High-Fat and Cholesterol Intake Affects Brain Homeostasis and Could Accelerate the Development of Dementia: A Systemic View

Alzheimer’s disease is the most common type of dementia in occidental countries. The majority of the cases develop the disease for no genetic reasons; therefore, it is crucial to establish which environmental factors trigger the development of the disease. It has been proposed that nutritional habits, especially main components of Western countries’ diet such as saturated fat or cholesterol, increase the risk for development of Alzheimer’s disease (AD) and/or accelerate the onset of the disease, which is a big concern in countries where obesity is a public health problem. It is crucial to understand the links between alimentary habits and the development of AD and other types of dementia. A possible mechanism is the disruption of blood–brain barrier (BBB), which is the protection of the brain from circulating blood. Such disruptions can result from consuming high-fat diet (HFD) or high-cholesterol diet (HCD) and inflammation produced by alteration in brain vasculature resulted for chronic consumption of such type of diets. What has named a "Systemic view" comprises the idea that; what happens outside of the brain environ‐ ment does affect brain functioning and the modifications experienced in the brain environment resulted from the influence of external factors will affect the entire body. In the current chapter, we will review the state of the art in the studies of the impact of a diet rich in fat or cholesterol on the brain and how the alterations induced in other organs can impact brain functioning increasing the susceptibility of development of dementia.