- Researchers recently studied the effects of mealtime on mood vulnerability in night shift workers.
- They found that eating only during the day, as opposed to eating both day and night, could significantly improve the mood of night shift workers.
- However, they note that further studies are still needed to confirm their findings.
Shift workers often experience a mismatch between their 24-hour biological clock – known as the circadian clock – and daily environmental and behavioral cycles due to irregular working hours.
Studies show that circadian misalignment has a negative impact on
More research on evidence-based circadian interventions is essential to improve the mental health of at-risk populations.
Recently, researchers conducted a randomized clinical trial (RCT) to see how daytime eating affects mood in those who worked in a simulated shift work environment.
They found that while participants who ate during the day showed no changes in mood, those who ate at night experienced an increase in depressed and anxious mood.
“This study shows that altering meal times can have clear and measurable effects on mood in shift work conditions,” said Stuart Peirson, Ph.D., professor of circadian neuroscience at the University of Oxford, not involved in the study. DTM.
“As the authors note, this study used simulated shift work schedules under laboratory conditions. It remains to be tested whether night workers will benefit,” he added.
The researchers published their findings in Proceedings of the National Academy of Sciences (PNAS).
For the study, the researchers recruited 19 participants including 12 men and 7 women with an average age of 26.5 years.
To prepare for the study, participants maintained a fixed bedtime of 8 hours for 2 weeks. They then underwent a stay of 14 days in the laboratory.
After several days of laboratory acclimatization and provision of baseline measurements, participants underwent a low-light forced desynchronization (FD) protocol for 4 “days” of 28 hours.
The protocol allowed participants to gradually shift to a “night work schedule”. By day four, they were misaligned from day one by 12 hours.
During the FD phase of the study, participants were randomly assigned to receive meals either day alone or day and night together, which is typical for night shift workers.
Other conditions remained the same among participants, including calorie and macronutrient intake, physical activity, sleep duration, lighting conditions and night work.
The researchers assessed participants’ depressive and anxious mood states hourly during FD days.
After analyzing the results, the researchers found that those who ate during the night and during the day had a 26.2% increase in depressed mood and a 16.1% increase in anxious mood, compared to the start of the study.
In comparison, people in the daytime eating group experienced no change in depressed or anxious mood levels.
By assessing participants’ glucose and body temperature rhythms, the researchers found that the degree of circadian misalignment was strongly linked to more depressed and anxious moods.
They further noted that eating only during the day despite inadvertent sleep was linked to maintaining internal circadian alignment.
When asked how mealtimes might interact with circadian rhythms, Sarah Chellappa, Ph.D., of the Department of Nuclear Medicine at the University of Cologne, Germany, and corresponding co-author of the study, told MNT:
“Our circadian system is made up of a master circadian clock in the brain and peripheral clocks in most body tissues. While the master clock is synchronized primarily by the daily light-dark cycle, many peripheral clocks are more strongly synchronized (e.g. timing of food intake).
“Thus, eating meals during the night may cause an uncoupling between peripheral circadian rhythms and the central clock. [For example]the central clock can be switched on [the] Boston (US) time zone, while peripheral clocks are on [the] Cologne (Germany) time zone,” added Dr Chellappa.
“This disruption of circadian alignment between different clocks throughout our bodies (called internal circadian misalignment) may explain the increased physical and mental health risks in night shift workers who eat frequently during the night.”
– Sarah Chellappa, Ph.D., co-corresponding study author
Gregory Nawalanic, Ph.D., a clinical psychologist at the University of Kansas Health System, not involved in the study, said DTM that clinicians are aware of the potential for depression and anxiety to produce circadian dysregulation, as patients’ sleep patterns are often disrupted.
“This dysregulation can produce a disconnection from the outside world, as an individual may only sleep with a commitment to wake up and experience depression/anxiety or heightened self-hatred as a result.” This fuels a vicious cycle which exacerbates their experience of depression or anxiety in terms of feeling hopeless or helpless about their situation,” Dr Nawalanic said.
“This study reveals an interesting new angle where we look at this impact in reverse – exploring how circadian misalignment affects mental well-being. That said, it stands to reason that the influence could very well be bi-directional.
Dr Chellappa added that as the vast majority of clinical evidence linking mental health issues to circadian misalignment is
“Animal work shows that – even in healthy animals – experimentally induced disruptions of circadian rhythms can negatively affect the activity of brain regions critical to mood control and lead to more depressive and anxiety-like behaviors. , while resynchronizing circadian rhythms may prevent such effects.Thus, circadian alignment may be essential for maintaining optimal activity in mood-regulating regions of the brain.
The researchers concluded that their findings offer proof of concept that mealtimes can prevent mood vulnerability in shift work schedules.
Asked about the limitations of the study, Dr Nawalanic noted:
“As circadian misalignment was created in a laboratory environment, the biggest limitation of this study comes in the form of a real-world application. They [also] disregard the interpersonal disconnect and relationship frustration that shift workers may experience due to their schedules. This is an important variable that can greatly influence depressive and anxious feelings and concerns.
Mahadir Ahmad, Ph.D., senior lecturer in clinical psychology at Universiti Kebangsaan Malaysia, not involved in the study, also said DTM:
“It would be nice to also measure [or] indicate biomarkers of psychological distress (eg, serotonin [and] cortisol levels) in addition to measuring self-administered questionnaires, the results will therefore be more conclusive.
When asked how these findings might influence mental health management, Dr. Chellapa noted that until further studies are conducted, “it might be useful for night shift workers to reconsider the amount of food (especially carbohydrates) that they eat at night”.
Dr Nawalanic added that these findings could point to a tool that therapists could use with shift workers struggling with depression and anxiety.
“It could also provide potential behavioral therapeutic intervention in the form of dietary recommendations that could help produce significant advances in the management of these conditions in shift workers,” he said.
“Describing the nascent state of these findings would be important, but sometimes providing a meaningful straw to reach for can be essential to producing significant positive change in someone who has begun to feel helpless and hopeless about their condition. “
– Gregory Nawalanic, Ph.D., clinical psychologist at the University of Kansas Health System