Multiple Dimensions of Sweet Taste Perception Altered after Sleep Curtailment

Sleep and the Mediterranean diet: A systematic review and meta-analysis

We conducted the current systematic review and meta-analysis to critically review and synthesize available evidence regarding the association between sleep duration, sleep quality, and chronotype with the Mediterranean diet (MedDiet) among the general population using observational studies. Online databases, including PubMed, Scopus, and ISI Web of Science, were searched from the earliest available date until December 2024. We enrolled 62 studies with a total sample size of 328,493. The mean age and BMI of the participants in the enrolled studies ranged from 6.1 to 74.7 years and 18.1-32.1 kg/m2. Individuals with sufficient sleep duration (OR: 1.39; 95 % CI, 1.04, 1.85; P = 0.030; I2 = 97.89 %, PQ-test < 0.001), good-quality sleep (OR: 1.38; 95 % CI, 1.10, 1.73; P < 0.001; I2 = 93.83 %, PQ-test < 0.001), and earlier chronotype (OR: 1.74; 95 % CI, 1.21, 2.50; P = 0.002; I2 = 89.72 %, PQ-test < 0.001) had significantly increased odds of high MedDiet scores, compared to those with insufficient sleep duration, poor-quality sleep, and later chronotype, respectively. Our study revealed that sleep duration, sleep quality, and chronotype are lifestyle-related factors linked to MedDiet. However, more longitudinal studies and clinical trials are needed to investigate causality, mediating factors, and underlying mechanisms.

The influence of sleep on human taste function and perception: A systematic review

Sleep problems are associated with increased risk of obesity. Multiple mechanisms have been identified to support this relationship, including changes in sensory processing and food choice. Taste researchers have recently begun to explore whether changes in taste occur as a result of short-term or long-term sleep habits. A systematic review was conducted to investigate these relationships. A total of 13 studies were included in the review. Heterogeneity in both the sleep and taste measurements used was noted, and most studies failed to assess sour, bitter and umami tastes. Still, the available evidence suggests that sweet taste hedonic perception appears to be undesirably influenced by short sleep when viewed through the lens of health. That is, preferred sweetness concentration increases as sleep duration decreases. Habitual sleep and interventions curtailing sleep had minimal associations or effects on sweet taste sensitivity. Salt taste sensitivity and hedonic responses appear to be relatively unaffected by insufficient sleep, but more work is needed. Solid evidence on other taste qualities is not available at the present time.

Comparative Analysis of Taste Perception Among Airline Pilots, Construction Workers, and Office Employees

Objective Occupational exposures may influence gustatory sensations through mechanisms such as fatigue, acute or chronic stress, circadian rhythm disruptions, and exposure to various chemicals. In this cross-sectional study, we sought to compare taste perception across three professional groups, namely airline pilots, construction workers, and office employees, by assessing taste identification times for sweet, salty, sour, and bitter flavors, alongside salivary pH levels. Methods The study cohort consisted of 90 healthy male participants, with 30 individuals in each occupational group, matched for age and professional experience. Salivary pH was measured using pH meter paper, whereas taste identification times were assessed using aqueous solutions applied to dissolvable strips for each taste. Results There were no significant differences in salivary pH among the study groups. However, airline pilots exhibited a significantly longer identification time for sweet taste (9.8 ± 3.9 seconds) compared to construction workers (7.0 ± 3.1 seconds, P < 0.05) and office employees (7.1 ± 3.3 seconds, P < 0.05). Conversely, construction workers demonstrated a significantly prolonged identification time for sour taste (6.1 ± 2.9 seconds) compared to pilots (4.2 ± 2.6 seconds, P < 0.05) and office employees (4.6 ± 2.5 seconds, P < 0.05). No significant differences were observed in the identification times for salty and bitter tastes across the groups. Conclusion We found significant differences in taste perception among airline pilots, construction workers, and office employees, particularly concerning sweet and sour tastes. These findings suggest that occupational factors may influence gustatory function in a complex manner. Further research is warranted to explore the underlying mechanisms and potential implications for dietary habits and health within specific occupational groups.

Comparing body composition between the sweet-liking phenotypes: experimental data, systematic review and individual participant data meta-analysis

BACKGROUND

Legislation aimed at reducing sugar intake assumes that sweet-liking drives overconsumption. However, evidence that a greater liking for sweet taste is associated with unhealthier body size is mixed and complicated by relatively small samples, an overreliance on body mass index (BMI) and lack of classification using sweet-liking phenotypes.

