Boosting NK Cells (Anti-Cancer) and Other Benefits of Forest Bathing and Diffusing Forest Essential Oils
The forest is a magical environment. There are many reasons this is true, and has little to do with the imaginative fairy tales that speak of such forestry magic. The feelings that come from a forest visit are partly due to a genetic connection we, as human animals, have to nature. This connection is called “biophilia.” There is also an emotional and healing response resulting from the compounds saturating the atmosphere released by the forest trees and plants, called phytoncides by the forest bathing community.
Studies have consistently shown that what happens when you visit a forest is a decrease in depression and stress levels, better sleep quality, improvement in overall health, and prevention of viral infections. This is an all powerful, magical environment for sure. An especially huge benefit coming from the forest environment is how it promotes NK cell activity and intracellular anti-cancer proteins in lymphocytes (1). This is potent and powerful for health and longevity.
NK Cells and forest phytoncides (essential oils)
Natural killer cells (NK cells), as part of innate (born with, non-specific) immunity, are vital to protecting the body from damaged and infected cells supporting human health and longevity. The NK cells are white blood cells containing enzymes that can kill tumor cells and virus infected cells. An important function is their ability to detect and control early signs of cancer, along with protecting against other disease. NK cells are the most effective cells of the immune system for early stage detection of damaged (tumor) or infected cells.
Studies have shown, among the many benefits, that forest bathing significantly increases NK activity (2). In one study, participants were in a room diffused with hinoki (Chamaecyparis obtusa), a Japanese forest tree, essential oil. The results were similar to the NK increasing benefits of visiting a forest environment (Li Q et al., 2009).
Other wellness benefits to forest bathing
I’m just going to go ahead and quote the benefits of forest bathing directly from this 2019 study by Qing Li (3), also supported by other studies (4).
“It has been reported that forest environments have the following beneficial effects on human health:
1. Increase human natural killer (NK) activity, the number of NK cells, and the intracellular levels of anti-cancer proteins, suggesting a preventive effect on cancers.
2. Reduce blood pressure, heart rate, and stress hormones, such as urinary adrenaline and noradrenaline and salivary cortisol.
3. Increase the activity of parasympathetic nerves and reduce the activity of sympathetic nerves.
4. Increase the levels of serum adiponectin [reduction of inflammation] and dehydroepiandrosterone sulfate [prevention of aging, improve sexual function, enhance athletic performance].
5. In the Profile of Mood States (POMS) test, forest bathing reduces the scores for anxiety, depression, anger, fatigue, and confusion, and increase the score for vigor, showing psychological effects as well.”
Forest remedy for health and wellness
How easy is it to go to the forest? It’s here, it’s there, and for the most part, it’s free. It’s not like you need a National Forest in your neighborhood to make this work. Just find a park with dense trees, or a city or local area designated for conservation, and for some, it’s your back yard.
No exercises, jogs, activity or any other requirements needed to make the most of your absorption of forest bathing phytoncides.
Not hard to do. You don’t need to do anything except show up. There are no exercises, jogs, activity or any other requirements needed to make the most of your absorption of phytoncides. From now on I’ll call them essential oils, since phytoncides are the very same compounds extracted from the very same plants that, once distilled from the plant, are the essential oils we use for health and wellness. Phytoncide is not a very attractive name. Break it down and it translates to plant (phyto) poison (cides). Not a pretty name for such beautiful airborne medicines.
Forest bathing guides
There are people and organizations that take you on forest bathing journeys. These are programed and guided trips into the forest generally including meditation, intention and mindfulness practices, or something similar. Most are based on the original shinrin-yoku (forest bathing) system developed and “coined by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and defined as making contact with and taking in the atmosphere of the forest” (5). The original research was conducted beginning in 1988 by Prof. Yoshifumi Miyazaki.
There are thoughts, intentions and practices that enhance the forest bathing effects. If you do some research you will find ways to practice forest bathing on your own or just do what comes naturally, let the forest and the volatile lipids (the essential oils) saturating the environment do the work and magic, as I’ve already mentioned, you just show up.
Bring the healing home
When the forest visit isn’t convenient, bring the forest home. This is easy with essential oils distilled from the very plants and trees that permeate nature. Much of the research conducted looked at the Japanese environment to understand the results attributed to forest bathing. This is why the Japanese tree Hinoki Cypress (Chamaecyparis obtusa) is the most talked about tree in forest bathing research, with mention of the aromatic compounds released into the atmosphere, ⍺-pinene and β-pinene, by the hinoki tree. The pinenes are very common essential oil compounds found in several distilled oils, especially abundant in needle tree oils like fir, pine, spruce and juniper.
