Stress and Immunity Blog

     
 

Posted: June 2024

Author: Katie Donnelly, Adv Dip HSc Naturopathy

Stress and Immunity

The relationship between stress and immunity is well established, with one implication of increased physical and psychological stress is to increase the potential for illness and chronic diseases. Increased cytokine secretion, as part of the immune response, then further alters the ability to regulate emotions recent studies have identified. Phytomedicine can support the body to reduce the overall stress load, and encourage immune system resilience.¹

Supporting the stress response

Regulation of cortisol secretion and hypothalamic-pituitary-adrenal (HPA) axis function is a key factor in stress management and immune wellbeing.

Used for thousands of years for adaptogenic actions, Withania somnifera (Withania) remains a top option for stress conditions, particularly long-term, or ongoing stress. The gently stimulating actions of this herb support increased resistance to stress and lower sensitivity to stressors.

Interactions with the HPA axis and the autonomic nervous system are behind these actions, with adrenal regulation also noted. A combination of constituents contributes to this activity of Withania, however, withanolides are the most extensively explored. Withaferin A is thought to interact with glucocorticoid receptors, altering cortisol levels. This may indirectly result in sedative actions.²

Also known as a stress-relieving herb, Lavandula angustifolia (Lavender) is rich in essential oils that contribute to many of the calming actions. Linalool, specifically, interacts with gamma-aminobutyric acid receptors in the central nervous system to enhance sedation. Parasympathetic nerve interaction has also been noted, calming sympathetic nerve stimulation. Improved sleep then directly enhances immune function and regulates the stress response.³

While the occurrence of anxiety and depressive states are commonly associated with ongoing stress, newer research indicates that cytokines play an important role in this development.

Chronic stress increases the secretion of interleukin- 6 and tumour necrosis factor-alpha, but also cytokine lipocalin 2, by hepatic cells. Lipocalin 2 prevalence was linked to depressive states and was associated with the development of neurodegenerative diseases. The animal model studies highlighted an important connection between the vagal nerve, hepatic cells, and neuron regulation in anxiety.⁴

This may further support recent studies on Passiflora incarnata (Passionflower), that identified potent antioxidant constituents as the mechanism of this herbs’ actions. Flavonoids, alkaloids, and phenol constituents are highlighted as enabling gentle sedative actions, supporting anxiety and sleep dysregulation. This has also been identified as a supportive option in cases of depression.⁵

Immune modulation

While short-term stress can stimulate immune responses, chronic stress inhibits this process.

An effective immune modulator, Astragalus membranaceous (Astraglaus) can enhance macrophage function and presence via stimulating increased tumour necrosis factor-alpha secretion. Furthermore, it can encourage dendritic cell maturation. Astragalus also showed increased B and T lymphocyte proliferation and prevention of viral replication with specific viruses including EBV, Hep B and corona 19 virus.⁶

Astragalus is also known as a tonic herb and adaptogen, assisting the body in recovery from illness and post-viral fatigue. Similarly, Ganoderma lucidum (Reishi) is a powerful regulator for both cognitive and immune stress.^6,7

Many of the anti-inflammatory and immune supporting actions of Reishi are attributed to triterpenoids. Ganoderic acids are among these compounds, and provide antiviral and anticancer actions, modulating immune system function. Rich in polysaccharides, this herb increases the presence of T cells, cytokines, and macrophages. The β-glucans are specifically identified as increasing pattern recognition receptors, helping to prevent infections. This includes coronaviruses and Covid 19.⁷

Polysaccharides in Rehmania glutinosa (Rehmania) have also been highlighted as contributing to immune supporting functions. This component has shown to reduce vascular inflammation, encourage natural killer cell maturation, and increased antigen presenting actions of dendritic cells. High antioxidant properties further support this.⁸

Commonly used as an adrenal tonic, Rehmania has also shown antidepressant actions in animal model studies. Findings were associated with regulating HPA axis function and influence over monoamine neurotransmitters.⁹

There are noted differences in the traditional prescribing of cured and uncured Rehmania, and the role of each herbal form. Cured Rehmania is revered as a warming, slightly sweeter tonic that nourishes the blood and deficiency conditions. It is an adrenal support for weak energy. Uncured Rehmania is more bitter and is for dry conditions, used to cool the blood and calm hot dispositions. Traditionally, this form was used for stimulating lymphatic flow and soothing sore throats.¹⁰

There are many phytomedicine options available for supporting both the physical and psychological stress responses. The synergy of herbs, and multi-action tendency of plant medicine helps to facilitate both cognitive and immune system health.