METHODS

We first examined body size data in two larger samples with sweet-liking phenotyping: extreme sweet-likers, moderate sweet-likers and sweet-dislikers. Adults (18-34yrs), attended a two-session lab-based experiment involving phenotyping for sweet-liking status and a bioelectrical impedance body composition measurement (Experiment One: N = 200; Experiment Two: N = 314). Secondly, we conducted an individual participant data (IPD) meta-analysis: systematic searches across four databases identified 5736 potential articles. Of these, 53 papers met our search criteria: a taste assessment that measured liking using sucrose (>13.7% w/v), which allowed sweet-liking phenotyping and included either BMI, body fat percentage (BF%), fat-free mass (FFM) or waist-circumference.

RESULTS

A significant effect of sweet-liking phenotype on FFM was found in both Experiment One and Two, with extreme sweet-likers having significantly higher FFM than sweet-dislikers. In Experiment One, sweet-dislikers had a significantly higher BF% than extreme sweet-likers and moderate sweet-likers. However, as these data are from one research group in a young, predominantly westernised population, and the results did not perfectly replicate, we conducted the IPD meta-analyses to further clarify the findings. Robust one-stage IPD meta-analyses of 15 studies controlling for sex revealed no significant differences in BF% (n = 1836) or waist-circumference (n = 706). For BMI (n = 2368), moderate sweet-likers had slightly lower BMI than extreme sweet-likers, who had the highest overall BMI. Most interestingly, for FFM (n = 768), moderate sweet-likers and sweet-dislikers showed significantly lower FFM than extreme sweet-likers.

CONCLUSION

The higher BMI often seen in sweet-likers may be due to a larger FFM and questions the simple model where sweet liking alone is a risk factor for obesity.

Dimensions of sleep quality are related to objectively measured eating behaviors among children at high familial risk for obesity

OBJECTIVE

The aim of this study was to evaluate whether dimensions of sleep quality were associated with homeostatic and hedonic eating behaviors among children with healthy weight (BMI-for-age < 90%) but varying maternal weight status.

METHODS

A total of 77 children (mean [SD], age: 7.4 [0.6] years; BMI z score: -0.10 [0.7]) with healthy weight and high (n = 32) or low (n = 45) familial obesity risk based on maternal weight status were served an ad libitum meal (homeostatic eating) followed by palatable snacks to assess eating in the absence of hunger (EAH; hedonic eating). Habitual sleep quality was quantified from seven nights of wrist actigraphy. Partial correlations, adjusted for child energy needs, pre-meal hunger, food liking, and socioeconomic status, evaluated associations of sleep with meal intake and EAH. Additionally, sleep-by-obesity risk interactions were assessed.

RESULTS

Greater sleep fragmentation was associated with higher homeostatic meal energy intake, but only among children at high familial obesity risk (p value for interaction = 0.001; β high risk = 48.6, p = 0.001). Sleep fragmentation was not associated with total EAH but was related to higher and lower intake of carbohydrates (r = 0.33, p = 0.003) and fat (r = -0.33, p = 0.003), respectively.

CONCLUSIONS

Adverse associations of poor sleep with energy intake may be amplified among children already predisposed to obesity. Furthermore, that fragmented sleep relates to preferential intake of carbohydrates over fat during EAH may suggest alterations in taste preferences with poor sleep.

The Effects of Acute Sleep Curtailment on Salt Taste Measures and Relationships with Energy-Corrected Sodium Intake: A Randomized Cross-Over Trial with Methodology Validation

(1) Background: Sleep may be a factor that influences the taste-dietary intake relationship. The effect of sleep on salt taste measures has not been adequately studied, and no standardized methodology has been developed for measuring salt taste preference. (2) Methods: A sweet taste forced-choice paired-comparison test was adapted and validated to determine salt taste preference. In a randomized cross-over trial, participants slept a curtailed night (33% reduction in sleep duration) and a habitual night, confirmed by a single-channel electroencephalograph. Salt taste tests were conducted the day after each sleep condition using five aqueous NaCl solutions. One 24-h dietary recall was obtained after each taste test. (3) Results: The adapted forced-choice paired-comparison tracking test reliably determined salt taste preference. No changes in salt taste function (intensity slopes: p = 0.844) or hedonic measures (liking slopes: p = 0.074; preferred NaCl concentrations: p = 0.092) were observed after the curtailed sleep condition compared to habitual sleep. However, sleep curtailment disrupted the association between liking slope and energy-corrected Na intake (p < 0.001). (4) Conclusions: The present study serves as the first step toward more standardized taste assessments to facilitate comparison between studies and suggests accounting for sleep when exploring taste-diet relationships.

