Link Between Abdominal Fat and Cognitive Decline
Growing Health Concerns
Excess weight, particularly around the waist, has been correlated with cognitive decline. The health risks associated with obesity are increasingly alarming. In 2018, Canada reported that 7.3 million adults over eighteen were classified as obese, while an additional 9.9 million were considered overweight. Although many individuals with excess weight maintain good health, some individuals experience significant cognitive issues.
Research Findings
Numerous studies have indicated a higher incidence of age-related cognitive decline among obese individuals, alongside the deterioration of brain regions associated with memory. However, the exact mechanism connecting obesity to cognitive impairment remains elusive. To address this gap, researchers from the Medical College of Georgia investigated the impact of abdominal fat on brain function.
For the first time, the researchers established a connection between visceral fat—fat stored within the abdominal cavity—and its detrimental effects on cognition. They discovered a specific signal produced by visceral fat that enters the bloodstream, crosses the blood-brain barrier, and subsequently impairs cognitive functions.
Role of Interleukin-1 Beta
Visceral fat produces elevated levels of interleukin-1 beta, a protein that over-activates microglia, the brain’s protective immune cells. This fat type also triggers the formation of inflammasome complexes, specifically involving the NLRP3 gene, leading to increased interleukin-1 beta production. Consequently, this inflammation in the brain contributes to cognitive difficulties.
Study Methodology and Results
Published in the Journal of Clinical Investigation, the study presented compelling evidence detailing how abdominal fat influences brain health. The researchers conducted experiments by removing the NLRP3 gene from mice, which resulted in a protective effect against obesity-induced brain inflammation. Transplants of visceral fat from both obese mice and those lacking the NLRP3 gene were performed on lean mice. Notably, the fat transplantation from genetically modified mice did not yield any adverse effects, while the transplant from obese mice with the intact gene heightened interleukin-1 beta levels in the brain, resulting in cognitive issues.
To assess cognitive abilities, the mice underwent a water maze navigation test after twelve weeks on either a low or high-fat diet. Those on the high-fat diet or that received visceral fat transplants from intact NLRP3 gene mice took longer to navigate the maze and struggled to locate a submerged platform they had previously learned to find. Additionally, the high-fat diet mice exhibited weaker neuronal connections related to learning and memory.
Implications and Recommendations
This study contributes to the growing body of evidence highlighting that the activation of the NLRP3 inflammasome in visceral fat negatively affects cognition in the context of obesity. While lifestyle changes, including improved diet and exercise, can positively influence cognitive health, achieving these changes can be challenging for many individuals. Emerging evidence also suggests that bariatric surgery may enhance memory and cognitive function; however, caution is advised, as surgical interventions carry greater risks for those with mild to moderate obesity.
References
EurekAlert!. 2020. Visceral Fat Delivers Signal To The Brain That Hurts Cognition. [online] Available at: [Accessed 10 March 2020].
Guo, D., Yamamoto, M., Hernandez, C., Khodadadi, H., Baban, B. and Stranahan, A., 2020. Visceral adipose NLRP3 impairs cognition in obesity via IL-1R1 on CX3CR1+ cells. Journal of Clinical Investigation.
www150.statcan.gc.ca. 2019. Overweight And Obese Adults, 2018. [online] Available at: [Accessed 10 March 2020].