Adelaide researchers are exploring a very big idea that would tackle the rise of allergies, asthma and immune diseases – and the spiralling cost of healthcare.

Scientists from The Environment Institute at the University of Adelaide argue that planting more native vegetation, tearing up the concrete plains that dominate our cities and maybe taking a regular dirt bath, like birds do will protect us against a slew of modern diseases.

The theory behind this – growing in support over the last decade – is that dwindling biodiversity isn’t just taking out animals and plant species, it’s also taking out varieties of healthy bacteria from the environment we live in, and from inside our own bodies.

In other words, it’s taking out people

Hence, “re-wilding” our environment – literally dirtying it up and bringing it closer to its pre-civilised state – will build healthier children. How this would actually look is something the researchers are now modelling, firstly with mice.

Predictably the biggest obstacle will be a political one – the will to transform parts of our cities to friendly germ parks. It goes further though, the scientists say.

What’s partly required is a germ-based understanding of our place in the world.

Microbial ecologist and lead author of a new paper, Jacob Mills, explained it this way: “The whole world is coated in microbes, fungi and parasites and they evolved before any multicellular life form. So any multicellular life form (such has humans) had to had to adapt to live with microbes.”

“Then it became a symbiotic relationship, where humans provided habitat (place to live) and collected resources (food). In return the microbes provided health benefits because it was in their interests to keep their vehicle in good shape,” Mr Mills said.

More germ than human

If this sounds a little icky, Mr Mills observes that we are, in effect, more than human.

“Cell for cell we are 57 per cent microbial, we’re walking ecosystems. Our symbiotic microbial partners… come from our mother and wider habitat when we’re young. These microorganisms play vital roles in our health, particularly our immune training and regulation,” he said.

When mentioning our mothers, Mr Mills is referencing the fact that when we are born we pick up useful bacterial, including that which digests breast milk, from our mother’s vagina.

And with the rise of the caesarean, another piece in the healthy microbiome is being lost, which in itself is a big issue.

The theoretical framework supporting the Adelaide project comes from Finland – where a group of scientists have championed the link between biodiversity loss and inflammatory disease – and an idea from the University College of London called the “Old Friends Theory”.

Resurrecting the Old Friends

The “Old Friends” are the microbes we’ve rid ourselves of – and it was written as an alternative to the popular hygiene theory that argues we’ve ruined our heath by being too aggressive in the use of soaps and anti-bacterials.

The London scientists believe the problem is more organic than that.

“Evidence suggests a combination of strategies, including natural childbirth, breast feeding, increased social exposure through sport, other outdoor activities, less time spent indoors, diet and appropriate antibiotic use, may help restore the microbiome and perhaps reduce risks of allergic disease,” Mr Mills said.

And now Mr Mills and his colleagues are taking a big step back to suggest we need to push a re-start button not just on how we live, but on where we live.