A study of older adults at risk of late-onset Alzheimer's disease found that those who consumed more omega-3 fatty acids did better than their peers on tests of cognitive flexibility -- the ability to efficiently switch between tasks -- and had a bigger anterior cingulate cortex, a brain region known to contribute to cognitive flexibility.
The new study focused on 40 cognitively healthy older adults between the ages of 65 and 75 who are carriers of a gene variant (APOE e4) that is known to contribute to the risk of developing late-onset Alzheimer's disease.
The researchers tested participants' cognitive flexibility, measured levels of the fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in their blood, and imaged their brains using MRI. Statistical analyses teased out the relationships between these factors.
"We wanted to confirm that higher omega-3 fatty acids related to better cognitive flexibility, and we did in fact see that," Zamroziewicz said.
"We also wanted to confirm that higher omega-3 fatty acids related to higher volume in the anterior cingulate cortex, and we saw that. Finally, we were able to show that higher volume in the anterior cingulate cortex was an intermediary in the relationship between omega-3 fatty acids and cognitive flexibility."
"Recent research suggests that there is a critical link between nutritional deficiencies and the incidence of both cognitive impairment and degenerative neurological disorders, such as Alzheimer's disease," said University of Illinois neuroscience, psychology, and speech and hearing science professor Aron Barbey, who led the study with M.D./Ph.D. student Marta Zamroziewicz.
"Our findings add to the evidence that optimal nutrition helps preserve cognitive function, slow the progression of aging and reduce the incidence of debilitating diseases in healthy aging populations."