Is soil really an antidepressant?
Cavan Images/Alamy
There are numerous claims circulating in the world of gardening, but one particularly intriguing notion gaining traction is that “Soil is an antidepressant.” This idea suggests that the microbe Mycobacterium vaccae, commonly found in soil, has the potential to uplift one’s mood simply by coming into contact with the earth. It is believed that these bacteria can be absorbed through the skin or inhaled, leading to a positive impact on brain chemistry. But is there any truth to this claim?
While the concept may sound far-fetched at first, several studies have delved into the effects of this microbe on various conditions, ranging from eczema to cancer. Initially isolated in soil samples from Uganda, M. vaccae sparked interest among researchers looking for a harmless alternative to Mycobacterium tuberculosis for immunotherapy. The bacteria unexpectedly showed mood-enhancing effects in individuals with lung cancer undergoing treatment, prompting further investigation into its potential benefits for depression.
Although several well-designed studies have replicated the positive impact of M. vaccae on mood, it is essential to note that these experiments were conducted on mice, not humans. Animal study results often do not translate directly to humans, with only a fraction of findings being replicated in human trials. Moreover, the experiments involving M. vaccae administration in mice were specific to a particular strain and method of delivery, either through injections or food mixing.
As someone intrigued by the connection between nature and mental well-being, particularly the benefits of spending time in green spaces, I am eager to see the outcomes of further research on M. vaccae. However, despite the enthusiastic claims circulating online, it is crucial to acknowledge that the statement “soil is an antidepressant” currently applies only to male mice injected with a purified form of the bacterium. Since you are reading this, it is safe to assume that you do not fall into that category.
James Wong, a botanist and science writer specializing in food crops, conservation, and the environment, received training at the Royal Botanic Gardens, Kew in London. He shares his living space with over 500 houseplants and can be followed on X and Instagram @botanygeek.
For more exciting projects, visit newscientist.com/maker
Topics:
