Effect of lozenge surface texture, taste and acidity on salivary flow rate: A crossover preclinical trial in healthy subjects.

Dry mouth is a multifaceted condition which is caused by reduced salivary secretion. This study aimed to evaluate and compare the effects of different lozenge surface textures, tastes and acidity levels on stimulated salivary secretion for increased oral moistening in participants without hyposalivation. This randomized, double-blind, clinical crossover trial with before and after comparison involved 33 healthy volunteers. Five lozenges, including a baseline control (C), apple (A), sour (S), sour apple (SA) and granular pectin (P) were tested on five different days with all the subjects. Salivary flow, pH value, and subjective feeling (visual analog scale) were measured before and after consuming the lozenge each day. Throughout all trial days the unstimulated whole salivary flow (UWSF) averaged 0.65 ± 0.26 ml/min. Lozenges S, SA, and P showed higher stimulated whole salivary flow (SWSF) than C (P < 0.001) by more than 0.5 ml/min. Lozenge P, with a rough surface, demonstrated the highest difference between UWSF and SWSF, 2.41 ± 0.69 ml/min. The stimulated saliva with the lozenges containing acidifiers (S, SA and P) was more than 1.4 pH units lower compared to lozenges C and A (P < 0.001). Subjects reported the strongest subjective feeling of increased saliva with lozenges SA and P. Overall lozenges SA and P provided the best objective results in enhancing salivary flow rate and subjective feeling of increased salivary flow.

Parotid hypersalivation after inferior salivatory nucleus glutamate/NMDA receptor excitation in the rat.

Although salivation is essential during eating behavior, little is known about the brainstem centers that directly control the salivary glands. With regard to the inferior salivatory nucleus (ISN), the site of origin of the parasympathetic preganglionic cell bodies that innervate the parotid glands, previous anatomical studies have located it within the rostrodorsal medullary reticular formation. However, to date there is no functional data that shows the secretory nature of the somas grouped in this region. To activate only the somas and rule out the activation of the efferent fibers from and the afferent fibers to the ISN, in exp. 1, NMDA neurotoxin was administered to the rostrodorsal medullary region and the secretion of saliva was recorded during the following hour. Results showed an increased secretion of parotid saliva but a total absence of submandibular-sublingual secretion. In exp. 2, results showed that the hypersecretion of parotid saliva after NMDA microinjection was completely blocked by the administration of atropine (a cholinergic blocker) but not after administration of dihydroergotamine plus propranolol (α and ß-adrenergic blockers, respectively). These findings suggest that the somata of the rostrodorsal medulla are secretory in nature, controlling parotid secretion via a cholinergic pathway. The data thus functionally supports the idea that these cells constitute the ISN.

An effective salivation-facilitating method for COVID-19 testing: An experimental study.

BACKGROUND: Simple tools, such as antigen test kits, are readily available for determining coronavirus disease 2019 infection at hospitals and homes. However, it is challenging for elderly people who are prone to dry mouth and other diseases. The main objective of this study was to investigate whether the presence or consumption of a plum pickle can facilitate salivation during coronavirus disease 2019 testing. METHOD: Twenty healthy adult women participated in the study. The participants were allocated to 2 groups: presentation and non-presentation (n = 10; with and without presentation of a plum pickle, respectively), and eating and non-eating (n = 10; with and without consumption of plum pickle, respectively). We recorded the number of saliva swallows in 1 minute under each condition, using a swallowing test device, which attached film sensors to the hyoid bone and thyroid cartilage. RESULTS: There was a significant difference in the number of swallows between the non-presentation and presentation groups ( P < .01, r = 0.89, Z = -2.82) as well as between the non-eating and eating groups ( P < .01, r = 0.85, Z = -2.68). CONCLUSIONS: The strength of 3 factors, namely: direct stimulation with citric acid, saliva buffer capacity, and motor learning, may have affected the results. Our study suggests that saliva collection using the plum pickle is an effective complementary method for facilitating salivation. This technique may be useful in avoiding the risk associated with citric acid intake and for efficient specimen collection during coronavirus disease 2019 testing. In the future, we need to verify this method in elderly participants in a clinical setting.

