Damaging effects of a high-fat diet to the brain and cognition: a review of proposed mechanisms

Abstract

The prevalence of obesity is growing and now includes at least one-third of the adult population in the United States. As obesity and dementia rates reach epidemic proportions, an even greater interest in the effects of nutrition on the brain have become evident. This review discusses various mechanisms by which a high fat diet and/or obesity can alter the brain and cognition. It is well known that a poor diet and obesity can lead to certain disorders such as type II diabetes, metabolic syndrome, and heart disease. However, long-term effects of obesity on the brain need to be further examined. The contribution of insulin resistance and oxidative stress is briefly reviewed from studies in the current literature. The role of inflammation and vascular alterations are described in more detail due to our laboratory's experience in evaluating these specific factors. It is very likely that each of these factors plays a role in diet-induced and/or obesity-induced cognitive decline.

Keywords: Brain Health; Cerebrovascularization; Cognition; Inflammation; Obesity.

Figure 1

Possible mechanisms of diet-induced cognitive decline. Mechanisms described in this review likely act in concert to cause cognitive decline. These mechanisms include, but are not limited to, altered vascularization and BBB integrity, inflammation, and oxidative stress. In this diagram, we show activation of endothelial cells which increases BBB penetration allowing more inflammatory molecules and ROS to enter the brain. Then, microglial cells perpetuate the inflammatory cascade causing damage to neuronal health.