Demystifying detox: Can yoga really cleanse the liver? | Science ...

Demystifying detox: Can yoga really cleanse the liver?
January is the month for detox myths, including yoga to 'cleanse the liver' and 'rinse the spine'. Ouch!
Nicole Slavin
Mon 13 Jan 2014 07.00 ESTLast modified on Wed 20 Sep 2017 15.23 EDT
If there’s one word that seems ubiquitous every January, it’s "detox". Anyone hoping to wash away the excesses of the holiday season will look for ways to be better and healthier, at least than they were the year before. The fact is, detoxing isn’t a thing. It is well dressed (and well marketed) pseudoscience. It is hard to pinpoint a single culprit responsible for this piece of bad physiology that persists. Who knows where the origins of this misnomer lay, but recently it’s been seen more and more in the ever-growing yoga industry.
One benefit of yoga’s visibility and popularity is the variety of styles and methods available for one to get a stretch on. Classes offered nowadays can range from more traditional yoga styles that honour its cultural or spiritual origins, to ones that cater to a more fitness-orientated crowd. It’s possible to find "hot" yoga, where the studio is warmed to 40C, there’s even yoga for "dudes". For the ultra-warrior, there is a fusion of Boxing Yoga, and the latest addition to the myriad of ways to stretch is disco-yoga! Regardless of whether you’re seeking the reverent or the physical, one thing still abounds in many yoga studios: bad science.
Type "yoga" and "detox" into any search engine and the claims you’ll find will be quite staggering. One yoga posture (or asana in Sanskrit) that seems to bear the brunt of being super magical and "detoxifying" is the spinal twist, performed in poses like Ardha Matsyendrasana (Half Lord Fish Pose). Some claims associated with this particular pose are reasonable, such as releasing muscles around the spine and lower back to ease pain or increase flexibility, for which there is some evidence.
But other claims are ridiculous, such as claims it can "rinse the spine". I don’t know about you, but I’m pretty happy with my cerebrospinal fluid un-rinsed, thanks. One of the more frequently made claims is that spinal twists detox the spine and subsequently massage the liver in order to increase its ability to detoxify (ie do its job). The sources of this myth are so numerous that a quick internet search will bring back hundreds, if not thousands, of hits. But it's simply not true.
The liver is astounding, and after the skin, it's the body's largest organ. It has evolved to put up with a great deal of biological abuse, and the way it works is nothing short of incredible. Because of its size and connection to two very large blood vessels, the liver is well situated to receive whatever comes through your intestinal tract, the good, bad or ugly. It takes on a bouncer-like job and keeps unwanted items, or toxins (such as byproducts from pharmaceuticals, or environmental carcinogens) from getting into the bloodstream; basically the liver has got your blood’s back.
The blood that comes into the liver from the spleen and gastrointestinal tract is greeted by Kupffer cells, a kind of macrophage (quite literally, "big eater"). They’re not picky and will, in plain English, eat the flotsam and jetsam right out of your blood by digesting these undesirable particles. They do the first pass of "toxin flushing", after which anything not caught here gets further broken down by enzymes produced by Hepatocytes, which are sensitive to blood sugar levels.
So what does the Ardha Matsyendrasana twist do? When performed correctly, after a proper warm-up and with attention to alignment, this humble but adaptable twist both strengthens and releases a host of muscles from your rhomboids (associated with the scapula) to your hamstrings, with a lot in between including both internal and external obliques and spinal extensors. Not to mention it feels pretty good too (one hopes).
One thing it’s not doing is directly affecting the cellular or biochemical workings of the liver, which are the primary mechanisms of "detoxification". And I don’t even know what "massaging the liver" means. If you’re manipulating your internal organs, you’re more likely to cause damage than improve their function.
Will practicing yoga, or exercising in general, get your cardiovascular system working? Yes. Does this have an impact on blood flow? Yes. Does change in blood flow impact on the other organ systems of the body? Yes. Can eating healthily, avoiding fatty food, alcohol etc give the liver a "break" from the demanding work of detoxing? Yes, it can. Does this mean you can make your liver work faster, better, stronger through an exercise or specific product/food/ritual? No, you can’t.
The best detox advice I know is:
Possess a (hopefully healthy) liver. Limit intake of high fat foods, excess calories, alcohol etc to maintain said healthy liver. And, of course, though it won’t "detoxify" you directly, do exercise.
To quote Sir Liam Donaldson, former Chief Medical Officer, in his 2009 report on the state of public health: “The potential benefits of physical activity to health are huge. If a medication existed which had a similar effect, it would be regarded as a ‘wonder drug’ or ‘miracle cure’.”
Namaste.
Nicole Slavin is a 200 Yoga Alliance-registered yoga teacherand holds a BSc in physiology and pharmacology. She can be found on Twitter @schrokit