Research shows intermittent fasting may prevent Alzheimer’s disease | Alzheimer's Prevention Registry

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February 17, 2021

Research shows intermittent fasting may prevent Alzheimer’s disease

By Alzheimer's Prevention Bulletin


You may have heard of intermittent fasting as a weight loss diet. Either by fasting one or two days a week or reducing the hours of the day in which you eat, these diets can alter your metabolism and lead to weight loss over time.  But you may not have heard about intermittent fasting as a possible way to improve learning and memory.

Animal studies of intermittent fasting have consistently demonstrated disease modifying benefits on a wide range of chronic disorders including obesity, diabetes, cardiovascular disease, cancers, and neurodegenerative diseases. Studies in animals show that intermittent fasting enhances cognition in multiple areas of memory and learning.

Intermittent fasting in animal studies has also been shown to reduce brain inflammation. There is strong evidence that forms of intermittent fasting can delay the onset and progression of Alzheimer’s disease and Parkinson’s disease in animal models. Researchers are now exploring opportunities to study intermittent fasting in humans; particularly the effect this might have on neurodegenerative diseases including Alzheimer’s disease.

“In animal studies, intermittent fasting has been shown to increase longevity, improve cognitive function and reduce brain plaque as compared with animals fed a regular diet,” said Allan Anderson, MD, Director of the Banner Alzheimer’s Institute in Tucson. “One hypothesis is that intermittent fasting enables cells to remove damaged proteins. It has been shown to delay the onset and progression of disease in animal models of Alzheimer’s disease and Parkinson’s.”

Leading experts in this field of study have been researching intermittent fasting for years. Our bodies predominantly use glucose produced by the food we eat for fuel. But when we fast, the body turns to alternate energy sources including fat. Fat metabolism leads to the production of ketone bodies which have been linked to improved thinking, learning and memory in animal studies.

In a review of intermittent fasting research in the December 2019 issue of the New England Journal of Medicine, the technique showed promise in animal models for a wide range of chronic disorders. The authors’ conclusion was that calorie restriction in animals increases life span, improves cognition and can even reverse the effects of obesity, diabetes and brain inflammation.

The most widely studied intermittent fasting regimens were alternate-day fasting, 5:2 fasting (fasting 2 days per week) and daily time-restricted eating.  The latter has recently become a diet craze where people reduce the window of time during which they eat in a day.

“The animal research is stunning,” concluded Dr. Anderson. “But we don’t know yet if this will have similar benefits in humans.”  There are no substantial human trials of intermittent fasting related to brain function. Some studies of caloric restrictions in humans have shown improvement in memory function and overall thinking ability, but these studies included small numbers of patients.  Many scientists believe a large, well-conducted study of intermittent fasting in humans to determine brain benefits is warranted at this time.

For now, however, Dr. Anderson cautions against trying intermittent fasting on your own. “A sudden change to intermittent fasting might negatively impact your health if you are a diabetic or have other medical issues,” said Dr. Anderson. “It’s important to consult your doctor before making any changes to your routine and take on the change gradually.”