Effects of chronic stress on bladder morphology of rats and impact of comfort food diet as an ameliorating agent.

OBJECTIVES: To investigate the effects of chronic stress on bladder morphology and the impact of food preference (standard or comfort foods) on the bladder of stressed rats. METHODS: In total, 32 Wistar male rats (3 months old) were divided into four groups: control (C), stressed (S), control + comfort food (C + CF), and stressed + comfort food (S + CF). Groups C and C + CF were maintained under normal conditions, while groups S and S + CF were subjected to chronic stress by the restraint method. Groups C and S received standard rat chow, while groups C + CF and S + CF received comfort food (Froot Loops®) and standard chow. The stress stimuli were induced daily for 2 h over 8 weeks. After 8 weeks, all animals were killed, and the bladders were removed and used for histomorphometric analysis. RESULTS: Body mass was similar among the groups. Stress did not promote differences regarding food intake, but animals receiving comfort food showed higher calories intake (in kcal/Kg) than animals receiving only standard chow. The C + CF and S + CF groups preferred comfort food over the standard chow; this preference was higher in the S + CF than in the C + CF group. The surface density of smooth muscle was reduced in stressed animals, while connective tissue and elastic system fiber content were increased in stressed groups. Further, epithelial height was increased in rats submitted to chronic stress. The surface density of elastic system fibers was decreased by the consumption of comfort food. CONCLUSIONS: Chronic stress induces morphological modifications on the bladder wall and epithelium. These modifications may be related to lower urinary tract symptoms. Additionally, chronic stress caused a higher preference for comfort food intake which did not ameliorate or aggravate the stress-induced bladder alterations.

Stress, rhythm, choice and the munchies - tribute to Mary F. Dallman.

In December 2021, we lost a pioneer in the field of stress research who inspired generations of scientists. Mary Dallman was an expert on the hypothalamic-pituitary-adrenal (HPA) axis, its interactions with a wide variety of other physiological systems and the impact of chronic changes of HPA function on energy metabolism and adiposity. She was not only an excellent scientist, she was a great role model and mentor for young scientists, especially women. She encouraged and supported many of her trainees even long after they left the lab. Her outside-the-box thinking, the fun and crazy discussions we had in the lab proved to be a beautiful basis for my own future research.

Effects of comfort food diet on the penile morphology of stressed rats.

Purpose: To investigate the effects of chronic stress, associated or not with comfort food, on the morphology of the penis. Materials & methods: Thirty-two adult Wistar rats were divided into four experimental groups: Control group (C), receiving standard rat chow, and under normal conditions; Stressed group (S), receiving standard chow, and submitted to stressful situations; Control + comfort food group (C + CF), receiving standard chow and comfort food, and under normal conditions; and Stressed + comfort food group (S + CF), receiving standard chow and comfort food, and submitted to stressful situations. At 10 weeks of age, food supply and stress were initiated. All groups had ad libitum access to standard chow and water, and groups receiving comfort food also had access to Froot Loops®. Chronic stress was induced by restriction, animals were contained daily in polypropylene tubes for 2 h, for eight weeks. After eight weeks all animals were killed; penises were removed for histomorphometric analysis. Results: Body mass was similar among the groups. Food intake in S + CF group was lower than in other groups. Concerning food preference, groups C + CF and S + CF preferred comfort food over the standard chow, with this preference being higher in S + CF than in C + CF. The area of the corpora cavernosa without tunica albuginea was lower in group S + CF than in group C. Most interestingly, the surface density of connective tissue in the corpora cavernosa was higher in groups S and S + CF compared to group C. In contrast, smooth muscle surface density was markedly lower in S + CF compared to groups C and C + CF, while group S also had reduced smooth muscle in comparison to group C. Conclusion: Chronic stress caused a morphological alteration on penile histomorphometry. Also, stress increased the preference for comfort foods which caused more deleterious effects in some parameters.

