Sometimes I learn things in science that just sound so damn cool that I track down the original papers and get obsessed. And I mean obsessed to the level that I spend a week neglecting human interaction and personal hygiene, hunched over my computer devouring information at the speed of the all-powerful interwebs.
One such obsession-inducing topic in my intellectual life has been gut bacteria. Yep, the bugs that live in our innards.
They’re like our own internal farm. And the creepy thing is that they kind of control us.
Anyone see that recent Pixar movie ‘Inside Out’? Well it’s kinda like that. Except not.
Our gut is home to around 36 000 species of bacteria, collectively called the ‘microbiome’. These intestinal hitchhikers compete with one another for space and your half-digested food, in your warm and cozy innards.
It’s well known that the microbiome is essential for keeping your gut healthy. Scientists have even been discussing whether this massive bacterial community could influence our mood and cravings (for the real sciencey stuff, check out this paper by Alcock and pals).
Basically, individual species of gut bacteria go crazy for different types of nutrients they get from our food. When we eat certain things, particular species of bacteria will thrive, winning the war for nutrients and space.
For instance, Bacteroidetes love certain types of fat, while Prevotella chow down on carbohydrates, and Bifidobacteria go nuts for dietary fibre. And there’s tons of different species! Specialist microbes that are especially good at digesting seaweed have even been isolated from Japanese people.
Because of the competition faced by these bacteria, studies have suggested that they might manipulate the eating behaviour of their human host, in order to promote their own fitness.
That’s some psychological warfare right there! Clever little buggers.
For example, some reports have shown that chocolate-desiring people have different microbial metabolites in their pee, compared to people that couldn’t give a toss about chocolate. Maybe the gut bacteria that grow better when given chocolate are influencing the cravings of chocolate-lovers, inspiring them to eat more.
Our microbial puppetmasters could drive our cravings through a number of possible ways, from production of compounds that alter our mood, to the alteration of taste receptors and hormones, and even by hijacking of the vagus nerve (the main connection between the brain and millions of nerve cells in the gut).
Trying to give up chocolate? Maybe it’s not completely up to you!
Perhaps dietary ‘self-control’ is a misnomer, if we’re not the only ones trying to control this ‘self’.
But, never fear! There are many ways we can influence our gut bacterial profile – prebiotics, probiotics, antibiotics, fecal transplants, and the choices we make in our diet can all have an effect. Plus, resisting those cravings for a chocolate today will eventually alter your microbiome (the chocolate-eating bacteria will die off a bit, if you keep eating apples and salad).
Every ounce of willpower today is making it easier to avoid those deliciously fattening treats in the future.
Beat the bacteria!