fuel further, and to extend the research to older populations.