Can the buzzy low-carb, high-fat diet really help with Alzheimer's Disease, Parkinson's Disease, and memory loss?

The most common issues affecting brain health—dementia, memory loss, Alzheimer’s disease, and Parkinson’s disease—all have slightly different symptoms and etiologies, yet are all the result of some type of reduced brain cell functioning or deterioration. Science hasn’t had much success to date in preventing or slowing brain conditions like these, but following a ketogenic diet is being suggested as a potential way to do this. Here, we explore if there’s any truth to it.

What Is the Ketogenic Diet?

The ketogenic diet is a very low-carb (less than 50g daily), high-fat eating plan, and the goal of the diet is to put the body in a state of ketosis. Similar to what happens during fasting, a body in ketosis has little glucose to use for energy due to insufficient carbohydrate intake. This forces the body to break fat stores down into ketone bodies for energy. The brain normally relies only on glucose for fuel, but it can use ketone bodies as a substitute in this situation.

Can the Keto Diet Help with Certain Brain Conditions?

Although it has recently resurfaced as a trendy approach to weight loss, the ketogenic diet was actually developed to treat epilepsy almost 100 years ago, and it is still routinely prescribed to those with epilepsy to reduce seizure frequency, often working better than medication. In fact, one study with children indicated a “nearly complete (>90%) resolution” in seizures for half of the participants—effects that epilepsy medications haven’t been able to come close to replicating.

Scientists still don’t fully understand the diet’s exact mechanisms responsible for reducing seizures, but it appears that ketosis triggers a metabolic shift in fuel sources to influence neurotransmitter activity and improve or protect neuron functioning. Since most forms of brain disease and deterioration stem from deteriorating neuron functioning, the suggestion that the keto diet could have a positive effect on brain health (like we’ve seen in some epilepsy patients) seems relatively plausible.

Until 10 to 15 years ago, most research looking at the ketogenic diet’s effect on the brain was from an epilepsy perspective, so the research to-date on the diet’s effect on other brain disorders is still small (plus, not many human studies have been done). However, the results have been promising enough to trigger additional studies, particularly in regards to Alzheimer’s and Parkinson’s Diseases. Here’s what research suggests about the keto diet’s potential.

Ketogenic Diet and Alzheimer’s Disease

Alzheimer’s Disease is an irreversible, progressive disorder in which the brain’s nerve cells begin to degenerate. The medical community has been unable to identify a cause, but it appears that the brains of Alzheimer’s patients contain abnormal deposits of proteins, called amyloid plaques, which begin to block communication leading to eventual cell death and cognitive decline.

Alzheimer’s is sometimes referred to as “Type 3 diabetes” because of the role glucose plays in the disease. Progression appears to occur when on has regularly elevated blood sugar levels as the neurons appear to become resistant to insulin and are unable to use glucose as a fuel. This triggers inflammation and inadequate blood flow, oxygen and fuel to brain cells, and individuals with Type 2 diabetes are 50 to 65% more  likely to develop Alzheimer’s disease.

A ketogenic or lower-carb diet decreases circulating levels of glucose and insulin, which help insulin resistance but may also prevent or slow brain deterioration. Conversely, individuals who consume higher carb diets are associated with an increased risk of developing the disease.

Another study suggests that following a ketogenic diet may reduce amyloid plaques in the brain, reversing the effects seen in Alzheimer’s, and restored some neural functioning to improve cognitive ability in mice. And when Alzheimer’s patients were given a ketogenic compound for 90 days, significant improvements in cognitive abilities were seen compared to those in the control group.

Ketogenic Diet and Parkinson’s Disease

Parkinson’s disease is another degenerative brain condition that researchers haven’t been able to pinpoint a direct cause or cure. While Alzheimer’s largely affects memory, Parkinson’s disease affects movement. It is characterized by the death of cells that produce dopamine and the build-up of another type of protein plaque called Lewy bodies, and it’s the lack of dopamine that leads to  triggers, rigid muscles, and problems controlling movement.

Following the keto diet seems to have some neuroprotective effects that may augment or support other therapies and treatments. There’s less research about its potential effects on Parkinson’s progression and symptoms with most being animal studies, the findings are still promising.

Research suggests that ketone bodies may provide fuel for those dopamine-producing brain cells when glucose is unable to reach them and certain ketone bodies may be able to “rescue” those neurons and prevent their death.

Another study using mice suggested that the ketogenic diet protected dopamine-producing neurons from death, increased the number of dopamine-producing cells, improved motor dysfunction, and reduced inflammatory markers.

Ketogenic Diet and Other Memory Disorders

There appears to be a general consensus that ketones may offer a protective effect to neurons to reduce risk or slow progression of dementia and memory loss association with aging. The mechanism is unclear, but likely due to the anti-inflammatory effect of a lower-carb or ketogenic diet.

A 2012 study compared memory between a group following a low-carb diet and one following a low-fat diet. The low-carb group showed significant improvements compared to the low-fat, higher carb group, and the improvements were directly correlated to ketone body levels. Another study showed that a ketogenic diet increased ketone body levels along with increased cognitive functioning in a study examining aging rats.

There have also been a few studies looking at the effect that the ketogenic diet may have as a treatment for autism, bipolar disorder, schizophrenia, depression and migraines. While most of the findings are promising, many more studies are needed and there is not enough data or understanding to use ketogenic diets as a form of treatment.

The Bottom Line

This is definitely an area of research to continue watching as researchers try to unravel the exact etiology of brain deterioration, and the effect that diet—particularly carb intake—plays.  

Research suggests using the ketogenic diet therapeutically for those with epilepsy, and it may be a possible option that some with a family history or beginning stages of Alzheimer’s disease want to try due to its neuroprotective effect.

There are still a lot of unknowns about long-term diet effects, but the research further solidifies the need for us all to reduce added sugar and refined carbohydrate intake—regardless of opinion about the ketogenic diet or its therapeutic usage.