A new study has found tiny particles found in air pollution from vehicles can also be found in the brain tissue of people with dementia.

Air pollution from vehicles releases magnetite, a magnetic form of iron oxide, which has been found in brain tissue of people who died with Alzheimer’s disease. That’s according to a new study by Lancaster, Oxford and Manchester Universities.

Researchers examined the brain tissue of 29 people who lived in Mexico City (one of the most polluted cities in the world) and eight people who lived in Manchester. They had all died with neurodegenerative diseases.

Within the brain tissue, they discovered a mineral called magnetite, which is toxic and linked to Alzheimer’s disease. Magnetite is produced in car engines, particularly diesel engines, which emit up to 22 times more particulates than petrol engines. It can also be produced when brakes are used on cars and trains.

While magnetite has been found in brains before, and was thought to occur naturally there, the researchers realised that this particular type of magnetite found in the study participants was in the form of tiny balls, which suggested that they had a fused surface and had been formed during extreme heat, such as in a car engine.

The study is particularly important as it’s the first time that researchers have proved that pollution particles inhaled through the olfactory system (the nose), could enter the brain.

Professor Anthony Seaton, an Emeritus Professor of Environmental and Occupational Medicine at the University of Aberdeen told the Daily Telegraph;

‘This is an important study and adds to the body of evidence that the combustion of fossil fuels has widespread toxic effects on our health.

‘The solution to this is literally in our own hands as we take hold of the steering wheel.’

So what does that actually mean for the average city-dweller? Should be decking ourselves out in masks or moving to the country?

Dementia charities were quick to point out that more research was needed, and that trying to avoid inhaling pollution fumes (which if you live in a busy city isn’t always the easiest thing to do), was only one of the lifestyle changes you can do to decrease your risk of dementia.

‘We know that air pollution can have a negative impact on certain aspects of human health, but we can’t conclude from this study that magnetite carried in the air are harmful to brain health,’ says Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK.

While Dr Clare Walton, Research Manager at the Alzheimer’s Society said:

‘Magnetite, a form of iron oxide, has previously been seen in amyloid plaques in the brains of people who have died with Alzheimer’s disease. This magnetite is generally thought to come from iron found naturally in the brain and there is no strong evidence to suggest that it causes Alzheimer’s disease or makes it worse.

‘This study offers convincing evidence that magnetite from air pollution can get into the brain, but it doesn’t tell us what effect this has on brain health or conditions such as Alzheimer’s disease.

‘The causes of dementia are complex and so far there hasn’t been enough research to say whether living in cities and polluted areas raises the risk of dementia.

‘Further work in this area is important, but until we have more information people should not be unduly worried. There are more practical ways to lower your chances of developing dementia such as regular exercise, eating a healthy diet and avoiding smoking.’

Our advice? If the day seems particularly smoggy (often if there is very high pressure), you could try to avoid routes into work where there is likely to be very heavy traffic, and stay indoors where possible (this is the advice given to people with breathing conditions such as asthma when pollution levels are high).

However, keep a sensible balance and try not to get too obsessed. Regular exercise, a healthy plate of food, cutting down on alcohol and cigarettes and keeping your brain stimulated with interesting activities and hobbies can all help, too.

Sources: alzheimers.org.uk and telegraph.co.uk