(L-R) Julie Dumas, Ph.D. and C. Lawrence Kien, M.D., Ph.D.

Professor of Psychiatry Julie Dumas, Ph.D. and C. Lawrence Kien, M.D., Ph.D., The Mary Kay Davignon Green and Gold Professor Emeritus of Pediatrics and Medicine have recently secured a $3.3M, five-year R01 grant from the National Institute on Aging (NIA): “Fatty Acid Modulation of Brain Functioning in Older Adults”. This award will enable the duo to delve deeper into the relationship between dietary fatty acids and cognitive health in older individuals.

During the course of the grant, Dumas, Kien, and their team of researchers from Larner College of Medicine will concentrate on understanding the impact of substituting palmitic acid (PA), a saturated fat, with oleic acid (OA), a monounsaturated fat.

“Our prior studies have shown that reducing the dietary saturated fat resulted in changes in brain functioning including mood and exercise,” said Dumas. “In this new study, we are interested in whether this fatty acid manipulation influences memory performance during cognitive testing in healthy older adults.”

In previous studies of young adults, this group observed that physical activity, resting energy expenditure, and mood were enhanced and pro-inflammatory cytokine secretion (small proteins produced by immune cells that regulate the body's response to infection, inflammation, and other stimuli) was reduced during the low PA diet. Importantly, the adverse effects of a high PA diet on mood, physical activity, and cytokine secretion were reversed by a low PA/high OA diet for a few days. 

The new grant also will build upon a recent study, also funded by NIA, which involved ten participants aged 65 to 75 years (Aging Brain 3, 2023, 100072). The subjects followed two distinct diets for one week each in random order: one with the typically high PA content of the North American Diet and the other low in PA but rich in OA. Brain imaging techniques were employed, alongside measurements of inflammatory markers in the blood.

The findings from this small study revealed that during the low PA/high OA diet, there was heightened brain activity in a memory-related brain region, despite no statistically significant change in overall memory performance. Additionally, alterations were observed in the intercommunication among different brain regions during rest. Furthermore, levels of inflammatory markers in the blood decreased during the low PA/high OA diet, suggesting potential anti-inflammatory effects of substituting PA with OA in older adults. The clinical trial funded by this new grant will expand upon these findings by recruiting a larger sample of fifty healthy older adults. This broader study aims to confirm previous observations and deepen the understanding of the relationship between fatty acids and cognitive function in the older adults.

Aside from the practical interest in improving cognition in older adults, there is also scientific importance to these studies. Kien points out that the study is built upon studies in both humans and rodents: “Consistently eating foods that promote secretion of pro-inflammatory cytokines can affect brain function by reducing signaling from insulin and brain-derived neurotrophic factors. This impacts sleep quality and physical activity, both crucial for cognitive functions like memory, attention, and judgment. So, what you eat, especially your recent meals, can change cognitive function in older adults with memory issues, particularly if they have increased secretion of pro-inflammatory cytokines due to aging.”