What are microbiomes?
Both inside and out, our bodies have a host of smaller bodies. While bacteria are the biggest players, we also deal with single-celled organisms known as archaea, as well as fungi, viruses and other viral infections – including viruses that attack viruses. Collectively these are called human microbiota. Your body microbiome all types of your micobiota contain, however, statistically both of these terms are used in the same way.
Sit down, aren’t the germs becoming dangerous?
There is little to see: some are viral, but some are harmful when they get in the wrong place or go up in numbers, and some are very useful for the body – such as helping to reduce the list of sugars found in human breast milk. “Those sugars are not broken by a baby,” said Prof John Cryan, a neurosurgeon and micobiome specialist at University College Cork. Instead, the germs in the baby’s stomach do the job.
Other important roles of our germs include antibodies, providing nutrients to our cells and protecting the colony from harmful germs and viruses.
Where do my intestinal germs come from? Do I just pick them up at my place of residence?
In part. But it is more complicated than that. “There is still a little controversy but it is especially thought that we are infertile when we are in utero, and as we are born, as we come out of the birth canal from our trunk, we get these infected bacteria,” said Cryan.
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Cryan notes that during pregnancy the mother is removed, which is clearly a fertility mix. “If you’re not born with a birth, but you’re born with a [caesarean] stage, things start to change,” she said. Indeed, studies have suggested that these differences may be one of the reasons why children born to caesarean section are at greater risk for conditions including asthma and type 2 diabetes. That said, doctors have warned parents not to try to find babies born caesarean section with female genitals.
Our stomach germs change quickly over a year or two, which are resistant to bacteria in nature, nature and other things, and settle down when we are three years old. But our environment, our long-term diet, stress and the drugs we take, such as antiotics, continue to play a role as we grow older, which means our micobiome can change for the rest of our lives.
It looks like germs are everywhere – how many are talking about?
A number already estimated since the 1970s that viruses exist in our cells by about 10 to one. But research from 2016 shows that actually the tiny cells and human cells live somewhere around 1.3 to one another – suggesting that they are much smaller than our cells, even though that may include viruses and viral particles.
Does this mean I’m not human?
Some say that it should be considered holobiont, a term that signifies close and supportive relationships with people who are infected. “I’m joking that the next time a person goes to the bathroom and removes one of its viruses it becomes human,” Cryan said.

But Ellen Clarke, a naturalist philosopher at the University of Leeds, is uncertain. “It all depends on what you mean by ‘man’ for the first time,” he said. “When you consider that the human cell is a whole set of cells that share copies of the same chromosomes, then it is surprising that we are told that our bodies contain cells with viral DNA.”
But as Carlke points out, human cells contain not only chromosomes, but also the DNA within our cell’s core, the mitochondria, which are the offspring of mutating viruses. Our genome also contains genes called transposons that, in some cases, are thought to have been introduced earlier by viruses. “I prefer to define a human in evolutionary terms, and if we do this then mitochondria are parts of a human, and so are transposons, but gut microbes are not, and neither are prosthetic limbs nor unborn foetuses,” said Clarke, pointing out that microbes can escape the body and live without us.
Are microbes the same in my gut as on my skin?
No, different parts of the body – the skin, vagina, gut – all have very different, distinct communities of microbes. While gut microbes have gained a lot of attention, microbes elsewhere are also important: in recent studies, scientists have found that bacteria commonly found on the skin might help to protect against skin cancer.