THE WORLD HEALTH ORGANIZATION calculates that more than 300-million people worldwide are obese, with a billion more overweight. With obesity comes an increased risk of cardiovascular disease, type 2 diabetes and hypertension. Now there is more discouraging news.
In a study published in Human Brain Mapping, UCLA Professor of Neurology Paul Thompson, Ph.D., Cyrus A. Raji, a medical student at the University of Pittsburgh School of Medicine, and their colleagues compared the brains of elderly people who were obese, overweight and of normal weight to see if they had diff erences in brain structure – that is, if their brains looked equally healthy.
They found that obese individuals had, on average, 8 percent less brain tissue than people of normal weight, while overweight people had 4 percent less tissue. According to Dr. Thompson, it is the fi rst time anyone has established a link between being overweight and having what he describes as “severe brain degeneration.”
“That’s a big loss of tissue, and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer’s and other diseases that attack the brain,” he says. “But you can greatly reduce your risk for Alzheimer’s if you can eat healthily and keep your weight under control.”
Researchers examined brain images from an earlier study called the Cardiovascular Health Cognition Study, and, using a neuroimaging method that off ers high-resolution mapping of anatomical differences in the brain, converted them into detailed three-dimensional images. In looking at both the gray matter and white matter, researchers found that the people defi ned as obese or overweight had lost tissue in several different areas of the brain. “The brains of obese people looked 16 years older than the brains of those who were lean, and in overweight people, they looked eight years older,” Dr. Thompson says. “It seems that along with increased risk for health problems such as type 2 diabetes and heart disease, obesity is bad for your brain. We have linked it to shrinkage of brain areas that are also targeted by Alzheimer’s,” says the University of Pittsburgh’s Raji. “But that could mean exercising, eating right and keeping weight under control can maintain brain health with aging and potentially lower the risk for Alzheimer’s disease and other dementias.”