We explore the sleepy secrets of the microbiome.
Words: Chantelle Pattemore
The days of thinking our intestines only play a role in the digestion of food are long gone. Scientists now refer to the gut as our ‘second brain’ – with studies linking beneficial bacteria to reduced risk of Alzheimer’s and depression. New research points to yet another reason to prioritise a thriving microbiome: it may help us nod off.
To make things even more interesting, studies suggest that the relationship between the gut and sleep is bidirectional – it goes both ways. Put simply, imbalanced gut bacteria can contribute to a poor night’s rest, while disturbed slumber can encourage ‘bad’ gut bacteria to thrive.
An unlikely pairing
In the grand scheme of things, knowledge around sleep and gut health is still in its relatively early days, and more research is needed to fully understand the link, explains Jordan Haworth, a gastrointestinal physiologist at Tummy MOT (tummymot.com). That said, scientists believe there are several mechanisms at play.
The first is the gut-brain axis. Jordan reveals that gut bacteria sends messages to the brain through various pathways, including the vagus nerve. These messages ‘can influence mood, stress levels and other factors that can have direct implications for sleep quality’, he says. Speaking of messages, it’s thought gut bacteria also influences ‘the production and regulation of neurotransmitters (brain chemical messengers) – serotonin and dopamine,’ Jordan shares. While these two neurotransmitters are known for their role in mood regulation, they’re also vital for good sleep.
Our gut microbiome may also indirectly impact sleep through our immune system, says Dr Emily Porter, PhD, a gut health specialist and registered dietitian at The Gut Health Clinic (theguthealthdoctor. com). ‘When digesting our food, gut bacteria produce byproducts called short-chain fatty acids, which have been shown to have a number of health benefits – including links with our immune system,’ she says. This is important, as there are links between immune markers and sleep.
While these mechanisms are unidirectional (one-way), some are more of a two-way street. For instance, an imbalanced gut microbiome is linked to inflammation in the brain – which can be detrimental to sleep. However, sleep deprivation can also trigger inflammation in the body, notes Jordan – and ‘this inflammation can negatively affect your gut health by altering the composition of your gut microbiot
