Dietary Interventions for Night Shift Workers: A Literature Review

The Effect of Meal Frequency and Glycemic Index During the Night Shift on Alertness, Hunger, and Gastrointestinal Complaints in Female Health Care Workers-A Two-Armed Randomized Crossover Trial

BACKGROUND

Nutrition strategies for night-shift workers could optimize alertness and minimize hunger and reduce gastrointestinal complaints, enhancing safety and well-being.

OBJECTIVES

This study aimed to investigate the effects of 1 or 3 small meals, with either low or high glycemic index (GI), compared with no meal, on alertness, hunger, and gastrointestinal complaints during the night shift.

METHODS

Fifty-one female health care workers, aged 18 to 61 y, participated in a 2-armed randomized crossover design. In 1 study arm, participants received 1 yogurt meal during the night shift, AND in the other, they received 3. Each study arm involved 3 intervention periods during night shifts, with participants consuming yogurt with low GI (1LGI or 3LGI) OR high GI (1HGI or 3HGI) carbohydrates, or no meal (0NGI). Objective alertness was assessed using a validated brief psychomotor vigilance task (PVT-B), subjective alertness with the Samn-Perelli scale, and hunger and gastrointestinal complaints through questionnaires.

RESULTS

Participants in the 1LGI (β: -4.6; 95% CI: 0.0, 9.3) and 3LGI (β: -3.4; 95% CI: 0.0, 6.8) conditions had fewer lapses during the PVT-B than those in the 3HGI condition. No differences were found between meal conditions for median and reciprocal reaction time or subjective alertness. All 4 conditions reported less hunger (β: from -0.6 to -1.2) compared with no meal. The 3LGI condition resulted in more rumbling intestines than the 3HGI (β: 1.1; 95% CI: 0.4, 1.7) and 0NGI (β: 0.74; 95% CI: 0.11, 1.37) conditions.

CONCLUSIONS

Our study suggests that consuming 3 small low GI meals during the night shift helps maintain alertness and reduces lapses compared with 3 high GI meals. It also minimizes hunger but may cause mild gastrointestinal complaints. This trial was registered at International Clinical Trial Registry (https://trialsearch.who.int/Trial2.aspx?TrialID%3dNL-OMON25574).

Personalized sleep and nutritional strategies to combat adverse effects of night shift work: a controlled intervention protocol

BACKGROUND

Working during the night interferes with the timing of normal daily activities and is associated with an increased risk of chronic diseases. Under controlled experimental conditions, interventions focusing on sleep and nutrition can mitigate the short-term adverse effects of shift work. However, it is unclear how these results translate to real-life, how they can be targeted to individual conditions, and how they relate to long-term health. Therefore, the current study aims to implement a personalized sleep and nutritional intervention among night shift workers in the field.

METHODS

A non-blinded controlled intervention study is used, consisting of a run-in period, an intervention of 3 months, post-intervention measurements, and a follow-up after 12 months. Three study arms are included: sleep intervention, nutritional intervention, and control group (n = 25 each). Participants are healthy 18-60-year male night shift workers, with at least one year of experience in night shift work. Information from the run-in period will be used to personalize the interventions. The main outcomes are sleep measurements and continuous interstitial glucose levels. Furthermore, general health biomarkers and parameters will be determined to further evaluate effects on long-term health.

DISCUSSION

This study aims to mitigate negative health consequences associated with night shift work by introducing two personalized preventive interventions. If proven effective, the personalized interventions may serve as practical solutions that can have a meaningful impact on the sustainable health and employability of night shift workers. This study will thereby contribute to the current need for high-quality data on preventative strategies for night shift work in a real-life context.

TRIAL REGISTRATION

This trial has been registered under ClinicalTrials.gov Identifier NCT06147089. Registered 27 November 2023.

A low-calorie meal replacement improves body composition and metabolic parameters in shift workers with overweight and obesity: a randomized, controlled, parallel group trial

BACKGROUND

Shift work has been identified as a risk factor for several chronic health conditions including obesity. This study evaluated the impact of a low-calorie meal replacement (MR) as a dinner substitute on body composition and metabolic parameters in shift workers with overweight and obesity.

