Severe sleep restriction suppresses appetite independent of effects on appetite regulating hormones in healthy young men without obesity

Prevalence and network analysis of internet addiction, depression and their associations with sleep quality among commercial airline pilots: A national survey in China

OBJECTIVE

Airline pilots are members of a unique occupational group that is often confronted with sleep routine disruptions, yet relatively few studies have examined their mental health status. This study assessed the prevalence and network structure of internet addiction, depression and sleep quality problems in commercial airline pilots.

METHOD

A total of 7055 airline pilots were included in analyses. Internet addiction and depression were measured with the Internet Addiction Test (IAT) and 9-item Patient Health Questionnaire (PHQ-9), respectively. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI). The network model was constructed based on an Ising model and its association with sleep quality was evaluated using a flow procedure.

RESULTS

Internet addiction, depression and sleep quality were common among airline pilots. The prevalence of internet addiction was 8.0 % (95 % CI: 7.3-8.6 %), while the rates of depression and poor sleep quality were 23.3 % (95 % CI: 22.3-24.2 %) and 33.0 % (95 % CI: 31.9-34.1 %), respectively. In the depression and internet addiction network model, "Fatigue" (PHQ4; Expected Influence (EI): 2.04) and "Depressed/moody/nervous only while being offline" (IAT20; EI: 1.76) were most central symptoms while "Fatigue" (PHQ4; Bridge EI: 1.30) was also the most important bridge symptom. The flow network model of sleep quality with internet addiction and depression showed that "Appetite" (PHQ5) had the strongest positive association with poor sleep quality.

CONCLUSION

Internet addiction, depression and sleep quality were common among airline pilots and warrant regular screening and timely treatment. Strategies to improve sleep hygiene may be useful in preventing onsets or exacerbations in depression and internet addiction among airline pilots.

Sleep deprivation induced fat accumulation in the visceral white adipose tissue by suppressing SIRT1/FOXO1/ATGL pathway activation

Sleep is critical for maintaining overall health. Insufficient sleep duration and poor sleep quality are associated with various physical and mental health risks and chronic diseases. To date, plenty of epidemiological research has shown that sleep disorders are associated with the risk of obesity, which is usually featured by the expansion of adipose tissue. However, the underlying mechanism of increased fat accumulation upon sleep disorders remains unclear. Here we demonstrated that sleep deprivation (SD) caused triglycerides (TG) accumulation in the visceral white adipose tissue (vWAT), accompanied by a remarkable decrease in the expression of adipose triglyceride lipase (ATGL) and other two rate-limiting lipolytic enzymes. Due to the key role of ATGL in initiating and controlling lipolysis, we focused on investigating the signaling pathway leading to attenuated ATGL expression in vWAT upon SD in the following study. We observed that ATGL downregulation resulted from the suppression of ATGL transcription, which was mediated by the reduction of the transcriptional factor FOXO1 and its upstream regulator SIRT1 expression in vWAT after SD. Furthermore, impairment of SIRT1/FOXO1/ATGL pathway activation and lipolysis induced by SIRT1 inhibitor EX527 in the 3 T3-L1 adipocytes were efficiently rescued by the SIRT1 activator resveratrol. Most notably, resveratrol administration in SD mice revitalized the SIRT1/FOXO1/ATGL pathway activation and lipid mobilization in vWAT. These findings suggest that targeting the SIRT1/FOXO1/ATGL pathway may offer a promising strategy to mitigate fat accumulation in vWAT and reduce obesity risk associated with sleep disorders.

Food-Oral Processing: Current Progress, Future Directions, and Challenges

Oral processing refers to the series of physical, chemical, and biological processes inside the oral cavity when we consume food. This process affects the taste, quality, and nutrient absorption of the body. In the human diet, oral processing plays a crucial role because it impacts not only the food flavor and texture but also the absorption and utilization of nutrients. With the progress of science and technology and the increasing demand for food, the study of oral processing has become increasingly important. This paper reviews the history and definition of oral processing, its current state of research, and its applications in food science and technology, focusing on personalized taste customization, protein structure modification, food intake and nutrition, and bionic devices. It also analyzes the impact of oral processing on different types of food products and explores its potential in the food industry and science research.

