Can Impaired Insulin Sensitivity Affect Cognition in Obese People?
Psychologists at the University of Texas at Austin discovered obesity can affect cognitive abilities. The culprit is impaired insulin sensitivity in obese people. In the case of poor insulin sensitivity, insulin levels are elevated in the blood due to an inability to force glucose into muscle tissue.
The results of the research study were published in the October 2010 issue of the journal Obesity. Obese and overweight adults 40-60 years of age were asked to complete a challenging task involving cognitive abilities.
The responses of the brain, while participants were doing specific tasks, were monitored using functional magnetic resonance imaging (MRI).
Individuals from various groups completed the tasks well, but obese people had a section of their brain, the inferior parietal lobe, functioning less. As observed, obese individuals had lower testing results when compared to other participating groups.
This means that glucose is broken down into energy less efficiently in their body, keeping blood sugar levels high for extended periods of time. The research study found that impaired sensitivity to insulin can be a potential mediator for causing cognitive decline in the later years of people who have obesity during mid-life.
A lower sensitivity to the hormone insulin disrupts the normal processing of the brain and carries out different chemical reactions, in order to produce the same cognitive abilities, in obese people similar to healthy weight individuals.
Significance of the Research on Lower Insulin Sensitivity and Poor Cognitive Abilities Nexus:
While obese, overweight and healthy weight participants performed equally well on all task, obese individuals displayed lower functional brain response. The study showed that impaired insulin sensitivity, which generally accompanies obesity and metabolic syndrome, may serve as a bridge between midlife obesity and cognitive decline in later years.
Researchers know that weight loss and increased physical activity result in improvements in insulin resistance. Sensitivity to insulin can be reversed by adopting a good diet and exercising regularly. Further supporting studies have consistently found reduced performance on exams, brain processing speed, attention, decision functioning, learning and recall.
Source: University of Texas at Austin
Awad N, Gagnon M, Messier C. The relationship between impaired glucose tolerance, type 2 diabetes, and cognitive function. Journal Of Clinical And Experimental Neuropsychology: Official Journal Of The International Neuropsychological Society. 2004;26:1044–1080.