LIMITED EVIDENCE SUGGESTS THAT END STAGE KIDNEY DISEASE AND HEMODIALYSIS MAY IMPACT SALIVARY FLOW RATE AND COMPOSITION.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Rodrigues RP, Vidigal MT, Vieira WA, Nascimento GG, Sabino-Silva R, Blumenberg C, Siqueira MF, Siqueira WL, Paranhos LR. Salivary changes in chronic kidney disease and in patients undergoing hemodialysis: a systematic review and meta-analysis. Journal of Nephrology. 2022 Mar 2:1-29. SOURCE OF FUNDING: The work has been partially funded by CAPES-Finance Code 001. The authors have also acknowledged The Brazilian National Council for Scientific and Technological Development (CNPq) and Minas Gerais State Agency for Research and Development, Brazil (FAPEMIG) for the support. TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data.

In Vivo Vascular Permeability Detection in Mouse Submandibular Gland.

Saliva plays an important role in oral and overall health. The intact endothelial barrier function of blood vessels enables saliva secretion, whereas the endothelial barrier dysfunction is related to many salivary gland secretory disorders. The present protocol describes an in vivo paracellular permeability detection method to evaluate the function of endothelial tight junctions (TJs) in mouse submandibular glands (SMG). First, fluorescence-labeled dextrans with different molecular weights (4 kDa, 40 kDa, or 70 kDa) were injected into the angular veins of mice. Afterward, the unilateral SMG was dissected and fixed in the customized holder under a two-photon laser-scanning microscope, and then images were captured for blood vessels, acini, and ducts. Utilizing this method, the real-time dynamic leakage of the different-sized tracers from blood vessels into the basal sides of the acini and even across the acinar epithelia into the ducts was monitored to evaluate the alteration of the endothelial barrier function under physiological or pathophysiological conditions.

A Stimulator of the Salivary Excretion Based on Physical Vibration of the Parotid Glands.

Oral dryness causes significant health problems both functional (difficulty speaking, chewing and swallowing) and structural in teeth (increased number of infections) and oral mucosa. The main objective of this study is to show an alternative treatment to help stimulate the salivary secretion thus improving the quality of life of the patient. In this study, a salivary stimulation equipment using vibrotactile stimuli is shown. The system has been placed bilaterally in the parotid glands and assessed the efficacy of the salivary secretion by sialometry before and after the stimulation. The new proposal is capable of stimulating salivary secretion, in a significative way after 7 minutes of use, at least in the cases analyzed, and fulfills low-cost, easy-to-use, and safe technical restrictions. In this setting, this paper suggests the performance of a deep clinical trial to measure the exact efficacy of the prototype and the times and frequencies needed to state the optimal treatment depending in each case.

Functional gland-preserving surgery via periauricular incision for pleomorphic adenoma of the parotid gland.

INTRODUCTION: Gland-preserving surgery is often used for benign tumours in the parotid gland. Partial superficial parotidectomy via a periauricular incision may bring satisfactory cosmetic outcomes but the disease control outcome remains unrevealed. This study evaluated functional and disease control outcomes after gland-preserving surgery via periauricular incision for pleomorphic adenoma of the parotid gland. METHODS: This longitudinal study included 248 consecutive patients with parotid pleomorphic adenoma who underwent the preservation of most normal parotid tissues and the facial nerve combined with the en-bloc resection of tumours via periauricular incision. Postoperative complications, subjective satisfaction, salivary function, and tumour recurrence were assessed in each patient. The secretory function of the salivary gland was measured using salivary scintigraphy at 6 months after surgery, and ultrasonography was regularly followed. RESULTS: Median tumour size was 2.5 cm (range, 0.8-5.2 cm) and median operation time was 55 min (range, 39-88 min). All tumours were safely removed by gland-preserving surgery via periauricular incision without extension to Blair or hairline incision and tumour spillage. Temporary and permanent paralysis of the facial nerve was 14 (5.6%) and none of the study patients, respectively. Postoperative complications were minor and Frey's syndrome was found in 6 (2.4%) patients. The Secretary function of the affected gland was equal to that of the unaffected gland. No patients had a recurrence for a median follow-up of 78 months (range, 24-126 months). CONCLUSIONS: Functional gland-preserving surgery via periauricular incision can treat pleomorphic adenoma in the parotid gland with satisfactory functional, cosmetic, and disease control outcomes.

