By Dr. Mercola
Synthetic polyester workout wear has become popular because it’s lightweight and fast-drying. But there‘s a downside to opting for synthetics over cotton, especially for those working out around you…
Certain fabrics will make you stinkier than others, although it’s not the fabric itself that’s to blame. It turns out that Micrococcus bacteria prefer the open-air lattice of synthetic fibers over cotton, according to new research by Chris Callewaert (aka “Dr. Armpit”) and colleagues.1
Because these odor-causing bacteria prefer to hang out on polyester, you might want to choose your workout gear accordingly…
Bacteria Thrive on Synthetic Fabric, Not Cotton
The study involved 26 volunteers who took a spinning class while wearing shirts made of cotton, polyester, or a cotton-polyester blend. The shirts were sealed in plastic bags then sniffed by trained panelists the next day.
The odor-causing bacteria Micrococcus were isolated in almost all synthetic shirts and were detected almost solely on synthetic shirts as compared to cotton, according to the researchers. As Scientific American reported:4
“…researchers say they [Micrococcus bacteria] thrive on the open-air lattice of synthetic fibers—where they sit chomping on the long-chain fatty acids in our sweat, turning them into shorter, stinkier molecules.”
Of note, Micrococcus aren’t commonly found in large numbers in armpits. Another type of bacteria, Corynebacterium, is regarded as the primary cause of armpit odor, yet no Corynebacterium was detected on the shirts. No one’s sure how the Micrococcus are transferring to the shirts, but the study’s lead researcher suspects it may be during washing.
Nanosilver Used to Target Bacterial Growth in Polyester, But Its Use May Backfire
It’s not a surprise that polyester shirts are bacteria magnets. Manufacturers have long known this and have turned to using antimicrobials as a solution. Among them are silver nanoparticles, or nanosilver, which are composed of tiny particles of silver (so tiny they’re smaller than a virus) that can kill bacteria on contact.
On one level, nanoparticles are an incredible advance of technology. For instance, in the supplement industry, nanotechnology can shrink the size of vitamin molecules down to microscopic nanodroplets that are much easier for your body to absorb.
On the other hand, nanoparticles are so small that that they can easily be inhaled or absorbed through your skin, so great care needs to be taken as to what types of particles are being produced on the nano-scale.
Its use in clothing may be problematic, as research has revealed that nanosilver does not simply stay in clothing, fighting bacteria and odors. Instead, the nanoparticles are leaching out of the clothing when they’re washed.
In one study, scientists added seven different nanoparticle fabrics to a washing machine with steel balls added to simulate mechanical stress that would occur under normal washing conditions. Four of the fabrics lost roughly 20 percent to 35 percent of their silver with the first wash.5
From there, of course, the nanosilver does not simply collect inside your washing machine. It raises the question of whether the nanosilver is also transferred to your skin during normal wear, and, certainly, it washes down your drain and out into the environment. Nanotechnology is quite new, so it’s unclear what effects nanoparticles might have in the environment, but there’s reason for concern.
Research published in the nanotechnology journal Small found that zebrafish embryos exposed to nanosilver were extremely mutated.6 Some fish died while others grew into the shape of the number nine or a comma. Others had mutations to their eyes, swim bladders, tails, and hearts. Said University of Utah researcher Darin Furgeson, who led the study:7
“I think we jumped the gun by creating such large volumes of nanoparticles… We should take more time and really look at these new nano-systems before we start to throw them into personal products and shoot them into these ecosystems.”
Some Synthetic Fabrics are Even Treated with Triclosan
Another antimicrobial sometimes added to fabrics, including clothing, is triclosan, a widely used antibacterial chemical. Research has shown that triclosan can alter hormone regulation and may interfere with fetal development.
Animal studies have also raised concerns about its ability to affect fertility, and bacteria exposed to triclosan may also become resistant to antibiotics. Even an increased cancer risk has been suggested.
And as noted by Professor Caren Helbing Ph.D. at the University of Victoria in Canada, the chemical structure of triclosan is similar to thyroid hormones and polychlorinated biphenyls (PCBs). This similarity allows it to attach to hormone receptors.
Helbing's research shows that tadpoles exposed to triclosan suffered stunted development and leg deformations, perhaps because the metamorphic process these frogs undergo is mediated by thyroid hormones.8
Triclosan also impairs muscle function and skeletal muscle contractility. In one study, after mice were exposed to just one dose of triclosan, heart muscle function was reduced by 25 percent, and grip strength was reduced by 18 percent.9 Fish were also exposed to triclosan – about the equivalent dose as would be accumulated in a week in the wild – and this led to poorer swimming performance.
Researchers also exposed individual human muscle cells (from heart and skeletal muscles) to a triclosan dose similar to everyday-life exposure, and this, too, disrupted muscle function and caused both heart and skeletal muscles to fail. Triclosan is one chemical that you certainly don’t want to risk more exposure to, so it’s wise to avoid all antibacterial fabrics (even cotton versions, as sometimes it, too, is treated with triclosan).
Toxic Stain Protection and NPEs Also Commonly Added to Clothing
Stain-proof clothing is a common source of perfluorinated compounds (PFCs), which are toxic to humans and the environment. You’ll most often hear about PFCs in relation to non-stick cookware, but they’re also common in fabrics. According to the US Environmental Protection Agency (EPA):10
“Long-chain PFCs are found world-wide in the environment, wildlife, and humans. They are bioaccumulative in wildlife and humans, and are persistent in the environment. They are toxic to laboratory animals and wildlife, producing reproductive, developmental, and systemic effects in laboratory tests. To date, significant adverse effects have not been found in the general human population. However, given the long half-life of these chemicals in humans (years), it can reasonably be anticipated that continued exposure could increase body burdens to levels that would result in adverse outcomes.”
