If you hope to maintain a sharp brain throughout old age, a new study suggests you start by maintaining another part of your body: your belly. According to research published in the British Journal of Nutrition, people with more belly fat were more likely to experience cognitive impairment, including dementia.
The study looked at the waist-to-hip ratio of over 5,000 people over the age of 60. They gave them tests like the Mini-Mental State Examination, a test commonly used to screen for dementia. The higher the difference in waist-to-hip ratio, the worse they performed on tests.
“While we have known for some time that obesity is associated with negative health consequences, our study adds to emerging evidence suggesting that obesity and where we deposit our excess weight could influence our brain health,” said Conal Cunningham, the senior author of the study and an associate professor of gerontology at Trinity College in Dublin. “This has significant public health implications.”
But what exactly is belly fat? According to experts, there are two kinds of fat that accumulate around the stomach. One, the fat between the abdominals and the skin, is necessary for proper hormone production and everyone has some. And then there’s what’s called visceral fat—the fat that sits between the organs. It’s that kind of fat, which is caused by exercising too little and eating fatty, inflammatory foods, that causes a high waist-to-hip ratio. It’s also the same fat that has been associated with a greater likelihood of having a heart attack and Type 2 diabetes. Researchers found that overweight people who carried their weight in their stomach had a greater chance of developing diabetes if their waists were more than 35 inches in women and 40 inches in men.
In Ireland, where the study was conducted, over half of adults over 50 are considered centrally obese. In the U.S., one-third of adults over 65 in the U.S. are obese and 57 percent of adults are considered centrally obese.
Obesity itself has been found to increase the risk of dementia. Higher levels of body fat can block blood flow to the brain, which can lead to the conditions that cause Alzheimer’s.
However, this was an observational study, meaning that researchers did not prove that having more belly fat directly causes brain problems. There could be other factors associated with having a lot of belly fat that also may be contributing to the lower scores on cognitive tests.
But for now, experts still recommend a healthy diet and regular, heart-pounding exercise to ward off dementia and memory problems. The MIND diet, a heart-healthy diet specifically developed to protect the brain, has been show to possibly lower the risk of dementia as much as 53 percent. The American Academy of Neurology stands behind exercise as an acceptable way to improve problems with memory and thinking. Their recommendation is aerobic exercise twice per week.
This study was conducted using data from the Trinity Ulster Department of Agriculture aging cohort study comprising, a collaborative research project that utilizes data from thousands of elderly adults in Northern Ireland and Ireland.