What this means to you, is that you can use hinoki essential oil or a beautiful combination of many tree and plant oils found in the forest for home diffusion. You will receive the same benefits as visiting the forest - almost.
Forest bathing essential oil lifestyle systems.
By combining a few application methods, a lifestyle system can be developed for your everyday use. The process is really quite simple. Using a diffuser, choose your desired forest bathing essential oil and add it to the diffuser according to manufacturers instruction. If you don’t have a diffuser, you can place a drop or two of the forest essential oil on a tissue and leave it close by. To mimic actual forest bathing it’s recommended to run the diffuser, at a very low rate called “level of detection,” for about 30 to 60 minutes. This can be repeated 2 to 3 times during the day. I prefer the diffusers that have a 10 minute on, 20 minute off rotation. This keeps just the right amount of scent in the atmosphere. A ritual of your choice, such as meditation, an intention practice, prayer or a shamanic type ritual, would enhance the experience. The options on how to conduct your own at home forest bathing system are limitless.
This can be combined with a forest bathing massage. Simply add 2 drops per teaspoon (5 mL) of the forest oil(s) to your favorite carrier, such as olive oil, sunflower seed, shea butter or an unscented natural lotion. Use a carrier that you find benefits your skin condition to get more from this practice than just the emotional and health benefits of forest bathing. Massage once or twice a day, leaving at least an hour between skin conditioning massage application and diffusing (not necessary, it just keeps a good flow of forest fragrance throughout the day).
Forest bathing facial care
When applying facial care, so close to the nose, you get the inhalation from the forest bathing oils, triggering all the health related advantages.
Along with the benefits of diffusing and a skin conditioning massage, your forest bathing oils may be added to your facial care routine. Though most oils found in forest bathing are not typically used in facial care, they still offer ideal benefits to protecting and regenerating healthy youthful skin. Any essential oil, due to coming from nature, will likely have a forest bathing effect. More specifically, along with the known therapeutic properties of the essential oils, they trigger biophilia, our genetic desire to connect with nature and the wellness benefits attributed. The benefit when applying facial care, so close to the nose, is you get the inhalation from the forest bathing oils, triggering all the health related advantages.
Enjoy the benefits of a healing forest bathing lifestyle
The forest bathing essential oils do not need to be used everyday. Your forest bathing lifestyle practice can be scheduled for once a week or so. It is highly recommended to periodically visit an actual forest. How you do this practice is completely up to you, focused on the results you desire from the practice. Pay attention to how you feel before and after a forest bathing session, or the weeks following a scheduled forest bathing lifestyle practice. This is your forest, bathe to your needs, desires, feelings and the emotional and health promoting effects.
Li Q, Kobayash.i M, Inagaki H, Hirata Y, Li YJ, Hirata K, Shimizu T, Suzuki H, Katsumata M, Wakayama Y, Kawada T, Ohira T, Matsui N, Kagawa T. A day trip to a forest park increases human natural killer activity and the expression of anti-cancer proteins in male subjects. J Biol Regul Homeost Agents. 2010 Apr-Jun;24(2):157-65. PMID: 20487629
Li Q, Morimoto K, Nakadai A, et al. Forest Bathing Enhances Human Natural Killer Activity and Expression of Anti-Cancer Proteins. International Journal of Immunopathology and Pharmacology. 2007;20(2_suppl):3-8.
Li Q. Effets des forêts et des bains de forêt (shinrin-yoku) sur la santé humaine : une revue de la littérature [Effect of forest bathing (shinrin-yoku) on human health: A review of the literature]. Sante Publique. 2019 May 13;S1(HS):135-143. French. doi: 10.3917/spub.190.0135. PMID: 31210473.
Gen Xiang Mao, Xiao Guang Lan, Yong Bao Cao, Zhuo Mei Chen, Zhi Hua He, Yuan Dong LV, Ya Zhen Wang, Xi Lian Hu, Guo Fu Wang, Jing Yan, Effects of Short-Term Forest Bathing on Human Health in a Broad-Leaved Evergreen Forest in Zhejiang Province, China, Biomedical and Environmental Sciences, Volume 25, Issue 3, 2012, Pages 317-324, ISSN 0895-3988
Park BJ, Tsunetsugu Y, Kasetani T, Kagawa T, Miyazaki Y. The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan. Environ Health Prev Med. 2010 Jan;15(1):18-26. doi: 10.1007/s12199-009-0086-9. PMID: 19568835; PMCID: PMC2793346.