Parent-offspring similarity in hunger and thirst sensations.

The internal (i.e., interoceptive) sensations that characterise hunger vary between people, and this may also be the case for thirst, although it has not been so well explored. There are probably both heritable and learning-based causes for this interoceptive variability. Consequently, it would seem plausible that parents and their offspring would have more similar patterns of hunger and thirst than pairs of strangers. We tested this idea, in addition to exploring its potential moderating variables, by studying the similarity of self-reported hunger and thirst sensations in 170 students and their primary caregivers from childhood. Both students and caregivers completed the same online-survey, covering hunger and thirst sensations, beliefs about the causes of hunger and thirst, the Three Factor Eating Questionnaire (revised) and demographic data. We find evidence of robust student-caregiver similarity in interoceptive hunger and thirst sensations (medium effect sizes), with these being moderated by caregiver beliefs about the homeostatic nature of each state (medium effect sizes). This suggests a potential role for caregivers in the development of their offspring's interoceptive cues for hunger and for thirst. In addition, thirst, like hunger, appears to be multidimensional, and varies between people. The implications of these findings are discussed.

Human hunger as a memory process.

Hunger refers to (1) the meaning of certain bodily sensations; (2) a mental state of anticipation that food will be good to eat; and (3) an organizing principal, which prioritizes feeding. Definitions (1) and (2) are the focus here, as (3) can be considered their consequent. Definition (1) has been linked to energy-depletion models of hunger, but these are no longer thought viable. Definition (2) has been linked to learning and memory (L&M) models of hunger, but these apply just to palatable foods. Nonetheless, L&M probably forms the basis for hunger generally, as damage to declarative memory can eradicate the experience of hunger. Currently, there is no general L&M model of hunger, little understanding of how physiology intersects with a L&M approach, and no understanding of how Definitions (1) and (2) are related. We present a new L&M model of human hunger. People learn associations between internal (e.g., tummy rumbles) and external cues (e.g., brand names) and food. These associations can be to specific foods (episodic memories) or food-related categories (semantic memories). When a cue is encountered, it may lead to food-related memory retrieval. If retrieval occurs, the memory's affective content allows one to know if food will be good to eat now-hunger-a cognitive operation learned in childhood. These memory processes are acutely inhibited during satiety, and chronically by multiple biological parameters, allowing physiology to modulate hunger. Implications are considered for the process of making hunger judgments, thirst, the cephalic phase response, and motivational and lay theories of hunger. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Predictors of state-based changes in wanting and liking.

People report wanting food when they are hungry, and on eating it they typically report liking the experience. After eating, both wanting and liking decline, but wanting declines to a greater extent, which we term the 'affective discrepancy effect'. In this study we examine the predictors - state, sensory and memory-based - of these affective changes. Hungry participants undertook three tasks: (1) written recollections of what certain foods are like to eat; (2) ratings of wanting and expected flavour liking and fillingness when looking at snacks, and ratings of food and flavour liking when eating them; (3) ratings of bodily state. These tasks were then repeated after lunch. State-based changes in food liking were best predicted by changes in flavour liking. For state-based change in wanting, memory-based information about flavour liking and fillingness from tasks (1) and (2) were all significant predictors. For recollections about eating (task 1), mentions of food fillingness significantly increased pre-to post-lunch and this was the best predictor of the affective discrepancy effect. Recollections of food fillingness are state-dependent, and can arise unbidden (i.e., such recollective content was unprompted). This may reflect one way that memory may selectively influence wanting, and hence whether food intake is initiated or not.

The psychological basis of reductions in food desire during satiety.

Satiety-the reduced desire to eat, drink or have sex in their respective aftermath-is particularly important for feeding, where it assists energy balance. During satiety, the anticipated pleasure of eating is far less than the actual pleasure of eating. Here we examine two accounts of this effect: (i) satiety signals inhibit retrieval of pleasant food memories that form desirable images, allowing unpleasant memories into mind; (ii) feelings of fullness reflect what eating would be like now, negating the need for imagery. To test these accounts, participants undertook two tasks pre- and post-lunch: (i) judging desire for palatable foods either with or without imagery impairing manipulations; (ii) explicitly recollecting food memories. Impairing imagery reduced desire equally, when hungry and sated. Food-memory recollections became more negative/less positive when sated, with this correlating with changes in desire. These findings support the first account and suggest imagery is used when hungry and when sated to simulate eating, and that the content of these memory-based simulations changes with state. The nature of this process and its implications for satiety more generally are discussed.

