Impulse control and restrained eating among young women: Evidence for compensatory cortical activation during a chocolate-specific delayed discounting task

Experience of diet in patients with inflammatory bowel disease: A thematic synthesis of qualitative studies

AIM

To synthesise the dietary expesriences of patients with inflammatory bowel disease by reviewing relevant qualitative studies.

BACKGROUND

Diet plays a crucial role in the development and progression of inflammatory bowel disease (IBD). There is no specific diet that can be recommended for all patients. We conducted a synthesis of qualitative studies to gain a comprehensive understanding of the dietary management experience of patients with IBD, aiming to provide better dietary guidance in the future.

DESIGN

A qualitative synthesis was conducted following the Thomas and Harden method and reported following the ENTREQ statement.

METHODS

Qualitative studies were systematically searched in five electronic databases: PubMed, PsycINFO, Embase, CINAHL, and Web of Science. There was no time limit for publication, and all database searches were up to 10 May, 2023. The Joanna Briggs Institute Qualitative Assessment and Review Instrument was utilised to appraise the quality of the included studies. Data for inclusion in articles were extracted and analysed using a thematic synthesis method.

RESULTS

Six studies involving 119 patients were eventually included. The studies were conducted in six different countries. Four major themes were identified: the diet of patients with IBD is completely different from the normal one; manage symptoms and live with the disease by modifying diet; psychological adjustment to eating (be frustrated; worried and afraid; feel ashamed; growth and resilience); barriers and challenges (barriers from perceived social support; conflicts between diet and nutrition; challenges from food hedonism and cravings).

CONCLUSIONS

Patients with IBD highlighted the distinction between their diet and the normal diet. Dietary modifications were used as a way to manage symptoms and live with the disease. In addition to physical symptoms, patients experienced diet-related psychological changes. Dietary modifications in patients with IBD encounters difficulties and challenges, necessitating prompt guidance and intervention. (1) The implementation of dietary modifications in patients with IBD encounters numerous obstacles and complexities, necessitating prompt guidance and intervention.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

REGISTRATION

The protocol was registered with PROSPERO (CRD42023391545).

Young Adults with Negative Body Image at Fatness Subscale Are More Restrained Than Normal Adults during a Chocolate Discounting Task

Research has confirmed that people with obesity exhibit special responses to food stimuli when it comes to food-related decision tasks. However, it is unclear whether the phenomenon exists in people who feel mentally obese, even though they are not obese. The aim of this study was to investigate the behavioral and neural correlations of food-related decision-making between young adults with negative body image at fatness subscale and a control group, so as to explore the differences in executive functioning between them. We used a time-delayed discounting task (DDT) and recruited 13 young female adults in each group to participate in the electroencephalogram (EEG) experiment. The number of selections for low immediate rewards and high delayed rewards was used as a performance indicator for DDT. Behavioral results showed a significant interaction effect between selection types and groups, where more delayed rewards and shorter immediate rewards were selected in the group with negative body image at fatness subscale than in the control group. Statistical correlations between body mass index (BMI) and selection times were found in the control group, but this phenomenon did not occur in the experimental group. The event-related potentials found that the P100 of young adults with a negative body image at fatness subscale was greater than those in the control group. P200 showed a significant interaction effect between groups, electrodes, and selection types. N200 and N450 in delayed rewards were more negative than in immediate rewards for both groups. These findings suggest that young adults with negative body image at fatness subscale are more restrained than young adults in the control group when choosing chocolates. Moreover, individuals with negative body image at fatness subscale might be more sensitive to food stimuli than individuals in the control group, because their P100 amplitude was significantly larger than that of individuals in the control group when exposed to food-related stimuli.

Reduction of drive for thinness and body dissatisfaction in people with self-reported dysregulated eating behaviors after intermittent theta burst stimulation (iTBS) of the left dorsolateral prefrontal cortex

Aim

This study aimed to explore the effect of intermittent theta burst stimulation (iTBS) of the right and left dorsolateral prefrontal cortex (DLPFC) in people with self-reported dysregulated eating behaviors but without a diagnosis of eating disorders (EDs).

