Assessment of fat taste in individuals with and without anorexia nervosa

Taste of Fat and Obesity: Different Hypotheses and Our Point of View

Obesity results from a temporary or prolonged positive energy balance due to an alteration in the homeostatic feedback of energy balance. Food, with its discriminative and hedonic qualities, is a key element of reward-based energy intake. An alteration in the brain reward system for highly palatable energy-rich foods, comprised of fat and carbohydrates, could be one of the main factors involved in the development of obesity by increasing the attractiveness and consumption of fat-rich foods. This would induce, in turn, a decrease in the taste of fat. A better understanding of the altered reward system in obesity may open the door to a new era for the diagnosis, management and treatment of this disease.

Risk of Dental Caries and Erosive Tooth Wear in 117 Children and Adolescents' Anorexia Nervosa Population-A Case-Control Study

INTRODUCTION

Restrictive type of anorexia nervosa (AN) is still one of the most severe eating disorders worldwide with an uncertain prognosis. Patients affected by AN should be encouraged to undertake psychiatric care and psychotherapy, but whether they should necessarily be included in careful dental care or not may still be questionable. Even though there is a constantly increasing number of AN studies, there are just a few data about the youngest group of AN children and adolescents aged < 18.

METHODOLOGY

This case-control study aimed to compare the dental health and gingival inflammation level in female adolescent inpatients affected by severe AN restrictive subtype vs. controls. Based on clinically confirmed 117 AN cases (hospitalized in years 2016-2020 in public Psychiatric Unit, BMI < 15 kg/m², mean age 14.9 ± 1.8), the dental status has been examined regarding the occurrence of caries lesions using Decay Missing Filling Teeth (DMFT), erosive wear as Basic Erosive Wear Examination (BEWE), gingival condition as Bleeding on Probing (BOP) and plaque deposition as Plaque Control Record (PCR). The results were compared with age-matched 103 female dental patients (BMI 19.8 ± 2.3 kg/m², age 15.0 ± 1.8, p = 0.746) treated in a public University dental clinic.

RESULTS

AN patients were found to present a higher incidence of oral-related complications according to dental status (DMFT 3.8 ± 4.5 vs. 1.9 ± 2.1, p = 0.005), erosive tooth wear (BEWE 18.9 vs. 2.9%, p < 0.001), less efficient in controlling plaque (PCR 43.8 vs. 13.7%, p < 0.001) and gingival inflammation (BOP 20.0 vs. 3.9%, p < 0.001) compared with female adolescents. In the AN group, a significant correlation between BOP, BEWE, and duration of AN disease (p < 0.05), similarly to the number of decayed teeth D, filled teeth F and PCR were detected (p < 0.05).

CONCLUSIONS

Although the obtained results did not reveal any severe oral status, our findings indicated impaired dental and gingival conditions in young anorexics. Considering AN's potential role in oral health, it is essential to monitor dental treatment needs and oral hygiene levels in their present status to prevent forward complications in the future.

A Systematic Review of Taste Differences Among People With Eating Disorders

BACKGROUND

Eating disorders are a significant cause of morbidity and mortality. The etiology and maintenance of eating-disorder symptoms are not well understood. Evidence suggests that there may be gustatory alterations in patients with eating disorders.

OBJECTIVE

This article systematically reviews research assessing gustatory differences in patients with anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED).

METHOD

A systematic review was performed, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, examining taste and eating disorders. We reviewed electronic databases and identified 1,490 peer-reviewed English-language studies. Of these, 49 met inclusion criteria.

RESULTS

Studies employed psychophysical measures (n = 27), self-reported questionnaires (n = 5), and neuroimaging techniques (i.e., electroencephalography, functional magnetic resonance imaging; n = 17). Psychophysical studies showed that individuals with BN, in general, had greater preference for sweetness than healthy controls, and those with AN had a greater aversion for fat than controls. In neuroimaging studies, findings suggested that predictable administration of sweet-taste stimuli was associated with reduced activation in taste-reward regions of the brain among individuals with AN (e.g., insula, ventral, and dorsal striatum) but increased activation in BN and BED.

DISCUSSION

To our knowledge, this systematic review is the first to synthesize literature on taste differences in AN, BN, and BED. The inconsistency and variability in methods used across studies increased difficulties in comparing studies and disease processes. Further studies with well-defined population parameters are warranted to better understand how taste varies in patients with eating disorders.

Taste sensitivity in anorexia nervosa: A systematic review

OBJECTIVE

There is evidence for altered processing of taste in anorexia nervosa, particularly in the areas of reward processing and hedonic sensitivity. However, research on whether people with anorexia nervosa identify taste stimuli accurately, known as taste sensitivity, has yielded mixed findings. The objective of this study was to synthesize the literature on taste sensitivity in this disorder to provide a basis for future discussion on whether altered taste sensitivity may be also implicated in wider atypical taste processing in anorexia.

METHOD

Electronic databases were searched systematically to identify published research examining taste sensitivity in anorexia. Search terms were "anorexia nervosa", or "eating disorder", combined with "taste". 18 studies met inclusion criteria.

RESULTS

The review of the findings suggest that individuals with AN may experience reduced taste sensitivity that may improve following recovery. However, there was a significant variability in results across studies, potentially reflecting methodological problems including low sample sizes, experimental designs, and uncontrolled confounding variables.

DISCUSSION

This review suggests that altered taste sensitivity could represent a component in the wider altered taste processing observed in anorexia nervosa. However, the heterogeneity of findings highlight the need for future research to consider methodological issues raised by this review.

N-methyl-d-aspartate receptor coagonist d-serine suppresses intake of high-preference food

d-Serine is abundant in the forebrain and physiologically important for modulating excitatory glutamatergic neurotransmission as a coagonist of synaptic N-methyl-d-aspartate (NMDA) receptor. NMDA signaling has been implicated in the control of food intake. However, the role of d-serine on appetite regulation is unknown. To clarify the effects of d-serine on appetite, we investigated the effect of oral d-serine ingestion on food intake in three different feeding paradigms (one-food access, two-food choice, and refeeding after 24-h fasting) using three different strains of male mice (C57Bl/6J, BKS, and ICR). The effect of d-serine was also tested in leptin signaling-deficient db/db mice and sensory-deafferented (capsaicin-treated) mice. The expression of orexigenic neuropeptides [neuropeptide Y (Npy) and agouti-related protein (Agrp)] in the hypothalamus was compared in fast/refed experiments. Conditioned taste aversion for high-fat diet (HFD) was tested in the d-serine-treated mice. Under the one-food-access paradigm, some of the d-serine-treated mice showed starvation, but not when fed normal chow. HFD feeding with d-serine ingestion did not cause aversion. Under the two-food-choice paradigm, d-serine suppressed the intake of high-preference food but not normal chow. d-Serine also effectively suppressed HFD intake but not normal chow in db/db mice and sensory-deafferented mice. In addition, d-serine suppressed normal chow intake after 24-h fasting despite higher orexigenic gene expression in the hypothalamus. d-Serine failed to suppress HFD intake in the presence of L-701,324, the selective and full antagonist at the glycine-binding site of the NMDA receptor. Therefore, d-serine suppresses the intake of high-preference food through coagonism toward NMDA receptors.