Why a ‘germier’ house is good for you

The world around us, including our homes, is full of micro-organisms such as bacteria, viruses and fungi. Some bacteria and viruses are bad for our health, but the vast majority of these microbes are harmless or actually beneficial, says Jack Gilbert, a paediatrics professor at the University of California at San Diego.

The micro-organisms in our homes, where we spend a large amount of time, can play an important role in our health, Gilbert says. Research suggests that being exposed to a greater diversity of microbes results in a better-functioning immune system and lower rates of asthma or allergies.

Cleaning your home with a lot of disinfectants could be doing you more harm than good.Credit: Getty Images

We still don’t understand much about the microbiome in homes, Gilbert says, but there is one emerging trend: Urbanisation appears to be associated with a loss of microbiome diversity in our environment and our bodies, which has probably contributed to a rise in disease, he says.

But, there are a few easy ways to support a more diverse microbiome in your home.

Open your windows

If you live in an area with good air quality, opening the windows can help diversify your home’s microbiome by allowing in more micro-organisms.

This is especially true if your home is within about 450 metres of diverse plants. Plants and soil release micro-organisms, and exposure to diverse micro-organisms can help train the immune system to better regulate itself, Gilbert says.

Without this type of exposure, he says the immune system can overreact to non-harmful allergens and organisms, which could lead to autoimmune conditions or allergies.

“What we’re exposed to in the world can shape how our body reacts,” Gilbert says.

Graham Rook, emeritus professor of medical microbiology at University College London (UCL), suggests that some microbes in the natural world are like “old friends” that evolved alongside us and benefit our health by strengthening our immune system’s ability to regulate itself and avoid harmful overreactions.

However, if you have allergies to spring pollen, allergists recommend keeping your windows closed to avoid exacerbating your symptoms.

Keep houseplants

Studies suggest that living in urban settings can reduce microbiome diversity in our homes and hinder the development of a varied microbiome in our bodies.

“In urban areas, there is a lot of asphalt or concrete, and we don’t have as much connection to the soil or plants, so we don’t get as much microbial exposure,” says Juulia Manninen, a doctoral researcher at the University of Helsinki who focuses on microbial diversity in urban environments.

But interacting with plants increases exposure to beneficial microbes, which are often limited in indoor and urban environments, she says.

Studies have shown that exposure to microbially diverse soils via indoor plants can boost anti-inflammatory proteins in your body.Credit: Getty Images

For example, one study from the Nature-Based Solutions Research Group at the University of Helsinki and the Natural Resources Institute in Finland found that people who worked in offices with vegetated “green walls” (vertical structures with plants growing on them) had increased levels of anti-inflammatory proteins in their blood than workers who did not get this intervention.

Similarly, another study found that adults living in urban areas who did indoor gardening using microbially diverse soil had increased levels of anti-inflammatory proteins in their blood after one month compared with those who gardened using soil with lower microbial diversity.

Indoor gardening – growing, repotting, or even harvesting herbs or vegetables indoors – is one way to increase our interaction with plants, but simply being exposed to a variety of potted plants in the home would still be beneficial, Gilbert says.

Clean strategically

When cleaning your home, don’t overuse harsh chemical disinfectants because they could kill too many beneficial microorganisms, says Erica M. Hartmann, an associate professor of civil and environmental engineering at Northwestern University.

Instead, when cleaning, ask yourself, “What problem do I want to solve?”

Focus on disinfecting areas where you know there may be harmful micro-organisms, such as the kitchen benchtop, where bacteria such as E coli could spread from handling raw meat, or the bathroom, where potentially harmful moulds could grow, she says.

When cleaning with chemical disinfectants, wear a mask and open a window to avoid breathing in chemicals, which could be harmful to your health, Hartmann advises.

To remove debris such as dust or dirt from floors and shelves, skip disinfectants and use a damp cloth instead, she says.

Consider getting a pet

Exposure to animals in or around the home, such as by growing up on a farm or having a pet, is associated with a reduced risk for asthma and allergies, as well as some inflammatory diseases.

Dogs, in particular, have been shown to alter and diversify the microbiome inside a home.

Having a family dog has been linked with lower rates of asthma and allergy-related conditions.Credit: Getty Images

Rook and Gilbert attribute this to dogs running around outside and getting dirty, then tracking micro-organisms into the house. Also, humans have a long history of living with dogs, which may mean that our immune system responds well to dog-associated microbes.

“Allow your dogs to come into the house, even if they’re a little dirty,” Rook suggests.

If all else fails – visit nature regularly

Not everyone can have a pet or keep houseplants in their home, and if they live in an area with significant air pollution, opening windows could do more harm than good, Gilbert says.

If you face any such restriction, or even if you don’t, try to get outdoors as much as possible to increase your exposure to more diverse micro-organisms.

“Even spending half an hour a week in a city park interacting with grass and trees will have health benefits,” Gilbert says.

The Washington Post

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