(CNN) — Inflammation caused by belly fat may be linked to the early stages of Alzheimer’s disease decades before symptoms begin, according to new research.
“We’ve known for a long time that as gut size increases, memory centers in the brain become smaller,” said Dr. Richard Isaacson, a preventive neurologist and Alzheimer’s disease researcher at the University of Florida’s Institute for Neurodegenerative Diseases.
“This study shows a marker of neuroinflammation on brain images that I haven’t seen before,” said Isaacson, who was not involved in the new study. “Brain imaging links abdominal or visceral fat to brain dysfunction through an inflammatory process.”
The study found that people in their 40s and 50s who have more hidden belly fat “have more amounts of an abnormal protein called amyloid in a part of the brain that we know causes One of the first places where Alzheimer’s occurs.” Senior author Dr. Cyrus Raji is associate professor of radiology at Washington University School of Medicine in St. Louis.
Plaques of beta amyloid in the brain are one of the key symptoms of Alzheimer’s, along with tangles of a protein called tau. Amyloid plaques usually appear first and tau tangles follow later as the disease progresses.
“There’s also a gender difference, with men having a greater association between belly fat and amyloid than women,” Raji said. “This is important because men have more visceral fat than women.”
The study found an association between deep abdominal fat and brain atrophy, or loss of gray matter in a part of the brain’s memory center called the hippocampus.
“This is important because brain atrophy is another biomarker of Alzheimer’s disease,” Raji said.
The gray matter of the brain contains most of the brain cells that tell the body what to do. White matter is composed of fibers, usually distributed in bundles called tracts, which form connections between brain cells and the rest of the nervous system.
“We also found that individuals who had higher amounts of visceral fat had more inflammation in widespread white matter pathways in the brain,” said lead author Dr. Mahsa Dolatshahi, a postdoctoral researcher at the University of Washington’s School of Medicine. “
Without functional white matter highways, the brain cannot properly communicate with different parts of the brain and body.
‘Push the envelope’
Published as a pilot study in the journal Aging & Disease in August, Raji and his team originally took images of the brains and stomachs of 32 adults between the ages of 40 and 60. The team continued to add participants and is now presenting information about 20 more people — a total of 52 — this Monday at the 2023 conference of the Radiological Society of North America.
As more people were added to the study, details of inflammation caused by belly fat in the parts of the brain where Alzheimer’s originates came into focus. Raji said the changes found in the brain were minor but significant.
“We showed a very subtle effect because we were looking at middle-aged people (people in their 40s and 50s), whereas previous studies had looked at people in their 60s and 70s,” he said. “These are people who, if they develop Alzheimer’s disease, they won’t have it for another 20 or 25 years.
“So, we’re really pushing the limits of how early we can detect some of the more subtle manifestations of abnormalities that may be related to Alzheimer’s pathology,” Raji said. “By identifying this pathological association with visceral fat, there are ways we can potentially intervene in this population.”
visceral fat and inflammation
When we think of fat, most of us think of subcutaneous fat, which can be stored under the skin or around the waist. According to the Cleveland Clinic, subcutaneous fat typically makes up 90% of the body.
Visceral fat cannot be pressed, excised or pressed. Visceral fat remains hidden behind the abdominal muscles, deep in the abdomen, covering vital organs. Both types secrete hormones and other molecules, but experts say visceral fat is more metabolically active and sends signals that can trigger insulin resistance and other health problems.
“Subcutaneous fat is not generally associated with insulin resistance,” Isakson said. “However, the higher the levels of visceral fat, the greater the insulin resistance a person will have, which causes inflammation in the body and brain.”
Insulin resistance occurs when the body’s cells do not respond well to insulin, a hormone needed to regulate blood sugar levels. This condition often causes diabetes and many other chronic diseases.
“We hypothesized that inflammation in fat cells leads to insulin resistance, and this is exacerbated by visceral fat,” Isaacson said. “Insulin resistance causes inflammation that accelerates the deposition of amyloid, one of the key markers of Alzheimer’s disease. “This is why people with diabetes have twice the risk of developing Alzheimer’s disease.”
Expensive MRIs and full body scans are the most accurate way to measure visceral fat, but many people use estimates based on waist circumference or waist size in proportion to height. To measure your waist, the Cleveland Clinic recommends wrapping a flexible measuring tape around your waist, just above your hips.
“For women, 35 inches (89 centimeters) or more means they are at risk for health problems from visceral fat. For men, this number is 40 inches (102 centimeters) or more,” the clinic states on its website.
“Regardless of weight, people should find out if they have hidden visceral fat,” Raji said. “If you use body mass index (BMI) or weight on a scale it may be missed completely.”
This is because even thin people can have excess visceral fat. This is called “skinny fat” or “TOFI” (thin on the outside, fat on the inside), it can occur when a person exercises but has a poor diet, and in certain ethnic groups. For example, Asian people have more visceral fat than black, white, or Hispanic people.
Visceral fat is “easy to lose”
There’s good news, Raji said: Visceral fat responds well to diet and exercise. “It is easier to lose visceral fat with diet and exercise than it is to lose subcutaneous fat because visceral fat is more easily metabolized and burned.”
“There are a number of things that can target body fat from both an exercise and nutrition standpoint,” Isaacson said.
“Eat a healthy diet and exercise regularly, which should include muscular strength training a few times a week, as well as less intense fat-burning cardio exercise for 45 to 60 minutes,” he says.
More tips: Eliminate or reduce ultra-processed foods, reduce portion sizes, replace sugary drinks with water, limit processed meats, and reduce high-fat meat and dairy products like cheese and butter. , which are full of saturated fat, other experts suggest.
Also keep an eye on your alcohol consumption: According to the Mayo Clinic, it’s not just beer that causes “beer belly.” Drinking any type of alcohol will increase your waistline.
Take care of your sleep also. Millions of Americans are sleep deprived every day, but studies have shown that people who sleep less than six hours a day have higher levels of amyloid in their brains.