Peri-threshold Trigeminal Stimulation with Capsaicin Increases Taste Sensitivity in Humans

Abstract Introduction Taste perception is affected by trigeminal stimuli, i.e., capsaicin. This has been studied at suprathreshold concentrations. However, little is known about taste perception at threshold level in the presence of low concentration of capsaicin. The aim of the study was to explore whether taste sensitivity for sweet, sour, salt, bitter, and umami is modulated by the presence of capsaicin in the peri-threshold range. Methods Fifty-seven adults (age range 19–85 years; 32 women) with functional gustation participated in the study. Based on their perception of phenylthiocarbamide (PTC), the group was stratified into non-tasters (n = 20) and tasters (n = 37). Threshold for sweet (sucrose), sour (citric acid), salty (sodium chloride), bitter (quinine-hydrochloride), and umami (sodium-glutamate) tastes was estimated using a single-staircase paradigm (3-alternative forced choice; volume per trial 0.1 ml) with or without 0.9-µM capsaicin added. This capsaicin concentration had been determined in pilot studies to be in the range of oral perception thresholds. Results The addition of capsaicin produced lower taste thresholds for sweet, sour, salty, and bitter but not for umami. In contrast, neither PTC taster status nor sex affected these results. Conclusion The current results indicate that a low concentration of capsaicin increases gustatory sensitivity. Implications The current findings provide evidence supporting different effects of capsaicin on taste perception at threshold level. It has implications for boosting taste sensitivity or flavor enjoyment with low concentration of capsaicin.

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To Assess the Influence of Habitual Mouth Breathing and its Associated Taste Alterations

Open Access Journal of Dental Sciences ◽

10.23880/oajds-16000274 ◽

2020 ◽

Vol 5 (4) ◽

Author(s):

Haramandeep Singh

Keyword(s):

Animal Experiments ◽

Health Condition ◽

Mouth Breathing ◽

Taste Perception ◽

Taste Sensitivity ◽

Minimum Concentration ◽

The Mean ◽

The Many ◽

Inorganic Constituents ◽

Age Range

Background: If the sense of taste is impaired, it may often negatively affect patient’s food intake, nutritional status and consequently health condition because it provides information about the food we eat. Aim and Objective: To study the influence of habitual mouth breathing and its associated taste alterations and also investigate the cause of this influence. Method and Methodology: Total eighty subjects were taken out of which forty healthy volunteers (male-26; female14) participated in this study. The mean age of these subjects was 25.6± 1.9 (SD) years (age range, 19-36 years). Furthermore forty subjects (male-21; female-19) with a habit of mouth breathing (MB) were taken. The mean age of these subjects was 29.5± 3.4 (SD) years (age range, 19-40 years). A taste threshold is the minimum concentration at which taste sensitivity to a particular substance or food can be perceived. The subjects were told to avoid eating or drinking anything, with the exception of water for 3 hours before evaluation. In addition, a complete Ear, Nose, Throat examination was performed. We carried out the chemical method of gustatory testing by using filter paper taste strips. This is a validated gustatory test, used to measure the gustatory sensitivity of the tongue for 5 tastants; sweet, sour, salty, bitter, and umami. We measured the recognition thresholds only on one side on the tongue either left or right. There are many factors that can alter taste senstivity. Considering these factors can help us better understand and ensure accurate sensory taste perception. Although there are a variety of factors but some that influence taste perception more than others are discussed in this study. These various effects are brought about by the many organic and inorganic constituents of saliva. In response to these variations in saliva, taste sensitivity may also fluctuate widely. Conclusion: Relationships between individual salivary constituents and certain taste substances have been explored in human psychophysical and animal experiments. However, there are many organic and inorganic salivary constituents whose effects on taste acuity have not yet been fully elucidated

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Bitter Taste Perception of the Human Tongue Mediated by Quinine and Caffeine Impregnated Taste Strips

Annals of Otology Rhinology & Laryngology ◽

10.1177/0003489420906187 ◽

2020 ◽

Vol 129 (8) ◽

pp. 813-820

Author(s):

