The gut harbours more bacteria than any other part of the body. This isn’t meant to put you off your food; the more diverse microbes we ingest, the healthier our gut is, and then the healthier our immune system overall. This is why diversifying our microbiome is so essential.
And it’s becoming ever-more urgent. “We are seeing a global rise in chronic diseases, which is typically a result of an immune system that doesn’t work very well,” warns Dr James Kinross, a consultant colorectal surgeon at Imperial College London and author of Dark Matter: The New Science of the Microbiome. “A classic example of this is a rise in allergies. By 2025, half of the European population is going to have an allergy. That is astonishing.”
Preventing allergies is not the only reason to want a healthy gut – we should be thinking about preserving the gut itself. According to one survey, 58 per cent of the UK have experienced gut health problems, while bowel cancer is now the fourth most common cancer in the UK, despite 54 per cent of cases being preventable.
One fail-safe way to diversify and enrich the stomach’s microbiome and to improve gut function is to eat a balanced diet that includes fermented foods and fibre, but, according to Kinross, there is also another way: sharing microbes.
“It might be seen as gross,” he admits. “[But] there are arguments that actually what we’re really experiencing [in modern life] is the catastrophic loss of exposure to really important bugs.” Here Kinross explains why getting up close and personal with a diverse range of people, and things, could help diversify our gut health.
Lots of sex is good for the gut
“When we think of health and sex, we often think about practising safe sex to prevent the transmission of pathogens,” says Kinross. “But the mechanics of social interaction play a big role in your microbiome. Kissing, and sex included.”
Thanks to exchanging saliva, kissing helps transfer the microbiome from one person to another. “In one kiss, you share about 80 million bacteria. For that reason, kissing can help you metabolise foods or treat infections,” he says.
Let the dog lick you
It isn’t just kisses from humans. Close contact with animals can also enrich our gut microbiome. “The majority of the world’s population today live in an urban environment, so we’re less likely to live with animals and in large families,” says Kinross. This is bad for nurturing diversity in our gut microbiome, and in turn, our immune system.”
It’s OK if the kids have grubby hands
It’s also important to be dirty occasionally. “This was a popular conversation in the 1990s; the hygiene hypothesis,” says Kinross. This hypothesis said that a rise in chronic disease globally could be due to a lack of exposure to bugs and thus a healthy immune system.
“It’s not necessarily an underexposure to these microbes,” says Kinross. “But instead, it could be that we’re killing them systematically [with cleaning products] and so we are killing all these really important microbes that we need to maintain our health.”
“Kids that grow up in modern flats or isolated, small households don’t get to play outside or with animals as much,” he says. “This will then give them a less diverse and rich microbiome, compared to a child who grows up on a farm, because they are less exposed to the microbiome of their dog or the outside.”
Don’t be afraid of dust
“You can identify a person based on the microbiome of the house that they live in, and their workspace,” says Kinross. This is largely because of dust.
“Dust mites have their own microbiome, which also turns out to be really good for our immune system,” says Kinross. “So actually, if we want to maintain a balanced ecology of the gut, we’ve actually got to think about how to maintain the ecology of the environments that we live and work in.”
The gut is so sensitive to the microbiome of your surroundings that even going on holiday can impact the gut. “A study has shown that just going to see family over Christmas changes your microbiome,” says Kinross.
Cook dinner with your hands
Failing to make dinner at home, with your hands, means microbiome aren’t being shared easily. “Physically getting your hands dirty has an impact on your microbiome, and how you cook it has an impact. Boiling your food, for example, will change the nutrients and that will change how your microbiome reacts,” says Kinross.
Worse still: ordering a takeaway. “If you’re using a food delivery app, you’re not just getting lower-quality foods, you’re also not engaged in the process of making the food,” says Kinross.
“We eat alone through a food app,” says Kinross, with a hint of exasperation. “And that’s not how we’re supposed to eat. We’re supposed to be socially interconnected. We have just become completely disconnected from this. ”
