Dietary Interventions for Night Shift Workers: A Literature Review.

(1) Background: Night shift workers have greater risks of developing cardiometabolic diseases compared to day workers due to poor sleep quality and dietary habits, exacerbated by circadian misalignment. Assessing effects of dietary interventions on health outcomes among this group will highlight gaps for future research. (2) Methods: A search of studies was conducted on PubMed, Cochrane Library, Embase, Embase Classic, Ovid Emcare, and Google Scholar, from earliest to June 2019. The population-intervention-comparator-outcomes-study design format determined inclusion criteria. (3) Results: 756 articles were retrieved; five met inclusion and exclusion criteria. Six-hundred-and-seventy night shift workers were from healthcare, industrial, and public safety industries. Dietary interventions included two longer-term nutrition programs and three shorter-term adjustments of meal composition, type, and timing. Outcome measures were varied but included weight and cardiometabolic health measures. Nutrition programs found no weight improvement at both six and 12 months; low-density lipoprotein (LDL)-cholesterol levels decreased at six months. Triglycerides peaked after meals at 7:30 pm; glucose and insulin area under the curve peaked after meals at 11:30 pm. (4) Conclusions: Weight loss was not achieved in the studies reviewed but LDL-cholesterol improved. Future studies should investigate the effects of energy reduction and altering meal timing on cardiometabolic risk factors of night shift workers in randomised controlled trials, while assessing hunger, sleepiness, and performance.

Jetlag related sleep problems and their management: A review.

OBJECTIVES: We reviewed Jetlag, particularly in view of its effects on sleep and how it can be managed. METHODS: The Proquest Central database of Kirikkale University, PubMed and Google scholar were used while searching for the following key words: "Jetlag", "symptoms", "sleep", "melatonin" and "treatment". RESULTS: Flight dysrhythmia, otherwise known as jetlag, is caused by flying globally over various time zones. Most passengers who fly over six or more different time zones generally require 4-6 days after travelling to resume their usual sleep patterns and to feel less lethargic during the day. Signs of jet lag can vary between debilitated awareness, insomnia, feeling tired during the day and frequent waking during the night. During the night our pineal glands excrete a hormone called melatonin; dim lights cause the continuation of excretion of these hormones whereas any exposure to bright lights stems the flow of release. Common precautionary measures are specific diets, bright lights and melatonin agonists (Ramelteon, Agomelatine). CONCLUSION: Sleep issues derived from jetlag were found to be most common in passengers who flew through various time belts. Melatonin assumes a critical part in adjusting the body's circadian rhythms and has been utilized restoratively to re-establish irritated circadian rhythms.

Modafinil in the treatment of idiopathic hypersomnia without long sleep time--a randomized, double-blind, placebo-controlled study.

In 2010 the European Medicines Agency withdrew the indication of modafinil for the treatment of obstructive sleep apnea, shift work sleep disorder and for idiopathic hypersomnia (IH). In uncontrolled studies, modafinil has been reported to be efficacious in the treatment of sleep disorders. We therefore performed a randomized, placebo-controlled study with the aim of proving the efficacy of modafinil treatment in these patients. Drug-free IH patients without long sleep according to ICSD2 criteria, age >18 years and disease duration >2 years were included. After a washout phase, patients at baseline received placebo or 100 mg modafinil in the morning and at noon over 3 weeks, followed by 1 week without medication. At each visit the Epworth Sleepiness Scale (ESS) and Clinical Global Impression (CGI) rating scale were performed. At baseline and on days 8 and 21 four Maintenance of Wakefulness Tests (MWTs)/day or per day were performed. Patients kept a sleep-wake diary throughout the study. Between 2009 and 2011 three sleep centres recruited 33 participants. Compared to placebo, modafinil decreased sleepiness significantly and improved mean sleep latency in the MWT non-significantly. The CGI improved significantly from baseline to the last visit on treatment. The most frequent adverse events were headaches and gastrointestinal disorders; skin and psychiatric reactions were not reported. The number of reported naps and duration of daytime sleepiness decreased significantly. Total sleep time of nocturnal sleep was slightly reduced. The sleep diaries showed increases in feeling refreshed in the morning; the diurnal diaries showed significant improvement of performance and of exhaustion. Modafinil is an effective and safe medication in the treatment of IH. Adverse events are mild to moderate.

