If you’re like most people, you’re afraid of developing Alzheimer’s disease as you age. Aging is hard as it is – loss of strength and vitality, hearing and vision loss, and often other health problems. But when aging includes loss of memory and cognitive function, inability to recognize family and friends, losing your way in your own neighborhood or home, and loss of self-awareness, there is fear and despair. Most people are willing to do anything to try to avoid dementia. Can a low-carb or keto diet help protect your brain from the ravages of aging? Could increasing ketones in your blood help preserve your memory or reduce your risk of Alzheimer’s disease?
This evidence-based guide reviews what we know about Alzheimer’s disease and how a ketogenic or low-carb diet may help.
What is Alzheimer’s Disease?
Alzheimer’s disease was first discovered by Dr. Alois Alzheimer, who observed a woman with symptoms of the disease in 1906 and examined her brain after she died. During the examination, Dr. Alzheimer found that the woman’s brain contained many strange clumps and fibrous tangles.
Today, we refer to these unusual lumps as beta-amyloid plaques and the strange fibrous tangles as neurofibrillary tangles. Each of these interferes with neuronal connections and brain cell function, which can lead to decreased thinking and memory abilities. As the tangles and plaques accumulate in the brain, symptoms become more severe and the patient enters a more advanced stage of Alzheimer’s disease.
Although beta-amyloid plaques and neurofibrillary tangles can begin to accumulate before old age, if a person has the disease, the first Alzheimer’s symptoms usually show up in the 60s. Because the disease tends to develop insidiously, with very subtle signs at first, many scientists are focused on finding ways to identify the disease in its early stages. By diagnosing the disease before memory loss, we have a greater likelihood of stopping its progression and reversing some aspects of the disease. At this point, however, there is no legitimate treatment – even if Alzheimer’s disease is diagnosed in its early stages.
Studies Show Efficacy of Keto for Alzheimer’s
Alternative approaches to treating Alzheimer’s disease and preventing cognitive decline are urgently needed. Although often widely overlooked, many functional medicine approaches are supported by the research literature and data suggest that the keto diet may be an effective treatment.
A keto diet is a low-carbohydrate, high-fat diet that induces a state of ketosis. Since carbohydrates are not available for energy production, the body turns to burning fat for energy. The fat is broken down into ketone bodies, which are then taken up by cells as an alternative fuel source. Ketone bodies function as a cleaner fuel than running on glucose: reducing inflammation, improving blood sugar balance and restoring energy production.
It is well known that glucose utilization in the brain is reduced in Alzheimer’s disease patients. Because of problems with glucose uptake, some researchers have described Alzheimer’s disease as: “Type 3 diabetes”. And problems with glucose metabolism usually exist decades before symptoms appear. Positron emission tomography (PET), used to identify these metabolic defects, has a sensitivity of 90% for detecting Alzheimer’s dementia (Mosconi 2005). While brain cells struggle to produce energy from sugar, there is no barrier to using ketone bodies as fuel (Castellano 2015). Thus, ketone bodies appear to circumvent the glucose utilization problems in Alzheimer’s disease and restore normal energy production in the brain.
A recent study review summarized the results of preclinical and human studies (Davis 2021). Amyloid plaques and tau tangles are misfolded proteins that become toxic when they build up in Alzheimer’s disease, slowly killing brain cells. Animal studies have shown that ketone bodies reduce the accumulation and toxicity of amyloid plaques and tau tangles and improve brain cell survival. In addition, ketone bodies have been shown to have anti-inflammatory effects that can help reduce overall damage to the brain.
Animal studies have found significant improvements in motor function in animal models of dementia treated with a ketogenic diet (Brownlow 2013). Although the data are less clear, some studies have shown improvements in cognitive function as well (Lilamand 2021).
Human trials are smaller and usually of shorter duration, but also point to the great potential of using a keto diet to treat cognitive decline and dementia. Interestingly, some studies in humans have found improvements in cognitive function with ketone supplementation alone, a relatively simple approach that mimics aspects of the ketog diet. However, other studies suggest that a low-carb keto diet may be more effective. A recent review of human clinical trials of keto diets or keto supplements (ketone supplementation) for Alzheimer’s disease found significant cognitive benefits, improvements in brain metabolism, and other positive changes in biomarkers of dementia (Lilamand 2021).
What is the Potential Problem with a Keto Diet for Alzheimer’s?
While it is true that a keto diet can provide a non-glucose source of energy for the brain, and that ketones may potentially influence the pathogenesis of Alzheimer’s disease, there are metabolic costs and nutrient sacrifices associated with this approach. In other words, adhering to a keto diet may provide your body with a needed alternative source of energy, but doing so may deprive the body and brain of many other essential nutrients that play a role in your overall vascular health – a key issue related to the overall risk of Alzheimer’s disease.
The body sees ketone bodies as a limited asset with associated risks. There are enzyme systems designed to prevent high levels of ketone bodies in the blood. This can be a problem in a keto diet because the body produces large amounts of ketone bodies.
Ketone bodies affect the pH (acid-base balance) of the blood. We usually have a higher (less acidic) pH, but ketone bodies are acidic and if higher levels are present, they can lower the pH of the blood, which can seriously disrupt our metabolism. What occurs in runaway diabetes called ketoacidosis can also occur in a poorly composed and monitored keto diet, which can be severe – even fatal.
On a biochemical level, the use of ketone bodies as an energy source for the brain does make some sense. In fact, the body relies on this alternative fuel source when no food is available-possibly an evolutionary advantage when food supplies are unstable.
However, a person does not need to adopt a keto diet to produce ketone bodies. In addition to disrupting the body’s acid-base balance, carbohydrates are eliminated from the keto diet or reduced to a minimum, which pushes many healthy foods-fruits and healthy grains-off the plate.
Alzheimer’s disease is still a mystery in many ways, but we understand some of the factors that cause it and how to slow it down. While we are not entirely sure how to prevent or treat Alzheimer’s disease, we do have some clues that give us some hope that it is possible. For example, it’s clear that inactivity and a high-carbohydrate diet with lots of processed foods greatly contribute to the development of Alzheimer’s disease, while keto and low-carbohydrate diets have a powerful positive effect on the brains of both healthy people and those with Alzheimer’s disease. However, it still has some negative side effects for people with Alzheimer’s disease. Consult your doctor before adopting a keto diet to treat this disease.