David T. Liu ◽

Gerold Besser ◽

Florian Oeller ◽

Christian A. Mueller ◽

Bertold Renner

Keyword(s):

Taste Perception ◽

Self Assessment ◽

Taste Strips ◽

Visual Analog Scales ◽

Human Tongue ◽

Perceived Intensity ◽

Gustatory Function ◽

Quinine Hydrochloride ◽

Magnitude Scales ◽

Age Range

Objectives: Tests for gustatory function have become increasingly important in diagnosis and treatment of patients with taste disorders. While caffeine and quinine hydrochloride solutions have been used for global testing of bitter perception, only quinine has been used to test regional bitter perception by means of taste strips. The aim of the present study was to validate caffeine impregnated taste strips as an alternative to quinine taste strips for assessment of regional bitter perception. Methods: A total of 46 healthy volunteers (mean age/range, 23/19-27 years) were included in this study. Quinine and caffeine impregnated taste strips were pairwise presented at different parts of the tongue. Perceived intensity and hedonic dislike were evaluated using labeled magnitude scales. Additionally, gustatory function was assessed using the taste strips test and overall sense of taste was rated using visual analog scales. Results: Assessment of gustatory function demonstrated scores within the normogeusic range in most included subjects (mean/SD, 13.1/2.5). Notably, equally concentrated quinine and caffeine impregnated taste strips placed on different regions of the tongue did not lead to significant differences in perceived intensity or hedonic dislike, whereas quinine and caffeine impregnated taste strips of different concentrations placed on the same region on the tongue led to significant differences of perceived intensity and hedonic dislike. Furthermore, no correlation was found between self-assessment of gustatory function and taste strips scores. Conclusion: Caffeine seems to be a valid bitter compound for regional testing using taste strips and may be used alternatively to quinine.

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Phenylthiocarbamide taste perception and susceptibility to motion sickness: linking higher susceptibility with higher phenylthiocarbamide taste acuity

The Journal of Laryngology & Otology ◽

10.1017/s0022215107001442 ◽

2008 ◽

Vol 122 (10) ◽

pp. 1064-1073 ◽

Cited By ~ 11

Author(s):

K Sharma ◽

P Sharma ◽

A Sharma ◽

G Singh

Keyword(s):

Motion Sickness ◽

Bimodal Distribution ◽

Taste Perception ◽

Taste Sensitivity ◽

Taste Threshold ◽

Threshold Distribution ◽

Increased Risk ◽

The Mean ◽

Age Range ◽

Taste Thresholds

AbstractObjective:This study is the first attempt to link quantified phenylthiocarbamide bitter taste recognition threshold with susceptibility to motion sickness.Subjects:The study was conducted on a sample of 291 teenage Rajput children (146 males and 145 females; age range 13–19 years) from the Sirmour district of Himachal Pradesh, India. Phenylthiocarbamide taste sensitivity was measured by administering a serial dilution of a freshly prepared phenylthiocarbamide solution, following the method of Harris and Kalmus. Motion sickness susceptibility was assessed retrospectively via interview.Results:About 40 per cent of the subjects had experienced motion sickness in the past. The mean and standard deviation of phenylthiocarbamide taste thresholds in non-tasters and tasters were 0.83 ± 0.87 and 7.98 ± 1.86, respectively. A bimodal distribution test (D/S) index of 5.24 confirmed bimodality of phenylthiocarbamide taste threshold distribution. The Mann–Whitney U test rejected the null hypothesis of μ1 = μ2 and thus confirmed the existence of differences in the distributions of phenylthiocarbamide taste threshold between individuals susceptible and not susceptible to motion sickness. Individuals susceptible to motion sickness had lower mean and median taste thresholds, indicating higher phenylthiocarbamide taste sensitivity, compared with non-susceptible individuals. The frequency of non-tasters was about 10 per cent in both motion sickness susceptible and non-susceptible individuals. The simple division of phenylthiocarbamide tasting ability into tasters and non-tasters was a less sensitive criterion with which to measure the association of this ability with motion sickness susceptibility. However, further differentiation of tasters into weak threshold, medium threshold and super threshold (‘supersensitive’) tasters clearly revealed a highly significantly increased risk of motion sickness in super threshold tasters (i.e. threshold solution number ≥12). The ratio of motion sickness susceptible individuals to non-susceptible individuals was 1:1.7 for non-tasters (threshold solution numbers zero to three) and weak and medium tasters (threshold solution numbers four to 11), but the trend was reversed for super threshold tasters (threshold solution numbers 12 and 13), in whom the ratio was 2:1.Conclusion:Individuals exhibiting greater phenylthiocarbamide taste acuity (i.e. supersensitive tasters) had a higher susceptibility to motion sickness than did non-, weak and medium phenylthiocarbamide tasters, as measured in terms of their taste thresholds (i.e. threshold solution numbers zero to 11).

