The Brain-Belly Connection

March 6, 2024

Do you have Alzheimer’s in your family? It may be especially important to watch your waistline. 

A new study found that in middle-aged people who have a family history of Alzheimer’s disease, increased amounts of abdominal fat were tied to greater declines in thinking and memory skills and decreased brain volumes in key areas of the brain tied to memory. The association was particularly strong for men.

The findings add to growing evidence about the dangers of “hidden” abdominal fat. This kind of fat, also known as visceral fat, surrounds organs deep within the abdomen. It’s not the subcutaneous fat you can “pinch” around your waist. But increased amounts of visceral fat may be marked by a bulging belly. Other studies indicate that having a waist size exceeding 40 inches in men or 35 inches in women is a sign of excess visceral fat. However, even people who are not overweight may have excess levels of hidden abdominal fat. 

For the current study, researchers in the U.S. and Israel looked at 204 healthy middle-aged men and women who had a parent with Alzheimer’s disease. They ranged in age from 40 to 65, with an average age of 59. 

The researchers used MRI scans to assess the amount of fat deep in the abdomen, including fat levels in and around the pancreas and liver. Participants also underwent tests of memory and thinking skills, and many also had brain scans to measure brain volumes in areas typically affected by Alzheimer’s disease.

The researchers found that in both men and women, higher levels of abdominal fat were tied to brain changes suggestive of early Alzheimer’s disease. Such changes may appear decades before memory loss and other symptoms appear. But the risks were particularly prominent in men who had high levels of fat around the pancreas. 

“In middle-aged males at high Alzheimer’s disease risk — but not females — higher pancreatic fat was associated with lower cognition and brain volumes, suggesting a potential sex-specific link between distinct abdominal fat with brain health,” said study author Michal Schnaider Beeri, of Rutgers University. The results were published in the journal Obesity.

The pancreas makes insulin, a hormone that regulates blood sugar levels, and impairment of the pancreas may lead to diabetes. The researchers speculate that high fat levels around the pancreas may damage the organ and set the stage for diabetes, a recognized risk factor for Alzheimer’s disease. Abdominal fat is also tied to higher levels of body-wide inflammation, which may also increase the risk for Alzheimer’s.

Many earlier studies have identified midlife obesity as a risk factor for Alzheimer’s disease. Most of those studies looked at body mass index, or BMI, a formula that considers a person’s height and weight. This study also considered BMI. But it found that the visceral fat that lies deep within the abdomen was a more reliable predictor of brain changes suggestive of Alzheimer’s disease. 

“Our findings indicate stronger correlations compared to the relationships between BMI and cognition, suggesting that abdominal fat depots, rather than BMI, is a risk factor for lower cognitive functioning and higher dementia risk,” said study author Sapir Golan Shekhtman of the Sheba Medical Center in Israel.

The authors say that the link between abdominal fat and Alzheimer’s brain changes may be more prominent in middle-aged men than in their female peers because premenopausal women tend to have lower levels of visceral fat, in part because they are protected by estrogen. After menopause, fat tends to become redistributed to the abdominal regions.

The good news is that lifestyle measures may help to reduce visceral fat. Eating plans that target “belly fat” specifically aren’t effective in reducing levels of abdominal fat, experts say. Instead, aim to keep overall weight levels down with a heart-healthy, high-fiber diet. Avoid excess sugar or alcohol. In addition, get regular exercise and aim for a good night’s sleep. Chronic stress, which causes high levels of the stress hormone cortisol, can also contribute to the accumulation of abdominal fat. Meditation, yoga, deep breathing exercises, and exercising in the great outdoors can all help to counter stress and may help to lower your Alzheimer’s risk.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University. 

Source: Sapir Golan Shekhtman, Ethel Boccara, Ramit Ravone-Springer, et al: Abdominal Fat Depots are Related to Lower Cognitive Functioning and Brain Volumes in Middle-aged Males at High Alzheimer’s Risk.” Obesity, February 27, 2024


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