New research suggests that a specific type of body fat, called visceral fat, may play a key role in the early buildup of harmful proteins in the brain that are linked to Alzheimer’s disease.
Scientists discovered this connection up to 20 years before the first signs of dementia appear, highlighting the potential for weight management and lifestyle changes to reduce the risk of developing the disease.
The study, led by researchers at Washington University School of Medicine in St. Louis, was presented at the Radiological Society of North America (RSNA) annual meeting. The findings suggest that targeting visceral fat through lifestyle changes or medication could slow or prevent Alzheimer’s-related brain changes long before symptoms begin.
What is Visceral Fat and Why Does It Matter?
Visceral fat is the deep fat that surrounds organs in the abdomen. Unlike subcutaneous fat, which is stored just under the skin, visceral fat is hidden inside the body and is more closely linked to serious health problems such as diabetes, heart disease, and now Alzheimer’s disease.
Although obesity is already known to affect brain health, this study is the first to show that visceral fat—not overall body weight—may be the key factor linking obesity to Alzheimer’s disease.
The Study and Its Findings
The research team studied 80 cognitively normal adults with an average age of 49.4 years, meaning they were decades away from developing dementia. Most participants were overweight or obese, with an average BMI of 32.3 (above the obesity threshold of 30).
Participants underwent several tests, including:
- Brain PET scans to detect amyloid plaques and tau tangles—two proteins that build up in the brains of Alzheimer’s patients.
- MRI scans to measure different types of body fat (subcutaneous vs. visceral).
- Blood tests to assess metabolic health, including insulin resistance and cholesterol levels.
Key Results
- People with more visceral fat had higher levels of amyloid and tau in their brains.
- Visceral fat accounted for 77% of the link between high BMI and amyloid buildup, suggesting it is the main driver of obesity-related Alzheimer’s risk.
- Subcutaneous fat did not have the same effect, meaning that fat stored under the skin is not linked to Alzheimer’s in the same way.
- Higher insulin resistance and lower levels of HDL (“good” cholesterol) were also linked to more amyloid in the brain. However, people with higher HDL had a reduced impact of visceral fat on Alzheimer’s risk.
A New Understanding of Alzheimer’s Risk
This study is groundbreaking because it looks at Alzheimer’s risk in midlife, rather than in older adults who already have symptoms. Since Alzheimer’s disease develops decades before memory problems appear, early detection of risk factors like visceral fat could help doctors intervene earlier with treatments and lifestyle changes.
Lead researcher Dr. Mahsa Dolatshahi emphasized the importance of this early focus, saying that midlife is when Alzheimer’s-related brain changes begin, and it is also the best time to reduce risk through weight loss and metabolic health improvements.
Blood Flow and Brain Health
In a related study, the research team also found that people with higher visceral fat had lower blood flow in their brains, which may contribute to cognitive decline. Obesity-related brain changes could reduce the brain’s ability to clear harmful proteins, increasing the risk of Alzheimer’s over time.
This finding is particularly concerning because three out of four Americans are overweight or obese, meaning a large portion of the population may unknowingly be increasing their risk of Alzheimer’s through excess visceral fat.
What Can Be Done?
The good news is that visceral fat is a modifiable risk factor, meaning that it can be reduced through:
- Diet and exercise: Healthy eating and regular physical activity help reduce visceral fat and improve insulin sensitivity.
- Weight-loss medications: New obesity drugs that target visceral fat may help reduce Alzheimer’s risk in the future.
- Cholesterol and glucose management: Keeping blood sugar and cholesterol levels in check can protect brain health.
Final Thoughts
This study adds to growing evidence that Alzheimer’s is not just a brain disease, but a whole-body condition influenced by lifestyle and metabolism. While genetics play a role, factors like obesity, visceral fat, and metabolic health may significantly impact brain aging and dementia risk.
By focusing on reducing visceral fat as early as midlife, people may be able to slow or prevent the brain changes that lead to Alzheimer’s. As researchers continue to explore the connection between body fat and brain health, new strategies for preventing dementia could emerge—potentially saving millions from the devastating effects of Alzheimer’s disease.
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