According to a recent study, individuals who accumulate significant quantities of fat around their organs in the belly region may be more susceptible to Alzheimer's disease.
Visceral fat, or "hidden" fat, is accumulated around internal organs like the liver and intestines and is kept deep inside the abdomen. It can accumulate around the organs of even people with healthy BMIs and is associated with changes in the brain potentially decades before any symptoms of cognitive decline are seen.
Senior author, Cyrus Raji of Washington University School of Medicine in St. Louis, noted during the annual meeting of the Radiological Society of North America on November 20 that visceral fat has previously been linked to higher levels of insulin and systemic inflammation, which happens when the immune system is constantly activated even when there is no threat to health.
Both of these factors are thought to be involved in the development of Alzheimer's.
We need to move beyond traditional conceptions of body fat, like BMI, and really look at the specifics of how fat is distributed to understand the health risks.Raji
Raji continues that there can be indicators that someone has visceral fat, but an MRI of the abdomen is necessary to confirm it.
The Alzheimer's Association estimates that over six million Americans have Alzheimer's disease. Nearly two-thirds of Americans 65 years of age and older suffer from the illness, which affects one in nine individuals in this age group.
The organization says the figure will increase to 13 million by 2050.
The team examined the relationship between visceral fat and Alzheimer's disease risk by analyzing data from 54 cognitively healthy individuals with average BMIs of 32 between the ages of 40 and 60.
The CDC defines obesity as a BMI of 30 or greater.
Blood sugar and insulin levels were among the health markers that the researchers analyzed. They evaluated the quantity of fat directly beneath the skin and the area around the organs using MRI imaging.
The thickness of the cortex, which thins as Alzheimer's disease worsens, was also measured using MRIs. A group of patients had PET scans to check for elevated levels of tau and amyloid, two proteins linked to Alzheimer's disease.
Visceral fat and Alzheimer’s
Upon combining the analysis of the brain scans with the fat measurements, the researchers discovered that individuals with greater levels of visceral fat had higher levels of amyloid buildup in their brains, indicating a possible increased risk of Alzheimer's disease.
Per Raji, other studies have connected visceral fat to inflammation and elevated insulin, which can inhibit the proteins in the brain that break down amyloid.
Because Alzheimer's can start developing in the brain up to 20 years before symptoms manifest, the researchers intend to follow up with study participants to investigate any possible long-term effects of visceral fat.
He says exercise—especially aerobic exercise—is the most effective approach to reduce visceral fat.
- Elsevier. Correlation of visceral body fat with waist–hip ratio, waist circumference and body mass index in healthy adults: A cross sectional study.
- Healthdirect Australia. How to reduce visceral body fat (hidden fat).
- Alzheimer's Association. Alzheimer's Disease Facts and Figures.