University students following the Mediterranean diet experienced improved overall sleep quality compared to their colleagues who did not adhere to the diet, the results of a new study suggest.
Researchers in the United Arab Emirates followed a group of 503 students at the University of Sharjah for five months at the beginning of 2021.
In recent years, sleep quality has decreased at “an alarming rate” globally, with excessive use of screens at night largely blamed. However, the researchers wanted to investigate the less-studied link between diet and sleep quality.
Previous studies have demonstrated that poor sleep quality is associated with increased risk for obesity, type 2 diabetes and cardiovascular disease. University students are among the population groups at the highest risk for sleep disorders.See Also:Health News
Researchers used the Mediterranean Diet Quality Index (KIDMED), the most widely used index to assess Mediterranean diet adherence among young people, to determine that 54 percent of participants had medium or high adherence while 46 percent reported low adherence.
The students also filled out an Arabic version of the Pittsburgh Sleep Quality Index (PSQI), a standardly-used index among researchers that scores users on seven components of sleep quality.
Overall, 83 percent of students reported poor sleep quality. An equal number of students with medium or high MedDiet adherence and low adherence reported poor sleep quality. However, two-thirds of students who reported better sleep quality also reported medium or high MedDiet adherence.
“In-depth analysis revealed that students with good adherence to the MedDiet were more likely to have a good sleep quality even after adjustment for age and sex,” the researchers wrote in the study.
“The regression analysis also showed that those with good adherence to the MedDiet had a significant association with better subjective sleep quality, less sleep latency [the time it takes to fall into a deep sleep], sleep disturbance and daytime dysfunction even after adjustment for age and sex,” they added.
While the researchers acknowledged that further work is required to confirm and better understand why adherence to the Mediterranean diet is linked with better sleep quality, they proposed a few hypotheses.
Previous studies have demonstrated that sleep quality is “strongly affected” by food quantity and quality, especially with foods that exacerbate and alleviate inflammation.
“[The] anti-inflammatory potential of the MedDiet may help to explain, in part, the strong positive association between the good adherence to the MedDiet and the reported good sleep quality components found among our study sample,” the researchers wrote.See Also:Mediterranean Diet Linked With Long-Term Health Benefits for Teenagers
They added that worsening sleep quality and increased inflammation could create a vicious cycle.
“When the bodily inflammatory state is increased, the sleep quality is worsened, and when sleep quality is worsened, the inflammatory state becomes increased,” the researchers wrote.
The relationship between sleep and inflammation partly comes down to cytokine secretion. Inadequate sleep leads to increased cytokine secretion, which increases inflammation. Higher levels of cytokines have been repeatedly linked with sleep deprivation.
“These pro-inflammatory cytokines are those consistently reported to be reduced in response to the long-term exposure and adherence to the MedDiet, as revealed by many reports,” the researchers wrote.
Along with lowering inflammation, the Mediterranean diet is also rich in fruits and vegetables that are good sources of melatonin. An increase in melatonin can improve sleep quality and prevent some sleep disturbances.
Along with sleep quality, the researchers also quizzed the students on their chronotype – an individual’s internal circadian rhythm that plays a part in determining whether they are a ‘morning person’ or ‘night person.’
They found that students with a morningness chronotype – who wake up early, accomplish their most important tasks in the morning and go to bed early – were six times more likely to have medium or high adherence to the Mediterranean diet than the other two chronotypes.
As a result, 30 percent of students with the morningness chronotype reported high sleep quality, while less than 11 percent of students with an eveningness chronotype reported high sleep quality.
The researchers said further studies investigating the relationship of chronotype on diet and sleep quality is required before any conclusions may be reached on these data points.
However, they said the study and its results were an important step in raising the issue of nutrition and sleep among university students.
“Improving the knowledge and attitude of the university students toward their dietary and lifestyle behaviors, and the significance of chronotype in determining their future disease risk factors are of pivotal importance,” the researchers wrote.
“Further long-term, controlled intervention research works are warranted for more elaboration on the impact of chronotype and dietary habits on sleep quality,” they concluded.