The role of mechanical control of biofilm in the salivary pH after sucrose exposure in children with early childhood caries.

This quasi-experimental study sought to investigate if the mechanical control of biofilm (3-times-a-day) modifies the saliva's ability to buffer the oral environment after 20% sucrose rinse (SR20%) in children with early childhood caries (ECC). Here, SR20% reduced the saliva's pH in both groups and the mechanical control of biofilm had a greater effect on this parameter after SR20% in CF children. The mechanical control of biofilm evidenced a higher buffering capacity in CF children before SR20%, which was not observed after SR20%. Otherwise, the absence of mechanical control of biofilm showed that buffering capacity was comparable in the two groups before SR20%, whereas after SR20% the saliva's buffering capacity of CF children was higher than ECC children. When biofilm was mechanically controlled, carbonic anhydrase VI activity did not change after SR20% whereas the absence of mechanical control of biofilm reduced this enzyme activity after SR20%. In conclusion, the mechanical control of biofilm did not change saliva's ability to buffer the oral environment after SR20% in children with ECC. On the other hand, CF children appeared to regulate more effectively the saliva's pH than ECC children while the absence of mechanical control of biofilm mediated their pH-modifying ability after SR20%.

Unstimulated whole salivary flow in Sjögren's Syndrome: systematic literature review and meta-analysis.

BACKGROUND: Sjögren's Syndrome compromises the exocrine function, producing xerostomia and xerophthalmia. It can appear as an isolated condition or associated with other autoimmune diseases (polyautoimmunity). The Unstimulated Salivary Flow rate (UWSF) is used to quantify saliva production. There is no objective evidence to differentiate the values in patients with Sjögren's versus healthy people or patients with non-Sjögren's sicca. The objective of the present review was to evaluate the UWSF in patients with Sjögren's syndrome in comparison to controls (healthy and non-Sjögren's sicca patients). METHODS: A systematic literature review was carried out (PRISMA guidelines). Analytical observational studies of cases and controls, cross-sectional studies, cohort studies and randomized clinical trials (including healthy controls) were considered. The Medline/OVID, Lilacs, Embase, and Cochrane/OVID databases were consulted. MeSH, DeCS, keywords, and Boolean operators were used. The meta-analysis (RevMan 5.2) was done through the random-effects model [mean difference (MD)]. Level and quality of evidence were evaluated by the Oxford Center Levels of Evidence and Joanna Brigs list respectively. RESULTS: Thirty-two articles were included (20 were case-control studies, 6 were cross-sectional, 2 prospective cohort, 2 retrospective cohort, and 2 studies were abstracts) and 28 were meta-analyzed. The unstimulated whole salivary flow rate in the Sjögren's group was lower than in controls (healthy and patients with non-Sjögren Sicca syndrome) (MD-0.18 ml/min; 95% CI, - 0.24 to - 0.13; chi2-P-value < 0.00001). Heterogeneity was 97% and there was publication bias (funnel plot). The level of evidence was mostly 3 or 4. The quality of evidence was met (97% of items valued). CONCLUSION: For the first time, the unstimulated whole salivary flow rate is found to be lower in patients with Sjögren's syndrome compared to controls (healthy and non-SS sicca) through a meta-analysis. TRIAL REGISTRATION: PROSPERO CRD42020211325 .

If painters give you lemons, squeeze the knowledge out of them. A study on the visual perception of the translucent and juicy appearance of citrus fruits in paintings.

