Can day feeding prevent mood swings in night workers?

Modern life requires immediate and continuous availability of goods and services, day or night. This made it necessary for people to work at night in ever-increasing numbers. However, night-shift workers are more likely to develop mood disorders, particularly anxiety and depression.

Stady: Eating during the day prevents poor mood at night work. Image Credit: Gorodenkoff / Shutterstock

A new study explores the effect of daytime feeding on the incidence of emotional distress in this subgroup of workers. “These results provide a proof-of-concept to demonstrate an evidence-based meal timing intervention that may prevent mood impairment in shift work settings.. “

an introduction

Night-shift workers have a risk of depression and anxiety by up to 40%, and mental health disorders contribute up to $1 trillion in lost productivity, along with other costs. This predisposition to pathological mood swings is attributed to out-of-sync circadian rhythms (circadian clock) with circadian cycles of behavior and cyclic environmental changes.

Knowing this, it is possible to explore interventions to stabilize mood in this working population and thus produce evidence to identify the most valuable measures. Previous research shows that eating during the day can overcome faulty sleep, to coordinate the internal and external clocks. The result is better glucose tolerance during nighttime work, avoiding a known risk factor for mood swings during this period.

The current study, reported in PNASet al., used two meal timings for a group of 19 individuals whose circadian rhythms were desynchronized by a forced desynchronization (FD) intervention. At the end of this protocol, participants were 12 hours out of alignment with Day 1, after a 28-hour day and night-work simulation.

In the control group, all physiological activities, including sleep/wake cycles, rest/activity cycles, supine/erect position, and light differences with sleep/wake cycles were transferred to this new cycle. Thus meals were taken during the times of the day and night, as night workers usually do.

In the first intervention group, with daytime meals only (DMI), 24-h fasting/eating cycles were established, with the rest of the 28-h cycles followed. This means that meals were eaten only during the day.

What did the study show?

The scientists found that with higher degrees of inconsistency between internal and external rhythms, as evidenced by the change in the phase difference between peak glucose and lowest body temperature during one cycle, depression and anxiety rose during nighttime work.

The DMI group showed lower levels of depression and anxiety, indicating the significant effect of changing meal timing among night workers. In the other group, depressive traits increased by more than a quarter from baseline, in contrast to the DMI group.

Meal timing during the day also prevented the 16% increase in anxiety symptoms observed in the control group. Previous studies have shown that poor quality diet, which is high in carbohydrates, is associated with poor sleep quality and poor mental health. On the contrary, the Mediterranean diet is associated with better mental health.

However, more research is needed to understand how they are related, in what direction, and why. Some evidence suggests that eating foods rich in sugar at night as well as during the day leads to glucose intolerance in night workers. This effect is absent when they stick to eating during the day on their own.

In other words, daytime eating may affect glucose metabolism but also mood stability. High blood sugar levels tend to be depressing, and insulin receptor signaling is deeply implicated in brain function and negative mood changes. Avoiding blood sugar swings can help stabilize mood in nocturnal conditions, and this can be achieved by limiting food intake during the day.

Additionally, food affects the gut microbiome, a vital component in regulating tryptophan and serotonin, both of which are important in mood regulation, oxidative stress control, and neuroplasticity. Disruption of the circadian clock affects the health of the microbiome and may shift this community toward an inflammatory profile, in addition to reducing levels of important metabolites such as tryptophan. This can lead to decreased serotonin in the brain, which predisposes to depressive moods.

In summary, our study provides proof of concept that eating during the day may prevent mood impairment in shift schedules. Additional studies could help validate the value of this intervention in actual night-shift conditions.