Sometimes it’s hard to keep up with the latest diet recommendations to maintain peak brain health. One study finds that canola oil may increase memory problems, while another shows that olive oil is thought to protect the brain against Alzheimer’s. Drinking coffee has been linked to a lower risk of dementia, but not if there’s sugar in it. And don’t even get us started on the flip-flopping research on alcohol.
But even though diet recommendations on specific foods might change as more research illuminates protective and harmful foods, there is one thing that the research points to as bad for the brain: any kind of food or inactivity that causes belly fat.
A new study has found that extra body fat around the midsection is actually linked to shrinkage in brain size. The study, published in the journal Neurology, followed 9,652 who were an average age of 55. They measured the participants’ body mass index, or BMI, as well as a hip-to-waist ratio.
The scientists then used magnetic resonance imaging, or an MRI, to measure brain volume in different regions of the brain as well as the volume of white and gray matter. White matter acts as the communicator between brain regions and contains nerve fiber bungles. Gray matter is full of the brain’s nerve cells and includes areas responsible for self-control, muscle control and sensory perception.
The numbers showed that a high BMI was enough to tip the scales when it came to brain volume. Those with a high number were more likely to have a smaller brain volume. People with a high BMI and a high hip-to-waist ratio had less gray matter. White matter wasn’t affected in the population the researcher sampled.
“Existing research has linked brain shrinkage to memory decline and a higher risk of dementia, but research on whether extra body fat is protective or detrimental to brain size has been inconclusive,” said study author Mark Hamer, Ph.D., of Loughborough University in Leicestershire, England. “Our research looked at a large group of people and found obesity, specifically around the middle, may be linked with brain shrinkage.”
The past studies Hamer referenced have shown that a shrinking hippocampus, the brain’s memory center, is one of the earlier indications of Alzheimer’s.
And it isn’t just the brain size that might be affected by waist size. An earlier study compared cognitive test results to waist-to-hip ratios amongst over 5,000 people. The bigger the ratio difference, the worse people performed on the tests.
But an association does not mean that obesity or belly fat actually causes the shrinkage in the brain. But scientists may use it as a way to track prevention efforts in the future.
“While our study found obesity, especially around the middle, was associated with lower gray matter brain volumes, it’s unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain,” said Hamer. “We also found links between obesity and shrinkage in specific regions of the brain. This will need further research but it may be possible that someday regularly measuring BMI and waist-to-hip ratio may help determine brain health.”