Are IBS & Insomnia Linked?

Over the last year or so, we’ve been inundated with books and articles claiming that poor sleep affects our mental health, physical health, general ability to deal with life, and even life expectancy.

For chronic insomnia sufferers like me, this surge in media coverage is a blessing and a curse; a blessing because it’s nice to have our struggle acknowledged by Times and Guardian readers, and a curse because our fear that lack of sleep is ruining our lives keeps getting confirmed by scientists and doctors.

Contributing to the conversation is memory foam mattress company Eve, whose desire to help us sleep seems to go beyond their product. Eve recently hosted a weeklong sleep clinic in east London with talks, panels, classes and one-to-one sessions with specialists, open to the public. There, we met sleep science coach and nutritional therapist, Christine Hansen, for a one-to-one session on how diet affects our sleep and vice versa. Christine is a holistic health practitioner and has developed her own line of treatment for insomnia, which includes looking carefully at the gut.

“We tend to overeat when we’re tired,” she said. “We get up tired, and then we crave caffeine and sugar, which makes our blood sugar levels spike, but then they drop just as quickly, so you get a zigzag pattern.” This pattern, Christine says, if continued throughout the day, can cause a spike at nighttime too, which disturbs sleep. “And then there’s ghrelin and leptin [the hunger hormones]. One makes you feel full and the other makes you feel hungry, but when you’re not sleeping well, those two become deregulated so you are hungry more quickly, and you’re full later than you would if you were well rested.”

It’s true, we eat more when we’re tired and crave caffeine and sugar to replenish our energy, but Christine says the relationship between our gut and our sleep runs much deeper. She says poor sleep and Irritable Bowel Syndrome (which affects 10-15% of the population and mainly women) “are totally intertwined – they feed off each other”. Another worrying piece of information for insomniacs, but it makes sense, and addressing both together might actually be beneficial. “If you have emotional stress – that breaks down your intestinal lining, and if your gut is in distress – that makes it more difficult for your emotions to be clear, which you need in order to sleep.”

Deep sleep (the first phase) helps our minds and bodies recover, so when we don't get enough, we can’t recover and this can wreak havoc on our digestive system. “Detoxification takes place at night in the liver during sleep,” explains Christine, “especially during deep sleep, so if your sleep is fragmented, this process doesn’t work properly and your body can start storing the waste in your adipose tissue, which are your fat cells. The other thing is that some toxins don’t get broken down because you don’t have enough bile so then the toxins just circle in your system, making you tired and causing inflammation.”

A few studies have shown correlations between IBS and insomnia beyond their mutual categorisation as 'functional disorders'. A [very old: 1997] paper in the British Medical Journal entitled "Sleep and gastric function in irritable bowel syndrome" summarised the findings of a small study which “showed a relation between subjective reports of good sleep quality and diminished IBS symptoms” ie. when the patients slept well, they said their IBS symptoms also decreased; "subjective" means there was no medical way of proving it beyond what the patients said. More recently, in 2016, a paper entitled "IBS: sleep disturbances a key factor for symptoms" concluded that “sleep disturbances are more common in patients with IBS versus healthy control participants, and correlate with IBS-related pain, distress and poorer IBS-related quality of life.”

“Often, doctors prescribe antidepressants for people who can’t sleep,” says Christine, “and they do help, but they’re not necessarily the best option.” Christine says there is very often a correlation between poor sleep and lack of serotonin (the happy hormone): “Serotonin is converted into tryptophan, which is converted into melatonin.” Melatonin is a hormone released by the body to regulate the human body clock, and studies show that when you don’t have enough melatonin, your body doesn’t recognise that it’s time for sleep. As Christine explains, “90% of melatonin is produced in your gut, so if you don’t have enough in the evening and you have a lot during the day, it’s going to make you feel exhausted and mess up your circadian rhythm.”

So if your gut is a mess, it may not be producing enough melatonin to allow you to fall asleep. And if you are anxious or depressed and your body isn't producing enough serotonin, that affects the melatonin production in your gut and therefore your sleep – it's a vicious cycle.

While there are plenty of melatonin supplements on offer at health food shops, Christine says these aren't a quick fix for sleep: "Melatonin is not meant to make you fall asleep, it’s just meant to regulate your inner clock, so if you have someone with a severe circadian rhythm disorder, it’s perfect to use for that, but it’s not really meant as a sleep help – a lot of people put a lot of hope into melatonin and get super disappointed.” Indeed, a study in 2015 concluded that the evidence for melatonin supplements improving insomnia was "insufficient".

Christine does recommend 5-HTP, which can be bought at health shops such as Holland & Barrett: “5-HTP is a precursor which produces natural serotonin (the happy hormone). 5-HTP is converted into serotonin, so it builds in your body." She also recommends vitamin D, which can be bought as a supplement or prescribed in more concentrated forms by a GP.

According to Christine, another potential problem contributing to both IBS and insomnia is ‘leaky gut syndrome’ – a term that the NHS doesn’t really support in relation to widespread problems such as IBS and insomnia – but Christine’s explanation is as follows:

“Our intestinal lining is not smooth. We have these little hairy things called ‘villi’ on our small intestine and they filter the molecules and break down things that are too big. But what happens when we’re stressed, is that these little hairy things (the villi) die, so it means that bigger molecules start coming in. So suddenly you have tons of things penetrating into your immune system that formerly didn’t. And that causes inflammation or a ‘leaky gut’. So you stop being able to absorb nutrients. We see this a lot with people who have sleep deprivation and stress because there’s just so much going on, the whole metabolic system stops working and your body can’t take what it needs. So I check to see if there is a healthy bacterial environment, and check to make sure the person doesn’t have any parasites or yeast infections like candida. I also test for food intolerances.”

A direct, objective correlation between gut health and various functional disorders such as insomnia is, as yet, unevidenced in mainstream medicine. These things are generally not tested by NHS doctors unless the patient is thought to have Crohn’s disease or coeliac disease. But Christine believes that understanding the gut in relation to sleep and vice versa is a critical step in treatment for insomnia. And if, like us, you've tried everything you can think of to improve your sleep, to no avail, investigating your gut health might well be worth a try.