Belly fat linked to signs of Alzheimer's 20 years before symptoms begin, study says
As the size of a person’s belly grows, the memory centre of their brain shrinks and beta amyloid and tau may appear — all of this occurring as early as a person’s 40s and 50s, well before any cognitive decline is apparent, according to new research. Both beta amyloid plaques and tau tangles are early signs of the brain’s march toward a possible Alzheimer’s disease diagnosis. Amyloid plaques typically appear first, with tau tangles arriving later as the disease progresses.
“The more amyloid or tau you have in the brain, the sicker the brain becomes,” said senior study author Dr. Cyrus Raji, associate professor of radiology at Washington University School of Medicine in St. Louis. “The way we can track a sicker looking brain is lower blood flow,” Raji said.
“We also saw brain atrophy, or a wasting away of gray matter, in a part of the brain’s memory center called the hippocampus.”Less blood flow in the memory center of the brain may cause shrinkage, another key biomarker for Alzheimer’s, said preventive neurologist Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida.
Having laser sharp focus on reducing belly fat can be one of our most powerful tools to fight this terrible disease,”
Obesity is a worldwide epidemic, according to the World Health Organization, which estimates more than half the world will be overweight or obese within 10 years. Raji said. “We’re trying to understand how obesity at midlife, in the 40s and 50s, is a risk factor for Alzheimer’s disease, which doesn’t usually appear symptomatically until the 60s, 70s or 80s.” Visceral fat is key.
A pilot study by Raji and his team, released in November 2023, found a type of deep abdominal fat called visceral fat, was linked to inflammation and amyloid buildup in the brains of 32 men and women in their 40s and 50s. Visceral fat wraps itself around the major organs of the body and is completely different than the subcutaneous fat on the rest of the body — subcutaneous fat typically makes up 90 per cent of the body’s fat, according to the Cleveland Clinic.
“The more visceral fat one has, the more inflammation happens in the body and it’s much worse than the inflammation that occurs with subcutaneous fat,” Raji said. Visceral fat receives more blood flow due to its placement near organs and is more hormonally active than subcutaneous fat, Raji said.“We looked at insulin resistance via fasting plasma insulin levels and glucose tolerance tests and found the most abnormally high insulin was seen in people with higher amounts of visceral fat,” he said.
“Visceral fat is the more metabolically abnormal, diabetes-inducing fat.”
Ways To Fight Visceral Fat
There are smart ways to reduce belly fat that can reverse these trends, Isaacson said.
First, don’t focus just on body weight, but also body composition. “This can be done easily at home by using a biometric scale or can be monitored by using an annual InBody scan or DEXA scan ordered by a healthcare provider.
Exercise is key, Isaacson added, but do it by working out “smarter — not harder.” "To more efficiently get into ‘fat burning’ mode and lose body fat over time, I suggest taking a brisk walk, at a steady pace, working up to at least 45 to 60 minutes two to three times per week,” he said. You want to follow “Zone 2 training,” which can be tracked using a simple method — being able to carry on a conversation while exercising, but just barely, Isaacson said. “Walking fast on a treadmill at a slight incline, or walking with a weighted vest, are ways to get into the fat burning zone more quickly and efficiently,” he said.
“Tracking and building muscle mass is also key — the more muscle a person has, the higher their metabolism and the better they can burn fat through the day.”If your muscle mass is low, try strength training for at least 30 minutes twice a week or more, and be sure to eat adequate amounts of protein intake throughout the day, he added.