Timing of Meals and Sleep in the Mediterranean Population: The Effect of Taste, Genetics, Environmental Determinants, and Interactions on Obesity Phenotypes

Circadian rhythms regulate the sleep-wake and feeding-fasting cycles. Sleep and feeding constitute a complex cycle that is determined by several factors. Despite the importance of sleep duration and mealtimes for many obesity phenotypes, most studies on dietary patterns have not investigated the contribution of these variables to the phenotypes analyzed. Likewise, they have not investigated the factors related to sleep or mealtimes. Thus, our aims were to investigate the link between taste perception and eating/sleep patterns and to analyze the effect of the interactions between sleep/meal patterns and genetic factors on obesity phenotypes. We conducted a cross-sectional analysis on 412 adults from the Mediterranean population. We measured taste perception (bitter, sweet, salty, sour, and umami) and assessed sleep duration and waketime. The midpoint of sleep and social jetlag was computed. From the self-reported timing of meals, we estimated the eating window, eating midpoint, and eating jetlag. Adherence to the Mediterranean diet was measured with a validated score. Selected polymorphisms in the TAS2R38, CLOCK, and FTO genes were determined, and their associations and interactions with relevant phenotypes were analyzed. We found various associations between temporal eating, sleep patterns, and taste perception. A higher bitter taste perception was associated with an earlier eating midpoint (p = 0.001), breakfast time (p = 0.043), dinner time (p = 0.009), waketime (p < 0.001), and midpoint of sleep (p = 0.009). Similar results were observed for the bitter taste polymorphism TAS2R38-rs713598, a genetic instrumental variable for bitter perception, increasing the causality of the associations. Moreover, significant gene-sleep interactions were detected between the midpoint of sleep and the TAS2R38-rs713598 (p = 0.032), FTO-rs9939609 (p = 0.037), and CLOCK-rs4580704 (p = 0.004) polymorphisms which played a role in determining obesity phenotypes. In conclusion, our study provided more information on the sleep and mealtime patterns of the general Spanish Mediterranean population than on their main relationships. Moreover, we were able to show significant associations between taste perception, specifically bitter taste; sleep time; and mealtimes as well as an interaction between sleep time and several genetic variants linked to obesity phenotypes. However, additional research is needed to better characterize the causality and mechanisms behind these associations.

Chronic Unpredictable Mild Stress Model of Depression: Possible Sources of Poor Reproducibility and Latent Variables

Major depressive disorder (MDD) is one of the most common mood disorders worldwide. A lack of understanding of the exact neurobiological mechanisms of depression complicates the search for new effective drugs. Animal models are an important tool in the search for new approaches to the treatment of this disorder. All animal models of depression have certain advantages and disadvantages. We often hear that the main drawback of the chronic unpredictable mild stress (CUMS) model of depression is its poor reproducibility, but rarely does anyone try to find the real causes and sources of such poor reproducibility. Analyzing the articles available in the PubMed database, we tried to identify the factors that may be the sources of the poor reproducibility of CUMS. Among such factors, there may be chronic sleep deprivation, painful stressors, social stress, the difference in sex and age of animals, different stress susceptibility of different animal strains, handling quality, habituation to stressful factors, various combinations of physical and psychological stressors in the CUMS protocol, the influence of olfactory and auditory stimuli on animals, as well as the possible influence of various other factors that are rarely taken into account by researchers. We assume that careful inspection of these factors will increase the reproducibility of the CUMS model between laboratories and allow to make the interpretation of the obtained results and their comparison between laboratories to be more adequate.

Sleep and Diet: Mounting Evidence of a Cyclical Relationship

Two factors intrinsic to health are diet and sleep. These two behaviors may well influence one another. Indeed, that insufficient sleep adversely impacts dietary intakes is well documented. On the other hand, diet may influence sleep via melatonin and its biosynthesis from tryptophan. Experimental data exist indicating that provision of specific foods rich in tryptophan or melatonin can improve sleep quality. Whole diets rich in fruits, vegetables, legumes, and other sources of dietary tryptophan and melatonin have been shown to predict favorable sleep outcomes. Although clinical trials are needed to confirm a causal impact of dietary patterns on sleep and elucidate underlying mechanisms, available data illustrate a cyclical relation between these lifestyle factors. We recommend adopting a healthful diet to improve sleep, which may further promote sustained favorable dietary practices.

Fatigue, Stress, and Functional Status are Associated With Taste Changes in Oncology Patients Receiving Chemotherapy

CONTEXT

A common complaint among oncology patients receiving chemotherapy is altered taste perception.

OBJECTIVE

The purpose of this study was to evaluate for differences in common symptoms and stress levels in patients who reported taste changes.

