Gut feelings: How does your body guide your choices?
When faced with a tough decision, how often have you been told to 'go with your gut feeling' or 'trust your gut instinct'? It's such a common turn of phrase that we're used to thinking of it as just one of those funny things that people say – but could it actually be a little more literal than you realise?
When it comes to the relationship between your brain and your gut, we're probably all familiar with the feeling of butterflies in your stomach on a first date, the way your stomach lurches when faced with something unpleasant or scary, or the absolute havoc that stress can wreak on your appetite and digestion!
In recent years, a body of research has found that 'gut feelings' are far more than just a metaphor for self-awareness, but part of a complex, computer-like system of communication between your nervous system and your digestive system.
Your gut – probably not an organ you think of as particularly glamorous or exciting – contains hundreds of billions of neurons and effectively acts much like a second brain. Its 'information highway' of chemicals and hormones allows the gut to process information, sending signals to the brain via the spinal cord. Ultimately, some of that data ends up in the prefrontal cortex – the part of your brain involved in decision-making.
And it isn't a one way street – the brain-gut axis runs both ways, communicating information about hunger, stress or anxiety, illness, and so on. So what does this mean in practice? Well, because your brain is aware of the makeup of microbes within your gut, any changes in your digestive bacteria (you know, the kind they talk about on yoghurt adverts) can have an influence on your emotions and behaviours.
One 2011 study found a difference between the gut microbiomes of shy, timid mice, when compared with the gut bacteria found in more adventurous mice. When the gut bacteria of the more timid group was given to a group of germ-free mice, they took on the same personality traits – and vice versa with the gut bacteria of the more adventurous mice. http://www.gastrojournal.org/article/S0016-5085(11)00607-X/abstract
Studies on both mice http://www.ncbi.nlm.nih.gov/pubmed/24315484?dopt=Abstract&holding=npg and humans http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0068322 have also found that the microbes found in the guts of those with autistic symptoms and other behavioural conditions are very different from those without. A more recent study (also conducted with mice) found a clear connection between the bacteria found in the gut, and the chances of developing stress, anxiety, and depression. http://www.sciencedirect.com/science/article/pii/S0022395615000655
So do different gut bacteria help to explain the reasons why your gut feeling is often to be cautious, while your best friend is more likely to take risks? Possibly – but of course there's still a lot more research to be done in this area.
The potential implications though are really interesting – could what we eat, and the probiotics we take, alter our personalities and behaviours in certain situations? Will this change the way we think about feeding ourselves, and about gut health in general? Some scientists are already exploring the use of probiotics to treat psychiatric problems such as depression, ADHD, eating disorders, OCD, and anxiety http://www.theverge.com/2013/8/21/4595712/gut-feelings-the-future-of-psychiatry-may-be-inside-your-stomach.
For the time being, it's probably not going to have a huge impact on the foods you eat or the supplements you take. But next time you feel your stomach lurch as your gut feeling tells you to be wary, stop and appreciate just how clever and sophisticated your digestive system really is.
Author: Sarah GrahamImage courtesy: