6 surprising ways soil and human health are linked

Soil may be everywhere but how often do we look down and think about what it does for us?

One of the planet’s largest living ecosystems, it provides 95% of our food, supports biodiversity and stores atmospheric carbon, which helps balance the climate.

A recent report from the United Nations Educational, Scientific and Cultural Organization, UNESCO, warned that this “crucial role in sustaining life on Earth” is at risk, with the prospect of 90% of the planet’s land surface being degraded by 2050. Climate change and human activity are behind this, causing a decline in soil quality that can include the loss of organic matter and changes in salinity, acidity or alkalinity. The impacts of this are substantial – many of the United Nations (UN) Sustainable Development Goals cannot be achieved without healthy soils, according to the European Environment Agency.

Everything from education to innovation will be key to improving this situation. In its report Scaling Technology Adoption for Soil Health, the World Economic Forum says that ambitious action, with data and digital infrastructure at its core, is needed to improve the health of the world’s soil.

This is vital not just for the planet but for us too – because healthy soil means healthy people. But how exactly? Here are just some of the ways it’s essential.

Healthy soil has a good structure, with physical spaces within the soil that allow for water drainage, air movement and root growth. It also has a high level of biodiversity, with enough organisms within it to convert dead and decaying matter into nutrients. This can be affected if the soil is regularly disturbed, for instance by agricultural practices.

Yet, from growing crops to rearing animals, soil is crucial to all agricultural activity. Helping farmers make the right decisions around soil health and providing them with the tools to make necessary changes will be key to delivering a real impact on soil health, the Forum report says.

This is vital to sustainable food systems that provide communities with sufficient and nutritious food, not least because healthy soils rich in organic matter and biodiversity yield crops richer in vitamins and minerals.

Healthy soil also has a crucial role in the management and quality of water. Well-structured soil with lots of organic matter acts as a natural sponge, increasing the amount of water captured and retained.

According to the UN, one cubic metre of healthy soil can retain over 250 litres of water. This means the soil requires less water from rainfall or irrigation, can reduce flooding and makes soil more resilient to drought.

Alongside, healthy soil is a natural filter, purifying the water as it passes through the ground.

Soil is a major natural carbon sink. Made from broken-down plant matter, it contains the carbon those plants once took from the atmosphere. Often, this carbon is stored for a long time, and the amount of carbon stored in soil is significant – estimated to be about 1,500 billion tonnes globally.

Carbon-rich soil is healthier and more fertile, benefiting farmers and food systems.

Healthy soils also have a big role in regulating air quality, by supporting plant growth. Plants and trees influence this by intercepting particles from the atmosphere and absorbing polluting gases.

When we think of developing new drugs, an image of a sterile lab environment probably comes to mind.

Yet soil is an important source of medicines. It has been estimated that about 40% of prescription drugs are derived from it.

This includes antibiotics, which bacteria such as species of Streptomyces produce to kill or inhibit the growth of other organisms. Alongside antibiotics, these bacteria produce other pharmaceutical products, including anticancer and antiparasitic drugs.

Scientists continue to find new drug discoveries in soil, such as newly identified protein particles in Streptomyces that researchers hope could help fight tuberculosis and diphtheria.

The microorganisms found in healthy soil are also crucial for gut health.

Our gut microbiome – the bacteria, fungi, viruses and other microbes that live in our intestines – helps regulate our health and hormones, according to The Guardian. According to the World Economic Forum report Transforming the Global Food System for Human Health and Resilience, the human gut and soil contain about the same number of these microorganisms.

But at the same time as urbanized societies have seen a large reduction in people’s contact with soil, communities across the globe have experienced a drop in gut microbiome diversity. And experts think this could be linked to an increase in chronic diseases such as asthma, food allergies and auto-immune disorders, The Guardian adds.

Finally, there is also a connection between healthy soil and our mental well-being – the soil microbes that help regulate our immune systems may also impact our mood.

As well as helping to create nutrient-rich food – which supports cognitive function – and being vital to the green spaces so crucial to our mental health, contact with microorganisms in soil supports a healthy gut-brain axis. As the Forum’s Transforming the Global Food System report says: “A large body of evidence now implicates the gut in modulating cognitive function and neuropsychiatric disorders”.

In other words, what’s happening in our gut is strongly linked to how our brain works and our mental health. And soil microbes are a crucial part of that.