Regular physical activity, normal body mass index (BMI), and a healthy diet may prevent the onset of Alzheimer’s disease by reducing the incidence of protein aggregates in the brain, according to a study that will appear in the September issue of the American Journal of Geriatric Psychiatry.

The study, developed by researchers at UCLA’s Semel Institute for Neuroscience and Human Behavior, shows that lifestyle choices may markedly influence the course of the disease in Alzheimer’s patients.

“The study reinforces the importance of living a healthy life to prevent Alzheimer’s, even before the development of clinically significant dementia,” Dr. David Merrill, the lead author of the study, said in a press release. “This work lends key insight not only into the ability of patients to prevent Alzheimer’s disease, but also physicians’ ability to detect and image these changes.”

The researchers examined 44 adults ages 40 to 85 who exhibited mild memory changes but no dementia. Subjects were assessed through an experimental type of positron emission tomography (PET) scan that measured the amount of beta-amyloid deposits between nerve cells in the brain and tangles of tau protein, both of which are indicators of Alzheimer’s.

Patients who exercised regularly or had a healthy BMI had lower levels of beta-amyloid deposits and tangles of tau protein. In addition, those who ate a Mediterranean diet, which is rich in fruits, vegetables, cereals, and fish and low in meat and dairy, and had mild to moderate alcohol consumption, also showed lower levels of these protein aggregates.

“The fact that we could detect this influence of lifestyle at a molecular level before the beginning of serious memory problems surprised us,” Merrill said.
Previous studies had shown that a healthy lifestyle could delay the onset of Alzheimer’s disease. But this is the first study that demonstrates an association between lifestyle factors and the levels of abnormal proteins in the brains of people with subtle memory loss who have not yet been diagnosed with dementia.

The researchers believe that future interventional studies that modify diet, exercise, and other lifestyle factors, such as cognitive health and stress, will include imaging of these abnormal proteins to understand how these factors influence the buildup of toxic aggregates in the course of the disease.