Taste And Odor Interactions After Metabolic Surgery.

Most patients report "taste" changes after undergoing metabolic surgeries. Yet, most studies that used validated sensory evaluation techniques, including ours, found no changes in perceived taste intensity from before to after surgery. However, we assessed participants with pure gustatory stimuli and after an overnight fast, which raises questions about whether patients' self-reported "taste" changes are due to conflating changes in retronasal smell/"flavor" with taste changes or whether they only manifest during the fed state. To investigate this, we conducted a cross-sectional study comparing sensory responses in women who underwent metabolic surgery 2-6 years ago (n=15) with two nonoperated control groups: one with a body mass index (BMI) equivalent (n=15) and one with a healthy BMI (n=15). Participants attended two sessions, one fed and one fasted. Using a sip-and-spit method, women tasted liquid samples containing gustatory and olfactory stimuli and puddings with varying fat content with and without nose clips. They used separate general labeled magnitude scales to rate their perceived intensity of taste, smell, flavor, and pleasantness. Mixed ANOVAs indicated that the surgery and BMI equivalent groups rated retronasal smell intensity of coffee stronger than the healthy BMI group (P≤0.015). However, there were no differences in taste/flavor intensity or liking ratings among groups. Additionally, feeding conditions did not significantly affect perceived intensity ratings. Our findings suggest that changes in the sensory-discriminatory component of taste or taste-odor interactions are not significant contributors to dietary modifications following metabolic surgery.

Weight Regain and Ingestive Behavior in Women after Metabolic Surgery.

This study investigated associations between maladaptive ingestive behaviors and weight regain in women who underwent metabolic surgery 2-10 years ago. Using a web-based survey, we assessed emotional, external, and restrained eating (Dutch Eating Behavior Questionnaire-DEBQ), food cravings (Food-Craving Inventory-FCI), and other behaviors (e.g., Eating Disorder Examination Questionnaire-EDE-Q; Alcohol Use Disorder Identification Test-Concise-AUDIT-C) in 36 women (42.9 ± 9.5 years old) post-surgery. We found that weight regain was specifically associated with increased frequency of cravings for sweets (r = 0.43), higher global scores in the EDE-Q (r = 0.38), and time elapsed since surgery (r = 0.35; all p's < 0.04). Multiple regression analysis revealed that the association between weight regain and sweet cravings interacted with time after surgery (p = 0.04), with the strongest association observed in women assessed closer to the surgery (i.e., 2.0-2.8 years). The combination of time after surgery and its interaction with sweet cravings accounted for 31% of the individual variations in weight regain (p = 0.005). Notably, among participants who reported alcohol consumption (31 of 36), 55% had an AUDIT-C score indicating hazardous drinking. These findings highlight the relevance of attending to patients' reports of frequent sweet cravings and screening for alcohol use to enhance strategies tailored to prevent weight regain and alcohol-related health problems post-surgery.

Enhancement of taste by retronasal odors in patients with Wolfram syndrome and decreased olfactory function.

Wolfram syndrome is a rare disease characterized by diabetes, neurodegeneration, loss of vision, and audition. We recently found, in a young sample of participants (mean age 15 years), that Wolfram syndrome was associated with impairment in smell identification with normal smell sensitivity and whole-mouth taste function. However, these senses were assessed separately, and it is unknown whether smell-taste interactions are altered in Wolfram syndrome, which was the focus of this study. Participants with Wolfram syndrome (n = 36; 18.2 ± 6.8 years) and sex-age-equivalent healthy controls (n = 34) were assessed with a battery of sensory tests. Using sip-and-spit methods, participants tasted solutions containing gustatory and olfactory stimuli (sucrose with strawberry extract, citric acid with lemon extract, sodium chloride in vegetable broth, and coffee) with and without nose clips, and rated perceived taste and retronasal smell intensities using the generalized Labeled Magnitude Scale. Participants also completed n-butanol detection thresholds and the University of Pennsylvania Smell Identification Test (UPSIT). Retronasal smell increased taste intensity of sucrose, sodium chloride, and coffee solutions similarly in both groups (P values <0.03). Compared with the control group, participants in the Wolfram group had lower UPSIT scores and reduced smell sensitivity, retronasal intensity, and saltiness (P values <0.03), but rated other taste intensities similarly when wearing the nose clip. Despite impairments in orthonasal smell identification, odor-induced taste enhancement was preserved in participants with Wolfram syndrome who still had some peripheral olfactory function. This finding suggests that odor-induced taste enhancement may be preserved in the presence of reduced olfactory intensity.