Researchers discover how junk food may harm deep sleep

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 dietThe findings of the study were published in the journal ObesitySeveral 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 orderBoth 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 socalled 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 UniversityPrevious 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 explainsFor 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 dietsEach 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 normalweight 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 nightIn 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 individuals daily requirements Among other things the unhealthier diet contained a higher content of sugar and saturated fat and more processed food items The meals of each diet had to be consumed at individually adjusted times which were matched across the two dietary conditions Each diet was consumed for a week while the participants sleep activity and meal schedules were monitored at an individual levelAfter each diet the participants were examined in a sleep laboratory There they were first allowed to sleep a normal night while their brain activity was measured to monitor their sleep The participants were then kept awake in the sleep laboratory before being allowed to catch up on sleep Their sleep was recorded in this case tooWhat we saw was that the participants slept for the same amount of time when they consumed the two diets This was the case both while they were following the diets as well as after they had switched to another identical diet In addition across the two diets the participants spent the same amount of time in the different sleep stages But we were particularly interested in investigating the properties of their deep sleep Specifically we looked at slowwave activity a measure that can reflect how restorative deep sleep is Intriguingly we saw that deep sleep exhibited less slowwave activity when the participants had eaten junk food compared with consumption of healthier food This effect also lasted into a second night once we had switched the participants to an identical diet Essentially the unhealthy diet resulted in shallower deep sleep Of note similar changes in sleep occur with ageing and in conditions such as insomnia It can be hypothesised from a sleep perspective that greater importance should potentially be attached to diet in such conditions explained CedernaesThe researchers do not currently know how longlasting the sleep effects of the unhealthier diet may be The study did not investigate whether the shallower deep sleep may alter functions that are regulated by deep sleep for exampleIt would also be interesting to conduct functional tests for example to see whether memory function can be affected This is regulated to a large extent by sleep And it would be equally interesting to understand how longlasting the observed effects may be Currently we do not know which substances in the unhealthier diet worsened the depth of deep sleep As in our case unhealthy diets often contain both higher proportions of saturated fat and sugar and a lower proportion of dietary fibre It would be interesting to investigate whether there is a particular molecular factor that plays a greater role Our dietary intervention was also quite short and both the sugar and fat content could have been higher It is possible that an even unhealthier diet would have had more pronounced effects on sleep noted CedernaesAlso Read Curd rice to carpaccio Make these savoury dishes with mangoes this summerThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its 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