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Genetic Variation in Taste Receptor Genes (SCNN1B, TRPV1) and Its Correlation with the Perception of Saltiness in Normotensive and Hypertensive Adults

International Journal of Hypertension ◽

10.1155/2021/5559831 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Pradtana Tapanee ◽

Diane K. Tidwell ◽

M. Wes Schilling ◽

Daniel G. Peterson ◽

Terezie Tolar-Peterson

Keyword(s):

Taste Receptor ◽

Recognition Threshold ◽

Taste Perception ◽

Taste Sensitivity ◽

Nucleotide Polymorphisms ◽

Cross Sectional ◽

Single Nucleotide ◽

Salt Taste ◽

Hypertensive Group ◽

Age Range

Background. Different taste preferences correlated with genetic variations may lead to food consumption patterns that contribute to nutrient-related health outcomes such as hypertension. Objectives. The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) in the salt taste receptor genes SCNN1B and TRPV1 affect salt taste perception among normotensive and hypertensive people. Materials and Methods. We conducted a cross-sectional case control study by design consisting of a normotensive and hypertensive group. Participants were 253 adults with age range of 20–82 residing in Mississippi, USA. For each of 128 normotensives and 125 hypertensives, the salt taste recognition threshold and salt taste receptor genotype were determined. Results. The hypertensive group had a higher salt taste recognition threshold than the normotensive group ( P < 0.001 ). The polymorphism of TRPV1, rs4790522, with the AA genotype was associated with a higher salt recognition threshold (lower salt taste sensitivity) in people with hypertension and obesity. Moreover, the polymorphism of TRPV1, rs8065080, and SCNN1B, rs239345, genes were associated with a risk of hypertension ( P = 0.016 and P = 0.024 ). Conclusion. Correlations between SNPs, salt taste sensitivity, and hypertension risk were observed. People with hypertension had a higher salt taste threshold than those with normotension.

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Repeatability of Taste Recognition Threshold Measurements with QUEST and Quick Yes–No

Nutrients ◽

10.3390/nu12010024 ◽

2019 ◽

Vol 12 (1) ◽

pp. 24

Author(s):

Richard Höchenberger ◽

Kathrin Ohla

Keyword(s):

False Alarm ◽

Nutrient Sensing ◽

Repeated Measurements ◽

Taste Perception ◽

Taste Sensitivity ◽

False Alarms ◽

Threshold Estimate ◽

Testing Procedures ◽

Quinine Hydrochloride ◽

Good Repeatability

Taste perception, although vital for nutrient sensing, has long been overlooked in sensory assessments. This can, at least in part, be attributed to challenges associated with the handling of liquid, perishable stimuli, but also with scarce efforts to optimize testing procedures to be more time-efficient. We have previously introduced an adaptive, QUEST-based procedure to measure taste sensitivity thresholds that was quicker than other existing approaches, yet similarly reliable. Despite its advantages, the QUEST procedure lacks experimental control of false alarms (i.e., response bias) and psychometric function slope. Variations of these parameters, however, may also influence the threshold estimate. This raises the question as to whether a procedure that simultaneously assesses threshold, false-alarm rate, and slope might be able to produce threshold estimates with higher repeatability, i.e., smaller variation between repeated measurements. Here, we compared the performance of QUEST with a method that allows measurement of false-alarm rates and slopes, quick Yes–No (qYN), in a test–retest design for citric acid, sodium chloride, quinine hydrochloride, and sucrose recognition thresholds. We used complementary measures of repeatability, namely test–retest correlations and coefficients of repeatability. Both threshold procedures yielded largely overlapping thresholds with good repeatability between measurements. Together the data suggest that participants used a conservative response criterion. Furthermore, we explored the link between taste sensitivity and taste liking or which we found, however, no clear association.

