In a new study, researchers from Uppsala University investigated how junk food affects sleep. In random order, healthy volunteers consumed an unhealthy and a healthy diet. The quality of deep sleep was decreased in participants who followed an unhealthy diet, compared to those who followed a healthy diet. The findings of the study were published in the journal Obesity. Several epidemiological studies have shown that what we eat affects how we sleep. However, few researchers have looked at how nutrition directly affects sleep. One method is to have the same individual consume different diets in a random order.
“Both poor diet and poor sleep increase the risk of many public health conditions. As what we eat is so important to our health, we thought it would be interesting to investigate whether some of the health effects of different diets Changes in our sleep may be involved.” ,
In this context, so-called intervention studies have been lacking so far; The studies “designed to allow the mechanistic effects of different diets on sleep to be isolated,” said Jonathan Sedernäs, physician and associate professor in medical cell biology at Uppsala University.
Also read: The Healthy Eating Effect: 7 Tips To Eat Better And Achieve Optimum Health
Previous epidemiological studies have shown that diets with a high sugar content, for example, are associated with poor sleep. Yet sleep is an interaction of different physiological states, as Cedernas explains:
“For example, deep sleep can be affected by what we eat. But no study had previously examined what happens if we eat an unhealthy diet and then compared that to sleep quality.” , when the same person follows a healthy diet. What’s exciting about this. The context is that sleep is very dynamic. Our sleep has different phases with different functions, such as deep sleep that regulates hormonal release. is, for example.
“In addition, each sleep stage is marked by different types of electrical activity in the brain. This controls aspects such as how much sleep occurs and varies among different brain regions. But the depth or integrity of the sleep stages can also be negatively affected by factors such as insomnia and aging. Previously, it has not been investigated whether similar changes can occur in our sleep phases after exposure to different diets.”
Each study session included several days of monitoring in the sleep laboratory. Therefore, only 15 individuals were included in the study. A total of 15 healthy normal-weight young men participated in two sessions. The participants were first screened for aspects such as their sleep habits, which should be normal and within the recommended range (an average of seven to nine hours of sleep per night).
In random order, participants were given both a healthy diet and an unhealthy diet. Both diets contain the same number of calories, adjusted for each person’s daily needs. Among other things, the unhealthy diet included high amounts of sugar and saturated fat, and more processed foods.
The food of each diet had to be consumed at individually adjusted times, which were matched across the two diet conditions. Each diet was consumed for one week, while participants’ sleep, activity and meal schedules were monitored on an individual level.
After each diet, the participants were examined in a sleep laboratory. There, they were first allowed a normal night’s sleep while their brain activity was measured to monitor their sleep. The participants were then kept awake before being allowed to fall asleep in the sleep laboratory. In this case also his sleep was recorded.
“What we saw was that participants slept for about the same amount of time when they consumed the two diets. This was the case while they were following either diet, as well as after switching to another, similar diet. Furthermore, across the two regimens, participants spent similar amounts of time in different sleep stages. But we were particularly interested in examining the properties of their deep sleep,” Cedernes explained.
“Specifically, we looked at slow-wave activity, a measure that may reflect how deep sleep is. Intriguingly, we observed that when participants ate junk food, compared to healthy food consumption, So deep sleep displayed less slow-wave activity. This effect persisted until the second night, once we switched the participants to a similar diet,” Cedernais explained.
“Essentially, unhealthy diet results in less deep sleep. Of note, similar changes in sleep occur in conditions such as aging and insomnia. It is conceivable from a sleep perspective, that in such conditions diet should be given more importance,” Cedernais explained.
Researchers currently do not know how long the sleep effects of an unhealthy diet may last. The study did not investigate whether shallow deep sleep might alter functions that are controlled by deep sleep, for example.
“It would also be interesting to do functional tests, for example, to see whether memory function might be affected. This is largely regulated by sleep. And it would be equally interesting to understand how long the observed effects last.” At present, we do not know which substances in an unhealthy diet impair the depth of deep sleep. As in our case, unhealthy diets often include high proportions of saturated fat and sugar, and have a lower proportion of fiber. It will be interesting to investigate whether there is a particular molecular factor that plays a greater role. Our dietary intervention was also significantly lower, and both sugar and fat intakes may have been higher. It is possible that a An unhealthy diet would have a more pronounced effect on sleep,” Cedernais said.