METHODS

Patients were receiving chemotherapy for breast, gastrointestinal, gynecological, or lung cancer. Change in the way food tastes (CFT) was assessed using the Memorial Symptom Assessment Scale before the patients' second or third cycle of chemotherapy. Valid and reliable instruments were used to assess for depressive symptoms, state and trait of anxiety, cognitive impairment, diurnal variations in fatigue and energy, sleep disturbance, and pain. Stress was assessed using the Perceived Stress Scale and the Impact of Events Scale-Revised. Multiple logistic regression was used to evaluate for risk factors associated with CFT.

RESULTS

Of the 1329 patients, 49.4% reported CFT. Patients in the CFT group reported higher levels of depression, anxiety, fatigue, and sleep disturbance as well as higher levels of general and disease specific stress. Factors associated with CFT group included being non-White; receiving an antiemetic regimen that contained a neurokinin-1 receptor antagonist with two other antiemetics; having a lower functional status; higher levels of morning fatigue; and reporting higher scores on the hyperarousal subscale of the Impact of Event Scale-Revised.

CONCLUSIONS

This study provides new evidence on associations between taste changes and common co-occurring symptoms and stress in oncology patients receiving chemotherapy. Clinicians need to evaluate for taste changes in these patients because this symptom can effect patients' nutritional intake and quality of life.

Feasibility and Acceptability of Wearable Sleep Electroencephalogram Device Use in Adolescents: Observational Study

Background

Adolescence is an important life stage for the development of healthy behaviors, which have a long-lasting impact on health across the lifespan. Sleep undergoes significant changes during adolescence and is linked to physical and psychiatric health; however, sleep is rarely assessed in routine health care settings. Wearable sleep electroencephalogram (EEG) devices may represent user-friendly methods for assessing sleep among adolescents, but no studies to date have examined the feasibility and acceptability of sleep EEG wearables in this age group.

Objective

The goal of the research was to investigate the feasibility and acceptability of sleep EEG wearable devices among adolescents aged 11 to 17 years.

Methods

A total of 104 adolescents aged 11 to 17 years participated in 7 days of at-home sleep recording using a self-administered wearable sleep EEG device (Zmachine Insight+, General Sleep Corporation) as well as a wristworn actigraph. Feasibility was assessed as the number of full nights of successful recording completed by adolescents, and acceptability was measured by the wearable acceptability survey for sleep. Feasibility and acceptability were assessed separately for the sleep EEG device and wristworn actigraph.

Results

A total of 94.2% (98/104) of adolescents successfully recorded at least 1 night of data using the sleep EEG device (mean number of nights 5.42; SD 1.71; median 6, mode 7). A total of 81.6% (84/103) rated the comfort of the device as falling in the comfortable to mildly uncomfortable range while awake. A total of 40.8% (42/103) reported typical sleep while using the device, while 39.8% (41/103) indicated minimal to mild device-related sleep disturbances. A minority (32/104, 30.8%) indicated changes in their sleep position due to device use, and very few (11/103, 10.7%) expressed dissatisfaction with their experience with the device. A similar pattern was observed for the wristworn actigraph device.

Conclusions

Wearable sleep EEG appears to represent a feasible, acceptable method for sleep assessment among adolescents and may have utility for assessing and treating sleep disturbances at a population level. Future studies with adolescents should evaluate strategies for further improving usability of such devices, assess relationships between sleep EEG–derived metrics and health outcomes, and investigate methods for incorporating data from these devices into emerging digital interventions and applications.

Trial Registration

ClinicalTrials.gov NCT03843762; https://clinicaltrials.gov/ct2/show/NCT03843762

The Effect of Sleep Curtailment on Hedonic Responses to Liquid and Solid Food

It is currently unclear whether changes in sweet taste perception of model systems after sleep curtailment extend to complex food matrices. Therefore, the primary objective of this study was to use a novel solid oat-based food (crisps) and oat-based beverage stimulus sweetened with sucralose to assess changes in taste perception after sleep curtailment. Forty-one participants recorded a habitual and curtailed night of sleep using a single-channel electroencephalograph. The next morning, overall sweetness, flavor, and texture liking responses to energy- and nutrient-matched oat products across five concentrations of sweetness were measured. Overall (p = 0.047) and flavor (p = 0.017) liking slopes across measured concentrations were steeper after curtailment, suggesting that sweeter versions of the oat products were liked more after sleep curtailment. Additionally, a hierarchical cluster analysis was used to classify sweet likers and non-likers. While the effect of sleep curtailment on sweet liking did not differ between sweet liking classification categories, sleep curtailment resulted in decreased texture liking in the solid oat crisps for sweet non-likers (p < 0.001), but not in the oat beverage. These findings illustrate the varied effects of sleep on hedonic response in complex food matrices and possible mechanisms by which insufficient sleep can lead to sensory-moderated increases in energy intake.