METHODS

An 8-week parallel, randomized controlled trial was conducted on overweight and obese shift workers in a large hospital. An intervention group (IG) (n = 25) was provided with a low-calorie MR shake (∼200 kcal) as a replacement for dinner, every day for 8 weeks, while the control group (CG) (n = 25) continued their habitual diet. Anthropometric measurements, body composition, biochemical, and lifestyle data were assessed at the first and last visits. Analyses were done per protocol (PP) and by intention to treat (ITT).

RESULTS

Over the study duration, both groups displayed moderate changes in anthropometric measurements and body composition, although these were not statistically significant according to the PP analysis. In the ITT analysis, apart from the hip circumference (HC), all other anthropometric parameters demonstrated significant group and time interactions, suggesting the advantageous effects of the meal replacement over the study period (P < 0.05). HDL and VLDL cholesterol measures showed significant main effects, influenced by both group (P = 0.031) and time (P = 0.050) respectively. The most pronounced dietary shift in the IG was a reduction in carbohydrate consumption and an increase in protein intake. Throughout the study, the meal replacement was well-tolerated, with no adverse events reported.

CONCLUSIONS

The meal replacement dietary intervention appears to offer beneficial health effects over time. Extended research is crucial to understand the broader implications of meal replacements across diverse populations.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12622000231741. Registered on 09 February 2022. https://www.anzctr.org.au/ACTRN12622000231741.aspx .

Healthily Nourished but Depleted? Is It Possible to Improve the Health of Shift Workers through Lifestyle Interventions?

The relationship between diet and health is well-researched, and there is also information regarding the effects of diet on mental health. This study aimed to investigate whether motivation to optimize lifestyles without regulations or restrictions could improve the health of rotating shift workers. In this pilot study, 18 male shift workers were randomly divided into two groups. All participants completed the Short Form Health Survey-36 questionnaire (SF-36) before the start and at the end of the study. Group I (n = 9, mean age 42 ± 6.6 y) received dietary and lifestyle information every other month for one year, and the other, Group II (n = 9 mean age 36 ± 7.3 y), one year later. All participants were motivated to follow the trained dietary recommendations and to engage in physical activity. Almost all scores had improved. Surprisingly, physical performance scores worsened, which was not expected. The impairment in mental health due to the change in ownership of the company could have been better explained. Nutritional advice over a longer period and the motivation to integrate more exercise into everyday life can potentially improve the health of rotating shift workers.

Dietary taste patterns and diet quality of female nurses around the night shift

PURPOSE

Night shift workers are at risk of making poor food choices: e.g. sleep deprivation may lead to higher food intake with innate preferred tastes, such as sweet, savoury and fatty foods. Therefore, better insight in dietary taste patterns of night shift workers may improve the understanding of their food choices.

METHODS

This observational study assessed dietary taste patterns of 120 female night shift working nurses and compared them to 307 women of a reference population. Dietary intake, assessed with 24-h dietary recalls, was combined with a taste intensity database, including taste profiles of 557 foods. The contribution to the daily intake of 6 taste clusters was assessed: fat, neutral, sweet/fat, sweet/sour, salt/umami/fat and bitter.

RESULTS

During night shifts, nurses consumed a significantly higher energy percentage (en%) of 'neutral' (5.9 en%), 'sweet/sour' (8.1 en%) and 'sweet/fat' (6.5 en%) tasting foods and a lower en% of 'fat' (- 17.1 en%) and 'bitter' (- 2.1 en%) tasting foods than outside the night shift. They consumed a larger en% from foods with a 'sweet/sour' (1.9 en%) taste and a lower en% from foods with a 'bitter' (- 2.1 en%) taste than the reference population, irrespective of age, BMI and smoking status. A higher en% and gram% of 'fat' tasting foods and a higher gram% 'fat/salt/umami' tasting foods were associated with lower diet quality.