Bacon, Brownie, or Broccoli? Beliefs about Stress-Relieving Foods and Their Relationship to Orthorexia Nervosa.

BACKGROUND: Nutritional beliefs play an important role when it comes to food choice. However, little attention has been paid to which foods individuals believe to be comforting when experiencing stress. With increasing health awareness in the general public, this study aims to examine whether the nutritional belief exists that only healthy foods relieve stress. If so, we are interested in its relationship to Orthorexia Nervosa (ON) tendencies. METHODS: 175 participants (mean age 28.5 ± 7.8 years, 124 females) completed questionnaires to assess beliefs about stress-relieving foods and ON tendencies. Principal component analysis was used to reduce foods to food groups. Subsequently, a latent profile analysis was performed to identify groups with distinct nutritional beliefs. RESULTS: Among eight distinct groups, one group (8% of the sample) reported the belief that exclusively healthy foods relieve stress. Multinominal logistic regressions showed that higher ON tendencies were associated with that group. CONCLUSIONS: Our findings suggest that individuals with stronger ON tendencies believe that, in particular, healthy foods relieve stress. This indicates that nutritional beliefs in ON concern not only the somatic consequences of certain foods, but also psychological consequences, which might also drive orthorexic behaviour. This offers a new target for the diagnosis and treatment of ON.

The effect of unhealthy food and liking on stress reactivity.

In many individuals, stress appears to stimulate an increase in energy intake as well as a shift in food choice toward unhealthy food items or "comfort foods". Eating during stress is widely assumed to have anxiolytic properties, but there is little empirical support for this. The current two studies examined if either an unhealthy food item or a healthy food item could reduce stress reactivity and extended previous findings by examining whether participant liking contributes to any potential stress reduction. In the first experiment, participants rated baseline anxiety, were assigned to eat no food, carrots, or a candy bar, rated their anxiety a second time, and reported their liking of the assigned condition. The second experiment followed a similar procedure, except participants underwent a stressor before being asked to eat a food item. In addition, physiological measures of stress (salivary cortisol and α-amylase, and cardiovascular measures) were recorded. In both experiments, there was no effect of food on any measure of emotional or physiological stress. In contrast, participants who highly liked their condition exhibited a suppression of anxiety in both experiments and showed enhanced post-stress recovery of α-amylase. The anxiolytic effects of liking were not dependent on whether participants engaged in the healthy, unhealthy, or no food condition, which indicates that the self-perceived liking of a post-stress activity affects stress recovery more than the nutritional value. This has potential implications in how the population thinks about which activities to engage in to stimulate stress recovery.

Mindfulness moderates daily stress and comfort food snacking linkages: a multilevel examination.

Stress is often associated with poor diet in young adulthood. However, very few studies have examined whether snacking on non-nutritious sweet or salty "comfort food" is directly linked with daily stress, a common intervention target. Further, trait mindfulness, a psychological resource that may be enhanced by psychological training and regular practice, has yet to be tested as a moderator of daily stress-eating linkages. This 11-day daily diary study examined multilevel linkages between daily stress appraisals and comfort food eating in undergraduates. Daily stress appraisals positively predicted comfort food eating at the between-, but not within-person, level. Mindfulness moderated these effects, such that only more mindful participants demonstrated a negative association between within-person stress and comfort food eating. Results illustrate that chronic stress exposure and acute stress reactivity relate differently to eating behavior. Mindfulness and chronic stress may be key intervention targets for non-clinical groups at risk for unhealthy eating.

