This blog post is an exclusive excerpt from my new book, The Physiology of Yoga. Join our 8-week Physiology of Yoga book club which begins in September 2023.
B.K.S. Iyengar, student of Tirumalai Krishnamacharya and creator of Iyengar Yoga, famously stated in his classes that deep twists cause a squeeze-and-soak effect on the body, especially the intervertebral discs and the internal organs. Whether or not Iyengar was the original source of this idea, the idea of twists detoxing the body has certainly become commonplace and is firmly planted in the minds of many yoga practitioners. An article published in 2008 in Yoga Journal attempts to explain Iyengar’s idea:
The theory is that twists cleanse the internal organs in much the same way that a sponge discharges dirty water when squeezed and can then absorb fresh water and expand again. The idea is that, when you twist, you create a similar wringing action, removing stale blood and allowing a freshly oxygenated supply to flow in. (Rizopoulos 2017, para 2)
While Iyengar, who died of kidney failure in 2014, may have been well meaning in his assertions about the physiology of detoxification, the squeeze-and-soak theory is inaccurate and has no scientific basis. Every second of every day, whether you are asleep or awake, your body is constantly detoxifying itself, and this detoxification is a cellular process, not a mechanical one that requires the compressing, wringing, or stretching of internal organs.
Your body is regularly exposed to toxins, poisonous substances produced by living organisms, including those produced in the body itself, such as lactic acid and microbial waste products in the gut. Your body removes these toxins through the liver, feces, and urine. The liver, specifically, alters toxic substances chemically, yielding them harmless and ready for excretion.
Even with our bodies’ integrated detoxification system, there are still some chemicals that cannot be easily removed through these processes, including persistent organic pollutants (found in pesticides), phthalates (found in hundreds of plastic products), bisphenol A (found in many food containers and hygiene products), and heavy metals (found in agriculture, medicine, and industry). Known to accumulate in the body and taking a very long time, potentially years, to be removed, these chemicals may be linked to various chronic diseases including asthma, cancer, autism, and attention-deficit/hyperactivity disorder (Sears and Genuis 2012).
The idea that a certain yoga pose, a certain diet, or a certain product can remove these stubborn toxins from the body is a tempting one. However, there is little to no evidence that one movement, diet, or product can do just that. In a 2015 review of all studies to date examining the efficacy of detox diets, Klein and Kiat found that we have very little clinical evidence to support the use of detox diets despite a booming detox industry and product packaging that makes bold but unsubstantiated claims. Although a small number of studies have found commercial detox diets might enhance liver detoxification and eliminate persistent organic pollutants, these studies had flawed methodologies and small sample sizes, thus reducing their scientific credibility. Klein and Kiat concluded:
To the best of our knowledge, no randomised controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans. This is an area that deserves attention so that consumers can be informed of the potential benefits and risks of detox programs. (2015, p. 1).
As for yoga, there has been no research to show that it improves the body’s natural detoxification system. This might be because our body already does a fantastic job of detoxification on its own. If you were not able to remove toxins from your body, you would know, as a plethora of symptoms would occur, even fatal ones.
This is not to say that yoga (or exercise in general) has no effect on our body’s ability to detoxify, but the benefits likely come from exercise’s ability to decrease inflammation and increase vascularity. While some inflammation is necessary in recovering from a wound or infection, chronic inflammation is hard on the body and weakens many systems. Long-term inflammation underlies many serious diseases, including cardiovascular disease and diabetes, while cancer, obesity, osteoporosis, Alzheimer’s disease, and cardiovascular disease have all been linked to increased biomarkers of inflammation (Tabas and Glass 2013).
It is well established that exercise creates an anti-inflammatory response in the body—one of its most potent benefits (Flynn, McFarlin, and Markofski 2007). When inflammation is reduced, all systems of the body can work more efficiently, including those of digestion and detoxification. Another well-known benefit of exercise is increased circulation, so more blood, which contains essential nutrients and oxygen, is available for digestion and detoxification. In these ways among other benefits, exercise can certainly help optimize our body’s detoxing processes.
The few studies that have examined yoga and inflammation have suggested that yoga also has the same anti-inflammatory benefits (Pullen et al. 2008; Pullen et al. 2010). Even though the research on yoga is much sparser, it is reasonable to assume that a physical yoga practice would provide many of the same exercise benefits such as decreased inflammation and increased circulation. If you are doing a lunge, your body doesn’t know if you are in a yoga class or a personal training session; the physiological effects would be largely the same. Interestingly, one small study found that even a nonphysical practice of mindfulness decreased inflammation (Ng et al. 2020).
So, does yoga detoxify your body? Not in the way Iyengar suggested. Twists do not detoxify your body. Neither yoga nor diet do anything that our bodies cannot do on their own. Nonetheless, yoga can optimize the body’s natural detoxification system, not through one specific pose such as a twist, but through exercise’s already powerful benefits of decreasing inflammation and increasing circulation. Trust that your body is fully equipped to handle toxins and other unwanted substances.
Another thing we can do to improve our detoxification process is to simply reduce our exposure to toxins. While detox diets do not work in the way they are often advertised to, nearly all diets encourage healthful, balanced eating, which reduces your exposure to harmful products, including artificial ingredients found in junk food. We can also reduce our exposure to persistent organic pollutants by eating organically grown food. We can reduce the burden on our liver by drinking only moderate amounts of alcohol. Finally, keeping active with moderate exercise, yoga or otherwise, will help the body do what it does very well.
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Join our 8-week Physiology of Yoga book club which begins in January 2023.