Summary: A new study links visceral fat, a deep layer of abdominal fat, to increased brain amyloid and tau proteins—key markers of Alzheimer’s disease—decades before dementia symptoms arise.
Researchers found that visceral fat accounted for 77% of the relationship between high BMI and amyloid accumulation, while other fat types showed no similar impact.
Managing visceral fat through weight loss or metabolic treatments may reduce dementia risk.
MRI scans of the abdomen were performed to measure the volume of the subcutaneous fat (the fat under skin) and visceral fat (deep hidden fat surrounding the organs).
The effects of visceral fat on amyloid pathology were partially reduced in people with higher HDL.
Decades before dementia symptoms appear, a new study relates visceral fat, a deep layer of abdominal fat, to elevated brain amyloid and tau proteins, which are important indicators of Alzheimer’s disease. Researchers discovered that whereas other types of fat had no discernible effect, visceral fat was responsible for 77% of the association between high BMI and amyloid buildup.
According to the study, lowering visceral fat through medication or lifestyle modifications may lower the risk of Alzheimer’s. Given the early onset of these pathologies in participants in their 40s and 50s, midlife interventions are particularly important. According to the findings, metabolic variables such as cholesterol and insulin resistance intensify the brain damage caused by obesity. The urgent need for focused preventative measures against the risk of Alzheimer’s disease associated with obesity is highlighted by this study.
Key Facts:.
The accumulation of tau and amyloid proteins in the brain is closely linked to visceral fat.
Obesity exacerbates Alzheimer’s disease pathology due to insulin resistance and low HDL cholesterol.
Reducing visceral fat with metabolic therapies or weight loss may lower the risk of dementia.
RSNA is the source.
According to a study being presented today at the annual meeting of the Radiological Society of North America (RSNA), researchers have connected a particular type of body fat to the aberrant proteins in the brain that are characteristic of Alzheimer’s disease up to 20 years before the first signs of dementia manifest.
The researchers underlined that changes in lifestyle aimed at lowering this fat may have an impact on Alzheimer’s disease development.
“We studied Alzheimer’s disease pathology as early as midlife—in the 40s and 50s—when the disease pathology is at its earliest stages and potential modifications like weight loss and reducing visceral fat are more effective as a means of preventing or delaying the onset of the disease,” said lead study author Mahsa Dolatshahi, M.D, who found this important result. M. P. A. is a post-doctoral research associate at Washington University School of Medicine’s Mallinckrodt Institute of Radiology (MIR) in St. Missouri, specifically Louis.
It is estimated by the Alzheimer’s Association that 6 to 9 million Americans 65 and older have Alzheimer’s disease. If no medical advances are made to prevent or cure the disease, the association predicts that by 2050, this number could rise to 13 million.
For this study, the researchers concentrated on the relationship between the pathology of Alzheimer’s disease and modifiable lifestyle factors, including obesity, body fat distribution, and metabolic aspects.
The study included 80 people in their midlife who were cognitively normal (average age: 49+4 years, female: 62+5 percent). Individuals’ average body mass index (BMI) was 32.31, and about 57.5 percent were obese.
A lipid (cholesterol) panel, body MRI, metabolic evaluation (glucose and insulin measurements), and brain positron emission tomography (PET) were performed on the participants.
The volume of visceral fat—the deep, hidden fat that surrounds the organs—and subcutaneous fat—the fat beneath the skin—was measured using abdominal MRI scans.
Dr. Dolatshahi, a member of the Raji Lab at MIR’s Neuroimaging Labs Research Center, stated, “We looked into the relationship between amyloid and tau deposition in Alzheimer’s disease and BMI, visceral fat, subcutaneous fat, liver fat fraction, thigh fat and muscle, as well as insulin resistance and HDL (good cholesterol).”.
The volume of muscle and fat was measured using thigh muscle scans. Using PET scans with tracers that attach to tau tangles and amyloid plaques, which build up in the brains of Alzheimer’s patients, the pathology of the disease was assessed.
The results showed that 77 percent of the effect of high BMI on amyloid accumulation was due to increased visceral fat, which was linked to increased amyloid. The increased Alzheimer’s pathology linked to obesity was not explained by other forms of fat.
Dr. Dolatshahi stated, “Our study demonstrated that higher visceral fat was associated with higher PET levels of the two hallmark pathologic proteins of Alzheimer’s disease—amyloid and tau.”.
To the best of our knowledge, no other study has shown these results at midlife, when participants are decades away from experiencing the first signs of dementia brought on by Alzheimer’s disease. “”.
Additionally, the research demonstrated that elevated amyloid in the brain was linked to both lower HDL and increased insulin resistance. People with higher HDL had a partial reduction in the effects of visceral fat on amyloid pathology.
Targeting the associated metabolic and lipid problems that frequently accompany increased body fat is a crucial part of managing Alzheimer’s risk in obesity, according to senior study author Cyrus A. M.D Raji. The Ph. D. a radiology associate professor at MIR.
While prior research has demonstrated that a high body mass index (BMI) can harm brain cells, no comparable study has examined the distinct roles of visceral and subcutaneous fat or metabolic profile, particularly with regard to Alzheimer’s amyloid pathology as early as midlife, Dr. Dolatshahi noted.
“This study provides important insights into why obesity can raise the risk for Alzheimer’s disease by going beyond using BMI to more accurately characterize body fat with MRI,” Dr. Dolatshahi stated.
Drs. A study by Raji, Dolatshahi, and associates that demonstrates how obesity and visceral fat impair blood flow to the brain will also be presented at RSNA 2024.
Researchers in that study compared whole-brain and regional cerebral blood flow on brain MRI in people with high vs. low BMI by performing brain and abdominal MRI on cognitively normal midlife individuals with a wide range of BMI. low levels of subcutaneous and visceral fat.
The group with a higher visceral fat percentage had reduced whole-brain blood flow. The groups with high cerebral blood flow did not differ significantly from those with low cerebral blood flow. low fat beneath the skin.
“With almost three out of four Americans being overweight or obese, this work will have a significant impact on public health,” Dr. Dot Raji stated.
Since visceral obesity has a detrimental effect on the brain, it may be possible to improve cerebral blood flow and lessen the burden and risk of Alzheimer’s disease by treating it with lifestyle changes or the right weight-loss medications. “”.
Paul K. is another co-author. Commean B. E. A. Mahshid Naghashzadeh, MdotS. Kassani, Sara Hosseinzadeh, Ph. A. Jake Weeks, B. A. Nguyen, B. Caitlyn. S. McBee-Kemper, Abby, B. S. Nancy Hantler, B. S. LaKisha Lloyd, Master of Science. Flores Shaney, MdotS. M.S and Yifei Xu. Liu Jingxia, Ph. A. as Claude B. M.D. Sirlin. Mitchell, Bettina, Ph. A. Joseph E. . Ippolito, M.D. , Ph. D. as John C. Morris, M.D. in addition to Tammie L. S. . Benzinger, M.D. as Ph. A.
The RSNA Trainee Research Prize was given for this study.
pertaining to this news about Alzheimer’s disease.
Writer: Linda Brooks.
The RSNA was the source.
Get in touch: RSNA Linda Brooks.
Picture: Neuroscience News is credited with this picture.
