The effects of olive oil and oleuropein on depression and anxiety

Depression and anxiety are mood disorders that affect approximately 280 to 301 million people worldwide. These disorders are characterized by excessive worry, low self-esteem, depressed mood, and other symptoms that impact daily life. In addition, depression and anxiety are often comorbid, with depression exacerbating anxiety symptoms and anxiety worsening depression. This study examined the potential antidepressant and anxiolytic properties of olive oil and oleuropein, a phenolic compound found in olive oil. Both olive oil and oleuropein may be feasible naturopathic treatments for depression and anxiety due to their ability to reduce oxidative stress in the brain. Additionally, they may promote the levels of noradrenaline, adrenaline, and BrainDerived Neurotrophic Factor. This study used three groups of six Sprague-Dawley rats, (n=18) selectively bred for genetic predispositions to depression and anxiety-related behaviors, (i.e., the Swim Low-Active line). One group was fed oleuropein daily, another was fed olive oil, and the last group remained on a control diet for 57 days. Data was analyzed using a one-way analysis of variance, utilizing data from three behavioral tests: the Open-Field Test, the Porsolt Swim Test, and the Elevated Plus Maze. The olive oil group exhibited significantly less anxiety-related behavior than the control group in the Elevated Plus Maze, which was measured by recording the number of times the rats entered the open arms of the maze. These findings indicate that olive oil had more effective anxiolytic effects than oleuropein in rodent models. However, there were no significant changes in depression-related behavior in either the experimental or control groups observed during the Porsolt Swim Test. These results support the potential naturopathic benefits of olive oil in treating anxiety. This paper also opens the door for further research into the interactions of specific phenolic compounds found in olive oil to reduce oxidative stress.