A ketogenic diet is very high in fats, low in carbs and moderate in protein. A keto breakfast, for example, might involve mixing your coffee with coconut oil, heavy cream and butter, and scrambling eggs with cream cheese, adding a side of smoked salmon for protein. It’s a way of forcing your body to make and rely on ketone bodies, a byproduct of metabolism when a person is not taking in enough carbohydrates. Ketones come from the breakdown of fat when there are not enough carbohydrates to keep the blood glucose within normal limits. Some believe that Alzheimer’s stems from trouble processing glucose, which is typically the brain’s preferred source of fuel. It is known that as we age, less glucose is able to cross the blood-brain barrier in order to fuel the brain. The ketogenic diet provides a way for ketones to take up the energy slack.
Sounds great, right? Well, much like popping an ibuprofen to lessen the inflammation many experts think is behind Alzheimer’s, it’s not always that simple. According to Ed Blonz, Ph.D., a nutritionist and assistant clinical professor at the University of California, San Francisco, using the ketogenic diet as a way to get this alternate fuel in to the brain is a questionable method for Alzheimer’s disease prevention and treatment.
What Is the Potential Problem With a Keto Diet for Alzheimer’s?
While a ketogenic diet can indeed provide a non-glucose source of energy for the brain, and ketones may have potential to affect the pathogenesis of Alzheimer’s disease, there are metabolic costs and nutrient sacrifices associated with this method. In other words, sticking to a ketogenic diet might provide your body with a needed alternate source of energy, but doing so could deprive the body and brain of many other essential nutrients that play a role in your overall vascular health—a key issue associated with the overall risk of Alzheimer’s disease.
The body treats ketones as a limited asset with associated risks. There are enzyme systems designed to prevent the blood level of ketones from getting too high. This can be a problem on a ketogenic diet, because the body cranks out a lot of ketones. Ketones affect the pH (acid/base balance) of the blood. We normally have a higher (less acid) pH, but ketones are acidic, and if present at elevated levels, they can lower blood pH, which can seriously mess with our metabolism. The condition called ketoacidosis, which occurs in out-of-control diabetes, can also occur in a poorly composed and monitored ketogenic diet, and this can be serious—even fatal.
On a biochemical level, using ketones as a source of energy for the brain does make some sense. 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.
The Effect of a Keto Diet on Heart Health
One of the accepted tenets in the battle against Alzheimer’s is that we need to focus on the health of the heart and vascular system to help prevent Alzheimer’s, or at least slow its progression. You’ve probably heard it before, but it’s true: What is good for the heart is good for the brain. This what the MIND diet—a diet high in fruits and vegetables, fish and poultry, and olive oil—is all about. Preliminary studies have shown that adhering to the Mediterranean-based, heart- and brain-healthy diet may lower the risk of Alzheimer’s by as much as 53 percent. If you opt, instead, for a ketogenic diet to provide ketones, you are thwarting the healthful eating element of the equation and missing out on a lot of nutrients. Relying on a ketogenic diet might provide some short-term benefits, but it would likely mess things up in the long run.
Using Diet to Lower Alzheimer’s Risk
With this as prologue, you can see why a ketogenic diet should not be the first approach to maintaining brain health. The primary focus must be to maintain vascular health by eating a healthy diet and exercising, doing everything in your power to reduce the incidence of health conditions associated with an increased risk of Alzheimer’s disease. These, what are referred to as “co-morbidities” include diabetes, insulin resistance, heart disease, obesity, and hypertension.
A High Fiber Diet for Brain Health
A different approach might be to take a supplement of ketones (like beta-hydroxy butyrate) or fats that the body metabolizes into ketones. Caprilic acid, an eight-carbon fatty acid that makes up eight percent of the fats of coconut oil, is a fat that gets metabolized into a ketone after absorption. Another important piece of this approach is maintaining a high-fiber diet. Aside from being a boon to general health, fiber is often fermented in our gut into a type of fatty acid that gets turned into a ketone after absorption. This latter point may help explain why cultures with a high fiber intake tend to have a lower incidence of Alzheimer’s disease. All these steps help maintain the health of our vascular system, while providing sources of ketones in the blood that can provide energy for the brain. It is an approach that can provide the benefit of ketones while helping maintain a plant-based, whole foods diet that contributes to all aspects of healthful living.