The impact that certain diets, foods, ingredients or nutrients have on cognitive decline or Alzheimer’s risk is notoriously difficult to study. But, while there are no foods that can actually reverse Alzheimer’s or dementia, mounting evidence does indicate eating a healthy diet is linked to better brain health. Let’s zero in on a popular one: the Keto diet.
You’ve likely heard about the ketogenic diet — a diet that revolves around eating fewer carbs, and more protein and fats. The goal of the diet is to release more ketones, a type of acid that the body can use for fuel, into the bloodstream, to help jumpstart weight loss. But could ketones also help fight against Alzheimer’s disease? A 2020 study argues: Yes it can.
But not just any old proteins and fats will do. Other studies indicate that processed meats, high cholesterol, and high-fat, high-sugar diets are all linked to higher dementia risk. With that in mind…
Ketones and the Alzheimer’s brain
Published in The Journal of Neuroscience and conducted by researchers including Aiwu Cheng, a biologist with the National Institute on Aging, the 2020 study shows that increasing the amount of ketones in the body may actually help fight Alzheimer’s disease. How does it work? Here’s what the researchers theorize:
During the early stages of Alzheimer’s disease, the brain may lose GABAergic interneurons, which help keep other neurons in the brain from over-firing. In Alzheimer’s, it’s possible beta-amyloid impairs the function of these interneurons. Beta-amyloid also damages mitochondria, the metabolic source in cells. It does this by weakening SIRT3, a protein that preserves mitochondria and neurons.
To test out the effect of ketones on the brain, Cheng and her fellow researchers genetically modified mice to have lower levels of SIRT3. When placed on a diet supplemented with ketones, the mice had fewer problems associated with decreased SIRT3: They experienced fewer seizures and had a better chance of lengthening their lifespan. It turns out the ketones were linked to the increase in SIRT3 levels, leading the researchers to conclude that ketones may help boost brain health in early stages of Alzheimer’s disease.
Past research has pinpointed ketones’ ability to boost mitochondrial activity, and to act as a supplement for the brain instead of having to rely on glucose. For these reasons, it’s being explored as a possible therapeutic channel for Alzheimer’s.
The study may hint at the benefits of a ketogenic diet. Cheng, however, is quick to point out that ketones aren’t naturally found in foods we eat; rather, they’re the product of a metabolic process in the liver that releases them into the body. And sticking to a ketogenic diet may not be the best way to get more of them.
“We have concerns about the side effects of the ketogenic diet,” Cheng said in an interview with Being Patient. “The ketogenic diet, which is high in fat, may boost ketones but it also increases triglycerides and cholesterol,” which isn’t so good for the long-term.
Instead, Cheng argues, “Exercise and intermittent fasting are two other ways to boost ketone generation in the body.” She added that “when we increased ketones in the animal model, it was beneficial in fighting Alzheimer’s disease.”
Past research has examined fasting as one way to fight against brain deterioration. One study found that fasting triggered an increase in several metabolites associated with better brain health, including leucine, isoleucine and ophthalmic acid.
What is the Keto Diet?
A popular trend in recent years, the ketogenic diet has made its rounds among people striving for weight loss, as well as among body builders and those who simply want to sculpt their diets for good health.
However, the evidence behind the ketogenic diet as the magic bullet for health remains unsubstantiated. Some studies did not find enough evidence to back these claims up. But the diet still holds some fascination, and continues to be investigated for its effects on the brain and overall health.
Ed Blonz, a nutritionist and assistant clinical professor at the University of California, San Francisco (UCSF) believes the idea of supplementing the body with ketones may make some sense for the brain. In a past interview with Being Patient, he explained that the brain can use ketones, which are a byproduct of fat metabolism, if it doesn’t have enough glucose for energy. One of the key goals of the ketogenic diet is to eat as few carbohydrates as possible to force the body to make ketones as a backup energy source.
“One of the secondary fuels is a breakdown product of fats,” Blonz said. “Now, when we’re not eating, we use fats for energy to fuel the body, but when we don’t have glucose, the fats don’t burn completely. They’re only partially metabolized and one of those bi-products is what’s called a ketone or a ketone body. That’s the substance which has the ability to go into our blood, cross that blood-brain barrier and provide fuel for the brain, even when we haven’t had a meal in days or weeks.”
It’s these ketones that may hold keys for brain health and possible therapies for Alzheimer’s disease, but researchers are still in the process of investigating them further.
In the meantime, Blonz echoes Cheng’s point that the ketogenic diet may not be the best way to boost ketones in the body.
“On a biochemical level, using ketones as a source of energy for the brain does make some sense,” Blonz said in another interview with Being Patient. “In fact, the body relies on this alternative source of fuel when there is not food available—likely an evolutionary advantage for when the food supply is less stable. However, a person does not need to adopt a ketogenic diet to produce ketones. In addition to messing with the body’s acid-base balance, carbohydrates get cut out of a keto diet, or down to a minimum, and this pushes many healthful foods–fruits and healthy grains—off the plate.”
UPDATE: 00:55, 6 February, 2023 — This article from January 2020 has been updated with new information to help our readers.
One thought on “Can Ketones Fight Alzheimer’s? The Keto Diet and Brain Health”
I’m disappointed this interview didn’t mention the effects on the gut microbiota from ketosis that may mediate brain health. The article in Cell, “The gut microbiota mediates the anti-seizure effects of the ketogenic diet”, illuminated how the Ketogenic Diet changes the gut flora in a way that increases the hippocampal GAMA/glutamate ratio (see diagram 6F). Can you find someone to interview who follows a broader swath of what the research is indicating?