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Orosensory Perception of Fat/Sweet Stimuli and Appetite-Regulating Peptides before and after Sleeve Gastrectomy or Gastric Bypass in Adult Women with Obesity

Nutrients ◽

10.3390/nu13030878 ◽

2021 ◽

Vol 13 (3) ◽

pp. 878

Author(s):

Arnaud Bernard ◽

Johanne Le Beyec-Le Bihan ◽

Loredana Radoi ◽

Muriel Coupaye ◽

Ouidad Sami ◽

...

Keyword(s):

Bariatric Surgery ◽

Gastric Bypass ◽

Sleeve Gastrectomy ◽

Gut Hormones ◽

Sweet Taste ◽

Taste Perception ◽

Taste Sensitivity ◽

Adult Women ◽

Before And After ◽

The Impact

The aim of this study was to explore the impact of bariatric surgery on fat and sweet taste perceptions and to determine the possible correlations with gut appetite-regulating peptides and subjective food sensations. Women suffering from severe obesity (BMI > 35 kg/m2) were studied 2 weeks before and 6 months after a vertical sleeve gastrectomy (VSG, n = 32) or a Roux-en-Y gastric bypass (RYGB, n = 12). Linoleic acid (LA) and sucrose perception thresholds were determined using the three-alternative forced-choice procedure, gut hormones were assayed before and after a test meal and subjective changes in oral food sensations were self-reported using a standardized questionnaire. Despite a global positive effect of both surgeries on the reported gustatory sensations, a change in the taste sensitivity was only found after RYGB for LA. However, the fat and sweet taste perceptions were not homogenous between patients who underwent the same surgery procedure, suggesting the existence of two subgroups: patients with and without taste improvement. These gustatory changes were not correlated to the surgery-mediated modifications of the main gut appetite-regulating hormones. Collectively these data highlight the complexity of relationships between bariatric surgery and taste sensitivity and suggest that VSG and RYGB might impact the fatty taste perception differently.

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The Associations between Biochemical and Microbiological Variables and Taste Differ in Whole Saliva and in the Film Lining the Tongue

BioMed Research International ◽

10.1155/2018/2838052 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Yunzi Feng ◽

Hélène Licandro ◽

Christophe Martin ◽

Chantal Septier ◽

Mouming Zhao ◽

...

Keyword(s):

Oral Microbiome ◽

Taste Perception ◽

Taste Sensitivity ◽

Sensory Data ◽

Metabolic Substrates ◽

Biological Variables ◽

Whole Saliva ◽

Saliva Flow ◽

Acetic Acids

The objective of this work was to investigate whether the biological film lining the tongue may play a role in taste perception. For that purpose, the tongue film and saliva of 21 healthy subjects were characterized, focusing on microorganisms and their main metabolic substrates and products. In parallel, taste sensitivity was evaluated using a test recently developed by our group, and the links between biological and sensory data were explored by a correlative approach. Saliva and tongue film differed significantly in biochemical composition (proportions of glucose, fructose, sucrose, and lactic, butyric, and acetic acids) and in microbiological profiles: compared to saliva, tongue film was characterized by significantly lower proportions of Bacteroidetes (p<0.001) and its main genus Prevotella (p<0.01) and significantly higher proportions of Firmicutes (p<0.01), Actinobacteria (p<0.001), and the genus Streptococcus (p<0.05). Generic taste sensitivity was linked to biological variables in the two compartments, but variables that appeared influent in saliva (flow, organic acids, proportion of Actinobacteria and Firmicutes) and in tongue film (sugars and proportions of Bacteroidetes) were not the same. This study points to two interesting areas in taste research: the oral microbiome and the specific characterization of the film lining the tongue.

