Excess Belly Fat Affects the Ability to Learn and Remember in Asians
Asians with an excess amount of visceral fat (the type of fat wrapped around the internal organs) tend to have poorer cognitive performance, according to a recently published study in The Lancet Regional Health - Western Pacific by researchers from Nanyang Technological University (NTU).
This finding is based on an analysis of the health data of close to 9,000 multi-ethnic Singaporeans and permanent residents collected for the Health for Life in Singapore (HELIOS) study between 2018 and 2021.
‘The prevention and control of obesity in Asian populations could play a role in protecting against the future risk of dementia.’
They found that an increase in the type of fat wrapped around the internal organs - known as visceral fat - is associated with poorer performance in cognitive tests of memory, executive function, processing speed, and attention.
When the scientists conducted a deeper dive into the relationship between body fat and cognition, using statistical analysis of genetic data from global databases, they found that a higher body mass index (BMI) and BMI-adjusted waist-to-hip ratio were also linked to a fall in cognitive performance.
Highlighting the Impact of Preventing Obesity on Cognitive Function
With dementia expected to afflict 78 million people in 2030, and 139 million people by 2050[1], understanding and addressing the determinants of cognitive function is a major public health priority.While earlier studies have shown that metabolic disorders could be risk factors for cognitive decline, scientists have been less certain that body fat is a risk factor for it. Most of these were performed in western populations, leaving out Asians.
To assess the link between body fat and cognitive function in an Asian population, researchers studied the health data of 8,769 participants living in Singapore of Chinese, Malay, or South-Asian ethnicity recruited for the Health for Life in Singapore (HELIOS) study.
The participants, aged between 30 and 84 years old, were evaluated through a series of cognitive tests, whole-body scans, physiological and biochemical assessments to derive a series of body fat and metabolic parameters.
Evaluation of data revealed that three parameters are consistently associated with a lower cognitive performance: reduced high-density lipoprotein (or �good' cholesterol), increased visceral fat mass index (a measure of visceral fat mass relative to body mass), and increased waist-to-hip ratio.
In contrast, parameters such as triglyceride levels (fat content in blood), blood pressure and glycaemic indices showed no association with cognitive performance.
Establishing A Biological Link Between Body Fat and Cognition
To form a clearer picture of the link between body fat and cognitive function, they turned to a statistical approach that makes use of small snippets of genes that vary from person to person. Through large-scale genetic studies - also known as genome-wide association studies - scientists have associated many of these snippets with specific health behaviours and risks.Such genetic variants are present in humans at birth at random and are not altered by the environment or a person's upbringing. Any difference observed in the health outcomes can be attributed to the presence or absence of specific genetic variants.
They found that genetic variants predicting excess visceral fat, elevated BMI, and increased BMI-adjusted waist-to-hip ratio are related to reduced cognitive performance.
Following these findings, researchers are now looking at how excess visceral fat across Asian ethnicities contributes to traits related to one's metabolism, such as insulin resistance, that are a result of a combination of factors, including genes, lifestyle, and the environment.
These findings would also give us evidence that visceral fat is more directly related to cognitive ageing, and not because of lifestyle or environmental factors.
Source: Eurekalert