Shift worker study raises the idea that meal timing can shape our mood
People subjected to irregular sleeping and eating habits through shift work are known to have higher risk of a wide range of health problems, and a new study has drilled into the impacts of this lifestyle on mental wellbeing. By simulating the lifestyles of shift work and carefully tracking measures of anxiety and depression, scientists have provided evidence that the timing of our meals may well influence our mood.
In recent years, we have seen studies shed important light on the health risks associated with shift work and a disrupted circadian rhythm, the 24-hour body clock tied to our sleep and wake cycles.
These include insights into how nighttime shift work heightens cancer risk and even how timing of cancer therapies might play a role in patient outcomes. We’ve also seen scientists discover mechanisms behind shifts in cardiac activity that help explain why these workers are at higher risk of heart trouble, and how eating at nighttime can increase the risk of diabetes and obesity.
Led by scientists at Brigham and Women’s Hospital, this new study also focuses on eating habits in the context of shift work, and how they impact on mental health. According to the authors, shift workers endure a 25 to 40% higher risk of depression and anxiety, and impaired control of blood-sugar levels is known to be a risk factor for mood disruption. So the team designed a study to explore the idea that daytime eating can stabilize somebody's mental health, even if they are working at night.
The study included 19 participants who were subjected to a regime that recreated the effects of nighttime work, which involved dim light and simulated 28-hour days, ultimately misaligning their circadian rhythms and inverting their behavioral cycles by 12 hours. The participants were then randomly put into a daytime or nighttime eating group, designed to simulate the eating habits of shift workers, or a daytime-only eating group.
By assessing depression and anxiety-like symptoms throughout, the scientists were able to gauge the impact of the different eating schedules on mood. This revealed a marked difference between the two, with depression-like mood levels increasing by 26 percent and anxiety-like mood levels by 16 percent in those on the shift worker eating regime, while the daytime-only group did not exhibit these changes.
According to the scientists, these results raise the prospect of using meal timing to reduce mood vulnerability in shift workers or other people enduring misaligned circadian rhythms. Though the results are promising and shed important light on the role of sleep and diet in mental health, the study is small and is considered a proof-of-concept only, with more research needed to really cement the idea that meal-timing can alleviate symptoms of depression and anxiety.
“Our findings provide evidence for the timing of food intake as a novel strategy to potentially minimize mood vulnerability in individuals experiencing circadian misalignment, such as people engaged in shift work, experiencing jet lag, or suffering from circadian rhythm disorders,” said co-corresponding author Frank A. J. L. Scheer. “Future studies in shift workers and clinical populations are required to firmly establish if changes in meal timing can prevent their increased mood vulnerability. Until then, our study brings a new ‘player’ to the table: the timing of food intake matters for our mood.”
The research was published in the journal the Proceedings of the National Academy of Sciences.
Source: Brigham and Women’s Hospital