Olfactory influences on mood and autonomic, endocrine, and immune function

Department of Psychiatry, The Ohio State University, 1670 Upham Drive, Columbus, OH 43210, USA.
Psychoneuroendocrinology (Impact Factor: 4.94). 05/2008; 33(3):328-39. DOI: 10.1016/j.psyneuen.2007.11.015
Source: PubMed


Despite aromatherapy's popularity, efficacy data are scant, and potential mechanisms are controversial. This randomized controlled trial examined the psychological, autonomic, endocrine, and immune consequences of one purported relaxant odor (lavender), one stimulant odor (lemon), and a no-odor control (water), before and after a stressor (cold pressor); 56 healthy men and women were exposed to each of the odors during three separate visits. To assess the effects of expectancies, participants randomized to the "blind" condition were given no information about the odors they would smell; "primed" individuals were told what odors they would smell during the session, and what changes to expect. Experimenters were blind. Self-report and unobtrusive mood measures provided robust evidence that lemon oil reliably enhances positive mood compared to water and lavender regardless of expectancies or previous use of aromatherapy. Moreover, norepinephrine levels following the cold pressor remained elevated when subjects smelled lemon, compared to water or lavender. DTH responses to Candida were larger following inhalation of water than lemon or lavender. Odors did not reliably alter IL-6 and IL-10 production, salivary cortisol, heart rate or blood pressure, skin barrier repair following tape stripping, or pain ratings following the cold pressor.

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Available from: Jennifer E. Graham-Engeland, Aug 19, 2014
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    • "Lavender, popular for relaxation and stress reduction [6], has been previously shown to improve cognition [7] and decrease agitation [8] [9], stress [10] [11] [12] [13], and anxiety [14] [15] [16] [17]. However, some studies demonstrated no specific lavender effects concluding that the changes after aromatherapy exposure occur solely due to expectancy of improvement [18] [19] and considered aromatherapy an " ineffective treatment but an effective placebo " [20]. To evaluate this idea, the role of expectancy in aromatherapy actions was the focus of our investigation. "
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    ABSTRACT: Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG) task performance and event related potentials (ERP) components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo) and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime). GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention.
    Full-text · Article · Jan 2015 · Evidence-based Complementary and Alternative Medicine
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    • "Herbal medicines usually have unique scents, and exposure to these odors may affect physiologic functions and clinical symptoms. Thus, aromatherapy is used for pain relief, induction of relaxation, reduction of anxiety, and energy enhancement [3]. Moreover, the olfaction process may have modulatory effects on the immune system [4,5]. "
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    ABSTRACT: Background Herbal medicines have unique odors, and the act of smelling may have modulatory effects on the immune system. We investigated the effect of olfactory exposure to Tokishakuyaku-san (TJ-23), a Japanese herbal medicine, on alloimmune responses in a murine model of cardiac allograft transplantation. Methods Naïve or olfactory-dysfunctional CBA mice underwent transplantation of a C57BL/6 heart and were exposed to the odor of TJ-23 until rejection. Some naïve CBA recipients of an allograft were given olfactory exposure to Sairei-to (TJ-114), trimethylthiazoline (TMT), individual components of TJ-23, or a TJ-23 preparation lacking one component. Adoptive transfer studies were performed to determine whether regulatory cells were generated. Results Untreated CBA mice rejected their C57BL/6 allografts acutely, as did olfactory-dysfunctional CBA mice exposed to the odor of TJ-23. CBA recipients of a C57BL/6 heart given olfactory exposure to TJ-23 had significantly prolonged allograft survival, whereas those exposed to the odor of TJ-114, TMT, one component of TJ-23, or TJ-23 lacking a component did not. Secondary allograft recipients that were given, at 30 days after transplantation, either whole splenocytes, CD4+ cells, or CD4+CD25+ cells from primary recipients exposed to the odor of TJ-23 had indefinitely prolonged allograft survival. Conclusions Prolonged survival of cardiac allografts and generation of regulatory cells was associated with exposure to the odor of TJ-23 in our model. The olfactory area of the brain may have a role in the modulation of immune responses.
    Full-text · Article · May 2014 · Journal of Cardiothoracic Surgery
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    • "Referring to a study of Kiecolt-Glaser et al. [27], we performed the olfactory function test on all subjects to assure that none had anosmia. Briefly, subjects were given two sets of three bottles—two held distilled water; the third contained essential oils (lavender or orange)—and were asked to choose the one that differed from the other two. "
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    ABSTRACT: Background A majority of reproductive-age women experience a constellation of various symptoms in the premenstrual phase, commonly known as premenstrual syndrome (PMS). Despite its prevalence, however, no single treatment is universally recognized as effective, and many women turn to alternative approaches, including aromatherapy, a holistic mind and body treatment. The present study investigated the soothing effects of aromatherapy on premenstrual symptoms using lavender (Lavandula angustifolia), a relaxing essential oil, from the perspective of autonomic nervous system function. Methods Seventeen women (20.6 ± 0.2 years) with mild to moderate subjective premenstrual symptoms participated in a randomized crossover study. Subjects were examined on two separate occasions (aroma and control trials) in the late-luteal phases. Two kinds of aromatic stimulation (lavender and water as a control) were used. This experiment measured heart rate variability (HRV) reflecting autonomic nerve activity and the Profile of Mood States (POMS) as a psychological index before and after the aromatic stimulation. Results Only a 10-min inhalation of the lavender scent significantly increased the high frequency (HF) power reflecting parasympathetic nervous system activity in comparison with water (aroma effect: F = 4.50, p = 0.050; time effect: F = 5.59, p = 0.017; aroma x time effect: F = 3.17, p = 0.047). The rate of increase in HF power was greater at 10–15 min (p = 0.051) and 20–25 min (p = 0.023) in the lavender trial than in the control trial with water. In addition, POMS tests revealed that inhalation of the aromatic lavender oil significantly decreased two POMS subscales—depression–dejection (p = 0.045) and confusion (p = 0.049)—common premenstrual symptoms, in the late-luteal phase, as long as 35 min after the aroma stimulation. Conclusions The present study indicated that lavender aromatherapy as a potential therapeutic modality could alleviate premenstrual emotional symptoms, which, at least in part, is attributable to the improvement of parasympathetic nervous system activity. This study further implies that HRV could evaluate the efficacy of aromatherapy using various fragrances to relieve premenstrual symptoms, and ultimately, support the mind and body health of women.
    Full-text · Article · May 2013 · BioPsychoSocial Medicine
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