Yoga is not "woo-woo" anymore: yoga can reduce inflammation, according to research

Yoga is not “woo-woo” anymore: yoga can reduce inflammation, according to research

The online space allows for easy access to health information, which may not always be from the most reputable sources. It doesn’t take much to find a lot of unfounded claims and fake news, making it hard to discern what to believe. Have you come across online articles that make you scratch your head in confusion? Can garlic really prevent COVID? Can meditation cure cancer?…and can certain yoga poses prevent hair loss?

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These questions can be answered by high-quality, peer-reviewed research published in reputable journals. When you want to look at the overall evidence that is out there for a certain topic, you look for scientific reviews — they summarise current knowledge giving an overview of what’s known at that point in time. I am a postdoctoral researcher and project manager at the Stress, Psychiatry and Immunology (SPI) Lab, and when I was asked to write a review for Brain, Behavior and Immunity — Health last year, I immediately knew what I was going to write about. Can you guess based on my previous blogs? Easy: yoga! Along with being a researcher, I am also a fervent yoga student and educator. You can see some of my publications on yoga philosophy & mental health, yoga and stress, and my recent paper on yoga and inflammatory markers. Yoga is an ancient system for integrating the mind, body, and spirit. Yoga promotes mental and physical health through lifestyle guidelines. Yoga practices are rooted in the belief that a practitioner’s mental state is the key to achieving holistic health. There is an abundance of compelling research on yoga for mental health, mainly in the areas of anxiety and depression…but being a researcher of the SPI lab, I wanted to take it a step further and look at the evidence on yoga for inflammation — after all, depression and anxiety have a bi-directional relationship with inflammation.

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Current medical knowledge recognises the role of stress in the development of psychiatric conditions and its interplay with the immune system; specifically, the field of psychoneuroimmunology and immunopsychiatry.

Acute and chronic stress, mainly through the hypothalamic-pituitary-adrenal (HPA) axis (the name given to the hypothalamus, pituitary gland, and adrenal glands; it plays an important role in the body’s response to stress) and the sympathetic nervous system (one of the divisions of the nervous system), play a crucial role in immune system dysregulation and psychiatric disorders, as the last few decades of psychiatric research have unveiled. Chronically high levels of cortisol, known as the “stress hormone”, can induce the production of inflammatory cytokines.

Inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-1 beta (IL-1β), as well as tumour necrosis factor-alpha (TNF-α) and C-reactive protein (CRP) play a central role in mood disorders. They have also been identified as biomarkers in psychiatric diseases such as depression, psychosis, bipolar disorder and schizophrenia.

Recently, the interaction of the immune system, stress, and mind-body practices has been attracting a lot of attention in academic research. Mind-body practices have been shown to induce positive effects on stress perception and the immune system.

But wait, what about yoga?

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The current literature bears strong evidence for the benefits of yoga on the levels of circulating cortisol and classical inflammatory markers, such as CRP, IL-1β, IL-6, TNF-α, as well as interferon-gamma (INF-γ) and Immunoglobulin A (IgA). A study on people experiencing depression found that along with having anti-depressant effects, yoga reduces IL-6 levels.

Regular practice of yoga has been shown to increase β-endorphins, and decreases IL-6, and TNF-α levels of yoga participants. β-endorphins are produced following HPA-axis stimulation and have inhibitory effects on the immune system.

Furthermore, a recent study that investigated the immune functions in middle-aged and older women found that cortisol concentration and secretion were lower following a yoga intervention, suggesting a reduced stress response in older adults.

There is also some evidence of the effects of yoga on inflammation in pregnant women. A randomised controlled trial that consisted of 94 healthy pregnant women and lasted 20 weeks, compared the effect of two weekly 70-minute yoga sessions. A randomised controlled study is a scientific study where participants are randomly assigned to two groups — a treatment group, receiving the treatment or intervention and a control group, that receives a comparator treatment or no treatment at all. The results of this study show that the yoga sessions reduced cortisol and enhanced IgA during pregnancy, indicating a diminishing of the inflammatory response.

Additionally, studies on people at risk of cardiovascular disease, observed that yoga had significantly superior outcomes in the reduction of IL-6 and CRP levels. Yoga may also be relevant for patients with high cholesterol levels, as the practice led to reduced cholesterol, IL-6, TNF-α and CRP levels in a randomised controlled study.

In the field of auto-immune diseases, studies on rheumatoid arthritis patients found that yoga resulted in significant decreases in CRP, IL-6, and TNF-α, alongside a reduction in depression scores.

Finally, yoga has also been advised for stress in patients with breast cancer. A large randomised clinical trial found that yoga practice led to lower levels of IL-6, TNF-α, and IL-1β in breast cancer patients. Another earlier study found evidence for lower blood levels of CD56 and IgA in these patients. CD56 is a marker of natural killer and other immune cells including T cells, and alterations in CD56 levels are associated with infectious and autoimmune diseases and malignant tumours. In breast cancer, IgA is directly associated with tumour load, which is essentially the number of cancer cells or the size of a tumour — and so it can be used as an indicator of disease severity.

Image credits to the author — Carolina Estevao

Altogether, yoga as a physical and spiritual practice may be beneficial for the immunity of populations suffering from mental or physical health disorders and could be employed as a preventative intervention for at-risk groups.

So, perhaps it’s time for you to get back on your yoga mat…