Methods

Participants were randomly divided into two equivalent groups according to the side (right or left) of the hemisphere to be stimulated and they were tested before and after a single iTBS session. Outcome measurements were scores on self-report questionnaires assessing psychological dimensions related to eating behaviors (EDI-3), anxiety (STAI-Y), and tonic electrodermal activity.

Results

The iTBS interfered with both psychological and neurophysiological measures. Significant variations of physiological arousal after iTBS of both the right and left DLPFC were witnessed by increased mean amplitude of non-specific skin conductance responses. With regard to the psychological measures, the iTBS on the left DLPFC significantly reduced the scores of the EDI-3 subscales drive for thinness and body dissatisfaction. Interestingly, these two scales are two of the three EDI-3 clinic scales (drive for thinness, body dissatisfaction, and bulimia) used as specific markers to assess the onset and/or maintenance of eating disorders.

Conclusion

Our results show that the left DLPFC iTBS has an impact on the psychological dimensions that are risk factors for the onset of eating disorders, suggesting that an altered hemispheric asymmetry similar to that encountered in clinical populations is present in normal subjects even in the absence of clinical symptoms.

The Neural Processes in Food Decision-making and their Effect on Daily Diet Management in Successful and Unsuccessful Restrained Eaters

This study aimed to explore the neural mechanisms underlying food decision making in unsuccessful restrained eaters (US-REs) and successful restrained eaters (S-REs). During a functional magnetic resonance imaging scan, participants were required to choose between pairs of high- and low-calorie foods under the following conditions: the congruent condition (choose between high- and low-calorie foods with the same level of tastiness) and incongruent condition (choose between high-calorie foods tastier than the corresponding low-calorie foods). Subsequently, the participants' diets were monitored for one week. The behavioral results showed that US-REs (n = 28) chose more high-calorie foods than S-REs (n = 26); in contrast, S-REs spent more time in choosing for the incongruent than the congruent condition. The fMRI results found that US-REs exhibited more activity in reward regions (caudate and thalamus) than S-REs in the congruent condition. In the incongruent condition, S-REs showed stronger functional connectivity between the conflict-monitoring region (anterior cingulate cortex) and inhibitory-control regions (inferior frontal gyrus [IFG] and medial frontal gyrus) than US-REs. In both the conditions, increased activation of the insula, putamen, middle frontal gyrus, and IFG could predict increased food intake among US-REs in the following week. Furthermore, in both the conditions, increased IFG activation could predict decreased food cravings among S-REs during the following week. Our results suggest that US-REs have a strong reward response to food. Compared to US-REs, S-REs are more guided more by the goal of weight control, and exhibit strong functional connections between the conflict-monitoring and inhibitory-control regions. Therefore, eating enjoyment and weight-control goals influence restrained eating in daily life.

A meta-analysis of the relationship between eating restraint, impaired cognitive control and cognitive bias to food in non-clinical samples

AIM

Food restriction is argued to be a precursor for unhealthy preoccupation with food, possibly leading to the development of an eating disorder. We updated previous meta-analyses that examined the relationship between eating restraint and deficits in either general or food-related attentional and inhibitory control. We hypothesized that inconsistencies in the literature around eating restraint, impaired cognitive control, impulsivity and cognitive biases for food could be attributed to the scale used to measure eating restraint.

METHOD

A (preregistered) subgroup meta-analysis examined whether patterns of impaired cognitive control and cognitive bias for food in predominantly healthy (non-clinical) samples differed as a function of the scale used to measure eating restraint. A series of exploratory meta-analyses were carried out for specific attentional bias tasks. In total 57 datasets were included.

RESULTS

The subgroup analysis did not provide evidence that the relationship between eating restraint and impaired or biased cognitions differed significantly as a function of restraint scale. Heterogeneity across studies was high. When examining specific attentional bias tasks there was no evidence that increased eating restraint was associated with increased attentional bias or distraction by food cues, regardless of which scale was used to measure eating restraint.

