Professor Adam Hart befriends our bacteria in this fascinating summary of how bacteria can help us - if we look after it.
If you look up bacteria in your Thesaurus then it’s likely that the top suggestion will be ‘germ’. Given that bacteria cause, among other diseases, anthrax, botulism, cholera, salmonella, and tooth decay then it is hardly surprising that there are negative connotations.
However, research is increasingly revealing that our relationship with bacteria is far from simple, far from negative, and far from fully understood.
Bacteria are incredibly small, astonishingly numerous and virtually ubiquitous. Some can survive hot springs, others thrive in Antarctic ice and some can even survive bleach. They are remarkable biochemical machines but they become really interesting when we consider them, not as germs, but as partners.
We are giant, walking ecosystems and our cells are outnumbered 10 to 1 by the bacteria living on and in us. From the rainforest of our mouths to the coral reefs of our lower intestine bacteria are there and a great many of them are helping us out. They assist with our digestion, they produce vitamins and they help us to absorb metals.
The reason why some bacteria cause disease while others can live happily within us is that our immune system has learned to distinguish friend from foe. We have evolved in partnership with a host of microorganisms, our ‘Old Friends’, and early exposure to them is how our immune system learns.
A lack of exposure to these Old Friends is not because of cleaner homes (there’s no evidence for that); it’s because of a lack of exposure to the natural world. This is what is causing a rise allergies and diseases like asthma in our children.
While our gut bacteria help us out, we tend to everything we can to hinder them. Our modern diets are poor in the nutrients they need (so-called prebiotics) and when we take antibiotics we nuke our internal communities. It is when we disrupt the bacterial communities living within our gut we really feel the effects.
A range of bowel diseases like IBD and Crohn’s are firmly linked to our gut bacteria and research is indicating they might affect our mental health too.
A “gut feeling” is already proving to be more than just a phrase and the coming years will undoubtedly see something of a revolution in medicine. We need to start thinking much more like ecosystem managers and take our unseen internal horde into account when we devise treatment plans.
We can help our bacteria. By eating substances that they digest easily we can “feed” our internal lawn and the hunt is on for every better and more effective prebiotics.
Much of this research is happening in the UK. I visited Professor Glenn Gibson’s laboratory at Reading University’s Department of Food and Nutritional Sciences a couple of years ago and had the great pleasure of seeing his “robot gut” at work.
The lab smelt pretty strongly of, well you can guess, but within the glass flasks and tubes Gibson and colleagues are simulating the human gut. They are considering the effect of different inputs on the bacterial communities they had nurtured and this sort of research, taking an ecological approach to microbiology, is both fascinating and of real value for human health in the future.