Rol de la emoción en la conducta alimentaria / The role of emotion in eating behavior

RESUMEN Las emociones tendrían un rol en la elección, calidad y cantidad de alimentos ingeridos, lo que llevaría al aumento o disminución del peso corporal. La relación entre las emociones y la conducta alimentaria es bidireccional y es dependiente del contexto, de la variabilidad de la emoción en cuanto a su valencia, excitación e intensidad, así como de la variabilidad fisiológica del sujeto. Dentro del contexto de la obesidad, se ha descrito el concepto del "comedor emocional" como aquel individuo que utiliza los alimentos como un mecanismo disfuncional para afrontar sus emociones negativas (ira, apatía, frustraciones, entre otras). Estas emociones negativas estarían más presentes en situaciones de alto estrés percibido, lo que conllevaría al aumento de la ingesta de alimentos llamados "reconfortantes", como lo son aquellos altos en azúcares y grasas. La presencia del comer emocional sería más prevalente en mujeres que en hombres; en personas obesas que en aquellas con estado nutricional normal y en contextos de restricción alimentaria. Las últimas investigaciones señalan que la forma en cómo regulamos nuestras emociones permitirían controlar la cantidad o calidad de los alimentos que se ingieren, siendo una estrategia efectiva para el control alimentario.

ABSTRACT Emotions may have a role in the choice, quality and quantity of food ingested, which may lead to an increase or decrease in body weight. The relationship between emotions and eating behavior is bidirectional and is dependent on the context, the variability of the emotion in terms of its valence, excitation and intensity, as well as physiological variability. Within the context of obesity, the concept of the "emotional eater" has been described as an individual who uses food as a dysfunctional mechanism to cope with negative emotions (anger, apathy, and frustrations, among others). These negative emotions would be more present in situations of high perceived stress, which would lead to an increase in the intake of so-called "comfort foods", such as those high in sugars and fats. The presence of emotional eating would be more prevalent in women than in men; in obese people than in those with normal nutritional status and in contexts of food restriction. The latest research indicates that the way in which we regulate our emotions would allow us to control the quantity or quality of the food we eat and an effective strategy for food control.

Towards a situational taxonomy of comfort foods: A retrospective analysis.

The concept of comfort food is heterogeneous and encompasses many different aspects that have been difficult to define. Here, we propose that a situational approach may provide a new perspective for categorizing comfort foods. Using a web-based survey, 322 respondents first provided their lay definition of comfort foods. These definitions included the components of emotions, unhealthiness, nostalgia, tastiness, and ease of preparation. Although some participants listed each of these components, half of the participants listed only one of these components, suggesting that most lay definitions of comfort food are rather sparse. Next, respondents evaluated each of 8 scenarios (illness, celebration, reward, stress, break-up, culture, lonely, and remembrance) in which comfort foods may develop. Each of these categories was endorsed by at least 19% of the sample. Subsequent analyses compared the scenarios that represented negative emotion situations (stress, break-up, lonely, and remembrance) or positive emotion situations (celebration, reward, culture, and remembrance). On the basis of these analyses, we propose a situational taxonomy of comfort food that includes 5 categories: negative emotion (stress, break-up, and lonely), positive emotion (celebration and cultural), illness, reward, and remembrance.

Influence of emotions evoked by life events on food choice.

PURPOSE: Considering the importance of replicating real-life experiences in studying emotional eating, this study investigated the influence of emotions evoked by life events on food choice in normal-weight and overweight women. METHODS: Normal-weight (n = 21) and overweight women (n = 23) aged 25-42 years were assigned to one of two different conditions: in one, they were shown a video with scenes of daily activities to elicit neutral responses; in the other, they were shown a video with scenes of common problems to evoke negative emotions. The participants were then offered a brunch containing sweet, salty, and healthy food items to evaluate their consumption and food choice. RESULTS: Exposure to negative emotions evoked by life problems increased energy intake in both groups, but they differed in terms of food choice. The normal-weight women increased only the consumption of sweet food (p = 0.044), whereas the overweight women significantly increased ingestion of sweet and salty foods (sweet food p = 0.031; salty food p = 0.008). CONCLUSIONS: The results show that common problems of life might trigger food consumption in the presence of high availability. Both groups increased food consumption after negative emotions and the normal-weight group had a higher increase than the overweight group. However, normal-weight women increased consumption of sweet foods, whereas overweight women consumed more salty, fried, and sweet foods. Healthy food was not chosen under these conditions. This should serve as a warning for the risks of excess exposure to high-sugar or high-fat food as everyday problems will not cease to exist. LEVEL OF EVIDENCE: Level II: evidence obtained from well-designed controlled trials without randomization.