CONCLUSION

Our results only partly support our hypothesis that nurses would select foods with more innate taste preferences. In addition, fat and savoury tasting foods were negatively associated with their diet quality.

Conceptualizing weight management for night shift workers: A mixed-methods systematic review

Shift workers have an increased risk of obesity and metabolic conditions. This mixed-methods systematic literature review on night shift workers aimed to: (1) identify barriers/enablers of weight management; (2) examine effectiveness of weight management interventions; and (3) determine whether interventions addressed enablers/barriers. Six databases were searched, articles screened by title/abstract, followed by full-text review, and quality assessment. Eligible qualitative studies documented experiences of behaviors related to weight change. Eligible quantitative studies were behavior change interventions with weight/body mass index outcomes. A thematic synthesis was undertaken for qualitative studies using the social-ecological model (SEM). Interventions were synthesized narratively including: weight/body composition change; components mapped by behavior change taxonomy; and SEM. A synthesis was undertaken to identify if interventions addressed perceived enablers/barriers. Eight qualitative (n = 169 participants) and 12 quantitative studies (n = 1142 participants) were included. Barriers predominated discussions: intrapersonal (time, fatigue, stress); interpersonal (work routines/cultural norms); organizational (fatigue, lack of: routine, healthy food options, breaks/predictable work); community (lack of healthy food options). The primary outcome for interventions was not weight loss and most did not address many identified enablers/barriers. One intervention reported a clinically significant weight loss result. Weight loss interventions that address barriers/enablers at multiple SEM levels are needed.

A qualitative exploration of the experiences of shift workers participated in a low-calorie meal replacement dietary intervention

OBJECTIVES

Shift work is associated with various health challenges, including obesity and metabolic disturbances. To address these concerns, a randomised controlled clinical trial was conducted to evaluate the efficacy of a low-calorie meal replacement (MR) dietary intervention for dinner among shift workers with obesity. This study focuses on the qualitative aspects of this intervention, aiming to explore the experiences and perceptions of shift workers who participated in the trial.

DESIGN

Following the completion of the intervention, semi-structured face-to-face or telephone interviews were conducted with a purposive sample of trial participants. Data analysis was inductive, thematic using NVivo V.10 software.

SETTING

The intervention was conducted among shift workers with obesity in a private hospital in Sri Lanka and resulted in a modest decrease in weight.

PARTICIPANTS

Using purposeful maximum variation sampling, we recruited eight healthcare shift workers who took part in a weight loss intervention.

RESULTS

All participants expressed satisfaction with the MR meal for dinner, highlighting its positive impact on their well-being. Despite initial difficulties, strong determination and motivation by results supported adherence. Some participants suggested that the MR could be improved with sweeter taste and more flavour options. Few reported mild bloating at the beginning, but no serious side effects were noted. Participants felt lighter in their bodies due to weight loss. The method's simplicity was the most frequently reported benefit, making it feasible even during busy night shifts. Overall, participants highly recommended the intervention to others in need.

CONCLUSION

Participants experienced weight loss by replacing their dinner with the MR. This study offers valuable insights for tailoring future workplace-based dietary interventions for this vulnerable population.

TRIAL REGISTRATION NUMBER

ACTRN12622000231741.

Evaluation of the "Shifting Weight using Intermittent Fasting in night-shift workers" weight loss interventions: a mixed-methods protocol

Introduction

Shift workers are at a greater risk for obesity-related conditions. The impacts of working at night presents a challenge for designing effective dietary weight-loss interventions for this population group. The Shifting Weight using Intermittent Fasting in night-shift workers (SWIFt) study is a world-first, randomized controlled trial that compares three weight-loss interventions. While the trial will evaluate the effectiveness of weight-loss outcomes, this mixed-methods evaluation aims to explore for who weight-loss outcomes are achieved and what factors (intervention features, individual, social, organisational and wider environmental) contribute to this.