Citrus fruits are characterized by a juicy and translucent interior, important properties that drive material recognition and food acceptance. Yet, a thorough understanding of their visual perception is still missing. Using citrus fruits depicted in 17th-century paintings as stimuli, we ran three rating experiments. In Experiment 1, participants rated the perceived similarity in translucency or juiciness of the fruits. In Experiment 2, different groups of participants rated one image feature from a list obtained in a preliminary experiment. In Experiment 3, translucency and juiciness were rated. We constructed two-dimensional perceptual spaces for both material properties and fitted the ratings of the image features into the spaces to interpret them. "Highlights," "peeled side," "bumpiness," and "color saturation" fit the juiciness space best and were high for the highly juicy stimuli. "Peeled side," "intensity of light gradient," "highlights," and "color saturation" were the most salient features of the translucency space, being high for the highly translucent stimuli. The same image features were also indicated in a 17th-century painting manual for material depiction (Beurs, 1692; Beurs, in press). Altogether, we disclosed the expertise of painters with regard to material perception by identifying the image features that trigger a visual impression of juiciness and translucency in citrus fruits.

Salivary flow, amylase, and total protein in hospitalized patients with HIV infection / AIDS complications.

BACKGROUND: Saliva is a complex secretion produced daily by the salivary glands. Saliva consists mainly of water, enzymes, ions and amino acids and performs several important functions in oral health. OBJECTIVE: The aim of this study was to investigate the flow rate and concentrations of amylase and total proteins in the saliva of hospitalized patients due to AIDS complications. METHODS: Ninety-three men and women (20-64 years of age) were divided into two groups (46 HIV-infected patients and 47 controls) and had salivary flow rate and levels of amylase enzyme and total proteins evaluated. RESULT: The mean salivary flow rate was lower in individuals with HIV when compared to controls (P < 0.05). No significant difference between amylase enzyme levels and total proteins were observed in the saliva of patients with HIV infection when compared to controls. CONCLUSION: Individuals with HIV / AIDS infection (in hospital treatment) suffer no interference in levels of amylase and total salivary proteins, but they have significantly reduced salivary flow.

The effect of sublingual atropine sulfate on clozapine-induced hypersalivation: a multicentre, randomised placebo-controlled trial.

BACKGROUND: Hypersalivation and drooling are commonly reported in clozapine-treated patients. Current management strategies have been evaluated using subjective measures. Many case reports describe the successful use of atropine in the treatment of the condition. AIMS: To measure the effect and safety of sublingual atropine on nocturnal unstimulated saliva secretion. Secondary aims were to evaluate the patient's satisfaction with the atropine effect on hypersalivation (or sialorrhea), drooling, and sleep. METHOD: Twenty-one clozapine-treated patients with hypersalivation, or drooling, were randomised to take a single 600-µg dose of sublingual atropine drops or a matching placebo. The saliva secretion was measured over 5 min at baseline and 2 h after the administration of the study medication. RESULTS: Sublingual atropine reduced the saliva secretion significantly more than the placebo (mean difference = - 57.21%, 95% CI: - 104.30, - 10.11, P = 0.02). A significant decrease in standing pulse rate was recorded in the participants in the atropine group (- 5.8 (- 9.54, - 2.15), P = 0.002). Subjectively, more patients in the atropine group found their pillow to have less saliva the following morning and found their sleep to be better. CONCLUSIONS: Sublingual atropine drops significantly reduces nocturnal unstimulated clozapine-induced saliva secretion. More research is required to compare the effect of sublingual atropine with other anticholinergic medications and different dosage forms. TRIAL REGISTRATION: ACTRN12618000051246.

Sauce it up: influence of condiment properties on oral processing behavior, bolus formation and sensory perception of solid foods.

