Research & Insights

Are we too clean?

As a society we’ve worked hard to sanitise our lives, but have we gone too far?  

Health Agenda magazine 
October 2017

Over the past century we’ve become adept at killing pathogens that cause disease and keeping infectious diseases at bay. Australians can now look forward to living 30 years longer than our late 19th-century counterparts.

Modern medicines, new technologies and better sanitation have all seen infectious disease rates plummet – yet chronic, non-infectious illnesses have done the opposite. Australians now stand a 1 in 5 chance of developing an allergy. The reasons are complex and not yet fully understood, but scientists are questioning whether our over-sanitised lives may have something to do with it.

Killing good bacteria

Our success at lowering the rate of infectious diseases like smallpox and cholera over the last century has been incredible, says microbiologist Professor B. Brett Finlay, head of the Michael Smith Laboratories at the University of British Columbia in Canada and co-author of the book Let Them Eat Dirt, but we really need to rethink what’s necessary hygiene.

“We’re taking microbes [microorganisms such as bacteria] out of our life that have evolved with us over millennia,” he says. “And we’re realising that there are consequences to that – asthma, allergies, even obesity, heart disease. We need to think about restoring some balance.”

The links to asthma and allergies have been discussed in science and the media for some time, but the possible connection with obesity and heart disease has only emerged in the last few years, with recent studies showing the link.

Over the last 3 generations, there’s been a decline in our exposure to bacteria. “Today, our kids don’t have the same rich mix of gut microbes as their great-grandparents,” says Prof Finlay. “We’ve decreased the number of microbes in our environment and those that are left are becoming more similar. We now know that’s not good.”

A healthy start to life

A person’s microbiota, their collective of microorganisms, is laid down in the first 18 months of life.

“That’s when the bacteria that live in your gut for the rest of your life are established,” explains Professor Barbara Fazekas de St Groth, immunologist at the University of Sydney.

“Once they’re there, they stop other microbes from getting established, so if you’re not exposed to good ones in that time, it can be hard to do anything about it later on.”

The vaginal bacteria and faecal matter a baby is exposed to during birth can help set up their immune system for life. These ‘good’ bacteria are the first to colonise babies’ intestines. The bacteria encountered in both breastfeeding and contact with other children may also play a role.

“We shouldn’t cosset small children,” says Prof Fazekas de St Groth. “Let them slobber over each other. Transmission of microbes at a very young age is important.”

Get microbe smart

“For medical benefits we have reduced the number of pathogenic microbes being transferred from one person to another, but in doing so we’ve stopped the good ones as well,” says Prof Fazekas de St Groth.

Some worries about germs are perfectly valid, with E. coli and salmonella causing gastro in Australian homes every year. How do we expose ourselves to good microbes without also copping the bad?

1. Use microbe friendly cleaning products: “Most cleaners have antimicrobial agents in them and we need to ask why we’re using them … In healthy households, are these germs that really need killing?” says Prof Finlay.

Learn more about cheap and low-risk cleaning products and methods at Eartheasy.

2. Wash your hands: This remains one of our best defences – it reduces the rate of infectious illnesses and, in turn, our need for antibiotics. Wash your hands before preparing food and eating, after using the toilet or handling garbage, and after being around someone ill.

3. Clean your teeth regularly: Good oral health provides an excellent first line of defence for many diseases.

4. When prepping food, avoid cross contamination: Use separate chopping boards for meat and vegetables, keep cooked meat separate from raw juices and don’t leave hot or cold food standing at room temperature.

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