Interoceptive hunger, eating attitudes and beliefs.

Interoceptive individual differences have garnered interest because of their relationship with mental health. One type of individual difference that has received little attention is variability in the sensation/s that are understood to mean a particular interoceptive state, something that may be especially relevant for hunger. We examined if interoceptive hunger is multidimensional and idiosyncratic, if it is reliable, and if it is linked to dysfunctional eating and beliefs about the causes of hunger. Participants completed a survey just before a main meal, with most retested around 1 month later. We found that interoceptive hunger has 11 dimensions, and while people differ considerably in their combinations of interoceptive hungers, these represent only 4% of all possible permutations. Hunger reports were reliable. We found relationships between variability in hunger interoception and dysfunctional eating, especially for uncontrolled eating. We also found that hunger beliefs were in some cases strongly related to aspects of hunger interoception. The implications of these findings are discussed.

The development of interoceptive hunger signals.

Hunger is often reported when people experience certain internal sensations (e.g., fatigue) or when they anticipate that a food will be good to eat. The latter results from associative learning, while the former was thought to signal an energy deficit. However, energy-deficit models of hunger are not well supported, so if interoceptive hungers are not "fuel gauges," what are they? We examined an alternate perspective, where internal states signaling hunger, which are quite diverse, are learned during childhood. A basic prediction from this idea is offspring-caregiver similarity, which should be evident if caregivers teach their child the meaning of internal hunger cues. We tested 111 university student offspring-primary caregiver pairs, by having them complete a survey about their internal hunger states, alongside other information that may moderate this relationship (i.e., gender, body mass index, eating attitudes, and beliefs about hunger). We observed substantial similarity between offspring-caregiver pairs (Cohen's ds from 0.33 to 1.55), with the main moderator being beliefs about an energy-needs model of hunger, which tended to increase similarity. We discuss whether these findings may also reflect heritable influences, the form that any learning might take, and the implications for child feeding practices.

Kynurenic acid as a biochemical factor underlying the association between Western-style diet and depression: A cross-sectional study.

Consumption of a Western-style diet (WS-diet), high in saturated fat and added sugar, is associated with increased depression risk. However, the physiological mechanisms underlying the relationship requires elucidation. Diet can alter tryptophan metabolism along the kynurenine pathway (KP), potentially linking inflammation and depression. This study aimed to examine whether urinary inflammatory markers and KP metabolites differed according to WS-diet consumption and depression severity. Depression symptoms and habitual WS-diet consumption were assessed in 169 healthy adults aged 17-35 recruited from two experimental studies. Targeted metabolomics profiling of seven KP metabolites, ELISA-based assays of interleukin-6 (IL-6) and C-reactive protein (CRP) were performed using urine samples collected from the participants. Parametric tests were performed for group comparison and associations analysis. Multilevel mixed-effect modelling was applied to control for biases. Higher intake of WS-diet was associated with lower levels of neuroprotective kynurenic acid (KA; R = -0.17, p = 0.0236). There were no differences in IL-6 or CRP across diet groups (p > 0.05). Physical activity had negative associations with most KP metabolites. Mixed-effects regression analysis showed the glutamatergic inhibitor, KA, was the only biomarker to have a significant association with depression symptoms in a model adjusted for demographic and lifestyle variables: a unit increase in KA was associated with 0.21 unit decrease in Depression Anxiety and Stress Scale-21 depression score (p = 0.009). These findings suggest that urinary KA is associated with both habitual WS-diet intake, and levels of depression symptoms, independent of inflammation. Findings support the role of neuroprotection and glutamatergic modulation in depression. We propose that KA may act as endogenous glutamatergic inhibition in regulating depression severity in the absence of inflammation. Further comparison with blood-based markers will assist in validating the utility of non-invasive urine samples for measuring KP metabolites.

Recollections about food when hungry and sated.

Memory processes may have several roles in appetite regulation. Here we examine one such role, derived from the animal literature, in which satiety cues lead to the inhibition of rewarding food-related memories. We tested this idea over three studies (n's of 58, 67, 50 respectively), by presenting participants with visual or verbal food cues, and asking them to describe what these foods were like to eat. This recollection task was undertaken hungry and sated. The resulting recollections were then coded and contrasted across state. Irrespective of state, participants took the same time to make their recollections, they were of similar length and included the same amount of sensory detail and affective content. However, in all three studies, sated recollections tended to include more reports about how filling a food would be. This increase in reports of food fillingness across state, was significantly correlated with increases in reports of stomach distension across state. While these results are consistent with the operation of memory inhibition, a further possibility is considered, whereby interoceptive satiety cues are integrated into food-related recollections (but not other recollections) to form a memory-inteorception-combination, thereby drawing attention to the consequences of eating when sated.

