Britain’s sweltering weather could interrupt the process that produces melatonin – the hormone that evokes feelings of tiredness, relaxation and causes our temperature to drop, allowing us to sleep4.
Even once we fall asleep, the warm external environment makes it harder to regulate body temperature which reduces the chances of us reaching the final stages of our sleep cycle where restorative physical processes occur. As such, we may wake feeling less rested and refreshed5.
However, new research from the University of Michigan6 shows that fruit and veg – particularly berries – could help with sleep insomnia.
In the study, 1165 young adults with low intakes of fruit and veg (less than three portions daily) were allocated to one of four different groups: 1) no change, 2) one serving more, 3) two servings more or 4) three servings or more.
It was found that three-months later women who had increased their fruit and vegetable intake by three servings or more daily had improvements in insomnia symptoms: better sleep quality and taking less time to fall asleep.
Mixed berries are particularly beneficial to sleep. Raspberries are rich in melatonin – the hormone that regulates our sleep-wake cycle – and blueberries are a super source of tryptophan, an essential amino acid that helps to produce melatonin7.
Given that data from the UK National Diet and Nutrition Survey shows that just 33% of adults aged 19 to 64 years achieve the five-a-day benchmark8 – eating more berries could help a chunk of the population to sleep better – especially as record temperatures sweep the nation.
Dr Emma Derbyshire, Public Health Nutritionist and adviser to British Berry Growers commented: “The research looking at fruit and vegetable intakes and sleep is interesting. We now need to find out more about why this may be.
“It is useful to reflect on and log our daily fruit and veg intakes to see how we are doing. More awareness may also be needed about what constitutes ‘a
portion’ – especially for berries which are particularly beneficial to sleep. It’s National Berry Month which celebrates British berries at the height of their season – just seven fresh strawberries, two handfuls of blueberries or raspberries and one handful
of blackberries each equate to one portion”.
