Implications for Aromatherapy
Many studies have shown that some significant indicators of immune system function are affected by psychological factors such as mood and perceived levels of stress. Essential oils have been shown to have significant effects on mood states and these effects are believed to arise from stimulation of the olfactory nerve which sends signals into the limbic system, an area of the brain involved in the regulation of mood and emotions. Because the olfactory connections to the limbic system are very direct, inhaled odors can affect brain function, mood, and mental state almost instantly. In fact, an inhaled aroma affects the brain and its electrochemical signaling activity more quickly than an IV injection and one way in which essential oils may help to support healthy, balanced immune function is indirectly through the fairly rapid situational induction of the relaxation response and the reduction of anxiety and stress. Used consistently over time essential oils may promote lasting improvements in mood and reduction of stress levels, thereby aiding in the restoration of healthy immune system function.
Essential oils may also exert more direct effects on the immune system via their actions on the hypothalamus, the pituitary gland, the brain stem and other neural centers. The projections of the olfactory nerve are complex and one of the more interesting and relevant features of this system is that specific odors are routed to specific locations, depending on which olfactory receptors they bond with. Thus, one aroma may travel a specific pathway to the pituitary gland, where it triggers or inhibits the release of ACTH, while a different aroma may travel to a nucleus in the brain stem and stimulate the release of epinephrine. Though this phenomena has not been extensively studied with regard to essential oils, it supports the general idea that different essential oils may have different effects on both mood and immune system function.
In clinical practice, I have found aromatherapy to be a useful adjunctive intervention in cases of chronic stress and/or depression with resulting immune system weakness, fatigue, low vitality and other symptoms. To be fully effective when used in these conditions, aromatherapy must be integrated into a comprehensive treatment program that also includes proper diet and exercise, stress management, counseling, alternative treatments and appropriate medical supervision and treatment of on-going medical conditions when needed. The use of essential oils in massage is an especially effective method in such instances since massage also has a well established ability to reduce stress and promote relaxation. However, because alteration of hypothalamic and limbic system function by essential oils relies on nerve transmission pathways, and not on the transport of essential oil molecules through the blood, it is the inhalation of essential oil aromas that is the key to altering mood states, reducing stress, and supporting a balanced immune system. While massage does have the advantage of incorporating two modalities useful for stress reduction (touch and inhalation of essential oils), topical application is not a necessity and this is an area where good use can be made of diffusers and other devices, such as aromatherapy jewelry, that release essential oils into the air.