Social cognition in female adults with Anorexia Nervosa: A systematic review.

Deficits in interpersonal and social functioning are well established in females with Anorexia Nervosa (AN), and are thought to be key features involved in the onset and maintenance of the disease. Growing literature suggests these may be attributed to poor social cognitive processes. This systematic review evaluates whether differences in social cognition exist in adult females with AN. A total of 32 studies that compared females with AN against a healthy control group using social cognitive measures and/or questionnaires were analysed. The majority of studies were deemed to have a low or moderate risk of bias. Overall, empathy appears to be intact in AN, however greater emotion regulation difficulties, elevated alexithymia and reduced emotional awareness are evident in AN. Findings relating to emotion recognition and emotional Theory of Mind were inconsistent. The nature of the task appeared to influence the domains of cognitive ToM and social perception, warranting further research. These findings are discussed within the broader context of social cognitive models and AN rehabilitation.

Exploring the roles of tryptophan metabolism in MS beyond neuroinflammation and neurodegeneration: A paradigm shift to neuropsychiatric symptoms.

The metabolism of tryptophan through the kynurenine pathway (KP) has been increasingly recognised in contributing to disease progression in the autoimmune and inflammatory disease multiple sclerosis (MS). In this review, the roles of inflammation and the KP are recontextualised to better understand the aetiology of the neuropsychiatric symptoms (depression, postpartum depression, suicidality, fatigue and cognitive dysfunction) in MS. These symptoms will be discussed in the context of cytokine-induced sickness behaviours, KP activation and levels of neurotoxicity and neuroprotection in MS. In particular, there will be emphasis on how neuropsychiatric symptoms in MS occur against the shared background of inflammation and KP dysregulation. The discourse of this review aims to promote future research in elucidating KP mechanisms in MS that would inevitably lead to more targeted treatment options for neuropsychiatric symptoms and disease progression.

Innate immunity impacts social-cognitive functioning in people with multiple sclerosis and healthy individuals: Implications for IL-1ra and urinary immune markers.

Social-cognitive difficulties can negatively impact interpersonal communication, shared social experience, and meaningful relationships. This pilot investigation examined the relationship between social-cognitive functioning and inflammatory markers in people with multiple sclerosis (MS) and demographically-matched healthy individuals. Additionally, we compared the immune marker profile in serum and urine-matched samples. Social cognitive functioning was objectively assessed using The Awareness of Social Inference Test - Short (TASIT-S) and subjectively assessed using self-reports of abilities in emotion recognition, emotional empathy, and cognitive theory of mind. In people with MS and healthy individuals, there were moderate-to-large negative relationships between pro-inflammatory biomarkers (serum IL-1ß, IL-17, TNF-α, IP-10, MIP-1α, and urine IP-10, MIP-1ß) of the innate immune system and social-cognitive functioning. In MS, a higher serum concentration of the anti-inflammatory marker IL-1ra was associated with better social-cognitive functioning (i.e., self-reported emotional empathy and TASIT-S sarcasm detection performance). However, there were mixed findings for anti-inflammatory serum markers IL-4 and IL-10. Overall, our findings indicate a relationship between pro-inflammatory cytokines and social-cognitive abilities. Future studies may provide greater insight into biologically-derived inflammatory processes, sickness behaviour, and their connection with social cognition.

The impact of saturated fat, added sugar and their combination on human hippocampal integrity and function: A systematic review and meta-analysis.

Paralleling animal research, there is emerging evidence that a Western-style (WS) diet - high in saturated fat and added sugar - impairs human hippocampal functioning. However, the conditions under which this occurs are not fully understood and there have been published failures to detect such effects. To date, there has been no systematic review or meta-analysis of relevant human studies. We undertook a systematic database search and review. Twenty studies were identified, two experimental, with the remainder correlational. The latter were included in a meta-analyses on the impact of WS-diet and its macronutrient components on human hippocampal function. Effects of age and sex were also examined. A WS-diet adversely impacted human hippocampal volume and functioning, with a small-pooled effect size. No effects were found for individual macronutrients. There was a high-level of study heterogeneity, which was not fully explained by study/sample characteristics. This may arise via the wide range of assessment tools used to measure both dietary intake and hippocampal functioning. Overall, a WS-diet clearly impacts human hippocampal functioning as in animals.

