WHAT’S LOVE GOT TO DO WITH IT?
While it may be tempting to assume that those butterflies are driven by love, Dr Keefer said, in reality, that roiling in the gut is a byproduct of a less romantic but nonetheless inevitable part of the whole process: Emotional stress.
In a 1949 study that investigated how different types of stress affected the gut, for instance, researchers peered into the colons of healthy medical students using a hollow metal tube with a light and lens at the end. With one student, the researchers suggested that they had discovered a cancer in his rectum (when in reality, his colon looked normal). As they relayed these false findings – even showing the student a “biopsy” of his tumour, which was actually a piece of potato – they saw the student’s colon begin to spasm. After they revealed their hoax, and the student realised he did not have cancer after all, his colon immediately relaxed.
Scientists have also shown that loud, cacophonous words and sounds played in different ears at the same time can disturb the rhythms of our guts, as can – as shown in one of my own experiments – telling a lie, or discussing uncomfortable life events such as being rejected by a love interest.
It would be challenging to do similar studies during a romantic dinner date (imagine having a probe in your colon while trying to make small talk at a restaurant), but scientists have used decades of research on gut-brain communication to theorise about why dating can trigger butterflies in the gut.
Yvette Tache, a neurobiologist and professor of medicine at the David Geffen School of Medicine at UCLA, has been studying how stress affects the communication between the gut and the brain since the 1980s. When you’re eager for your date to go well or are unsure of how your date feels about you, that stress can cause the brain to release a molecule called corticotropin-releasing hormone, which ramps up adrenaline in the “fight-or-flight” response. (This hormone is also responsible for a racing heart when the meal is over and your date twiddles with their keys by their door – will you be invited in or is the evening finished?) At the same time, this molecule boosts cortisol, a hormone that rises in the first few months of falling in love, but later drops as a relationship stabilises.
The sensation of “butterflies” likely occurs because, on top of everything else, this molecule also delays our stomachs from emptying, while simultaneously speeding up our colons, Dr Tache said. This might happen as a means of protection, she said: Our intestines become more permeable – or “leaky” – under stress, which could be harmful if it caused waste from inside our guts to enter our bloodstreams. In theory, she said, halting our stomachs and emptying out our colons might minimise the chances of that happening.