Nonylphenol ethoxylate (NPE), meanwhile, is a toxic surfactant used to manufacture clothing; when consumers wash their clothes, NPEs are released into local water supplies where wastewater treatment plants are unable to remove it. When NPEs enter the environment, they break down into nonylphenol (NP), a toxic, endocrine-disrupting chemical that accumulates in sediments and builds up in fish and wildlife. One simple strategy you might be able to use to reduce smells on synthetic clothing is to put them in the bright sun. Sunlight has ultraviolet rays and will kill most of the bacteria that are multiplying and causing the odors.
If You Opt for Cotton Clothing, Choose Organic
Natural cotton clothing is important for helping you reduce odors, but you might be surprised to learn that cotton is considered the world’s dirtiest crop due to the cotton industry’s heavy use of hazardous herbicides and insecticides. According to the Organic Trade Association:11
“Cotton covers 2.5% of the world's cultivated land yet uses 16% of the world's insecticides, more than any other single major crop. Aldicarb, parathion, and methamidopho, three of the most acutely hazardous insecticides to human health as determined by the World Health Organization, rank in the top ten most commonly used in cotton production. All but one of the remaining seven most commonly used are classified as moderately to highly hazardous. Aldicarb, cotton's second bestselling insecticide and most acutely poisonous to humans, can kill a man with just one drop absorbed through the skin, yet it is still used in 25 countries and the US, where 16 states have reported it in their groundwater.”
As you might suspect, this is hazardous on multiple levels – for the farmers working with these chemicals, the people living nearby, the consumers buying the cotton and virtually everyone else who will eventually be impacted by this widespread environmental pollution, much of which inevitably travels up the food chain where it bioaccumulates within your body. This is one reason why I strongly encourage you to choose organic cotton clothing whenever possible. The other reason is that organic cotton will not be genetically modified, which is equally important.
The introduction of Monsanto’s genetically modified Bt cotton in 2002 only added to the toxicity problem, requiring even more pesticides, creating super-pests, and putting Indian farmers into debt who bought into biotech’s false promises – which is why many are now committing suicide. Another alternative is to choose cotton products through the Better Cotton Initiative, which is striving to make global cotton production better for the environment and the economies in cotton-producing areas. Though not necessarily organic, member farmers of the Better Cotton Initiative in Brazil, India, Mali, and Pakistan are using more sustainable ways of growing cotton. Their production principles include cotton produced by farmers who:12
- Minimize the harmful impact of crop protection practices
- Use water efficiently and care for the availability of water
- Care for the health of the soil
- Conserve natural habitats
- Care for and preserve the quality of the fiber
- Promote decent work
Tips for Reducing Your Body Odor Naturally
Even with an organic cotton shirt, body odor can still be offensive and often has little to do with the fabric your shirt is made out of. Foul body odor is typically related to the toxins being expelled – it's not your "natural" scent. If you're living a "clean" lifestyle, meaning a lifestyle in which you're minimally exposed to dietary and environmental toxins and therefore have a low toxic burden, your sweat will be close to odorless. Please don’t attempt to stop your body’s natural sweating by using antiperspirants. Not only do they typically contain toxic chemicals like parabens and metals like aluminum, but profuse sweating can actually help decrease body odor. Your body releases sweat to help regulate its body temperature to prevent you from overheating, but there are actually many other benefits to it as well.
Sweating helps your body to eliminate toxins, which supports proper immune function and helps prevent diseases related to toxic overload. Sweating may also help kill viruses and bacteria that cannot survive in temperatures above 98.6°F, as well as on the surface of your skin. Interestingly, the lead author of the featured study is conducting research involving bacterial transplants to stop excessive body odor. The idea is to fight odor-causing bacteria with their own kind: more bacteria.
He explained:13 "We have done transplants with about 15 people, and most of them have been successful… All have had an effect short term, but the bad odor comes back after a few months for some people." Another option for eliminating body odor, aside from washing regularly with soap and water, of course, is exposure to sunlight. Ultraviolet light, specifically UVB, is a very potent germicidal. I have noticed that by tanning my armpits, it eliminates armpit odor nearly completely, probably because the UVB kills any odor-causing bacteria. If you have clothing with resistant odors, putting them outside in the sun can also be helpful for freshening them up and removing odors.
Do You Want Clothes That are Toxin-Free?
Pure, non-toxic clothing isn’t too much to ask for, right? To join in the fight for toxin-free clothing, Join the Greenpeace Detox campaign, which is campaigning to stop industry poisoning waterways around the world with hazardous, persistent and hormone-disrupting chemicals. Nike, Adidas, Puma, H&M, and C&A are among the clothing brands that have already committed to the campaign, but many top brands still need some persuading. On a personal level, you can "detox" your wardrobe using these tips from Greenpeace:
- Buy organic clothing
- Support "green" brands that use environmentally friendly fabrics and natural dyes, or make clothing from recycled materials
- Buy secondhand clothes, and when buying new choose "classics" that you can wear again and again
- Buy quality clothing items that are made to last, instead of cheaply made garments you'll be forced to replace often
- Before tossing a garment, fix it if possible (with a new zipper/buttons, etc.) or take it to a tailor (or be crafty yourself!) to be re-fashioned (turning a dress into a skirt or jeans into shorts, for instance)