Walnuts are abundant in alpha-linolenic acid, which is a plant-derived omega-3 fatty acid. They also contain a higher amount of polyphenolic compounds compared to other nuts. Both omega-3 fatty acids and polyphenols are essential for brain health as they have the potential to combat oxidative stress and inflammation, which are two factors contributing to the decline in cognitive function.
Oxidative stress has been consistently associated with the decline in cognitive function that occurs with aging, often preceding the onset of dementia. Studies examining the connection between consuming diets rich in antioxidants and a reduced risk of cognitive impairment provide further support for the idea that oxidative stress contributes to cognitive decline.
Walnuts contain a substantial amount of alpha-linolenic acid, a type of plant-based omega-3 fatty acid. They also possess a higher concentration of polyphenolic compounds compared to other nuts. These omega-3 fatty acids and polyphenols are recognized as important nutrients for brain health, as they have the potential to counteract the harmful effects of oxidative stress and inflammation—both of which play key roles in driving cognitive decline. Therefore, the consumption of walnuts could have a positive impact on cognitive function.
A research study conducted across two locations, Barcelona (Spain) and Loma Linda (California), utilized a randomized controlled trial to investigate the cognitive effects of a two-year dietary intervention involving walnuts among initially healthy elderly individuals. This study, which was published in The American Journal of Clinical Nutrition, involved 708 older adults who were randomly assigned to either a diet enriched with walnuts (30-60g/day) or a diet without walnuts. A comprehensive set of neurocognitive assessments was conducted at the beginning of the study and again after two years. Additionally, a subset of 108 participants from Barcelona underwent repeated brain magnetic resonance imaging (MRI) scans, both structural and functional, to further analyze changes in the brain.
Out of the 636 individuals who successfully completed the two-year study, it was found that consuming walnuts did not have a significant overall impact on cognitive function. However, when the data was analyzed based on different study locations and brain imaging results for participants from Barcelona, who had lower education levels and less dietary alpha-linolenic acid compared to those from Loma Linda, there were indications that walnuts might have the potential to slow down cognitive decline in certain subgroups facing higher risk. The researchers, led by Emilio Ros and his team at Hospital Clinic in Barcelona, acknowledged these findings as promising, but not definitive, regarding the influence of walnuts on brain health. The study calls for further exploration, particularly focusing on disadvantaged populations that stand to gain the most benefit from such interventions.
Dr. Kathy Beerman is a distinguished faculty member at Washington State University’s School of Biological Sciences. Her academic contributions encompass a range of published articles, with a particular focus on innovative approaches for addressing iron deficiency anemia in rural areas of Guatemala and Ecuador. Dr. Beerman plays a pivotal role in educating students, both through her undergraduate nutrition course tailored for health majors and a specialized program preparing students for a 10-day medical mission to Guatemala.
With an illustrious tenure at Washington State University dating back to 1990, Dr. Beerman has garnered multiple accolades for her exceptional teaching skills. Noteworthy awards include the Burlington Northern Faculty Meritorious Achievement in Teaching Award, the R.M. Wade Foundation Award for Excellence in Teaching, and the Sahlin Faculty Excellence Award for Instruction. Her remarkable contributions have also earned her the CAS Outstanding Achievement Award in International Activities in 2017 and the prestigious President’s Award for Leadership in 2018.
Among her scholarly pursuits, Dr. Beerman has co-authored two introductory nutrition textbooks: “Nutritional Sciences: From Fundamentals to Food” and “NUTR.” These accomplishments underscore her dedication to advancing knowledge and nurturing the academic growth of her students.