Sleep deprivation in development of obesity, effects on appetite regulation, energy metabolism, and dietary choices

Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today's life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

Late, but Not Early, Night Sleep Loss Compromises Neuroendocrine Appetite Regulation and the Desire for Food

OBJECTIVE

There is evidence that reduced sleep duration increases hunger, appetite, and food intake, leading to metabolic diseases, such as type 2 diabetes and obesity. However, the impact of sleep timing, irrespective of its duration and on the regulation of hunger and appetite, is less clear. We aimed to evaluate the impact of sleep loss during the late vs. early part of the night on the regulation of hunger, appetite, and desire for food.

METHODS

Fifteen normal-weight ([mean ± SEM] body-mass index: 23.3 ± 0.4 kg/m²) healthy men were studied in a randomized, balanced, crossover design, including two conditions of sleep loss, i.e., 4 h sleep during the first night-half ('late-night sleep loss'), 4 h sleep during the second night-half ('early-night sleep loss'), and a control condition with 8h sleep ('regular sleep'), respectively. Feelings of hunger and appetite were assessed through visual analogue scales, and plasma ghrelin and leptin were measured from blood samples taken before, during, and after night-time sleep.

RESULTS

Ghrelin and feelings of hunger and appetite, as well as the desire for food, were increased after 'late-night sleep loss', but not 'early-night sleep loss', whereas leptin remained unaffected by the timing of sleep loss.

CONCLUSIONS

Our data indicate that timing of sleep restriction modulates the effects of acute sleep loss on ghrelin and appetite regulation in healthy men. 'Late-night sleep loss' might be a risk factor for metabolic diseases, such as obesity and type 2 diabetes. Thereby, our findings highlight the metabolic relevance of chronobiological sleep timing.

Severe, short-term sleep restriction reduces gut microbiota community richness but does not alter intestinal permeability in healthy young men

Sleep restriction alters gut microbiota composition and intestinal barrier function in rodents, but whether similar effects occur in humans is unclear. This study aimed to determine the effects of severe, short-term sleep restriction on gut microbiota composition and intestinal permeability in healthy adults. Fecal microbiota composition, measured by 16S rRNA sequencing, and intestinal permeability were measured in 19 healthy men (mean ± SD; BMI 24.4 ± 2.3 kg/m², 20 ± 2 years) undergoing three consecutive nights of adequate sleep (AS; 7-9 h sleep/night) and restricted sleep (SR; 2 h sleep/night) in random order with controlled diet and physical activity. α-diversity measured by amplicon sequencing variant (ASV) richness was 21% lower during SR compared to AS (P = 0.03), but α-diversity measured by Shannon and Simpson indexes did not differ between conditions. Relative abundance of a single ASV within the family Ruminococcaceae was the only differentially abundant taxon (q = 0.20). No between-condition differences in intestinal permeability or β-diversity were observed. Findings indicated that severe, short-term sleep restriction reduced richness of the gut microbiota but otherwise minimally impacted community composition and did not affect intestinal permeability in healthy young men.

Sleep duration irregularity is associated with elevated blood pressure in young adults