CONCLUSIONS

There is little experimental evidence for the common narrative that increased eating restraint is related to impaired cognitive control generally or increased cognitive bias for food, in non-clinical samples.

Application of Magnetic Resonance Imaging in the Evaluation of Nutritional Status: A Literature Review with Focus on Dialysis Patients

Magnetic resonance imaging (MRI) is indispensable in clinical medicine for the morphological and tomographic evaluation of many parenchymal organs. With varied imaging methods, diverse biological information, such as the perfusion volume and measurements of metabolic products, can be obtained. In addition to conventional MRI for morphological assessment, diffusion-weighted MRI/diffusion tensor imaging is used to evaluate white matter structures in the brain; arterial spin labeling is used for cerebral blood flow evaluation; magnetic resonance elastography for fatty liver and cirrhosis evaluation; magnetic resonance spectroscopy for evaluation of metabolites in specific regions of the brain; and blood oxygenation level-dependent imaging for neurological exploration of eating behavior, obesity, and food perception. This range of applications will continue to expand in the future. Nutritional science is a multidisciplinary and all-inclusive field of research; therefore, there are many different applications of MRI. We present a literature review of MRI techniques that can be used to evaluate the nutritional status, particularly in patients on dialysis. We used MEDLINE as the information source, conducted a keyword search in PubMed, and found that, as a nutritional evaluation method, MRI has been used frequently to comprehensively and quantitatively evaluate muscle mass for the determination of body composition.

Role of Food Neophobia and Allergen Content in Food Choices for a Polish Cohort of Young Women

Young women are vulnerable to a number of factors which influence their food choices, including beliefs about food products, or information about nutritional value, while information, that product is free from specific component generates consumer perceptions of its healthfulness. Among the factors which may influence such perception, there is food neophobia (FN). The aim of this study was to determine the influence of FN and information about allergens on the food product choices in the Polish cohort of young women, in the choice experiment when given a model restaurant menu. The web-based choice experiment, in a group of 600 women, aged 18-30 years, with no food allergies diagnosed, was conducted using a mock Italian-style restaurant menu. For 2 starters, 2 soups, 3 main courses and 3 desserts that were included, the allergen content, neophobic potential and perceived lack of healthiness, for a Polish population, were defined. Each respondent randomly received the version containing only a description of dishes, or a description accompanied by the allergens listed. The FN was assessed using the Food Neophobia Scale (FNS). The type of menu (with or without allergens listed) did not influence the choices of dishes. The highest FN level was observed for the women being inhabitants of villages (median of 32). The respondents characterized by a high level of FN less commonly chose dishes characterized by neophobic potential as a starter (Carpaccio), main course (Risotto ai frutti di mare) and dessert (Zabaglione). At the same time, the highest FN level was observed for respondents who chose dishes with no neophobic potential (median of 34.5). However, for allergen content and perceived lack of healthiness, no association with FN was observed, so it may be stated that for neophobic respondents, only neophobic potential is a factor limiting the choice of dishes. It may be concluded that food neophobia in young women may limit the consumption of dishes with unknown food products, and the influence is observed independently of other features of a dish, such as allergen content or perceived healthiness. The problem may appear especially for inhabitants of villages, who are characterized by the highest level of FN.

Overweight adults are more impulsive than normal weight adults: Evidence from ERPs during a chocolate-related delayed discounting task

