Everyday exposure poses challenge

Many of you may have heard of the term ‘neuroplasticity’. It has been used in scientific circles probably since the 1940s or ’50s and popularised into mainstream neuroscience since the 1970s after research conducted by an American neuroscientist, Michael Merzenich (one of the co-founders of BrainHQ which is one of the brain-training apps with most evidence to support its use).

Neuroplasticity is generally regarded as a hopeful concept, denoting the brain’s ability to change in response to the environment in which it finds itself.

New neural connections are formed and existing pathways strengthened or weakened, depending on the stimulus the brain receives. This means that if we engage in active learning, our brain changes for the better, becoming a stronger and more efficient system.

It underpins the whole idea of  ‘use it or lose it’. ‘Exercising’ the brain  leads to helpful adaptations; not doing so leads to the loss of neurons and otherwise helpful circuitry.

Recently, however, I have become aware that a different – and literal – type of neuroplasticity is emerging, and it is not good news.

Specifically, a recent study looking at the brains of people post-mortem showed that, on average, 0.5 per cent of their brain was made of micro and nanoplastics. This is the same amount as a plastic spoon. The finding is staggering, and clearly a modern phenomenon (the first fully synthetic plastic, Bakelite, only came into being in 1907, just over 100 years ago).

Even more worryingly, the brains of those with established dementia diagnoses had levels three-to-five-times more than those without the condition. This raises the obvious question of whether the plastic in the brain may cause the dementia.

Though this is not established, there are plausible mechanisms by which this could happen. These include by causing inflammation and oxidative stress in the brain, and through the additives in plastic (for example, pththalates and bisphenol A or BPA) causing hormonal changes.

At a most basic level, it is fair to say the brain was not designed to incorporate plastic into its substances.

It is thought that we ingest or inhale about 5g of plastic per week, or the equivalent of a credit card through living our everyday lives. Sources include the clothing we wear and the cosmetics and personal care products we use. Then there is the food and drink we consume when it is stored and transported in plastic containers: bottles, bags and packaging.

Adding to the issue, microplastics never fully degrade: they are with us to stay.

So, what can we do to reduce our exposure? Here are some tips:

• use glass, ceramic or stainless steel containers instead of plastic ones
• filter tap water
• eat more fresh, whole foods – processed or packaged items have more microplastics
• use your own ceramic or metal cup when ordering your daily coffee
• choose loose produce to avoid the plastic packaging of pre-wrapped fruit and vegetables
• wash synthetic clothes such as those made of polyester less often – friction may release plastics
• choose natural fibres including organic cotton or wool when buying clothes
• vacuum and dust frequently as many microplastics come from indoor fibres
• avoid bottled water – it contains twice as many microplastics as tap water
• avoid cheap, plastic kettles which can release particles when heated
• avoid microwaving food in plastic containers as heat accelerates the leaching of particles into the food
• avoid air fresheners, sprays and cleaning products in plastic containers.

You can’t avoid all microplastics, but small, consistent choices add up. Think “less plastic, less heat, less friction”. Your brain will thank you for it.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, available at bookstores and online. Visit yourbraininmind.com or uqp.com.au