Sleep irregularity (i.e., highly variable sleep patterns) is an emerging risk factor for cardiometabolic disease. Though irregular sleep patterns are common among young adults, the cardiometabolic health (CMH) repercussions of sleep irregularity in this population are unclear. We examined associations between sleep duration and irregularity with measures of CMH in 44 (24 M/20 F, 23 ± 5y, BMI 26 ± 4 kg/m², blood pressure (BP): 125/71 ± 14/9 mmHg) young adults. Participants wore actigraphy monitors for seven-days and sleep duration irregularity was operationalized as the standard deviation of nightly sleep duration (sleep SD). CMH variables of interest included brachial and aortic BP, arterial stiffness (cf-PWV), augmentation index (AIx75), and fasting blood glucose and lipids. Associations between sleep duration and sleep SD with CMH variables were assessed via correlations adjusted for sex and BMI. Sleep duration generally was not associated with CMH indices. However, sleep SD was associated with brachial systolic (r = 0.433, p = .027) and diastolic BP (r = 0.415, p = .035). Similarly, sleep duration SD was associated with aortic systolic BP (r = 0.447, p = .022). Our findings show that sleep irregularity, but not duration, is associated with higher brachial and central BP in young adults.Abbreviations: AIx75: augmentation index at a heart rate of 75 beats per minute; BP: blood pressure; CMH: cardiometabolic health; cf-PWV: carotid-femoral pulse wave velocity; DXA: dual x-ray absorptiometry; mg/dl: milligrams per deciliter; PWA: pulse wave analysis; PWV: pulse wave velocity; sleep duration SD: standard deviation of nightly sleep duration.

The impact of 16-h heat exposure on appetite and food reward in adults

Heat exposure is thought to reduce energy intake (EI) but studies are sparse and results not always concordant. The aim of this study was to examine whether a 16-h exposure to 32 °C leads to reduced EI compared to a control session (22 °C) and whether modifications in appetite sensations or food reward are implied. Sixteen healthy, lean, and active participants (9 women and 7 men, 25 ± 5 yo, body mass index: 22.0 ± 2.4 kg.m^-2) were passively exposed to two different thermal temperatures from 4:00 pm to 8:00 am under controlled conditions. Hunger and thirst scores were regularly assessed using visual analogue scales. A fixed dinner meal (3670 ± 255 kJ) was consumed at 7:30 pm and an ad libitum breakfast buffet (20 foods/drinks varying in temperature, fat, and carbohydrate content) at 7:30 am. Components of reward (explicit liking [EL] and implicit wanting [EI]) for fat and sweet properties of food were assessed before each meal using the Leeds Food Preference Questionnaire (LFPQ). Ad libitum EI at breakfast did not differ between sessions (2319 ± 1108 vs 2329 ± 1141 kJ, in 22 and 32 °C sessions, respectively; p = 0.955). While thirst scores were higher in the 32 than the 22 °C session (p < 0.001), hunger scores did not differ (p = 0.580). EL and IW for high fat foods relative to low fat foods were decreased in 32 compared to 22 °C before dinner and breakfast (p < 0.001 for all). Although EI and hunger were not affected by a 16-h exposure to heat, modifications in food reward suggested a reduction in the preference of high-fat foods. Future research should investigate whether reduced EI in response to heat exposure is due to spontaneous selection of low-fat foods rather than altered appetite sensations.

Role of Sleep Restriction in Daily Rhythms of Expression of Hypothalamic Core Clock Genes in Mice

Lack of sleep time is a menace to modern people, and it leads to chronic diseases and mental illnesses. Circadian processes control sleep, but little is known about how sleep affects the circadian system. Therefore, we performed a 28-day sleep restriction (SR) treatment in mice. Sleep restriction disrupted the clock genes’ circadian rhythm. The circadian rhythms of the Cry1 and Per1/2/3 genes disappeared. The acrophase of the clock genes (Bmal1, Clock, Rev-erbα, and Rorβ) that still had a circadian rhythm was advanced, while the acrophase of negative clock gene Cry2 was delayed. Clock genes’ upstream signals ERK and EIFs also had circadian rhythm disorders. Accompanied by changes in the central oscillator, the plasma output signal (melatonin, corticosterone, IL-6, and TNF-α) had an advanced acrophase. While the melatonin mesor was decreased, the corticosterone, IL-6, and TNF-α mesor was increased. Our results indicated that chronic sleep loss could disrupt the circadian rhythm of the central clock through ERK and EIFs and affect the output signal downstream of the core biological clock.