Can what we eat affect how we sleep? It seems so, and we're not just talking about the evening binge that makes falling asleep difficult. In fact, some choices at the table can even promote a good, restful sleep. Let's see what emerges from a recent review that appeared in the Nutrients journal thanks to the collaboration between British and Greek scientists (Vlahoyiannis et al, Nutrients, 2021).
Diet and its interactions on sleep
Previous studies have been able to show that diet may influence sleep, its duration and the time taken to fall asleep. For example, the intake of tryptophan, an amino acid contained in milk, cheese, eggs, legumes and chocolate, has been shown to act by improving the quality of sleep. These beneficial effects on night rest were also observed thanks to the consumption of kiwifruit. Not to forget the tart cherries that, thanks to their ability to increase the levels of melatonin in the body, are able to lengthen the duration of sleep and improve its quality, reducing sleep disorders that lead to non-continuous and frequently interrupted rest. Carbohydrates are also considered foods capable of modifying sleep and its quality, given their influence on the regulation of hormones that regulate the sleep-wake cycle. In fact, glucose metabolism alters the concentration of tryptophan, which is a precursor of serotonin and melatonin, which affect the ability to fall asleep and the duration of sleep itself. However, to date, complete clarity has not yet been made on the role of carbohydrates in influencing the quality of sleep. To fill this gap, the researchers performed a comparison with the results of previous studies in order to understand the action of a high or low carbohydrate diet on the quality of rest.
The role of carbohydrates
What emerged is that modifying the diet by introducing a lower quantity of carbohydrates (attention, the article does not talk about removing carbohydrates!) leads to a significant lengthening of the phase of deep sleep, namely the sleep in which the body relaxes and regenerates, connected to the sensation of restful sleep. Not only that, such a diet has also led to an increase in the time spent in bed while asleep. On the other hand, the type of carbohydrates, therefore with a high or low glycemic index, has not been shown to modify the quality of sleep in any way.