New discovery predicts Alzheimer’s risk 20 years prior to symptoms

Research presented at the annual meeting of the Radiological Society of North America (RSNA) reveals a striking connection between visceral fat and Alzheimer’s disease.

Scientists found that this deep fat, surrounding internal organs, is linked to abnormal brain proteins associated with Alzheimer’s up to 20 years before symptoms appear.

Their findings highlight how targeted lifestyle modifications could play a significant role in lowering the risk of developing the disease.

“This crucial result was discovered because we investigated Alzheimer’s disease pathology as early as midlife—in the 40s and 50s,” said Dr. Mahsa Dolatshahi of Washington University’s Mallinckrodt Institute of Radiology (MIR). “At these early stages, interventions such as weight loss and reducing visceral fat are more effective in preventing or delaying the disease.”

Approximately 6.9 million Americans aged 65 and older live with Alzheimer’s, a figure projected to double to 13 million by 2050 without breakthroughs in prevention or treatment, according to the Alzheimer’s Association. This looming public health crisis underscores the urgency of understanding modifiable risk factors.

Obesity has long been suspected as a contributor to Alzheimer’s disease, but this study provides unprecedented detail about how visceral fat uniquely impacts brain health. The researchers focused on identifying links between obesity, body fat distribution, metabolic health, and Alzheimer’s disease pathology.

The study included 80 cognitively healthy individuals in midlife, with an average age of 49.4 years. Sixty-two percent were women, and over half of the participants were obese, with an average body mass index (BMI) of 32.31. Advanced imaging and metabolic assessments allowed the researchers to investigate relationships between different fat types and Alzheimer’s pathology.

Participants underwent brain positron emission tomography (PET) scans to measure amyloid plaques and tau tangles, the hallmark proteins of Alzheimer’s disease. Detailed body scans assessed visceral fat, subcutaneous fat (under the skin), and liver fat, while thigh muscle scans measured muscle and fat distribution. Blood tests evaluated markers of metabolic health, including insulin resistance and cholesterol levels.

“We investigated the association of BMI, visceral fat, subcutaneous fat, liver fat fraction, thigh fat and muscle, as well as insulin resistance and HDL (good cholesterol), with amyloid and tau deposition in Alzheimer’s disease,” Dr. Dolatshahi explained.

The study found that higher levels of visceral fat correlated with increased amyloid in the brain, accounting for 77% of the effect of high BMI on amyloid accumulation. Other fat types, including subcutaneous fat, did not show the same link to Alzheimer’s pathology.

“Our study showed that higher visceral fat was associated with higher PET levels of amyloid and tau,” said Dr. Dolatshahi. “To our knowledge, our study is the only one to demonstrate these findings at midlife, decades before dementia symptoms develop.”

These results indicate that visceral fat may play a unique and direct role in Alzheimer’s progression, distinct from general obesity. The researchers also found that higher insulin resistance and lower HDL cholesterol levels were associated with increased amyloid accumulation.

Interestingly, the effects of visceral fat on amyloid were less pronounced in individuals with higher levels of HDL cholesterol, suggesting that lipid management could mitigate some of the risk.

“This study goes beyond using BMI to characterize body fat more accurately with MRI,” Dr. Dolatshahi noted. “In doing so, it reveals key insights about why obesity can increase risk for Alzheimer’s disease.”

The research builds on previous findings that obesity damages brain cells, but it is among the first to distinguish between the impacts of visceral and subcutaneous fat. The study’s midlife focus is particularly important, as this is when Alzheimer’s pathology begins to develop and when preventive measures can be most effective.

In a related study also presented at RSNA 2024, researchers examined how visceral fat affects brain blood flow. Using advanced MRI techniques, they compared cerebral blood flow in individuals with high and low levels of visceral fat.

Those with higher visceral fat showed reduced blood flow throughout the brain, while no significant differences were observed between groups with varying levels of subcutaneous fat.

“This work will have a considerable impact on public health because nearly three out of four Americans are overweight or obese,” said senior study author Dr. Cyrus A. Raji. “Knowing that visceral obesity negatively affects the brain opens up the possibility that treatment with lifestyle modifications or appropriate weight-loss drugs could improve cerebral blood flow and potentially lower the burden of and reduce the risk for Alzheimer’s disease.”

The findings underscore the importance of addressing obesity, particularly visceral fat, as part of Alzheimer’s prevention strategies. Lifestyle changes, such as a healthy diet and regular exercise, along with targeted medical interventions, could significantly reduce risk. Moreover, these results highlight the need to manage metabolic and lipid-related complications that often accompany obesity.

“This research provides actionable insights for managing Alzheimer’s risk,” Dr. Raji emphasized. “By reducing visceral fat and improving metabolic health, individuals may protect their brains decades before symptoms appear.”

As scientists continue to investigate Alzheimer’s disease, these findings offer hope for early prevention. By identifying visceral fat as a key driver of brain changes, researchers have opened new avenues for reducing the risk of dementia through targeted interventions.

With millions of lives at stake, understanding and addressing modifiable risk factors such as visceral fat could play a pivotal role in curbing the Alzheimer’s epidemic. While medical breakthroughs are needed to fully halt the disease, lifestyle and metabolic improvements provide a promising path forward for reducing its devastating impact.

Note: Materials provided above by The Brighter Side of News. Content may be edited for style and length.

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