The congruence of interoceptive predictions and hippocampal-related memory.

Interoceptive deficits are associated with medial temporal lobe (MTL) lesions, and especially the hippocampus, which may relate to interoception's reliance upon predictive coding and hence on mnemonic processes. Here, we develop a new task to assess interoceptive predictions and assess their dependence upon MTL memory systems. Healthy participants were asked to imagine and predict what they would feel like across nine interoceptive situations. Later, each situation was physically experienced, and participants reported what they actually felt. An index of predictive congruence was derived and correlated with a neuropsychological measure of hippocampal dependent learning and memory (HDLM), finding that more accurate predictions were associated with better HDLM (Cohen's d = 0.5). We suggest the MTL, and in particular the hippocampus, generates contextually appropriate episodic memories, providing a predictive framework for interpreting afferent bodily neurohormonal signals. The loss of this capacity may account for the profound interoceptive deficits observed following MTL lesions.

Hippocampal-dependent appetitive control is impaired by experimental exposure to a Western-style diet.

Animals fed a Western-style diet (WS-diet) demonstrate rapid impairments in hippocampal function and poorer appetitive control. We examined if this also occurs in humans. One-hundred and ten healthy lean adults were randomized to either a one-week WS-diet intervention or a habitual-diet control group. Measures of hippocampal-dependent learning and memory (HDLM) and of appetitive control were obtained pre- and post-intervention. HDLM was retested at three-week follow-up. Relative to controls, HDLM performance declined in the WS-diet group (d = 0.43), but was not different at follow-up. Appetitive control also declined in the WS-diet group (d = 0.47) and this was strongly correlated with HDLM decline (d = 1.01). These findings demonstrate that a WS-diet can rapidly impair appetitive control in humans-an effect that could promote overeating in consumers of a WS-diet. The study also suggests a functional role for the hippocampus in appetitive control and provides new evidence for the adverse neurocognitive effects of a WS-diet.

A brief diet intervention can reduce symptoms of depression in young adults - A randomised controlled trial.

There is strong epidemiological evidence that poor diet is associated with depression. The reverse has also been shown, namely that eating a healthy diet rich in fruit, vegetables, fish and lean meat, is associated with reduced risk of depression. To date, only one randomised controlled trial (RCT) has been conducted with elevated depression symptoms being an inclusion criterion, with results showing that a diet intervention can reduce clinical levels of depression. No such RCTs have been performed in young adults. Young adults with elevated levels of depression symptoms and who habitually consume a poor diet were randomly allocated to a brief 3-week diet intervention (Diet Group) or a habitual diet control group (Control Group). The primary and secondary outcome measures assessed at baseline and after the intervention included symptoms of depression (Centre for Epidemiological Studies Depression Scale; CESD-R; and Depression Anxiety and Stress Scale- 21 depression subscale; DASS-21-D), current mood (Profile of Mood States), self-efficacy (New General Self-Efficacy Scale) and memory (Hopkins Verbal Learning Test). Diet compliance was measured via self-report questionnaires and spectrophotometry. One-hundred-and-one individuals were enrolled in the study and randomly assigned to the Diet Group or the Control Group. Upon completion of the study, there was complete data for 38 individuals in each group. There was good compliance with the diet intervention recommendations assessed using self-report and spectrophotometry. The Diet group had significantly lower self-reported depression symptoms than the Control Group on the CESD-R (p = 0.007, Cohen's d = 0.65) and DASS-21 depression subscale (p = 0.002, Cohen's d = 0.75) controlling for baseline scores on these scales. Reduced DASS-21 depression subscale scores were maintained on follow up phone call 3 months later (p = .009). These results are the first to show that young adults with elevated depression symptoms can engage in and adhere to a diet intervention, and that this can reduce symptoms of depression. The findings provide justification for future research into the duration of these benefits, the impacts of varying diet composition, and their biological basis.

Wanting and liking for sugar sweetened beverages and snacks differ following depletion and repletion with energy and fluids.

