Diet and Exercise Can Reduce Alzheimer's Plaque: Study

A healthy diet, regular physical activity, and a normal body weight can reduce the buildup of proteins in the brain associated with Alzheimer's disease, says a study from UCLA's Semel Institute for Neuroscience and Human Behavior.

Researchers studied 44 adults ranging in age from 40 to 85 with mild memory changes but no dementia. An experimental type of PET scan measured the level of plaque and tangles in the brain.

Plaque, deposits of a toxic protein called beta-amyloid in the spaces between nerve cells in the brain; and tangles, knotted threads of the tau protein found within brain cells, are considered the key indicators of Alzheimer's.

The researchers also accumulated information on participants' body mass index (BMI), levels of physical activity, diet, and other lifestyle factors.

The study found that each one of several lifestyle factors — a healthy BMI, physical activity and a Mediterranean diet — were linked to lower levels of plaques and tangles on the brain scans. (The Mediterranean diet is rich in fruits, vegetables, legumes, cereals and fish, and low in meat and dairy. It is also characterized by a high ratio of monounsaturated to saturated fats, and mild to moderate alcohol consumption.)

"The fact that we could detect this influence of lifestyle at a molecular level before the beginning of serious memory problems surprised us," said Dr. David Merrill, the lead author of the study.

While earlier studies have linked a healthy lifestyle to delays in the onset of Alzheimer's, the new study is the first to demonstrate how lifestyle factors directly influence abnormal proteins in people with subtle memory loss who have not yet been diagnosed with dementia, Merrill said. Healthy lifestyle factors also have been shown to be related to reduced shrinking of the brain and lower rates of atrophy in people with Alzheimer's.

"The study reinforces the importance of living a healthy life to prevent Alzheimer's, even before the development of clinically significant dementia," Merrill said. "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 study was published in the American Journal of Geriatric Psychiatry.