Obesity and Cognitive Deficits
According to the World Health Organization, (WHO) obesity has become a global epidemic, with numbers reaching more than one billion individuals worldwide (World Health Organization, 2013). As noted by the Center for Disease Control and Prevention, obesity increases the risk for coronary heart disease (CHD), stroke, Type 2 Diabetes, and certain types of cancer, all of which are the leading causes of preventable death (Center for Disease Control, 2015). Deficits across a variety of cognitive domains including attention, processing speed, memory, and executive functioning have been demonstrated in patients with medical diagnoses such as hypertension, diabetes, and obstructive sleep apnea (Manschot et al., 2006; Battersby et al., 1993). While these medical conditions are often resultant from obesity, recent studies indicate that neurocognition is affected in obese individuals independent of comorbid medical conditions (Gunstad et al, 2007; Whitmer, Gunderson, & Barrett-Connor, 2005). Increased Body Mass Index (BMI) has been implicated in the reduction of cognitive performance, specifically in the areas of memory and executive function, in samples of older adults, middle-age adults, and young adults (Elias, Elias, Sullivan, Wolf, & D’Agostino, 2003; Gustad et al, 2007). Additionally, research has shown that executive dysfunction has been positively associated with disinhibited eating and increased food cravings (Spinella & Lyke, 2004), and that decision-making impairments have been positively associated with elevated BMI (Davis, Levitan, Muglia, Bewell, & Kennedy, 2004). When studying neuropsychology within obesity, a question regarding direction of causality typically emerges; do cognitive deficits lead to obesity, or does obesity lead to cognitive deficits? Emerging research has attempted to elucidate these questions by utilizing obesity-associated biomarkers in order to tease apart these closely linked ideas.
Miller, A.L, Lee, H.J., Lumeng, J.C. (2015). Obesity-associated biomarkers and executive function in children. Pediatric Research, 77, 143-147. http://www.ncbi.nlm.nih.gov/pubmed/25310758
There is a growing focus on links between obesity and cognitive decline in adulthood, including Alzheimer's disease. It is also increasingly recognized that obesity in youth is associated with poorer cognitive function, specifically executive functioning skills such as inhibitory control and working memory, which are critical for academic achievement. Emerging literature provides evidence for possible biological mechanisms driven by obesity; obesity-associated biomarkers such as adipokines, obesity-associated inflammatory cytokines, and obesity-associated gut hormones have been associated with learning, memory, and general cognitive function. To date, examination of obesity-associated biology with brain function has primarily occurred in animal models. The few studies examining such biologically mediated pathways in adult humans have corroborated the animal data, but this body of work has gone relatively unrecognized by the pediatric literature. Despite the fact that differences in these biomarkers have been found in association with obesity in children, the possibility that obesity-related biology could affect brain development in children has not been actively considered. We review obesity-associated biomarkers that have shown associations with neurocognitive skills, specifically executive functioning skills, which have far-reaching implications for child development. Understanding such gut-brain associations early in the lifespan may yield unique intervention implications.
Obesity and Addiction: https://www.youtube.com/watch?v=Mnd2-al4LCU
Neuroscientist Nora Volkow, director of the National Institute on Drug Abuse at the NIH, applies a lens of addiction to the obesity epidemic.
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- Center for Disease Control (2015). Overweight and Obesity. Retrieved July 2, 2015 from http://www.cdc.gov/obesity/
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- Davis, C., Levitan, R. D., Muglia, P., Bewell, C., & Kennedy, J. (2004). Decision-making deficits and overeating: A risk model for obesity. Obesity Research, 12, 929–935. http://www.ncbi.nlm.nih.gov/pubmed/15229331