Decreased comfort food intake and allostatic load in adolescents carrying the A3669G variant of the glucocorticoid receptor gene.

BACKGROUND: The A3669G single nucleotide polymorphism (SNP) of the glucocorticoid receptor (GR) gene NR3C1 is associated with altered tissue sensitivity to glucocorticoids (GCs). GCs modulate the food reward circuitry and are implicated in increased intake of palatable foods, which can lead to the metabolic syndrome and obesity. We hypothesized that presence of the G variant of the A3669G SNP would affect preferences for palatable foods and alter metabolic, behavioural, and neural outcomes. METHODS: One hundred thirty-one adolescents were genotyped for the A3669G polymorphism, underwent anthropometric assessment and nutritional evaluations, and completed behavioural measures. A subsample of 74 subjects was followed for 5 years and performed a brain functional magnetic resonance imaging (fMRI) paradigm to verify brain activity in response to food cues. RESULTS: Sugar and total energy consumption were lower in A3669G G allele variant carriers. On follow-up, this group also had reduced serum insulin concentrations, increased insulin sensitivity, and lower anxiety scores. Because of our unbalanced sample sizes (31/37 participants non-G allele carriers/total), our imaging data analysis failed to find whole brain-corrected significant results in between-group t-tests. CONCLUSION: These results highlight that a genetic variation in the GR gene is associated, at the cellular level, with significant reduction in GC sensitivity, which, at cognitive and behavioural levels, translates to altered food intake and emotional stress response. This genetic variant might play a major role in decreasing risk for metabolic and psychiatric diseases.

Statistical modeling implicates neuroanatomical circuit mediating stress relief by 'comfort' food.

A history of eating highly palatable foods reduces physiological and emotional responses to stress. For instance, we have previously shown that limited sucrose intake (4 ml of 30 % sucrose twice daily for 14 days) reduces hypothalamic-pituitary-adrenocortical (HPA) axis responses to stress. However, the neural mechanisms underlying stress relief by such 'comfort' foods are unclear, and could reveal an endogenous brain pathway for stress mitigation. As such, the present work assessed the expression of several proteins related to neuronal activation and/or plasticity in multiple stress- and reward-regulatory brain regions of rats after limited sucrose (vs. water control) intake. These data were then subjected to a series of statistical analyses, including Bayesian modeling, to identify the most likely neurocircuit mediating stress relief by sucrose. The analyses suggest that sucrose reduces HPA activation by dampening an excitatory basolateral amygdala-medial amygdala circuit, while also potentiating an inhibitory bed nucleus of the stria terminalis principle subdivision-mediated circuit, resulting in reduced HPA activation after stress. Collectively, the results support the hypothesis that sucrose limits stress responses via plastic changes to the structure and function of stress-regulatory neural circuits. The work also illustrates that advanced statistical methods are useful approaches to identify potentially novel and important underlying relationships in biological datasets.

Stress exposure, food intake and emotional state.

