Health and Disability

"We've known for some time that components of diet, both healthy and unhealthy, have a rapid impact on aspects of the brain that affect hippocampal size and function, but up until now these studies have only been done in rats and mice. This is the first study to show that this also appears to be the case for humans."

The researchers used magnetic resonance imaging to measure the size of hippocampi (there are two in the brain - left and right) in Australian adults aged 60-64 years and participating in the PATH study - a large longitudinal study of ageing conducted at the ANU. They also measured the participants' regular diets and took into account a range of other factors that could affect the hippocampus.

The results of the study, now published in the international journal BMC Medicine, suggest that older adults who eat more unhealthy foods, such as sweet drinks, salty snacks and processed meats, have smaller left hippocampi. It also shows that older adults who eat more nutrient-rich foods, such as vegetables, fruits and fish, have larger left hippocampi. These relationships existed over and above other factors that may explain these associations, such as gender, levels of physical activity, smoking, education or depression itself.