Condiments are rarely consumed on their own. Although addition of condiments to carrier foods is known to affect oral processing behavior and sensory perception, an understanding of how different condiment properties impact oral processing behavior and sensory perception of solid carrier foods is lacking. This study aimed to understand the role of condiments varying in composition and/or rheological properties in bolus formation facilitation, and how they influence oral processing behavior and sensory perception of solid carrier foods. Two carriers (bread, cooked potato) were combined with mayonnaises differing in fat content and viscosity. Addition of mayonnaises changed bolus properties of solid carrier foods considerably (i.e. decreased bread firmness, increased potato cohesiveness, increased lubrication of both bread and potato bolus) and, consequently, facilitated faster bolus formation. While addition of mayonnaises to bread and potatoes decreased the number of chewing cycles before swallowing, consumers did not change muscle activities or jaw movements per chew. No effect of mayonnaise fat content on oral processing behavior of composite foods was observed. Low viscosity mayonnaise resulted in faster bolus formation and swallowing compared to high viscosity mayonnaise. Low viscosity mayonnaise penetrated faster into bread boli leading to faster softening of bread boli. Also in the case of potato, low viscosity mayonnaise lead to faster bolus formation than for high viscosity mayonnaise. The low viscosity mayonnaise mixed more easily with potato bolus pieces, enhancing adhesion between pieces. Both mayonnaise fat content and viscosity influenced sensory perception of composite foods considerably, especially in terms of fattiness and creaminess. We conclude that oral processing behavior, bolus formation and sensory perception of solid carrier foods can be modified considerably by condiments. While composition and rheological properties of condiments have a large effect on bolus formation and sensory perception of solid carrier foods, these aspects have a limited effect on oral processing behavior of composite foods. Oral processing behavior is dominated by the properties of the solid carrier food. Tailoring condiment-carrier combinations could be an effective strategy to increase healthy eating, alter food intake for populations such as the elderly, and increase food appreciation.

Effects of lingual exercises on oral muscle strength and salivary flow rate in elderly adults: a randomized clinical trial.

AIM: The present study investigated the effects of two types of lingual exercise (tongue-hold swallowing and tongue-pressure resistance training) on oral muscle strength, salivary flow rate and subjective oral health of the elderly. METHODS: We randomly assigned 74 elderly adults (≥65 years) to three groups (tongue-hold swallowing, tongue-pressure resistance training and control groups). Each group participated in 8 weeks of their appropriately prescribed intervention. We measured anterior tongue strength, posterior tongue strength, lip strength, salivary flow rate and Oral Health Impact Profile-14 score before and after 8 weeks. Differences before and after intervention were observed with a paired sample t-test. Moreover, analyses of covariance and variance were performed to determine the differences in the measured values between the groups. RESULTS: The tongue-hold swallowing group showed improvement in both anterior and posterior tongue strength, while the tongue-pressure resistance training group showed a significant increase in only anterior tongue strength. Both the tongue-hold swallowing and tongue-pressure resistance training groups showed increased salivary secretion, with the tongue-pressure resistance training group showing a higher level of salivary secretion. However, the difference in the subjective oral health scores before and after the intervention was not significant. CONCLUSIONS: The two lingual exercises strengthened some aspects of tongue muscles and increased the salivary flow rate, with more salivary secretion in the tongue-pressure resistance training group than in the tongue-hold swallowing group. Any evidence of the lingual exercises being able to enhance subjective oral health could not be found. Geriatr Gerontol Int 2020; ••: ••-••.

Revisión de la literatura: composición salival y su relación con caries dental en embarazadas / Review of the literature: salivary composition and its relationship with dental caries in pregnant women

La saliva es un fluido complejo muy importante en las funciones de la cavidad bucal. El embarazo es un estado normal en el que el embrión se forma y evoluciona durante nueve meses. En este proceso la mujer sufre una serie de cambios fisiológicos y psicológicos. Entre ellos, tiene modificaciones en la saliva y, por consiguiente, en el flujo, pH y concentración de proteínas salivales, que desempeñan un papel importante en la protección contra la infección en los seres humanos. Su nivel en la cavidad oral está sujeto a constantes fluctuaciones que dependen de numerosos factores. El embarazo genera adaptaciones en la fisiología femenina que pueden repercutir en la salud bucal de la gestante. Las afecciones bucales más frecuentes son la caries dental y la gingivitis. Si estas afecciones no son tratadas a tiempo, pueden repercutir en la salud del futuro bebé. Se realizó una revisión bibliográfica con el objetivo de conocer acerca de los componentes de la saliva y su relación con caries dental en las embarazadas, considerando los tres trimestres de gestación (AU)

