1.13 - Natural fabrics

You're in skin contact with whatever you're wearing for roughly 24 hours a day. The shirts and pants during waking hours, the sheets and pajamas overnight. That's about as much exposure as it gets to anything in your environment.

For most of human history, what you wore was a natural fiber: cotton, wool, linen, silk, hemp, leather. For the last few decades, that's changed. The majority of modern clothing is now synthetic - polyester, nylon, acrylic, spandex, or some blend - and the materials are doing things to your body that nobody talks much about.

The problem with synthetic clothing

Four issues worth knowing about:

• Microplastic shedding. Synthetic fabrics shed enormous quantities of microfibers, both during wear and especially during washing. A single load of synthetic laundry can release hundreds of thousands of microplastic particles into the water system. Some of what you shed off your clothes during wear is small enough to be absorbed through the skin or inhaled. Microplastics have now been found in human blood, placentas, breast milk, and brain tissue. The full health implications are still being studied, but minimizing your daily contact with the source is a reasonable precaution.

• Chemical loads. Most synthetic clothing carries a chemical history: petroleum-derived base, synthetic dyes, formaldehyde-based anti-wrinkle finishes, PFAS-based water repellents, flame retardants, antimicrobial treatments. Many of these chemicals leach onto the skin during normal wear and absorb through it. Some are endocrine disruptors. Some are known carcinogens. The regulatory environment around clothing chemistry is much looser than around, say, food.

• Breathability and moisture handling. Natural fibers breathe and absorb moisture. Synthetic fibers mostly don't. This is why synthetic underwear is associated with more frequent infections, why polyester shirts smell faster than cotton ones, and why synthetic bedding leaves you damp during sleep.

• Possible muscular and bioelectric effects. Practitioners of applied kinesiology and some traditional medicine frameworks have long claimed that synthetic fabrics produce weaker muscular responses than natural fibers when tested side by side. The proposed mechanisms involve the substantial static electricity that synthetics generate against the skin, and possibly electromagnetic interference with the body's natural bioelectric activity. The clinical evidence is mixed and the muscle-testing methodology itself is contested, but some research (including studies on the electrostatic effects of polyester) suggests there may be something real here worth knowing about, even if it isn't yet fully understood.

The natural fiber alternatives

The good news is that natural fibers are widely available, and once you start reading labels, the difference becomes obvious:

• Cotton. The most accessible natural fiber. Available in almost everything. Look for organic cotton where possible, since conventional cotton is among the most chemically intensive crops on earth.

• Wool. Excellent for outerwear, base layers, and bedding. Regulates temperature, wicks moisture, naturally antimicrobial. Merino wool in particular is fine enough to wear next to the skin without itching.

• Linen. Made from flax. Incredible for warm-weather clothing and bedding. Gets softer with every wash. Wrinkles, but that's the trade-off.

• Hemp. Stronger and more durable than cotton, with similar feel. Becoming more available as cultivation regulations relax.

• Silk. Beautiful and gentle for everyday wear, sleepwear, and pillowcases. Naturally temperature-regulating and easy on skin and hair.

Where it matters most

You don't have to throw out your entire wardrobe. The places to prioritize first are the items in longest skin contact, especially with the most sensitive areas:

• Underwear. All-day skin contact in regions where the skin is thin and absorbent. Switch to cotton, silk, or merino wool first.

• Sleepwear. Eight hours of skin contact every night. Worth investing in good natural-fiber pajamas, or just sleeping in nothing.

• Bedding. Sheets, pillowcases, duvet covers are touching most of your body for a third of your life. Cotton, linen, or silk sheets are a substantial upgrade over polyester.

• Workout clothing. Synthetic athletic wear is convenient, but you're sweating directly into the material, which increases both microplastic absorption and the chemical leach. Cotton, wool, or hemp athletic wear works for most non-elite training.

• Items that touch the face or neck. Pillowcases especially, but also scarves and turtlenecks. The skin around the face is sensitive and absorbs differently than skin elsewhere.

A note on mattresses

The same logic that applies to clothing applies even more to mattresses. You sleep on one for roughly a third of your life. Conventional mattresses are made of polyurethane foam, treated with flame retardants and other chemical additives, off-gassing slowly for years.

Switching to a mattress made from natural materials (latex, wool, organic cotton, with no synthetic flame retardants) is one of the larger one-time investments in this book. It's also the easiest to defend. If you're going to spend serious money on health, the thing you sleep on every night is a reasonable place to put it.

If a full mattress replacement isn't realistic, an organic wool or cotton mattress topper between you and the synthetic mattress goes most of the way.

How to start

You don't have to overhaul everything at once. Replace items as they wear out, starting with the highest-impact ones (underwear and bedding), then sleepwear, then everyday clothing, then eventually the mattress when the time comes.

Read labels carefully. A surprising number of "cotton" t-shirts are actually 60% polyester. Check the small print on the inside of the collar. The cleaner the fiber composition, the better.