Microplastics are plastic fragments smaller than 5 mm. Nanoplastics are smaller still — less than 1 micrometre — and can pass through cell membranes. Both have been found in human blood, lungs, placentas, the brain and breast milk.
How to read the numbers: Today’s average = common in today’s population – not a target or optimum · Risk = what to watch out for · Term = a key term or marker worth knowing
Average intake
This figure comes from a widely quoted 2019 estimate; newer analyses suggest actual intake is probably considerably lower, and uncertainty is high. You can reduce exposure by not heating food in plastic and drinking filtered tap water.
In 1L of bottled water
Newer methods that also detect nanoplastics find far more particles in bottled water than older measurements; results, however, vary greatly by method and brand. In practice: drink filtered tap water from glass or stainless steel and do not leave bottles in the sun.
Disruptors in plastics
Endocrine disruptors such as bisphenols and phthalates can interfere with the hormonal system and leach from plastics especially with heat and wear. Replace scratched plastic containers with glass ones and keep plastics out of the microwave and dishwasher.
A 2022 study found microplastics in the blood of 77% of the individuals tested. Another study identified them in 100% of the breast milk samples tested. Research is ongoing — but the picture is not encouraging.
The biological impact
Many plastics contain or absorb endocrine disruptors (BPA, phthalates, bisphenol S). These substances mimic oestrogen, block testosterone and disrupt hormonal signalling. Physical microplastics themselves cause inflammation in the tissues where they accumulate.
Where the biggest sources are
Plastic water bottles (especially when exposed to heat). Microwaving food in plastic containers. Synthetic textiles (polyester sheds microplastics in the wash). Seafood from contaminated waters. Sea salt. Urban air.
Detoxification
The body has no specific mechanism for eliminating microplastics. Supporting the body against the inflammatory burden (an anti-inflammatory diet, exercise, sweating in the sauna) may help. Research into active detoxification is still in its infancy.