Saliva is a complex fluid very important in the functions of the oral cavity. Pregnancy is a normal state in which the embryo forms and evolves for nine months. In this process, women undergo a series of physiological and psychological changes. Among them, it has modifications in saliva and, consequently, in the flow, pH and concentration of salivary proteins, which play an important role in protecting against infection in humans. Its level in the oral cavity is subject to constant fluctuations that depend on numerous factors. Pregnancy generates adaptations in female physiology that can affect the oral health of the pregnant woman. The most common oral conditions are dental caries and gingivitis. If these conditions are not treated in time, they can affect the health of the future baby. A bibliographic review was carried out with the objective of knowing about the components of saliva and its relationship with dental caries in pregnant women, considering the three trimesters of gestation (AU)

Disruption of tight junctions contributes to hyposalivation of salivary glands in a mouse model of type 2 diabetes.

Tight junction (TJ) plays an important role in regulating paracellular fluid transport in salivary glands; however, little is known about the involvement of TJs in diabetes salivary glands. This study aimed to investigate the alterations of TJs and their possible contribution in diabetes-induced hyposalivation. Here, we observed that the morphologies of submandibular glands (SMGs) were impaired, characterized by enlarged acini accumulation with giant secretory granules, which were significantly reduced in atrophic ducts in SMGs of db/db mice, a spontaneous model of type-2 diabetes. However, the secretory granules were increased and scattered in the acini of diabetes parotid glands (PGs). Other ultrastructural damages including swollen mitochondria, expansive endoplasmic reticulum, and autophagosomes were observed in the diabetes group. The levels of TJ proteins including claudin-1 (Cldn1) and claudin-3 (Cldn3) were increased, whereas those of claudin-4 (Cldn4), occludin (Ocln), and zonula occludens-1 (ZO-1) were decreased in SMGs of db/db mice. Higher Cldn1 and Cldn3 and lower claudin-10 (Cldn10) and Ocln levels were observed in PGs of diabetes mice. Taken together, the structures of SMGs and PGs were impaired in diabetes mice, and the disruption of TJ integrity in both SMGs and PGs may contribute to diabetes-induced hyposalivation.

A preliminary study on submariners with xerostomia after a 3-month deployment.

To observe the clinical manifestations and salivary secretion of xerostomia patients in submariners who engaged in a three-month deployment. The general conditions and clinical examination of the 136 submariners were evaluated, by which the patients with xerostomia were screened out and their clinical manifestations were recorded. Besides, the flow rate of unstimulated saliva and stimulated saliva was measured and calculated. Subsequently, the related factors of xerostomia were quantitatively classified and statistically analyzed. In all the involved submariners, 42 were diagnosed to have xerostomia by physical examination after they returned from the task, among which 71.4% showed a decrease in unstimulated salivary flow rate and it was significantly correlated with the accompanying symptoms and their general conditions. Therefore, it was concluded that the occurrence of xerostomia could be related to the service life and job responsibilities of the submariners. The main manifestations were the reduction of unstimulated salivary secretion and the accompanying clinical symptoms such as cheilosis and angular cheilitis. Noticeably, the high psychological pressure and harsh living conditions need to be concerned, and further study should place more concentrations on these comprehensive influence factors and preventive actions of xerostomia.

Evaluation of oral mechanical and gustatory sensitivities and salivary cotinine levels in adult smokers.

Objective: The aim was to examine oral mechanical and gustatory sensitivities in adult smokers and to estimate salivary levels of cotinine by tobacco consumption. A total of 54 adults (20-45 years old; 28 males/26 females) were divided into two sex-paired groups: smoker group (n = 27), tobacco consumers with no other chronic disease/use of chronic medication, and a control non-smoker non-exposed group with similar age (n = 27).Materials and Methods: 24 h-Recall was used to gather information about tobacco consumption, date of onset and duration of the habit. Oral mechanical evaluation comprised touch detection threshold (MDT) of upper and lower lips and tongue tip and two-point discrimination (TPD) assessments. Taste sensitivities for sweet, salty, sour and bitter were evaluated in four concentrations. Salivary cotinine was determined by high performance liquid chromatography. Statistical analysis comprised Mann-Whitney, Two-way ANOVA test and regression analysis.Results: The mean smoking time was 13.6 years (mean 8.4 mg/day; 13 cigarettes/day). A sex-effect was observed on MDT of tongue tip (higher sensitivity in females), while group-effect was observed on TPD of lower lip, showing a smaller sensitivity among smokers (p < .05; moderate effect: Eta partial2 = 0.076). Although the total score of gustatory sensitivity did not differ between groups, smokers exhibited an irregular pattern of correctly identified tastants among the different concentrations of salty, sour and bitter. The predictive model showed that salivary cotinine was dependent on "nicotine consumption on the day before" (R2 = 49%).Conclusion: A difference in tactile sensitivity of the lower lip and qualitative changes in taste sensitivity were observed in smokers.

