Most of us considered microbes little more than nasty germs before science recently began turning our view of the microbial world on its head. A “microbe” is a bacterium and any other organism too small to see with the naked eye. After decades of trying to sanitize them out of our lives, the human microbiome – the communities of microbes living on and in us – is now all the rage. And yet, some insist that we can’t really call microbes “good.” That’s nonsense.
Of course no one thinks microbes can be morally righteous. They don’t have intentions – good or bad. But it is fast becoming clear that certain microbial communities are vital to our individual health and that of our crops. Most of them either benefit us or do no harm most of the time.
This new realization is driving discoveries and an ongoing reevaluation of practices at the heart of two of humanity’s essential and iconic endeavors – medicine and agriculture. Members of our microbiome, especially those living in the gut, not only help keep their disease-causing cousins at bay, they also make many compounds that we need, but that our own bodies cannot make. Butyrate is one such compound – without a steady supply, cells lining the colon start to malfunction, which can lead to certain cancers and leaky gut syndrome, among other ailments. The neurotransmitter serotonin is another compound that gut microbiota make. Insufficient levels of it can make us feel grumpy.
In the botanical world the beneficial microbes living in and on a plant’s roots produce plant growth hormones and stimulate plants to produce their own defensive compounds. Plants, in turn, make and release sugars and proteins from their roots to feed microbial allies in the soil. Why? It’s mutually beneficial.