Plastic baby bottles are light and practical. It is no wonder that they represent more than 80% of the global baby bottle market.
However a study published in the prestigious journal Nature Food reveals something worrying: plastic baby bottles can expose babies to thousands – even millions – of microplastic particles per day. A significantly higher amount than previously estimated.
According to the study, a bottle-fed baby is exposed to an average of more than 1.5 million microplastic particles per day. That is 2,600 times more than the average adult intake. In North America and Europe the numbers are even higher, as plastic bottles are particularly popular in these regions. In China, where glass bottles are more common, the figure drops to tens of thousands.
Heat accelerates plastic degradation
Researchers selected 10 of the most common plastic baby bottles and measured microplastic release when preparing infant formula following WHO guidelines. These guidelines require heating water to at least 70 degrees to eliminate bacteria.
The finding was clear: microplastic release is extremely temperature-sensitive. Researcher Boland describes the phenomenon: "It is an interaction between the polymer and the water – like flaking of the plastic surface itself." Hot water and shaking the bottle make the situation even worse.
Simply shaking a bottle filled with room-temperature water for about 60 seconds already generates hundreds of thousands of particles. When the temperature was raised to 70 degrees, the bottles released between 1 and 16 million particles per litre. In addition billions of nanoplastics are generated – particles so small that researchers stopped counting them.
The plastic bottles continued to release particles throughout the entire 21-day testing period.
What does this mean for the baby's health?
The big question is: how does this affect the child's developing organism?
Although research is ongoing, animal experiments suggest that microplastics can cause digestive disorders and even affect brain development. Microplastics have already been found in human blood, testicles and even in the placenta.
The plastics industry emphasises that the finding does not automatically mean a health risk. However paediatricians think differently.
Particularly concerning are the chemicals present in plastic – phthalates, which can disrupt metabolism and reduce testosterone levels, and bisphenol A, which mimics oestrogen in the body.
"Science is only scratching the surface. When we see microplastics we know that the plastic is degrading – and the deeper concern is what we cannot yet see", says Professor Leonardo Trasande from NYU Grossman School of Medicine.
"Parents should be worried", adds paediatrician Claire McCarthy from Boston Children's Hospital. "We do not know exactly how much exposure is harmful. But it is reasonable to say that we should all use less plastic – especially when it comes to feeding babies and children."
Practical advice for parents
If you use plastic baby bottles, researchers recommend minimising shaking and heating. Four important steps to reduce exposure:
- Rinse the sterilised baby bottle with cold sterile water to remove any microplastic particles.
- Always prepare infant formula in a plastic-free container – for example a steel or glass jug.
- Allow the mixture to cool to room temperature before pouring it into the sterilised baby bottle.
- Never heat prepared infant formula in plastic containers – especially not in the microwave.
The simplest and safest solution is to switch to 100% plastic-free alternatives. Stainless steel and glass are the safest choices for your child's health and future.
Sources used in the article:
- Nature Food "Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation"
- Oxford Academic "Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis"
- Science Direct "Discovery and quantification of plastic particle pollution in human blood"
- Science Direct "Temporal trends in microplastic accumulation in placentas from pregnancies in Hawaiʻi"