Methods

A convergent, mixed-methods evaluation design was chosen where quantitative and qualitative data collection occurs concurrently, analyzed separately, and converged in a final synthesis. Quantitative measures include participant engagement assessed via: dietary consult attendance, fulfillment of dietary goals, dietary energy intake, adherence to self-monitoring, and rates for participant drop-out; analyzed for frequency and proportions. Regression models will determine associations between engagement measures, participant characteristics (sex, age, ethnicity, occupation, shift type, night-shifts per week, years in night shift), intervention group, and weight change. Qualitative measures include semi-structured interviews with participants at baseline, 24-weeks, and 18-months, and fortnightly audio-diaries during the 24-week intervention. Interviews/diaries will be transcribed verbatim and analyzed using five-step thematic framework analysis in NVivo. Results from the quantitative and qualitative data will be integrated via table and narrative form to interrogate the validity of conclusions.

Discussion

The SWIFt study is a world-first trial that compares the effectiveness of three weight-loss interventions for night shift workers. This mixed-methods evaluation aims to further explore the effectiveness of the interventions. The evaluation will determine for who the SWIFt interventions work best for, what intervention features are important, and what external factors need to be addressed to strengthen an approach. The findings will be useful for tailoring future scalability of dietary weight-loss interventions for night-shift workers.Clinical trial registration: This evaluation is based on the SWIFt trial registered with the Australian New Zealand Clinical Trials Registry [ACTRN 12619001035112].

Association of eating habits with health perception and diseases among Chinese physicians: a cross-sectional study

Background

Some eating habits may be related to the development of gastrointestinal diseases, obesity, and related metabolic dysfunctions. Because of long working hours, and shift schedules, physicians are more likely to form such eating habits and have a high risk of developing these diseases.

Objectives

We aimed to investigate the association between physicians' eating habits and their health perception and diseases.

Methods

Between 24 June and 5 August 2020, we performed convenience sampling of in-service physicians in hospitals in mainland China. A questionnaire was administered to collect data pertaining to basic sociodemographic characteristics, eating habits, health-related information such as body mass index classification, and prevalence of common diseases. The associations among eating habits and perceived suboptimal health status, micronutrient deficiency-related diseases, obesity, and related metabolic diseases were analysed.

Results

The prevalence of unhealthy eating habits was high: more eating out-of-home (53.4% in hospital canteens, 23.0% in restaurants and takeaways), fewer meals at home, irregular meals (30.5%), and eating too fast (the duration <10 min, 34.6%). Among those with the above eating habits, the prevalence rates of sub-optimal health and disease were higher than among those without the above eating habits.

Conclusion

Eating habits such as frequent eating out-of-home, irregular meals, and eating too fast were common among physicians, and were significantly related to perceived sub-optimal health status and disease occurrence.

Meal replacement as a weight loss strategy for night shift workers with obesity: a protocol for a randomized controlled trial

BACKGROUND

Shift work is considered a risk factor for a number of chronic health conditions including obesity. Weight reduction in obese patients lowers the risk for cardiovascular disease, diabetes, certain cancers, and mortality. Achieving a negative energy balance by providing low-calorie meal replacements is widely used for weight management. This study aims to evaluate the impact of a low-calorie "meal-replacement" on the weight and metabolic parameters of shift workers with obesity.

METHODS

This trial will be conducted in a parallel, randomized controlled design for a period of 8 weeks. A total of 44 shift workers with body mass index over 25 kg/m² will be recruited after assessing eligibility. Participants will be randomly assigned to the test and control groups on a 1:1 ratio. The intervention group (N = 22) will be provided with a low-calorie (~200 kcal) meal replacement shake as dinner, and the control group (N = 22) will continue their habitual diets. The visits and the evaluations will be done as follows: screening (visit 0), 4 weeks (visit 1), and 8 weeks (visit 2). Anthropometric measurements will be taken at 0, 4, and 8 weeks. Body composition, biochemical parameters, dietary intake, and physical activity will be assessed during the first and the last visit.

OUTCOMES

The primary outcome will be the proportion of participants that had a 5% body weight loss from baseline. The secondary outcomes will be post-intervention changes in other metabolic parameters.

