It is no surprise that food has evolved to reflect our ‘fast-paced’ lifestyles. Despite the negative consequences that ‘junk food’ has on our bodies, it is affordable, convenient and tasty – which increases its popularity. Consequently, 27% of Canadian adults suffer from obesity (Statistics Canada, 2018). Obesity can be considered “a disease in which excess body fat has accumulated such that health may be aversively affected” (Kopelman, 2000). In a clinical practice, body fat is most commonly measured by using a formula which combines weight and height – ‘Body-Mass Index’ (BMI) (Kopelman, 2000). Obesity can influence or exacerbate a number of health problems including Type 2 diabetes, Coronary Heart Disease (CHD), certain types of cancer, respiratory complications and osteoarthritis (Kopelman, 2000). Obesity poses a number of health risks for the body, but a new study suggests that it may also affect brain structure.
A study conducted by Hamer and Batty (2019) examined the combined association of BMI and WHR (waist-to-hip ratio) with brain structure. The researchers analyzed brain structure using MRI (magnetic resonance imaging), a medical technique that is used to form pictures of the anatomy and physiology of the body, and found that higher levels of body fat were linked to lower brain volumes in certain areas. To emphasize, the results from this study demonstrate associations between obesity and lower gray matter volume in the caudate nucleus, a c-shaped structure in the brain that plays a vital role in learning and the control of behaviour, and the putamen, a structure that is involved in learning and motor control. Gray matter is a tissue in the brain that consists mainly of nerve cell bodies and dendrites (branches of neurons that receive signals from other neurons). Structural alterations in gray matter have been shown to decline episodic memory, a memory system involved for the recollection of everyday events and increase the risk of developing dementia (Hamer and Batty, 2019). To emphasize, obesity may be a predictive factor in declining episodic memory recall and increasing the risk of developing dementia.
Brain atrophy is observed in those suffering from obesity. It cannot be determined whether obesity results in the shrinkage of brain volume or whether atrophy in certain areas of the brain lead to obesity. One possible explanation is that high levels of visceral body fat (fat stored in the abdomen) may cause an inflammation that harms our brain tissue (Hamer and Betty, 2019). Given the large amount of people that suffer from obesity, it is important to understand the negative consequences that high levels of fat intake have on all bodily systems, including the nervous system.
Hamer, M., & Batty, G. D. (2019). Association of body mass index and waist-to-hip ratio with brain structure: UK Biobank study. Neurology, 92(6), e594-e600.
Kopelman, P. G. (2000). Obesity as a medical problem. Nature, 404(6778), 635-643.
Statistics Canada, 2016 and 2017, Canadian Health Measures Survey, Ottawa.
