Obesity may cause "severe brain degeneration" study says

By Sheilah Downey (sheilahd@foodconsumer.org)

New research indicates that obesity, which can lead to heart disease, diabetes and hypertension, can also prematurely age the brain.

In the journal Human Brain Mapping today, the study compared the brains of obese, overweight and normal weight people, and found brain sizes in the overweight group had actually decreased.

"The brains of obese people looked 16 years older than the brains of those who were lean, and in overweight people looked eight years older," said the study's senior author Dr. Paul Thompson, UCLA professor of neurology.

Researchers, who studied 94 people in their 70s, found that obese people had 8 percent less brain tissue than people of normal weight. The lost brain tissue, both white and grey matter, was from the frontal and temporal lobes, areas of the brain critical for planning and memory.

"That's a big loss of brain tissue," said Thompson, "and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer's and other diseases that attack the brain."

Thompson, also a member of UCLA's Laboratory of Neuro Imaging, said the study was the first to to establish a link between being overweight and "severe brain degeneration."

For purposes of the study, a body mass index of 18.5 to 25 was used to define normal weight; overweight were those with a BMI of 25-30 and obese were defined as over 30 BMI.

In addition to lowering risk factors for heart attack, stroke, and diabetes, a sound nutritional plan can also cut risks for dementia, said the study's lead author Cyrus A. Raji, of the University of Pittsburgh.

"It seems that along with increased risk for health problems...obesity is bad for your brain," said Raji. "We have linked it to shrinkage of brain areas that are also targeted by Alzheimer's. 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 and other dementias."

The World Health Organization estimates that obesity affects more than 300 million people globally, with one billion more overweight.