DISCUSSION

To our knowledge, this is one of the first randomized controlled trials evaluating the effects of a meal replacement as the night meal for weight loss in shift workers with obesity. Moreover, improvement of metabolic parameters in shift workers will be an added benefit to this high-risk group.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12622000231741 . Registered on 09 February 2022.

Shift workers’ perceptions and experiences of adhering to a nutrition intervention at night whilst working: a qualitative study

This study explored the feasibility of implementing a meal timing intervention during night shift work. Data were collected via semi-structured interviews. Interviews were coded inductively by two researchers independently, then three major themes were collaboratively developed. Subthemes from each major theme were mapped to the theoretical domains framework and the Capability Opportunity Motivation model of behaviour change. Seventeen night shift workers (rotating or permanent) aged between 25 and 65 years were interviewed. Participants predominately worked as health professionals. The feasibility of a simple meal timing intervention to avoid eating between 1 and 6 am on night shift is largely affected by three major influences (1) physical and emotional burden of shift work which drives food temptations; (2) the workplace context including the meal break environment, social and cultural context at work, and break scheduling; and (3) motivation of the individual. Facilitators to avoiding eating at night were, keeping busy, having co-worker support, management support, education of health benefits and/or belief that the intervention was health promoting. The barriers to avoiding eating at night were the emotional and physical toll of working at night leading to comfort eating and not having rest areas away from food environments. To support night shift workers with changing timing of meals, interventions at work should target both individual and organisational level behaviour change.

The emerging importance of tackling sleep-diet interactions in lifestyle interventions for weight management

Sleep habits are directly related to risk of obesity, and this relationship may be partly mediated through food choices and eating behaviour. Short sleep duration, impaired sleep quality and suboptimal sleep timing are all implicated in weight gain and adverse cardiometabolic health, at least partly mediated through their associations with diet quality. Short-term sleep restriction leads to increased energy intake, and habitually short sleepers report dietary intakes that indicate a less healthy diet compared with adequate sleepers. Evidence is emerging that sleep extension interventions in short sleepers may reduce intake of sugars and overall energy intake. Poor sleep quality, night shift work patterns and social jetlag are also associated with lower diet quality and consumption of energy-dense foods. Incorporating sleep advice into weight management interventions may be more effective than energy-restricted diets and exercise advice alone. However, there are a lack of intervention studies that aim to lengthen sleep, improve sleep quality or adjust irregular sleep timing to investigate the impact on dietary intakes and eating behaviour in participants aiming to lose weight or maintain weight loss. Finally, future research should take account of individual characteristics such as age, sex, life stage and changing working practices when designing combined lifestyle interventions including sleep behaviour change for health and well-being.

Timing and Composition of Last Meal before Bedtime Affect Sleep Parameters of Night Workers

Night workers tend to eat irregularly, both in terms of meal times and composition. The disruption in energy metabolism caused by inappropriate eating habits can negatively affect the sleep quality of these individuals. The objectives of this study were to determine the interval between the last meal and bedtime and its relationship with both diurnal and nocturnal sleep parameters, as well as to evaluate the association of the adequacy of this meal with sleep parameters. The analyses were carried out for a usual sleep routine on a workday and a day off. This cross-sectional study was part of a controlled, randomized, double-blind, crossover clinical trial. The sample comprised 30 female nursing professionals who worked permanent night shifts of 12 × 36 h. Timing and composition of the last meal were obtained from food diaries, and sleep parameters were collected via actigraphy. On multiple linear regression analysis, every hour decrease in the interval between the last meal and sleep onset there was an increase of 0.39 h on diurnal sleep duration. Regarding food intake, every 1 g of fat and 1 g of carbohydrate consumed was associated with an increase in diurnal sleep onset latency of 0.13 h and 0.02 h, respectively. These findings suggest that both timing and composition of the last meal before bedtime may be potential key factors for good diurnal and nocturnal sleep among night-shift workers.

Cardiometabolic Benefits of Intermittent Fasting

This review aims to summarize the effects of intermittent fasting on markers of cardiometabolic health in humans. All forms of fasting reviewed here-alternate-day fasting (ADF), the 5:2 diet, and time-restricted eating (TRE)-produced mild to moderate weight loss (1-8% from baseline) and consistent reductions in energy intake (10-30% from baseline). These regimens may benefit cardiometabolic health by decreasing blood pressure, insulin resistance, and oxidative stress. Low-density lipoprotein cholesterol and triglyceride levels are also lowered, but findings are variable. Other health benefits, such as improved appetite regulation and favorable changes in the diversity of the gut microbiome, have also been demonstrated, but evidence for these effects is limited. Intermittent fasting is generally safe and does not result in energy level disturbances or increased disordered eating behaviors. In summary, intermittent fasting is a safe diet therapy that can produce clinically significant weight loss (>5%) and improve several markers of metabolic health in individuals with obesity.

A Nutritional Counseling Program Prevents an Increase in Workers' Dietary Intake and Body Weight During the COVID-19 Pandemic

The COVID-19 pandemic caused thousands of deaths and changed lives all over the world. Daily life has also altered people's eating habits, mainly among those who stayed working at home. However, changes in the eating habits of workers who remained working during the pandemic are still unknown. The aim of this study was to evaluate the impact of the COVID-19 pandemic on the dietary habits of day and shift workers from a condominium management company, as well as to measure adherence to a nutritional counseling program and its effect on workers' food intake and body weight. One hundred and fifty-one workers (77.5% of day workers and 22.5% of shift workers) were followed up in the pre-pandemic period and during the pandemic. Data on anthropometry, food consumption, and adherence to nutritional counseling were collected during nutritional meetings, which focused on qualitative modification of food intake and control of energy consumption. The rate of adherence to the program did not differ between shifts. The pandemic significantly increased the intake of calories, macronutrients, and several micronutrients in workers of both shifts. Adherence to the nutritional counseling program had an impact on the consumption of proteins and some micronutrients, and also promoted a reduction in body weight and body mass index of workers of both shifts. Evening/night shift workers overall ate their meals later than day workers and also presented an earlier afternoon snack during the pandemic when compared with the pre-pandemic period. In conclusion, the pandemic seems to contribute to the increase in food intake of workers, regardless of the work shift. Those who joined a nutritional counseling program managed their food intake and lost weight.

Protocol of the Study on Emergency Health Care Workers' Responses Evaluated by Karasek Questionnaire: The SEEK-Study Protocol

BACKGROUND

Stress is a significant public health concern that can be self-evaluated using the job control demands model from Karasek. Emergency health care workers are particularly exposed to stress because of the intrinsic characteristics associated with the job (i.e., life-threatening emergencies, overcrowding, lack of bed spaces). However, these attributes have never been studied using the Karasek model.

METHODS

An observational, prospective, multicentric study in French Emergency Departments will be conducted using a cohort of emergency health care workers. Four questionnaires before a control day and after a nightshift will be assessed every 5 years in the same emergency departments. Also, the Karasek questionnaire, a sociodemographic questionnaire, the Maslach Burnout Inventory scale, the Hospital Anxiety, Depression Scale, and a food intake questionnaire will be evaluated. Salivary biomarkers (cortisol, immunoglobulin A, lysozyme) will be collected from every emergency health care worker who consents to participating in the study.

CONCLUSION

This study will provide a point of care for the emergency health care workers' stress situation every 5 years. Ethics: This protocol was registered in Clinical Trials under the identification NCT02401607 after the French Ethics Committee's approval.

Top 10 evidence-based countermeasures for night shift workers

Emergency edicine providers are responsible for ensuring the emergency department is staffed 24 hours a day. As such, providers must efficiently transition between day, swing and night shift on an almost weekly basis. There is no formal education in medical school or residency on how to approach the transition to and from night shift, remain alert and productive and maximise sleep during the day. There are a multitude of blogs and online sources discussing night shift, but few, if any, provide an evidence-based approach. This article will provide the top 10 evidence-based recommendations to increase sleep, maximise performance, decrease fatigue on shift and improve quality of life outside the workplace.