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Bitter Taste Sensitivity Is Determined by TAS2R38 Haplotype, Associated with Saturated Fat Intake and Is Lower in Overweight and Obese Compared to Normal Weight UK adults

Current Developments in Nutrition ◽

10.1093/cdn/nzaa058_029 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 1271-1271

Author(s):

Leta Pilic ◽

Catherine Anna-Marie Graham ◽

Nisrin Hares ◽

Megan Brown ◽

Jonathan Kean ◽

...

Keyword(s):

Dietary Fat ◽

Bitter Taste ◽

Saturated Fat ◽

Normal Weight ◽

Taste Perception ◽

Taste Sensitivity ◽

Lower Sensitivity ◽

Fat Intake ◽

Fat Taste ◽

Total Fat

Abstract Objectives Taste perception (sensitivity) may be determined by genetic variations in taste receptors and it affects food intake. Lower fat taste sensitivity is associated with higher dietary fat intake and body mass index (BMI). Recently, associations between bitter and fat taste sensitivity have been reported whereby bitter taste perception may be involved in textural perception of dietary fat. However, it is not clear if lower sensitivity to bitter taste would lead to an actual higher fat intake. Our objectives were to explore the associations between haplotypes in the bitter taste receptor TAS2R38, bitter taste sensitivity and fat intake and if bitter taste sensitivity is lower in individuals with higher BMI. Methods Ethical approval was obtained from the St Mary's and Oxford Brookes University Ethics Committee. Eighty-eight healthy Caucasian participants (44% male and 56% female; mean BMI 24.9 ± 4.8 kg/m2 and mean age 35 ± 14 years) completed this cross-sectional study. Height and weight were measured and genotyping performed for rs713598, rs1726866, rs10246939 genetic variants in the TAS2R38. Haplotypes were determined with Haploview software. Participants rated the intensity of a phenylthiocarbamide (PTC) impregnated strip on the general Labelled Magnitude Scale (gLMS) to determine bitter taste sensitivity and were classified as bitter tasters and non-tasters. Dietary fat intake was calculated from the EPIC-Norfolk Food Frequency Questionnaire and expressed as % total energy intake. Results TAS2R38 haplotypes were associated with bitter taster status (P < 0.005). PTC ratings of intensity were negatively correlated with % saturated fat (SFA) intake (rs = −0.256, P = 0.016). %SFA and %total fat (rs = 0.656, P < 0.005) and %total fat and energy intake (kcal) (rs = 0.225, P = 0.035) were positively correlated. Normal weight participants rated PTC strips as more intense compared to overweight and obese participants (mean rank 53 vs. 41, P = 0.033). Conclusions Bitter taste perception is determined by genetics and lower sensitivity to this taste is associated with higher intake of SFA. Lower bitter taste sensitivity in overweight/obese participants suggests that impaired bitter taste may be associated with an overall unhealthier and more energy dense dietary pattern. Funding Sources St Mary's and Oxford Brookes University.

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101 Amyotrophic Lateral Sclerosis (ALS) - Not Just a Motor Disease? Isolated Bitter and Sweet Taste Loss in ALS

CNS Spectrums ◽

10.1017/s109285292000019x ◽

2020 ◽

Vol 25 (2) ◽

pp. 266-266

Author(s):

Ahmed A Ashary ◽

Dev N Patel ◽

Alan R Hirsch

Keyword(s):

