We’ve all experienced the brain-gut link – from first date butterflies to anxiety-induced toilet trips, via that sinking feeling you get when you realise you’ve locked yourself out – again. But did you know that the brain and digestive system are so intimately linked that scientists have dubbed the gut the ‘second brain’? Also known as the enteric nervous system, or ENS, the gut lining, which contains around 100 million nerves, is formed from the same tissue as the brain and central nervous system (or CNS) during foetal development.
It also contains up to 100 trillion bacterial microorganisms. Our so-called microbiome weighs more than 1kg (equivalent to a large bag of sugar) and plays a key role in keeping our bodies – and minds – healthy.
Our gut bacteria break down and synthesise nutrients, allowing us to absorb their benefits. They’re also in constant communication with our brains. Poor gut health (which may be caused by an overabundance of bad bacteria and/or insufficient levels of good bacteria) has been linked with memory problems, MS, autism, Parkinson’s disease, OCD, depression and anxiety. Animal evidence indicates that probiotics can improve many of the symptoms associated with these conditions, whilst eating probiotic yoghurts twice a day for four weeks has been found to change the human brain’s reactions to images of facial expressions.
The diversity of bacteria living in our guts may also be a key factor in the success (or not) of our attempts at losing weight. More efficient bacteria can actually hinder weight loss by enabling our bodies to extract more calories from the food we eat. Don’t bin the Yakult just yet, though. A lack of inflammation-fighting ‘good bacteria’ has been linked to metabolic syndrome (which encompasses diabetes, high blood pressure and obesity) and excess belly fat.
And the gut-brain connection works both ways. You’re probably familiar with the association between stress and belly fat. Well, researchers believe that this link may well be mediated by our gut bacteria. But did you know that the ‘fight or flight’ response associated with stress effectively switches off the digestive system? If you’re suffering from chronic stress, your gut’s failure to produce sufficient digestive enzymes could result in long-term, painful bloating.
Dr Anton Emmanuel, of the British Society of Gastroenterology, believes that these gut-brain links may be stronger in women. “Women may have a more finely-tuned nervous system than men,” he says, which can make them “more vulnerable to stress” and prone to “internalising” feelings. So what can we do about it? The usual advice on managing stress applies, of course (meditate, exercise, get plenty of sleep), but it might also be prudent to tackle things from the inside out, with a daily dose or two of pre- or probiotics. It might just help you shift those last few pounds…