This manuscript summarizes the proceedings of the symposium entitled, "Stress, Palatable Food and Reward", that was chaired by Drs. Linda Rinaman and Yvonne Ulrich-Lai at the 2014 Neurobiology of Stress Workshop held in Cincinnati, OH. This symposium comprised research presentations by four neuroscientists whose work focuses on the biological bases for complex interactions among stress, food intake and emotion. First, Dr Ulrich-Lai describes her rodent research exploring mechanisms by which the rewarding properties of sweet palatable foods confer stress relief. Second, Dr Stephanie Fulton discusses her work in which excessive, long-term intake of dietary lipids, as well as their subsequent withdrawal, promotes stress-related outcomes in mice. Third, Dr Mark Wilson describes his group's research examining the effects of social hierarchy-related stress on food intake and diet choice in group-housed female rhesus macaques, and compared the data from monkeys to results obtained in analogous work using rodents. Finally, Dr Gorica Petrovich discusses her research program that is aimed at defining cortical-amygdalar-hypothalamic circuitry responsible for curbing food intake during emotional threat (i.e. fear anticipation) in rats. Their collective results reveal the complexity of physiological and behavioral interactions that link stress, food intake and emotional state, and suggest new avenues of research to probe the impact of genetic, metabolic, social, experiential and environmental factors on these interactions.

Is comfort food really good for the soul? A replication of Troisi and Gabriel's (2011) Study 2.

We report the results of three high-powered replications of Troisi and Gabriel's (2011) idea that writing about comfort food reduces feelings of loneliness amongst securely attached individuals after a belongingness threat. We conducted our studies amongst a large group of participants (Total N = 649) amongst American (MTurk), Dutch (Tilburg University; TiU), and Singaporean (Singapore Management University; SMU) samples. Participants first completed an attachment style scale, followed by writing two essays for manipulating a sense of belongingness and salience of comfort food, and then reporting their loneliness levels. We did not confirm the overall effect over all three countries. However, exploratory results provide the preliminary suggestion that (1) the comfort food explanation likely holds amongst the American samples (including Troisi and Gabriel's), but not amongst the TiU and SMU samples, and potentially that (2) the TiU and SMU participants self-regulate through warmer (vs. colder) temperature foods. Both of these should be regarded with great caution as these analyses were exploratory, and because the Ns for the different temperature foods were small. We suspect we have uncovered first cross-cultural differences in self-regulation through food, but further confirmatory work is required to understand the cultural significance of comfort food for self-regulation.

Threatened belonging and preference for comfort food among the securely attached.

Research has shown that comfort food triggers relationship-related cognitions and can fulfill belongingness needs for those secure in attachment (i.e., for those with positive relationship cognitions) (Troisi & Gabriel, 2011). Building on these ideas, we examined if securely attached individuals prefer comfort food because of its "social utility" (i.e., its capacity to fulfill belongingness needs) in one experiment and one daily diary study using two samples of university students from the United States. Study 1 (n = 77) utilized a belongingness threat essay among half of the participants, and the results showed that securely attached participants preferred the taste of a comfort food (i.e., potato chips) more after the belongingness threat. Study 2 (n = 86) utilized a 14-day daily diary design and found that securely attached individuals consumed more comfort food in response to naturally occurring feelings of isolation. Implications for the social nature of food preferences are discussed.

Relation between salivary cortisol as stress biomarker and dietary pattern in children.

PURPOSE: Psychological stress has been suggested to result in hormonal effects (e.g. changes in cortisol pattern) that may change food selection in unhealthy ways. This study examines whether children's dietary pattern is indeed related to salivary cortisol levels. METHODS: In 323 children (5-10 years old) participating in the Belgian ChiBS study, salivary cortisol samples, a biomarker for stress, was sampled when waking up, 30 and 60 min after wake up and in the evening on two consecutive weekdays. Data on the children's dietary pattern (frequency of sweet foods, fatty foods, snacks, fruit and vegetables) was collected with a food frequency questionnaire. Multilevel time modelling was used with adjustments for sex, age, body mass index, parental education and wake up time. RESULTS: Higher overall cortisol levels and a large cortisol awakening response (CAR) were associated with more frequent consumption of sweet foods. A steeper diurnal cortisol decline was associated with a higher sweet, fatty and snack food consumption frequency. No associations with fruit and vegetables consumption were found. CONCLUSIONS: High cortisol levels were linked to an unhealthier dietary pattern (more fatty food, snacks and especially sweet food). This supports the theory of cortisol-induced comfort food preference and strengthens the stress-diet relation.