Weight Loss ◽

Insular Cortex ◽

Sweet Taste ◽

Voluntary Contraction ◽

Upper Extremities ◽

Taste Perception ◽

Study Objective ◽

Quinine Hydrochloride ◽

Abductor Digiti Minimi ◽

The Right

Abstract:Study Objective:Specific taste quality deficits in ALS has not heretofore been described.METHOD:Case Study: A 71 year old right handed female presented with a two year course of progressive reduction in strength in her hands, arms and legs with difficulty tying shoe laces, opening jars, writing and walking. She described nocturnal muscle spasms involving all extremities. Gradually, over eight months prior to presentation, all food began to taste bad and horribly bitter. Associated with no appetite and a seven pounds weight loss.RESULTS:Abnormalities in Neurological examination: Cranial Nerve (CN) examination: CN IX and X: Gag absent bilaterally. Motor examination: Bulk: atrophy in thenar and hypothenar eminences and intrinsics in both upper extremities. Percussion induced fasciculation and myotonia in both shoulders and arms. Fasciculation of tongue with percussion myotonia of tongue. Strength: Intrinsic 4/5 in both upper extremities, 3/5 in abductor policis brevis bilaterally, 3/5 right gastrocnemius soleus, 4/5 bilateral anterior tibialis. Drift testing: left abductor digiti minimi sign. Gait: Heel and toe walking unstable with circumduction of left leg. Tandem gait unstable. Cerebellar: Holmes rebound phenomena positive in the left upper extremity. Deep tendon reflexes: 1+ left brachioradialis. 1+ left triceps. 3+ right ankle jerks. 0 left ankle jerk. Positive jaw jerk. Chemosensory Testing: Normosmia to: Alcohol Sniff Test (46), Pocket Smell Test (3/3) and Retronasal Smell Index (9). Taste Quadrant Testing: ageusia in the palate to sodium chloride and citric acid. Ageusia throughout the palate, tongue and whole mouth to sucrose and quinine hydrochloride. Fungiform papillae count: left 18, right 20 (normal). Lip biopsy (normal). MRI: T2 flair in bilateral corticospinal tracts, left greater than right in the spinal cord and the brain. EMG: fibrillation, positive waves with fasciculation in all four extremities. Voluntary contraction with polyphasic unstable motor unit action potentials.CONCLUSION:While Lang found no taste loss in ALS (Lang, 2011), Pelletier found reduction in intensity of taste to all modalities in different sectors of the tongue, but paradoxically demonstrated normogeusia in whole mouth taste perception (Pelletier, 2013). Pathological specimens of those with ALS revealed degeneration in the nucleus parabrachialis medialis and tractus trigeminothalamicus dorsalis (Oyanagi, 2015), suggesting that taste deficit may be due to central white matter abnormalities. Sweet taste is localized in the most posterior and rostral aspect of the right insular cortex, immediately adjacent to bitter (Prinster, 2017), suggesting a neighborhood effect phenomena. Weight loss in ALS may be due to sensory distortion and secondary impairment of appetite. It would be worthwhile to investigate those with ALS for evidence of otherwise overlooked gustatory deficits, correction of which may improve appetite and nutritional state.

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Association between Salivary Leptin Levels and Taste Perception in Children

Journal of Nutrition and Metabolism ◽

10.1155/2017/7260169 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 12

Author(s):

Lénia Rodrigues ◽

Rosa Espanca ◽

Ana Rodrigues Costa ◽

Célia Miguel Antunes ◽

Clarinda Pomar ◽

...

Keyword(s):

Bitter Taste ◽

Taste Receptor ◽

Sweet Taste ◽

Normal Weight ◽

Taste Perception ◽

Taste Sensitivity ◽

Threshold Detection ◽

Leptin Receptors ◽

Whole Saliva

The satiety inducing hormone leptin acts not only at central nervous system but also at peripheral level. Leptin receptors are found in several sense related organs, including the mouth. A role of leptin in sweet taste response has been suggested but, until now, studies have been based on in vitro experiments, or in assessing the levels of the hormone in circulation. The present study investigated whether the levels of leptin in saliva are related to taste perception in children and whether Body Mass Index (BMI) affects such relationship. Sweet and bitter taste sensitivity was assessed for 121 children aged 9-10 years and unstimulated whole saliva was collected for leptin quantification, using ELISA technique. Children females with lower sweet taste sensitivity presented higher salivary leptin levels, but this is only in the normal weight ones. For bitter taste, association between salivary leptin and caffeine threshold detection was observed only in preobese boys, with higher levels of salivary hormone in low sensitive individuals. This study is the first presenting evidences of a relationship between salivary leptin levels and taste perception, which is sex and BMI dependent. The mode of action of salivary leptin at taste receptor level should be elucidated in future studies.

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