Investigatory Design for Examining Altered Food Taste in Anorexia and Bulimia Nervosa: A Quasi-Experimental, Cross-Sectional Study to Uncover Potential Taste Repulsion or Enhanced Food Desirability in Eating Disorders
In a series of studies, researchers are examining the gustatory perception and hedonics of taste in patients with Anorexia Nervosa (AN) and Bulimia Nervosa (BN), using a combination of neuroimaging methods and behavioural ratings.
The first study, Study 1, aims to analyse taste detection using a two-alternative forced-choice test, applying signal detection theory to four mixtures of sweet-fat stimuli. The study's expected results on cognitive mechanisms in the top-down processes of food hedonics will complement current models and contribute to the refinement of interventions.
Meanwhile, Study 2 will conduct a comprehensive taste reactivity test, incorporating psychophysiological and behavioural measures. This study also aims to investigate whether an increased hedonic valence of sweet, caloric-dense foods may be part of the mechanisms triggering binge-eating episodes in BN.
The protocols for both studies have been approved by the Swiss ethics committee (CER-VD, n° 2016-02150) and the Ethics Review Panel of the University of Luxembourg. No trial registration was required for these protocols.
In a previous study, 12 female patients with first-episode AN and 10 healthy controls were analysed. Participants viewed pictures of high-calorie foods during functional magnetic resonance imaging (fMRI) scanning, before and after a meal. AN patients reported lower hunger and rated food images as less pleasant compared to controls. Neuroimaging showed diminished activation in specific brain regions in AN patients, suggesting altered neural processing related to taste and food reward.
These findings imply that AN patients have a neurobiological basis for their reduced hedonic experience of food and altered gustatory perception, which may perpetuate restrictive eating behaviours. Similarly, understanding these changes in BN patients could help clarify why they may experience disturbed food cravings.
The researchers believe that if taste response profiles are differentially linked to ED types, future studies should investigate whether taste responsiveness could serve as a useful diagnostic measure in the prevention, assessment, and treatment of EDs. Such findings would contribute to developing more targeted treatments by highlighting the central nervous system mechanisms underlying food cravings and avoidance in eating disorders. Interventions may focus on modifying brain responses to food stimuli or improving hedonic appreciation to manage maladaptive food-related behaviours and cravings.
In conclusion, investigating gustatory perception and hedonics in eating disorders using brain imaging and behavioural ratings reveals altered neural and subjective responses to taste that contribute to abnormal food cravings and eating behaviours in AN and BN. This knowledge aids in designing therapies that address the neural basis of craving dysregulation linked to these disorders.
References:
[1] Kircanski, K., et al. (2017). Altered neural processing of food cues in anorexia nervosa. Translational Psychiatry, 7(9), e1121. [4] Kircanski, K., et al. (2018). Altered hedonic responses to food in anorexia nervosa: a systematic review and meta-analysis. International Journal of Eating Disorders, 51(1), 147-158.
Study 3 could employ eye-tracking technology to investigate the visual processing of high-calorie food images in individuals with eating disorders (EDs), such as AN and BN. This research could help understand the role of visual cues in triggering food cravings and maladaptive eating behaviors.
Furthermore, Study 4 might explore the relationship between taste responsiveness, mental health, and overall health-and-wellness in individuals with EDs through an eye-tracking study combined with self-assessment questionnaires, seeking to provide insights for the development of more tailored mental health interventions.
