Read a book, have a hot bath, perhaps count sheep — we all have our own ways of trying to fall asleep. Yet all too often these efforts prove unsuccessful.
Studies have found that around a third of people in the UK suffer from insomnia, meaning they struggle to fall or stay asleep, and around two million people rely on sleeping pills.
But a growing body of research suggests there may be a simpler way to improve your slumber — and that is by improving what you eat.
While it’s long been recognised that drinks and food containing caffeine, a stimulant, may hamper sleep, it seems that certain food groups — including fruit, vegetables and even certain breads — may have the opposite effect.
A growing body of research suggests there may be a simpler way to improve your slumber — and that is by improving what you eat
This was the finding from a review of studies, recently published in the journal Annual Review of Nutrition.
Marie-Pierre St-Onge, an associate professor of nutritional medicine at Columbia University in New York, one of the authors of the paper, told Good Health: ‘We found that eating a diet containing plenty of fruit and veg, plus legumes and dark wholegrain breads, was associated with better quality sleep.’
The review was based on other findings, including one study published in Nutrients in 2020 and involving 400 women, which found that the more they adhered to a Mediterranean-style diet rich in fruit, vegetables, nuts and lean protein, then the more their sleep quality improved.
This study was self–reported, i.e. the women themselves were noting down their diet and sleep, but other scientists have seen similar results.
Indeed, following their own study, researchers from the University of Leeds, writing in BMJ Open in 2018, were so convinced of the link between diet and sleep, they said it could have ‘important implications for lifestyle and behavioural change policy’.
TheIr research involved 1,612 adults who had to note their sleep patterns plus their fruit and vegetable intake over four days. Those who had fewer than seven hours sleep a night had 24g less fruit and vegetables a day than those who slept the optimum seven to eight hours.
This study was self–reported, i.e. the women themselves were noting down their diet and sleep, but other scientists have seen similar results
What’s more, while a healthy diet may benefit sleep, previous research by Dr St-Onge and her team suggests that eating more saturated fat and sugar may disturb it.
In a study in 2016, published in the Journal of Clinical Sleep Medicine, 26 volunteers underwent sleep polysomnography over five nights, with sophisticated monitoring equipment being used to record brainwaves and other vital signs that can determine the quality and quantity of sleep.
This kind of analysis can determine, for example, how long people spend in deep sleep and how often they wake up.
‘The advantage of this study was that we had controlled their diet so we knew exactly what they were eating,’ says Dr St-Onge. ‘So for the first four days they had a healthy diet, low in saturated fat and containing recommended levels of fibre and sodium [salt]. On the fifth day, they were able to self-select what they ate — and that’s when we saw them have a far higher intake of saturated fat, salt and sugar.’
When the team analysed the group’s sleeping habits, they found some surprising differences.
‘On the fifth day, it took almost twice as long for them to get to sleep — 12 minutes longer — compared to the previous days,’ Dr St-Onge told Good Health. ‘They also spent less time in deep sleep, which is the most restorative stage of sleep.’
This is when brainwaves slow right down, allowing memories to be filed, and when the pituitary gland pumps out the growth hormone needed to regenerate cells. The study found the volunteers had 24 minutes of this deep sleep on the fifth night, compared to 29 minutes on the days when they ate a better diet.
‘That represents a 15 per cent reduction, which is quite a
