Microorganisms have always had a bad reputation. Some deserve it; they are responsible for infectious diseases that have proven to be fatal, including tuberculosis, smallpox, cholera, AIDS and Ebola, just to name a few. Yet 99.99 percent of bacteria actually play an essential role in human health and environmental function.


Our microbiome—which consists of a community of trillions of microbial cells and the genes they contain—not only influence our wellbeing, but also play an important role in protecting us from some of these harmful pathogens. The millions of microbes that live on our skin and inside us form a protective barrier against more dangerous microbes. Without them, our bodies would be open to a pathogen attack. Research has also shown that bacteria in our digestive tract can bind to immune cells and stimulate them to divide and reproduce, further helping us fight away illness.

"Taking antibiotics can wipe out our healthy microbes, which can alter our metabolism, mental health and even leave us vulnerable to a pathogen attack."

Additionally, microbes play an important role in our basic physiological response by helping us digest foods, as well as by producing chemicals that shape our metabolic rates. Studies have suggested that when the bacterial community in our gut changes it can change how we respond to foods, so that disrupting the microbiome can lead to weight gain and obesity. Research has also suggested a link between the microbiome and mental health, showing that gut microbes could influence stress responses in the brain, with the possibility of using probiotic treatments to treat depression, anxiety and even neurological degenerative diseases, such as Alzheimer’s, Parkinson’s and autism.

Outdoor elements

Humans in the developed world now spend more than 90 percent of their lives indoors, and the invention of air conditioning and sterile indoor environments may be leading to a significant reduction in the exposure we have to the bacteria that may build up our defense against diseases as well as keeping our immune system from attacking us. Our homes and workplaces may be clean, but they may be so clean that we have removed the exposure our bodies need to be healthy. Analyses of home and hospitals have started to map the movement of bacteria between ourselves and our spaces, and found that, especially for homes, the majority of bacteria come from human skin. This is obviously very different to what we evolved to be exposed to on farms, and in the natural world.

Along with our bodies, microbes are extremely important in both the natural world and in our industries. For example, in addition to breaking down all the dead and decaying plants and animals in the world, microbes also produce 50-70 percent of the world’s oxygen. It is also common knowledge that microbes play a role in food production, such as yogurt, cheese, wine, bread, vitamins and chocolate. Newer research is now showing that by altering the DNA sequence of microbes, scientists can create compounds that the microbes wouldn’t normally produce. This includes medical products like insulin, or new sources of fuel.

These are just a few ways in which microbes shape our lives and ensure that we maintain a healthy balance. This is why taking antibiotics unnecessarily can be so detrimental—they can wipe out our healthy microbes, which can alter our metabolism, mental health and even leave us vulnerable to a pathogen attack.