The impact on an individual’s brain and cognitive abilities is not solely determined by the total amount of body fat, but also by where that fat is stored. This conclusion was reached by researchers who examined data from over 18,000 adult participants in the UK Biobank. The findings of this study have been published in the journal Nature Mental Health (NMH).
Typically, body mass index (BMI) is used to gauge obesity, yet this metric fails to account for the distribution of adipose tissue. However, fat located in different bodily regions can exert varied effects on health. A research team, led by Anqi Qiu from the Hong Kong Polytechnic University, set out to investigate the correlation between fat deposits in distinct body areas and the brain’s structure and functionality.
The research encompassed more than 18,000 individuals, with an average age of approximately 62 years. Utilizing dual-energy X-ray absorptiometry, scientists measured body fat in the limbs, torso, and surrounding the internal abdominal organs, specifically referring to visceral fat. Subsequently, participants underwent various types of brain magnetic resonance imaging and a series of cognitive assessments designed to evaluate memory, information processing speed, reasoning capabilities, and executive functions.
The analysis revealed that different types of fat accumulation are linked to distinct alterations in the brain. Visceral fat emerged as the most detrimental. It demonstrated the strongest correlation with a decline in the condition of the brain’s white matter, which comprises the network of nerve fibers responsible for transmitting signals between different parts of the nervous system. Individuals with a higher proportion of visceral fat exhibited indicators of reduced nerve fiber density, fluid accumulation within brain tissues, and disorganization of these tissues.
The researchers also calculated what is termed “brain age,” a metric reflecting the extent of neural network aging. It was discovered that accelerated brain aging serves as the primary pathway through which excess body fat impairs cognitive functions. Across all tests administered, visceral fat consistently displayed the most significant negative impact on thinking and memory.
The researchers posit that these findings underscore the importance of considering not only an individual’s overall weight but also the specific locations of fat tissue accumulation within the body when assessing the risks associated with age-related cognitive decline.
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