Make us your home page

Today’s top headlines delivered to you daily.

(View our Privacy Policy)

Obesity weighs on brain function, too

Obesity promotes diabetes, heart disease, high blood pressure and other maladies associated with increasing aging. • Excess weight may damage thinking, reasoning and memory as well, possibly by eroding the fatty insulation around the fibers that connect regions of the brain. • Losing weight through bariatric surgery, however, appears to restore at least some cognitive function, according to John Gunstad, a neuropsychologist at Kent State University in Ohio.

Gunstad recently subjected 150 obese people to cognitive tests that measured memory, attention, verbal fluency and other mental functions.

On average they performed on the low end of normal, although scores on memory and learning tests were in the impaired range for about 25 percent of participants, he and his colleagues reported in a recent article in the journal Surgery for Obesity and Related Diseases.

Twelve weeks later, however, the 109 patients who had undergone bariatric surgery and shed about 50 pounds scored within the average or above-average range for all cognitive tests. Those who didn't have surgery scored worse.

What made the difference? The change occurred not in brain cells themselves, but in the myelin — the fatty white insulation around the "wires" that connect brain cells, Gunstad believes.

This "white matter," as it is known, facilitates the transmission of signals between brain cells and brain regions.

The thicker and more robust the white matter, the faster and more reliably signals travel. Anything that damages myelin or causes it to thin, such as multiple sclerosis or aging, can disrupt brain functions.

In a study published last year in Obesity, Gunstad and his colleagues determined that as weight increases, the integrity of the myelin decreases, which could account for deficits in thinking and memory.

"Other research has linked obesity to white matter changes," he said. "Our research is the first to suggest that these changes can occur before the onset of more severe pathology. That's worrisome because subtle changes might be happening in the background in otherwise healthy people."

Gunstad began to suspect that obesity contributed to mental decline when he worked with older people in a large study.

Obese patients seemed to have mental difficulties more often than nonobese people. "I saw that obese patients had problems linked with attention, concentration, problem solving, and so on — all problems that have been linked to white matter changes," he said.

Although he can't explain the specific mechanism that causes mental decline, Gunstad thinks that obesity damages the brain in a number of ways.

"For example," he said, "it could trigger inflammation, which could damage blood vessels, and perhaps the brain itself."

In a recent study in the Archives of Neurology, researchers found that people who have insulin resistance — a condition that reduces the ability of cells, including brain cells, to utilize glucose for fuel — show some of the brain changes that precede Alzheimer's disease.

They concluded that even mild insulin resistance, which increases dramatically in people who are overweight and obese, can increase the risk of Alzheimer's.

Losing weight, however, makes the entire body, including the brain, more responsive to glucose, and therefore probably less susceptible to Alzheimer's and other forms of brain dysfunction, the researchers said.

Tom Valeo writes frequently about health matters. He can be reached at

Obesity weighs on brain function, too 05/24/11 [Last modified: Tuesday, May 24, 2011 4:30am]
Photo reprints | Article reprints

© 2017 Tampa Bay Times


Join the discussion: Click to view comments, add yours

  1. Trigaux: Florida's jobless rate looks great — but 25 other state rates look even better

    Economic Development

    No debate here: Florida's unemployment rate continues to drop — even as more people move to Florida and enter the workforce. What's not to like?

    Who remembers the remarkable lines of hundreds of people looking for construction work in Tampa back in March of 2010 at a job fair at the Encore construction site near downtown Tampa? Now the construction industry is struggling to find skilled workers to meet building demand. [
  2. Tampa police investigating fatal shooting at Busch Boulevard motel


    TAMPA — Police are investigating a shooting at a motel near Busch Gardens that left one woman dead.

  3. On the Camino de Santiago, Day 21: Tears of love and parting mark the beginning of the final leg of a pilgrim's journey.


    Day 21: León to Hospital de Orbigo: 32.6 km, 8.75 hours. Total for Days 1-21 = 498 km (309 miles)

  4. Pinellas detectives investigating shooting that led to car crash

    Public Safety

    LARGO — Pinellas Sheriff's detectives are investigating a shooting that investigators said led to a man crashing his car after he was shot in the abdomen early Tuesday.

  5. Trump tweets, McCain return set stage for health bill vote (w/video)


    WASHINGTON — President Donald Trump urged Republicans to "step up to the plate" for Tuesday's crucial Senate vote on their bill eviscerating much of the Obama health care law. The stage was set for high drama, with Sen. John McCain returning to the Capitol to cast his first vote since being diagnosed with brain …

    President Donald Trump, accompanied by Vice President Mike Pence, Health and Human Services Secretary Tom Price, and others, speaks about healthcare, Monday, July 24, 2017, in the Blue Room of the White House in Washington. [Associated Press]