Drinking sugar-sweetened beverages (SSBs) seems to uniquely contribute to excess weight gain, and several mechanisms have been proposed to account for this. Here we examine a further proposal, namely that explicit wanting and liking for SSBs may be less sensitive to changes in physiological state, when contrasted to equi-palatable solid sweet snacks. Study 1 explored this by having participants rate wanting for (on seeing) and liking of (on tasting) several SSBs and snacks, before and after receiving a solid lunch with ad libitum water. Participant reports of hunger and thirst, obtained at multiple time-points, equally reduced across lunch. Wanting for the snacks decreased significantly more across lunch than liking, but for the SSBs, wanting and liking decreased in parallel. Study 2 engineered a far more dramatic alteration in thirst, by using fluid deprivation, a liquid lunch, and encouraging drinking to satiation. This time, reduction in thirst exceeded reduction in hunger. However, all this served to achieve was an equivalent change across lunch for snacks and SSBs, with wanting reducing more than liking now for both. These findings suggest that changes in wanting, relative to liking, for SSBs, are less sensitive to alterations in physiological state than equi-palatable solid snacks, enhancing the chance of consumption.

They Shall Be One: Sexual Satisfaction Among Men and Women Married in the LDS Faith.

Sexual satisfaction is understudied among highly religious communities, such as the Church of Jesus Christ of Latter-day Saints (LDS). Through an Internet-based self-report survey, this study (N = 266) examined potential predictors of sexual satisfaction among adults living in Utah who had married in the LDS faith, regardless of current faith practice. Both men and women reported their perceived partner satisfaction as the top contributing factor to their own overall sexual satisfaction. These findings have implications for clinicians, educators, and researchers evaluating the sexual lives, including sexual satisfaction, of men and women who have married in the LDS faith.

Hippocampal dependent neuropsychological tests and their relationship to measures of cardiac and self-report interoception.

The hippocampus is involved in interoceptive processing (i.e., perceiving internal bodily states), with much of this evidence relating to hunger and fullness. Here we examine whether cardiac and self-report measures of interoception are related to two measures of hippocampal dependent learning and memory (HDLM) - the Rey Auditory Verbal Learning Test (RAVLT) and Logical Memory. Healthy adults completed a neuropsychological test battery including all of these measures, along with assessments of intelligence and executive function. Biographical, medical and psychological-related data that might confound detecting an HDLM-interoception relationship was also collected. Both measures of HDLM were associated with cardiac interoception after controlling for confounding variables. More accurate cardiac interoception was linked to better HDLM performance. On the self-report measure of interoception, better performance on the RAVLT was associated with better-reported attention regulation, consistent with the hippocampus's known role in mindfulness. Overall, these findings suggest hippocampal involvement in cardiac and self-report interoceptive capacity. The broader functional role of the hippocampus in interoception is discussed.

Potential for diet to prevent and remediate cognitive deficits in neurological disorders.

The pathophysiology of many neurological disorders involves oxidative stress, neuroinflammation, and mitochondrial dysfunction. There is now substantial evidence that diet can decrease these forms of pathophysiology, and an emerging body of literature relatedly suggests that diet can also prevent or even remediate the cognitive deficits observed in neurological disorders that exhibit such pathology (eg, Alzheimer's disease, multiple sclerosis, age-related cognitive decline, epilepsy). The current review summarizes the emerging evidence in relation to whole diets prominent in the scientific literature-ketogenic, caloric restriction, high polyphenol, and Mediterranean diets-and provides a discussion of the possible underlying neurophysiological mechanisms.

Explicit wanting and liking for palatable snacks are differentially affected by change in physiological state, and differentially related to salivation and hunger.

Incentive salience theory (IST) suggests that 'wanting' and liking are dissociable processes. We argue that explicit measures of wanting in humans can reflect the impact of implicit 'wanting' as envisaged by IST, suggesting that dissociations should also be evident for explicit judgments of wanting and liking. To test this, participants were asked to make ratings of these variables for 8 palatable snack foods - and in a related test salivation rate was also assessed. Participants viewed and sniffed each snack food and rated wanting, and then sampled it and rated liking and whether they wanted more of it. Following a lunch eaten to satiety, and composed in part of half of the palatable snack foods, participants repeated their evaluations of the snack foods (and salivation rate). Liking changed less across lunch than wanting and want more ratings, the last-mentioned changing the most. Change in liking was associated with change in salivation rate, independent of wanting, and change in wanting was associated with change in hunger independent of liking. We argue these dissociations are consistent with 'wanting' influencing explicit wanting, and that want more ratings may represent a 'purer' measure of IST 'wanting'.