References

1.Ishikawa Y, Furuyasahiki T. The impact of stress on immune systems and its relevance to mental illness. Neuroscience Research. 2021 October 1; 175:16-24. https://doi.org/10.1016/j.neures.2021.09.005

2.Della Porta M, Maier JA, Cazzola R. Effects of Withania somnifera on Cortisol Levels in Stressed Human Subjects: A Systematic Review. Nutrients. 2023;15(24):5015. https://doi.org/10.3390/nu15245015

3.Batiha GES, Teibo JO, Wasef L, Shaheen HM, Akomolafe AP, Teibo TKA, Al-kuraishy HM, Al-Garbeeb AI, Alexiou A, Papadakis M. A review of the bioactive components and pharmacological properties of Lavandula species. Naunyn-Schmiedeberg's Arch Pharmacol. 2023;396: 877–900. https://doi.org/10.1007/s00210-023-02392-x

4.Yan L, Yang F, Wang Y, Shi L, Wang M, Yang D, Wang W, Jia Y, So KF, Zhang L. Stress increases hepatic release of lipocalin 2 which contributes to anxiety-like behavior in mice. Nat Commun 15. 2024; 3034. https://doi.org/10.1038/s41467-024-47266-9

5.Amini F, Amini-Khoei H, Haratizadeh S, Setayesh M, Basiri M, Raeiszadeh M, Nozari M. Hydroalcoholic extract of Passiflora incarnata improves the autistic-like behavior and neuronal damage in a valproic acid-induced rat model of autism. J Tradit Complement Med. 2023 Feb 23;13(4):315-324. https://doi.org/10.1016/j.jtcme.2023.02.005

6.Wang XY, Wang RC, Qu ZY, Zhu YZ, Li YL. Advances on immunoregulation effect of astragalus polysaccharides. Frontiers. 2022 September 7; 1. https://doi.org/10.3389/fntpr.2022.971679

7.Ekiz E, Oz E, Abd El-Aty AM, Proestos C, Brennan C, Zeng M, Tomasevic I, Elobeid T, Çadırcı K, Bayrak M, Oz F. Exploring the Potential Medicinal Benefits of Ganoderma lucidum: From Metabolic Disorders to Coronavirus Infections. Foods. 2023 Apr 3;12(7):1512. https://doi.org/10.3390/foods12071512

8.Feng JC, Cai ZL, Zhang XP, Chen YY, Chang XL, Wang XF, Qin CB, Yan X, Ma X, Zhang JX, Nie GX. The Effects of Oral Rehmannia glutinosa Polysaccharide Administration on Immune Responses, Antioxidant Activity and Resistance Against Aeromonas hydrophila in the Common Carp, Cyprinus carpio L. Front Immunol. 2020 May 8;11:904. https://doi.org/10.3389/fimmu.2020.00904

9.Wang JM, Pei LX, Zhang YY, Cheng YX, Niu CL, Cui Y, Feng WS, Wang GF. Ethanol extract of Rehmannia glutinosa exerts antidepressant-like effects on a rat chronic unpredictable mild stress model by involving monoamines and BDNF. Metabolic Brain Disease. 2018 February; 33:885-892. https://link.springer.com/article/10.1007/s11011-018-0202-x

10.Bian Z, Zhang R, Zhang X, Zhang J, Xu L, Zhu L, Ma Y, Liu Y. Extraction, structure and bioactivities of polysaccharides from Rehmannia glutinosa: A review. Journal of Ethnopharmacology. 2023 April 6; 116132. https://doi.org/10.1016/j.jep.2022.116132