You may have heard a lot about the gut microbiome, the community of microorganisms that inhabit your digestive tract.
These microbes, mostly bacteria, have been linked to many aspects of your health, from your immune system and metabolism, to your mood and brain function.
But how much do you really know about the gut microbiome? There are many myths and misconceptions that circulate in the media and online, some of which may be misleading or inaccurate.
In a recent review article published in Nature Microbiology, two UK microbiologists, Alan Walker and Lesley Hoyles, debunk 12 common myths about the gut microbiome. They also provide a critical assessment of the current state of knowledge in this field.
Here are some of the myths they address:
- The gut microbiome is not a new discovery. Scientists have been studying the microbes in the human intestine since the late 19th century, when they first isolated bacterial samples from fecal matter.
- The gut-brain axis, the communication between the gut and the brain, is not a recent concept either. Researchers have been exploring the connection between the digestive system and the nervous system for centuries, but only in recent decades have they uncovered how it works in both directions.
- The human microbiota does not weigh 1 to 2 kilograms (2.2 to 4.4 pounds), as often reported. This figure is based on an estimate that has no clear source. Walker and Hoyles calculate that the human microbiota probably weighs less than 500 grams (1.1 pounds), based on the weight of fecal matter, colonic contents, and microbial cells.
- The human body does not contain 10 times more microbial cells than human cells. This ratio is based on a rough calculation from the 1970s that has been challenged by more recent studies. The actual ratio is likely closer to 1:1, depending on factors such as body mass, age, and diet.
- Babies do not inherit their microbiota from their mothers at birth. While some microbes are transferred from the mother to the baby during delivery, most of them do not persist in the long term. The baby’s microbiota develops over time and is influenced by many environmental factors.
- The gut microbiome is not static or fixed. It changes throughout life in response to various internal and external stimuli, such as diet, medication, stress, infection, and aging. The gut microbiome is also highly variable among individuals, even among identical twins.
These are just some of the myths that Walker and Hoyles address in their article. They also discuss other topics, such as the role of probiotics and prebiotics, the effects of antibiotics and fecal transplants, and the challenges of studying the gut microbiome in humans.
The authors hope that their article will help to clarify some of the common misunderstandings about the gut microbiome and provide a balanced perspective on its importance for human health.
They also acknowledge that there is still much to learn about this complex and dynamic ecosystem, and that more rigorous and reproducible research is needed to advance this field.
The gut microbiome is a fascinating topic that has many implications for our well-being. But it is also a topic that requires careful interpretation and critical thinking.
As Walker and Hoyles conclude: “We should be excited by what we know about our gut microbes but also mindful of what we do not know.”