Could having lots of friends give us a healthier gut?

Being surrounded by a good group of friends can have a huge impact on mental health and happiness.

But it could also lead to a healthier gut and a better immune system, according to a new study.

Having ‘good’ bacteria within our digestive system is important for general health and can reduce the risk of some illnesses such as heart disease and diabetes.

Now, researchers have discovered that being sociable could lead to more of the ‘good’ gut bacteria and less of the tiny microbes than could potentially lead to illness.

A team from the University of Oxford collected a total of 50 uncontaminated stool samples from rhesus macaques – a species of monkey – living on an island off the coast of Puerto Rico.

They measured each monkey’s social connectedness by calculating the amount of time each one spent grooming or being groomed, and their number of grooming partners.

The team analysed the DNA of the stool samples to measure how healthy their gut bugs were.

Results, published in the journal Frontiers in Microbiology, revealed those who had more social interactions had a higher level of the ‘good’ gut bacteria.

The most social monkeys had less of the Streptococcus bacteria, which in humans can causes diseases such as pneumonia.

These animals also had more of a bacteria called Faecalibacterium, which is known for its anti-inflammatory properties and is associated with good health.

Co-author Dr Robin Dunbar, from the Department of Experimental Psychology at Oxford, said: ‘As our society is increasingly substituting online interactions for real-life ones, these important research findings underline the fact that as primates, we evolved not only in a social world but a microbial one as well.’

The authors suggest that when the monkeys groom each other, it allows for the transmission of tiny microbes.

Or, it could be that monkeys with more friends could be less stressed, which can also have an impact on the bacteria in our gut.

Lead author Dr Katerina Johnson said: ‘This study was on primates, which of course are close relatives of humans and these were non-captive animals roaming freely on an island.

‘I have also actually previously shown in humans that people with larger social networks have a more diverse gut microbiome, and we know a more diverse gut microbiome is generally linked to better gut health and health in general.

‘This pattern we see here in the monkeys, and also in humans, of this relationship between social interactions and gut health may be partly because of a direct effect of social interactions – we transmit microbes between us when we interact.

‘Obviously this can transmit any nasty microbes, like we’re all very aware of now in terms of Covid, but we’re also transmitting lots of harmless and beneficial bacteria too.

‘Our findings may also reflect an indirect effect as we know friendships are very good at buffering against stress and stress is known to negatively affect our gut microbial community.’