The foods we eat affect both our daytime wakefulness and the quality of our sleep, but the nutritional mechanisms that influence sleep regulation are complex. Total caloric intake and some foods may be important in regulating sleep through the regulation of other related factors.
Unbalanced intake of macronutrients (protein, carbohydrates and fat), excessive caloric intake, contribute to a decrease in sleep quality and may affect the occurrence of insomnia. For example, insufficient protein intake seems to negatively affect the quality of sleep, but conversely high protein intake seems to lead to difficulties in maintaining sleep. There are also studies that identify a significant relationship between the quality of the carbohydrates consumed (i.e., how much fibre is included, how processed a food is, what the glycaemic index of the food is) and sleep quality. It seems that high consumption of noodles, sweets and sugary drinks is linked to poor sleep.
The frequency and timing of meals, as well as skipping breakfast and irregular meals, also play a role in sleep quality.
Eating foods rich in tryptophan, melatonin and serotonin improves sleep quality. Vitamins and minerals (e.g. B vitamins, zinc) affect the quality of sleep.
Increasingly, there is a trend towards shorter sleep duration, less than 6 hours a night in the general population, leading to increased coffee consumption – increased caffeine intake. The half-life of caffeine is on average 2 to 10 hours, but can be as long as 20 hours. Caffeine obviously increases performance, but it also has side effects: it affects both the quality of sleep and the overall duration of sleep, which reduces it. People who consume large amounts of caffeine are more likely to be sleepy in the morning than those who consume moderate amounts.
Adults often drink alcohol and some of them believe that alcohol even helps them sleep. However, alcohol has a negative effect on sleep, affecting biorhythms and increasing insomnia. In studies using moderate doses of alcohol (<1 g/kg body weight), there was a reduction in REM sleep, which was mainly in the second half of sleep.
Food can also affect the microflora, which can lead to the formation of certain metabolites. Poor nutrition in the long term can contribute to inflammation, which is closely related to insomnia.
Although much remains to be studied, a first glance sheds light on the importance of an adequate diet rich in protein, carbohydrates and fats, fruits, vegetables and whole grains with a weekly intake of fish as a positive influence on sleep.
