This article originally appeared on Tonic.
Let's face it: The modern world is generally a toxic place to live in. We are constantly surrounded by the detritus of our industries. Pollution settles in the water, in the earth, and in our bodies, and many of us are constantly trying to find ways to offset the damage we do. Many of us are on a quest for purity—purity promised to us by infra-red saunas and detox teas.
Do we need all of it? Is fasting in a sweat lodge after getting our colons cleansed really going to remove all the residue of late capitalism?
“The basic concept of ‘detoxifying’ is blatantly flawed, because our natural processes, especially liver and kidney function, cleanse our bodies far better than any extrinsic activities or substances could possibly achieve,” says Morton Tavel, professor emeritus of medicine at Indiana University. Tavel tells me that “the idea of ‘detoxifying’ or ‘purifying’ the body of ‘harmful’ substances has been around for centuries and returns periodically to haunt the modern world.” The idea behind such "cleansing" schemes is to rid the body of some unknown substance, usually only vaguely specified.
You do not need a specialized detox plan to detoxify the body. Your body will do it all on its own. But what about sweating, the sacred cow of the detox world? We definitely need to sweat out the pollution, right?
Um. No. That’s not what sweat does.
“Sweating is a normal body function that is used to regulate temperature. Is not a means of excreting waste or removing toxins,” says Tsippora Shainhouse, a Los Angeles-based dermatologist. There are two kinds of sweat, she says: “Sweating that happens when you are hot comes mainly from eccrine glands all over the body. It is a response to elevated body temperatures, a way to cool down the body. This occurs when you have a fever, are in a hot environment, and when exercising.”
This first kind of sweat, then, is a very smart temperature-control system that the body uses to make sure you don’t die of heat stroke in hot yoga. The second kind of sweat, Shainhouse says, is called stress sweating. “Stress sweating is actually a sympathetic nervous system response to adrenaline, the hormone that is produced when we are nervous, anxious, excited. It is part of our innate, primitive fight-or-flight response,” she says. This type of sweating is more associated with apocrine glands—found in your armpits, areola/nipples, genitals, palms, soles, and inside your ears. Because these glands contain fatty acids which, in conjunction with bacteria and other things in and on your skin, results in smelly sweat. Think classic, stress-induced BO.
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That second kind of sweat is the gross sweat that you'd rather not ever have to deal with. But it isn’t meant to detoxify you either. It’s just a byproduct of adrenaline being released into the body, Shainhouse says.
“Most of the 'toxins' that concern people include pesticides, residue from plastics, or from air pollution," Tsippora says. "These tend to be fat-soluble, and do not dissolve well in water, so they will not be removed from the body in any significant quantity, given that sweat is 99 percent water.” So not only is sweat not meant to detox you, most of the toxins that we worry about can’t be released in sweat, no matter how hot the steam bath is.
But, then, why can I tell the difference between my sweat from one day to the next? Doesn’t smelly sweat mean something evil is leaving my body? That’s a nope too, Shainhouse confirms.
“There are definitely certain foods that once digested, can leave an odor that gets ‘sweated’ out of the body. These usually include foods containing sulfur compounds: broccoli, cabbage, cauliflower, as well as garlic and onions,” she says. “Most of these by-products are metabolized and broken down in the gut and liver, but some molecules, such as allyl methyl sulfide, are absorbed into the bloodstream and released through the lungs—breathing, and pores—sweating.”
Basically, what you smell is broken-down molecules being released through the pores, and to be clear, that isn’t the same as toxins being released, since whatever it is has already been processed by the body.
So if sweat isn’t going to do it, what kind of detox does the body need? Science points to none at all. “Don’t believe the hype," says Cale Parkyn, an Alberta-based physiotherapist, “nutritional or body ‘detox,’ is an industry in itself to create and market fear. The truth is that the body is excellent at self-regulating toxins, bacteria and viruses.” People with high stress levels, chronic fatigue, or autoimmune issues may be less able to self-regulate, but bodies that are generally healthy will remove toxins all on their own.
In other words, your body is a smart machine. You can save your money, stay hydrated, and let it take care of itself.