Eating during the day prevents mood vulnerability at night work Summary Shift workers have a 25-40% increased risk of depression and anxiety, in part due to a mismatch between the central circadian clock and daily environmental/behavioral cycles that can negatively impact mood and emotional well-being . Therefore, evidence-based circadian interventions are required to prevent mood vulnerability in shift work environments. We used a tightly controlled 14-day circadian paradigm to assess mood vulnerability during simulated night work with day and night feeding or daytime alone compared to simulated day work (baseline). Simulated night work with day and night feeding increased depressive-like mood levels by 26.2% (p value adjusted using False Discovery Rates, pFDR = 0.001; effect size r = 0.78) and levels anxiety-like mood by 16.1% (pFDR = 0.001; effect size r = 0.47) compared to baseline, while this did not occur with sham night work in the eating-only group during the day. Importantly, a greater degree of internal circadian misalignment was strongly associated with mood levels more similar to depression (r = 0.77; P = 0.001) and anxiety (r = 0.67; P = 0.002) during the Simulated night work. These findings offer a proof-of-concept demonstration of an evidence-based mealtime intervention that may prevent mood vulnerability in shift work settings. Future studies are required to establish whether changes in meal timing can prevent mood vulnerability in night workers. |
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Overcome sadness with food? A new study adds evidence that meal timing can affect mental health, including levels of depression and anxiety-related mood. Researchers at Brigham and Women’s Hospital, a founding member of the Mass General Brigham health care system, designed a study that simulated night work and then tested the effects of eating during the day and at night compared to eating only during the day.
The team found that, among participants in the day and night feeding group, depression-like mood levels increased by 26 percent and anxiety-like mood levels by 16 percent. Participants in the daytime-only group did not experience this increase, suggesting that meal timing may influence mood vulnerability. The results are published in the Proceedings of the National Academy of Sciences.
"Our findings provide evidence of the timing of food intake as a novel strategy to potentially minimize mood vulnerability in people who experience circadian misalignment, such as people who work shifts, experience jet lag, or suffer from circadian rhythm disorders. "said author Frank AJL Scheer, PhD, Director of the Medical Chronobiology Program in the Brigham’s Division of Circadian and Sleep Disorders. “Future studies are required in shift workers and clinical populations to firmly establish whether 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 is important for our mood."
Shift workers represent up to 20 percent of the workforce in industrial societies and are directly responsible for many hospital services, factory work, and other essential services. Shift workers often experience a misalignment between their central circadian clock in the brain and daily behaviors, such as sleep/wake and fasting/eating cycles. Importantly, they also have a 25 to 40 percent higher risk of depression and anxiety.
“Shift workers, as well as people experiencing circadian disruption, including jet lag, may benefit from our meal timing intervention,” said co-corresponding author Sarah L. Chellappa, MD, PhD, who He completed work on this project while at the Brigham. Chellappa is now at the Department of Nuclear Medicine at the University of Cologne, Germany. “Our findings open the door to a new behavioral strategy during the circadian/sleep cycle that could also benefit people experiencing mental health disorders. "Our study adds to a growing body of evidence finding that strategies that optimize sleep and circadian rhythms may help promote mental health."
To conduct the study, Scheer, Chellappa, and their colleagues recruited 19 participants (12 men and 7 women) for a randomized controlled study. Participants underwent a low-light forced desynchronization protocol for four 28-hour "days," so that by the fourth "day" their behavioral cycles were reversed by 12 hours, simulating night work and causing circadian misalignment.
Participants were randomly assigned to one of two meal timing groups: the Day and Night Eating Control Group, which ate according to a 28-hour cycle (resulting in eating both day and night, which which is typical among night workers), and the Daytime Eating Only Intervention Group, which had meals on a 24-hour cycle (resulting in daytime eating only). The team assessed depression-like and anxiety-like mood levels every hour.
The team found that meal timing significantly affected participants’ mood levels. During the simulated night shift (day 4), those in the daytime and nighttime meal control group had increased depression-like mood levels and anxiety-like mood levels, compared to baseline ( day 1). In contrast, there were no changes in mood in the Daytime Meal Intervention Group during the simulated night shift. Participants with a greater degree of circadian misalignment experienced a mood more similar to depression and anxiety.
“Meal timing is emerging as an important aspect of nutrition that can influence physical health,” Chellappa said. “But the causal role of the timing of food intake on mental health remains to be proven. "Future studies are required to establish whether changes in meal timing can help people experiencing depressive and anxiety/anxiety-related disorders."
Reference: Qian J et al. “Daytime eating prevents mood vulnerability in night work” PNAS DOI: 10.1073/pnas.2206348119
