new delhi: Uppsala University researchers examined how junk food impacts sleep in a new study. In random order, healthy volunteers consumed an unhealthy and a healthier diet. The quality of the participants deep sleep had decreased after the unhealthy diet, compared to those who had followed the healthier diet. The findings of the study were published in the journal Obesity. Several epidemiological studies have found that what we eat influences how we sleep. However, few research have looked into how nutrition impacts sleep directly. One method is to have the same individual consume various diets in a random order. Both poor diet and poor sleep increase the risk of several public health conditions. As what we eat is so important for our health, we thought it would be interesting to investigate whether some of the health effects of different diets could involve changes to our sleep. In this context, so called intervention studies have so far been lacking; studies designed to allow the mechanistic effect of different diets on sleep to be isolated, said Jonathan Cedernaes, Physician and Associate Professor in Medical Cell Biology at Uppsala University. Previous epidemiological studies have shown that diets with greater sugar content, for example, are linked to poorer sleep.
Yet sleep is an interplay of different physiological states, as Cedernaes explains: For example, deep sleep can be affected by what we eat. But no study had previously investigated what happens if we consume an unhealthy diet and then compared it to quality of sleep after that same person follows a healthy diet. What is exciting in this context is that sleep is very dynamic. Our sleep consists of different stages with different functions, such as deep sleep which regulates hormonal release, for example. Furthermore, each sleep stage is hallmarked by different types of electrical activity in the brain. This regulates aspects such as how restorative sleep is, and differs across different brain regions. But the depth or integrity of the sleep stages can also be negatively affected by factors such as insomnia and ageing. Previously, it has not been investigated whether similar changes in our sleep stages can occur after exposure to different diets. Each study session involved several days of monitoring in a sleep laboratory. Therefore, only 15 individuals were included in the study. A total of 15 healthy normal weight young men participated in two sessions. Participants were first screened for aspects such as their sleep habits, which had to be normal and within the recommended range an average of seven to nine hours of sleep per night .
In random order, the participants were given both a healthier diet and an unhealthier diet. The two diets contained the same number of calories, adjusted to each individual s daily requirements.