Overweight or obesity can be accompanied by abnormalities in executive function and related neural markers. The aim of the present study was to investigate the behavioral and neural correlates of food-related decision-making in overweight and normal-weight adults. We used a delayed discounting task (DDT), which requires participants to choose between smaller immediate rewards and larger delayed rewards. In total, 24 overweight adults and 24 normal-weight adults participated; all participants engaged with a food-related DDT, and their responses were measured using event-related potentials (ERPs). In the current study, we take the area under the curve (AUC), number of smaller immediate rewards, and reaction times (RTs) as behavioral indicators of DDT. AUC is an individual's discounting rate, with smaller AUC reflecting more impulsive decision-making. Number of smaller immediate rewards also reflects impulsivity. For ERPs, N2, reward-related positivity, P3, and late positive component (LPC) were investigated. Behavioral results showed smaller AUC, more choice of smaller immediate rewards, and longer RTs in overweight adults than in normal-weight adults. Neural markers showed that overweight adults elicited greater N2 in larger delayed rewards than in smaller immediate rewards and also elicited greater reward-related positivity than normal-weight adults. Moreover, the P3 and LPC mean amplitudes of overweight adults were greater than those of normal-weight adults. Pearson correlation analysis showed that body mass index (BMI) was positively related to P3 and LPC, while AUC was negatively related to P3. The findings thus suggest that overweight adults are more impulsive than normal-weight adults. Moreover, overweight adults might experience more cognitive conflict before their reaction, and they might allocate more cognitive resources to food-related stimuli and might have higher-order cognitive processes more involved in motivation or emotion regarding food-related stimuli. This is the first study investigating ERP correlates of food-related decision-making in overweight adults, and it enriches the theoretical models by providing neural markers for future study.

Impulsiveness in Reactive Dieters: Evidence From Delay Discounting in Orthodontic Patients

Introduction: Researchers have made efforts to distinguish the behavioral differences and underlying mechanisms that explain the various possible outcomes of dieting (success, failure and relapse). Although extensive research has demonstrated that eating behavior and individual impulsiveness are closely related to subjective appetite and decision making, very few studies have investigated how subjective and appetite impulsiveness is affected by reactive dieting. Methods: In the present study, we utilized the power of food scale (PFS) and the intertemporal choice task and to examine subjective appetite and impulsivity of decision making in orthodontic patients. As a result of their orthodontic devices and the subsequent pain and discomfort caused by eating, these patients become reactive dieters. In order to explore the dynamic influence of orthodontic treatment on appetite and impulsiveness, we collected data for both patients and control participants across three testing sections. We also computed a regression model for further exploration in explaining how potential factors contributed to different choices. Results: We found that the orthodontic group scored significantly lower in PFS than the control group, which indicated a suppression in appetite. Besides, reward and waiting time were significant factors in computational perspective. Moreover, although patients showed a bias in choosing smaller, immediate reward options, they exhibited a decrease in the delay discounting rate as treatment progressed. These findings confirm that subjective appetite and impulsiveness were inhibited due to reactive dieting.

Got chocolate? Bilateral prefrontal cortex stimulation augments chocolate consumption

BACKGROUND

Understanding the mechanisms behind exerting self-control may reveal why health behaviors are resistant to change. Activity in the right inferior frontal gyrus (rIFG) plays a role in self-control processes and may be modulated using transcranial direct current stimulation (tDCS).

OBJECTIVE

In this early phase behavioral research study, we investigated whether anodal stimulation over the rIFG with cathodal stimulation over the left IFG (versus sham) reduced chocolate consumption.

METHODS

Twenty-three healthy females (ages 18-35) completed two tDCS sessions (2.0 mA vs. sham; order counterbalanced) in a within-subject, double-blind, randomized design with a 4-week washout. Participants were self-reported "chocolate cravers" and restrained eaters. Self-report assessments on disinhibited eating were completed at intake. Delay discounting and inhibitory control were assessed at the remaining visits. During stimulation, participants completed an inhibitory control training task (chocolate go/no-go task) and were randomized to the chocolate no-go condition (inhibit all responses to chocolate cues) or the control condition (inhibit responses to chocolate cues on half the trials). Following stimulation, participants completed a 15-min chocolate "taste test" with chocolate rating forms. Afterwards, staff measured the remaining chocolate to determine total consumption.

RESULTS

Contrary to our hypotheses, active tDCS significantly increased chocolate consumption vs. sham (mean = 43.2 vs. 32.2, p=0.005) in both task conditions, but had no effect on chocolate ratings (ps > 0.05). Higher delay discounting and self-reported disinhibited eating predicted greater consumption (ps < 0.05).

