Daytime eating helps combat anxiety, depression among night shift workers

Among individuals who work at night, taking meals during the day appears to minimize the chances of experiencing mood symptoms related to anxiety and depression, as reported in a recent study.

“We found evidence that meal timing had moderate to large effects on depression-like and anxiety-like mood levels during simulated night work, and that such effects were associated with the degree of internal circadian misalignment,” according to the investigators.

“[The observed] effects were unlikely due to differences in study design, as the laboratory protocol of both groups was identical (ie, caloric/macronutrient intake, physical activity, posture, sleep duration, lighting conditions), except for the timing of meals,” they added.

In the study, 19 adults (mean age 26.5 years, 63.16 percent male) were randomized to have meals according to a 28-hour cycle (resulting in eating both during the night and day, which is typical among night workers; daytime and nighttime meal control [DNMC] group) or have meals on a 24-hour cycle (resulting in eating only during the day; daytime-only meal intervention [DMI] group).

All participants underwent a Forced Desynchrony protocol in dim light for four 28-hour “days,” such that by the fourth “day” their behavioural cycles were inverted by 12 hours, simulating night work and causing circadian misalignment.

Meal timing significantly modified the impact of simulated night work on depression- and anxiety-like mood levels (p=0.001). In the DNMC group, simulated night work contributed to an increase of 26.2 percent (95 percent confidence interval [CI], 21–31.5) in depression-like mood levels (p=0.001) and 16.1 percent (95 percent CI, 8.5–23.6) in anxiety-like mood levels (p=0.005) relative to each participant’s baseline. Conversely, there were no significant effects observed in the DMI group.

The investigators also noted that depression- and anxiety-like mood levels during simulated night work increased commensurate to the degree of internal circadian misalignment (p=0.001 and p=0.002, respectively).

“Shift workers have a 25–40 percent higher risk of depression and anxiety partly due to a misalignment between the central circadian clock and daily environmental/behavioural cycles that may negatively affect mood and emotional well-being. Hence, evidence-based circadian interventions are required to prevent mood vulnerability in shift work settings,” the investigators said.

“These findings offer a proof-of-concept demonstration of an evidence-based meal timing intervention that may prevent mood vulnerability in shift work settings,” they added.

The study’s co-corresponding author Dr Sarah Chellappa, from Brigham and Women's Hospital, Boston, Massachusetts, US, believes that shift workers, as well as individuals experiencing circadian disruption such as jet lag, may benefit from the described meal timing intervention.

“Our findings open the door for a novel sleep/circadian behavioural strategy that might also benefit individuals 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,” Chellapa said.

“Meal timing is emerging as an important aspect of nutrition that may influence physical health. But the causal role of the timing of food intake on mental health remains to be tested,” she added.

Chellapa and colleagues called for additional studies to establish whether changes in meal timing can help individuals experiencing depressive and anxiety/anxiety-related disorders.