Evaluation of olive oil effects on human stress response by measuring cerebral blood flow

Abstract

In this paper, we evaluated the effects of olive oil on human's stress level. In recent years, mental stress from harsh working environment have been causing serious problems to human health, both mentally and physically. Symptoms of stress may include feelings of worthlessness, agitation, anxiety, lethargy, insomnia, and behavioral changes. Additionally, the harsh working environments may cause the workers to adopt unhealthy dietary habits, contributing to the health issue. On the other hand, olive oil has been known to provide stress‐relieving effects both by ingestion and by inhaling the scent. Here, we examined the effects of extravirgin olive oil ingestion for mitigating stress from deskwork. Three best‐selling extravirgin olive oil in Japan were tested, and typing task was selected to emulate deskwork situation. Near‐infrared spectroscopy (NIRS) is utilized in this study to visualize the response in brain via cerebral blood flow analysis and to measure participants’ stress level. Statistical analysis showed that the stress levels were lower during the olive oil ingestion experiment compared to no‐oil experiment, even when measured one hour after the ingestion.

fNIRS neuroimaging in olfactory research: A systematic literature review

“…One study opted to use a fragrances liquid, rose water, as a stimuli (Moss et al, 2018 ). A significant proportion of studies incorporated odor in an in-context paradigm, e.g., foot massage using essential oils (Eto et al, 2014 , 2015 , 2016 ), presentation with or in food or drink (Matsumoto et al, 2012 ; Onuma et al, 2018 ; Rajagoplan, 2018 ; Mitsukura et al, 2021 ), chewing gum (Hasegawa et al, 2013 ), incense (Fujii et al, 2007 ), and household spray (Tanida et al, 2008 ). One study aimed to develop a novel odor delivery system.…”

“…Yamashita et al ( 2022 ) also utilized a combinatory study, with visual light displays as well as odor. Mitsukura et al ( 2021 ) employed a cognitive typing task prior to and after olive oil consumption. Similarly, Tanida et al ( 2008 ) tested mental arithmetic prior to and after exposing participants to a floral fragrance for 4weeks.…”

“…Nishitani et al ( 2014 ) observed increased Δ[HbO2] in mothers in response to infant odor, a finding which was not replicated in non-mothers. Seven studies observed significant decreases in Δ[HbO2] in response to various odors, e.g., relaxing essential oil odors during a massage (Eto et al, 2015 , 2016 ), olive oil odor (Mitsukura et al, 2021 ), forest odor (Song et al, 2019 ), Hinoki oil (Ikei et al, 2015 ), rose and orange oil (Igarashi et al, 2014 ), and floral spray (Tanida et al, 2008 ). It is important to note that some studies observed no significant effect of odor on cerebral hemodynamics (Maharjan et al, 2018 ; Onuma and Sakai, 2018 ; Kaimal et al, 2021 ; Tomono et al, 2021 ).…”

“…Other studies used olfactory function tests as the basis for odor stimuli implementation (Schecklmann et al, 2011a , b ; Azuma et al, 2016 ; Kim et al, 2022 ). Multiple studies employed food or drink as a means to introduce odor stimuli (Matsumoto et al, 2012 ; Hasegawa et al, 2013 ; Onuma et al, 2018 ; Rajagoplan, 2018 ; Tomono and Tomono, 2020 ; Mitsukura et al, 2021 ; Muelbert et al, 2021 ; Tomono et al, 2021 ).…”