The Effect of Western diet on cognition in humans

The typical Western diet, high in saturated fat and refined sugars (HFS), has been observed to cause neurological changes, with a subsequent effect on cognition. The present chapter presents animal and human research demonstrating that high intake of saturated fat, refined sugar or the two in combination, has an effect on cognitive functions, including memory, attention, working memory, inhibition and affective states related to food intake. Putative causal factors thought to underlie these effects are discussed, such as neuronal inflammation, oxidative stress, reduced blood-brain barrier integrity and reduced levels of brain-derived neurotrophic factor. The chapter also discuses evidence that the neurological effects of HFS diets are linked to disorders that are prevalent in Western societies and also impair cognition, such as depression and neurodegenerative disease. Preliminary evidence suggests that these changes may be reversible through dietary intervention and exercise.