CONCLUSIONS

The results suggest widespread activation of the prefrontal cortex may reduce the ability to resist chocolate. Our data highlights important methodological considerations for conducting tDCS studies to target health behaviors.

Modulation of appetitive motivation by prefrontal cortical mu-opioid receptors is dependent upon local dopamine D1 receptor signaling

Opioid neurotransmission has been implicated in psychiatric disorders featuring impaired control over appetitive motivation, such as addiction and binge-eating disorder. We have previously shown that infusions of the μ-opioid receptor (μOR) agonist DAMGO into the ventromedial prefrontal cortex (vmPFC) induced hyperphagia, increased motor activity, and augmented sucrose-reinforced responding in the task progressive ratio (PR) task, which assesses the motivational value of an incentive. These effects were not reproduced by intra-PFC infusion of a variety of dopamine (DA) agonists and antagonists, suggesting that manipulation of intra-PFC DA systems alone is not sufficient to reproduce μOR-like effects. Nevertheless, this does not rule out interactions between PFC DA and μ-opioid systems. Here we used intra-vmPFC drug cocktails containing DAMGO and SCH 23390 (a DA D1 receptor antagonist) to determine whether increases in appetitive motivation and motor activity elicited by intra-vmPFC μOR stimulation require intact signaling through vmPFC D1 receptors. Blockade of D1 receptors with SCH 23390 attenuated the enhancement of PR breakpoint, and increases in exploratory-like behavior and feeding initiation elicited by intra-vmPFC μOR stimulation. These results establish that intra-vmPFC D1 signaling is required for the expression of behavioral effects evoked by μOR stimulation within the PFC, and further suggest that D1 tone plays an enabling or permissive role in the expression of μOR -elicited effects. Simultaneous targeting of both μ-opioid and D1 systems may represent a more efficacious treatment strategy (compared to μOR blockade alone) for psychiatric disorders characterized by dysregulated appetitive motivation.

Feeding-modulatory effects of mu-opioids in the medial prefrontal cortex: a review of recent findings and comparison to opioid actions in the nucleus accumbens

RATIONALE

Whereas reward-modulatory opioid actions have been intensively studied in subcortical sites such as the nucleus accumbens (Acb), the role of cortical opioid transmission has received comparatively little attention.

OBJECTIVES

The objective of this study is to describe recent findings on the motivational actions of opioids in the prefrontal cortex (PFC), emphasizing studies of food motivation and ingestion. PFC-based opioid effects will be compared/contrasted to those elicited from the Acb, to glean possible common functional principles. Finally, the motivational effects of opioids will be placed within a network context involving the PFC, Acb, and hypothalamus.

RESULTS

Mu-opioid receptor (μ-OR) stimulation in both the Acb and PFC induces eating and enhances food-seeking instrumental behaviors; μ-OR signaling also enhances taste reactivity within a highly circumscribed zone of medial Acb shell. In both the Acb and PFC, opioid-sensitive zones are aligned topographically with the sectors that project to feeding-modulatory zones of the hypothalamus and intact glutamate transmission in the lateral/perifornical (LH-PeF) hypothalamic areas is required for both Acb- and PFC-driven feeding. Conversely, opioid-mediated feeding responses elicited from the PFC are negatively modulated by AMPA signaling in the Acb shell.

CONCLUSIONS

Opioid signaling in the PFC engages functionally opposed PFC➔hypothalamus and PFC➔Acb circuits, which, respectively, drive and limit non-homeostatic feeding, producing a disorganized and "fragmented" pattern of impulsive food-seeking behaviors and hyperactivity. In addition, opioids act directly in the Acb to facilitate food motivation and taste hedonics. Further study of this cortico-striato-hypothalamic circuit, and incorporation of additional opioid-responsive telencephalic structures, could yield insights with translational relevance for eating disorders and obesity.