Evaluation of an mHealth intervention aiming to improve health-related behavior and sleep and reduce fatigue among airline pilots.

OBJECTIVES: The aim of this study was to evaluate the effects of an mHealth intervention (intervention using mobile technology) consisting of tailored advice regarding exposure to daylight, sleep, physical activity, and nutrition, and aiming to improve health-related behavior, thereby reducing sleep problems and fatigue and improving health perception of airline pilots. METHODS: A randomized controlled trial was conducted among 502 airline pilots. The intervention group was given access to both the MORE Energy mobile application (app) with tailored advice and a website with background information. The control group was directed to a website with standard information about fatigue. Health-related behavior, fatigue, sleep, and health perception outcomes were measured through online questionnaires at baseline and at three and six months after baseline. The effectiveness of the intervention was determined using linear and Poisson mixed model analyses. RESULTS: After six months, compared to the control group, the intervention group showed a significant improvement on fatigue (ß= -3.76, P<0.001), sleep quality (ß= -0.59, P=0.007), strenuous physical activity (ß=0.17, P=0.028), and snacking behavior (ß= -0.81, P<0.001). No significant effects were found for other outcome measures. CONCLUSIONS: The MORE Energy mHealth intervention reduced self-reported fatigue compared to a minimal intervention. Some aspects of health-related behavior (physical activity and snacking behavior) and sleep (sleep quality) improved as well, but most did not. The results show offering tailored advice through an mHealth intervention is an effective means to support employees who have to cope with irregular flight schedules and circadian disruption. This kind of intervention might therefore also be beneficial for other working populations with irregular working hours.

Health-related interventions among night shift workers: a critical review of the literature.

OBJECTIVES: Associations between shift work and chronic disease have been observed, but relatively little is known about how to mitigate these adverse health effects. This critical review aimed to (i) synthesize interventions that have been implemented among shift workers to reduce the chronic health effects of shift work and (ii) provide an overall evaluation of study quality. METHODS: MeSH terms and keywords were created and used to conduct a rigorous search of MEDLINE, CINAHL, and EMBASE for studies published on or before 13 August 2012. Study quality was assessed using a checklist adapted from Downs & Black. RESULTS: Of the 5053 articles retrieved, 44 met the inclusion and exclusion criteria. Over 2354 male and female rotating and permanent night shift workers were included, mostly from the manufacturing, healthcare, and public safety industries. Studies were grouped into four intervention types: (i) shift schedule; (ii) controlled light exposure; (iii) behavioral; and, (iv) pharmacological. Results generally support the benefits of fast-forward rotating shifts; simultaneous use of timed bright light and light-blocking glasses; and physical activity, healthy diet, and health promotion. Mixed results were observed for hypnotics. Study quality varied and numerous deficiencies were identified. CONCLUSIONS: Except for hypnotics, several types of interventions reviewed had positive overall effects on chronic disease outcomes. There was substantial heterogeneity among studies with respect to study sample, interventions, and outcomes. There is a need for further high-quality, workplace-based prevention research conducted among shift workers.

Effects of a carbohydrate-enriched night meal on sleepiness and sleep duration in night workers: a double-blind intervention.

The aim of this study was to investigate the effects of an intervention involving night meal composition on sleepiness and sleep duration in night security guards. A total of 54 male night security guards with a mean age of 30.8 years (SD = 5.5 years) filled out a 24-h dietary recall and were submitted to anthropometric measurement. Twenty-four workers were assigned to the intervention. The intervention was carried out over three consecutive weeks under three conditions. On the first week, no change in workers' food composition was introduced. On the second week, the amount of carbohydrates was increased by 20-30% compared with the first week's intake, whereas during the third week protein intake was increased by 30-40% compared with baseline levels (first week). Throughout the study period, workers wore an actigraph device to estimate sleeping and waking times. A two-factor mixed model analysis with sleep duration as the outcome showed an interaction effect between body mass index (BMI) and condition (F2,56 = 3.9; p = 0.03). Sleep duration was higher in obese workers compared with nonobese workers during the Carbohydrate condition (357 and 267 min, respectively). The analysis of variance (ANOVA) showed an increase in sleepiness under all conditions at 3:00 h (F1,276 = 165.73; p < 0.01) postprandially. A significant difference in sleepiness was also found between the obese and nonobese groups (F1,276 = 14.8; p < 0.01). The effect of the night meal content on sleep duration seems to be mediated by BMI. A carbohydrate-rich meal increased the duration of sleep in obese workers, and may therefore also influence sleepiness.

Improving the quality of infant sleep through the inclusion at supper of cereals enriched with tryptophan, adenosine-5'-phosphate, and uridine-5'-phosphate.

The present study evaluated whether the administration of cereals enriched with nutrients that are facilitators of sleep could help improve the sleep of infants who had sleep disorders at night time. Thirty infants aged 8-16 months with sleep disorders involving at least three nocturnal waking episodes took part in the study. They were given a night-time 'sleep facilitating cereal' product containing 225 mg tryptophan, 5.3 mg adenosine-5'-P, and 6.3 mg uridine-5'-P per 100 g of product. These cereals were given in a double-blind procedure lasting 5 weeks, with ingestion of the cereal between 18:00 and 06:00. In the control week, the children received a standard cereal (75 mg tryptophan/100 g product without nucleotides) dissolved in a standard formula milk (231.5 mg tryptophan, 2.6 mg adenosine-5'-P, 5 mg uridine-5'-P, per 100 g product). In one experimental week, the children received the night-time sleep facilitating cereal together with the standard formula milk. In another week, they received the sleep facilitating cereal together with a night milk specially formulated to attain the sleep rhythm (480 mg tryptophan, 8.8 mg uridine-5'-P, and 7.6 mg adenosine-5'-P per 100 g product). The three experimental weeks were separated by two wash-out weeks in which the milk and cereal administered was identical in composition to that of the control week. All the infants received a programmed writer actimeter which they wore continually, attached to their ankles, to record their motor activity. The recorded activity was used to calculate information about the time in bed, assumed sleep, actual sleep, sleep efficiency, sleep latency, immobility, and total activity. The infants receiving the enriched cereal during the time of darkness showed improvements in their sleep parameters, regardless of whether the milk they took at night was standard or enriched with tryptophan, adenosine-5'-P, and uridine-5'-P. In summary, the administration of enriched cereals led to an improvement in sleep, regardless of the type of infant milk used. These results support the concept of chrononutrition since they confirm that the sleep/wake rhythm can be influenced by diet.

Improved circadian sleep-wake cycle in infants fed a day/night dissociated formula milk.

On the basis of the circadian nutritional variations present in breast milk, and of the implications for the sleep/wake cycle of the nutrients present in infant formula milks, we designed a formula milk nutritionally dissociated into a Day/Night composition. The goal was to improve the bottle-fed infant's sleep/wake circadian rhythm. A total of 21 infants aged 4-20 weeks with sleeping difficulties were enrolled in the three-week duration study. The sleep analysis was performed using an actimeter (Actiwatch) placed on an ankle of each infant to uninterruptedly record movements during the three weeks. The dissociated Day milk, designed to be administered from 06:00 to 18:00, contained low levels of tryptophan (1.5g/100g protein) and carbohydrates, high levels of proteins, and the nucleotides Cytidine 5 monophosphate, Guanosine 5 monophosphate and Inosine 5 monophosphate. The dissociated Night milk, designed to be administered from 18.00 to 06.00, contained high levels of tryptophan (3.4g/100g protein) and carbohydrates, low levels of protein, and the nucleotides Adenosine 5 monophosphate and Uridine 5 monophosphate. Three different milk-feeding experiments were performed in a double-blind procedure covering three weeks. In week 1 (control), the infants received both by day and by night a standard formula milk; in week 2 (inverse control), they received the dissociated milk inversely (Night/Day instead of Day/Night); and in week 3, they received the Day/Night dissociated formula concordant with the formula design. When the infants were receiving the Day/Night dissociated milk in concordance with their environment, they showed improvement in all the nocturnal sleep parameters analyzed: total hours of sleep, sleep efficiency, minutes of nocturnal immobility, nocturnal awakenings, and sleep latency. In conclusion, the use of a chronobiologically adjusted infant formula milk seems to be effective in improving the consolidation of the circadian sleep/wake cycle in bottle-fed infants.