The longer term effects of diet on the human brain



Department of Psychology, Macquarie University, Sydney, NSW2109, Australia


Habitual diet can affect several aspects of brain function. The most well documented effects come from the animal literature and show that diets rich in added sugar and/or saturated fat cause adverse changes to the hippocampus (learning and memory), prefrontal cortex (impulsivity) and brain reward pathways. Several studies have now started to document similar effects in humans. In addition, longitudinal studies are now beginning to identify dietary risk and protective factors in the development of Alzheimer’s and Parkinson’s disease. This article provides a brief but comprehensive review of this literature, offering the latest insights from the emerging field of nutritional neuroscience, alongside their implications.


While much attention has been given to the effects of nutritional problems during childhood on brain development (e.g., breastfeeding, malnourishment), it is only more recently that the impacts of habitual diet in adulthood have started to emerge as a distinct research area (e.g., 1, 2).  One particular focus has been on the consequences of consuming a ‘Western-style’ diet, characterised by high intakes of saturated fat, added sugar and salt, and low intakes of fresh fruit and vegetables.  The impacts of such a diet have become a target for research in nutritional neuroscience for several reasons, including: (i) the increasing number of people who consume this type of diet; (ii) its association with the development of obesity, diabetes and mental health problems; and (iii) the concern that consuming a Western-style diet may lead to significant impairments in brain function (3). The latter are especially worrying because they indicate that a Western-style diet may disrupt the brain’s ability to control food-intake, thereby directly contributing to the development of obesity (1).  Moreover, habitually consuming a Western-style diet may be a fac ...