Sensory Science and Metabolism; Molecular and Neuronal Mechanisms

National Institute On Alcohol Abuse And Alcoholism

Investigators

Linked publications & trials

Abstract

The Section of Sensory Science and Metabolism (SenSMet) laboratory at NINR/NIAAA conducts translational and clinical inpatient and outpatient studies. Active collaborations to investigate areas of common interest in nutrition, taste, and obesity have been undertaken. Specifically, double-blind clinical protocols for which sensory phenotyping measures have been implemented in collaboration with Dr. Gibbons in the National Human Genome Research Institute (NHGRI) and Dr. Hall, formerly of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). In addition, new partnerships have developed as follows: a) to investigate neuronal mechanisms in obesity, b) to investigate multi-sensory alterations in AUD/OUD participants, c) to investigate how taste and smell are affected by COVID-19. (Appetite 2024) Obesity rates have been increasing worldwide, with estimates predicting as many as 1 billion adults, 12% of the world population, will have obesity by 2025. A growing area of research examines the role of taste perception on eating behavior in obesity and metabolic diseases. The human gustatory system influences physiological and genetic factors, allowing us to distinguish between tastes - sweet, sour, bitter, salty, and umami - and regulating our eating behaviors by influencing our preferences. Genetic variations affecting taste receptor functionality can skew this perception, often leading to a predilection for high-calorie foods and increasing the risk of obesity and metabolic syndromes. Modern lifestyle factors include overexposure to sugar and high-fat diets, dysregulated taste perception, and enhanced preferences for unhealthy foods. Considering evidence about the plasticity of the taste system, the consumption of high calorie foods may reshape taste sensation and preference. Thus, using a crossover design, we investigated how differing degrees of processing in different diets affect peoples’ taste perception when measured in a controlled environment. Secondly, we aimed to explore associations between taste and cardiometabolic parameters. We measured dietary intake in a sample of 20 participants and observed that participants gained and lost nearly 1 kg during 2-week processed and unprocessed diets, respectively. When looking at the impact on taste perception, we found no significant differences between sweet and salt sensitivity following each diet (p-value ¼ 0.945). Similarly, taste preferences did not differ by diet (p-value ¼ 0.998). Thus, a 2-week consumption of these diets did not appear to impact sweet or salty taste sensitivity or preference acutely. In self-reported measures, participants did not report differences in pleasantness between unprocessed and ultra-processed foods, despite the latter group consuming more calories and sodium. Salt preference was found to have a small significant association with BMI (r ¼ 0.50, P ¼ 0.03), and systolic BP (r ¼ 0.59, P ¼ 0.01) while subjects were consuming the ultra-processed diet (Jaime-Lara et al, 2023) suggesting that salty taste may be linked to changes in blood pressure that lead to hypertension. Participants were majority Black with no prior diagnosis of hypertension. While some studies have found no association between salt taste and obesity, others have found an association between liking for salt and increased BMI. Similarly, studies examining the association between weight and sweet preference have obtained varied results. Findings from a large body of literature are consistent with our results and report no associations between sweet taste and weight status. A lack of consistent use of similar measures across studies makes comparison challenging. Some studies have noted associations between sweet perception, BMI, and obesity. Thus, more studies are needed to determine the relationship between salt and sweet preference and anthropometric measures. However, this study underscores that if salty taste preference and BP share a link, these studies could improve our understanding of the associations among taste preference, dietary intake and cardiometabolic health. (International Journal of Eating Disorders, 2024) We collaborated with Dr. Chao on a randomized controlled trial (RCT) that assessed changes in BOLD response to binge-eating cues following Cognitive Behavioral Therapy (CBT) versus wait-list control (WLC). The overall retention rate was 87.5%. CBT achieved significantly greater reductions in binge-eating episodes than WLC (mean ± standard error decline of 14.6 ± 2.7 vs. 5.7 ± 2.8 episodes in the past 28 days, respectively; p = 0.03). CBT and WLC did not differ significantly in changes in neural responses to binge-eating stimuli during the fMRI sessions. Compared with WLC, CBT significantly improved reward-based eating drive, disinhibition, and hunger as assessed by questionnaires (ps < 0.05). CBT was effective in reducing binge eating, but contrary to our hypothesis, CBT did not improve BOLD response to auditory binge-eating stimuli in reward regions of the brain. Further studies are needed to assess mechanisms underlying improvements with CBT for Binge-Eating Disorder (BED).