The Role of Dietary Lipids in Cognitive Health: Implications for Neurodegenerative Disease

Abstract

Neurodegenerative diseases are a group of disorders characterised by progressive loss of brain function. The most common of these is Alzheimer's disease, a form of dementia. Intake of macro- and micro-nutrients impacts brain function, including memory, learning, mood, and behaviour. Lipids, particularly phospholipids and sphingolipids, are crucial structural components of neural tissues and significantly affect cognitive function. The importance of functional foods in preventing cardiovascular disease is well-documented in the current literature. However, the significance of such foods for central nervous system health and neurodegenerative diseases is less recognized. Gut microbiome composition affects cognitive health and function, and dietary lipids are known to influence gut health. Thus, this review will discuss different sources of dietary lipids and their effect on cognitive functioning and their interaction with the gut microbiome in the context of neurodegenerative disease.

Keywords: Alzheimer’s disease; dementia; functional foods; gut microbiota; gut-brain axis; inflammation; neurodegenerative disease; polar lipids.

Figure 1

Dietary lipids in the gut-brain axis. Dietary lipids intake can alter gut microbiome balance by increasing the Gram-negative bacteria population [58]. Saturated fatty acid consumption and metabolism affect gut health through reactive oxygen species generation [59]. Chronic gut inflammation can disrupt the intestinal tight junction and consequently lead to a “leaky gut”. Neurotoxins can penetrate the intestinal epithelium and, through the bloodstream, reach the BBB. A compromised BBB facilitates neurotoxins entering the brain and inducing inflammation [53,54]. Active microglia cells and reactive astrocytes can harm neuron cells.

Figure 2

Representation of common phospholipid structures: Glycerophospholipids (GPLs); an example of sphingosine-backbone phospholipid (SPLs), Sphingomyelin; and Alkyl-GPLs, which contain a fatty chain linked with an ether-bond at the sn-1 position of the glycerol backbone [71].