Impact of food odors signaling specific taste qualities and macronutrient content on saliva secretion and composition.

Olfactory food cues can induce appetite for similar food products in humans. Odors may thus signal essential information about a foods' composition such as taste or even macronutrient content and may stimulate specific physiological responses in anticipation of food intake. Several studies have shown that sensory food cues could stimulate saliva secretion. However, potential differences between food odors in their effect on saliva secretion, or the effects of olfactory stimulation on changes in saliva composition remain to be elucidated. To gain more insight, we conducted two studies to determine the influence of various odors, representing different taste qualities (study 1) and macronutrients (study 2), on salivary biomarkers. In study 1, 36 participants were randomly exposed to no-odor, non-food, and odors signaling sweet, savory, and sour taste. In study 2, 60 participants were randomly exposed to no-odor, non-food, and odors signaling carbohydrates, protein, fat, and low-calorie food. For each condition, whole-mouth saliva was collected and saliva secretion rate determined. Furthermore, we determined mouth-watering perception (subjective salivation), visco-elasticity (study 1 only), mucin concentration, α-amylase and lingual lipase activity (study 2 only). For both studies, linear mixed model analyses showed that saliva secretion rate significantly increased by food odor exposure compared to no-odor and non-food conditions. However, no changes in salivary composition were observed. These findings indicate that food odors play a crucial role in anticipatory saliva responses and can thereby affect subsequent eating behavior.

Influence of olfactory dysfunction on the perception of food.

PURPOSE: Eating-related problems are among the most frequent issues in olfactory impairment, causing a noticeable loss of quality of life for some of the affected persons. To what extent olfactory dysfunction impacts on the sensory perception of food is less explored. The aim of the present study was to examine the impact of olfactory dysfunction on the perception of food aromas, as well as the perception of the "basic tastes" salty, sour, sweet, and bitter. METHODS: Eighty-nine participants were recruited for the prospective study. Group 1 consisted of thoroughly examined patients with olfactory dysfunction (n = 48, mean age = 60.0 years), group 2 consisted of people with normal olfactory function (n = 41, mean age = 50.4 years). First, olfactory and gustatory functions were assessed for all participants with the help of the "Sniffin'Sticks" battery and the "taste strips" test. Second, food odors were rated for their pleasantness, intensity, familiarity and desirability. Last, real food items were tasted orally and the intensity for basic taste qualities (sweet, bitter, salty, and sour) and pleasantness was rated. In addition, salivation was measured following exposure to the food odors. RESULTS: In comparison to controls, patients rated orthonasal food odors as less pleasant, intense, familiar, and less appetizing. "Taste strip" scores were significantly lower in patients (M = 9.56, SD = 2.76) as compared to controls (M = 10.88, SD = 1.89). In addition, ratings of food liking for chocolate and peanut were lower in patients compared to controls (chocolate: patients-M = 6.85, SD = 2.09, controls-M = 7.90, SD = 1.53; peanut: patients-M = 4.88, SD = 2.20, controls-M = 6.80, SD = 2.33). No significant differences were found regarding the comparison of the salivary flow rate in controls (M = 0.52 g/min, SD = 0.19) and patients (M = 0.50 SD = 0.17). CONCLUSIONS: Changes in the perception of odors may change the perception of food with specific effects on food liking. Olfactory dysfunction affects gustatory function, indicating the central-nervous interaction between taste and smell. Still, olfactory dysfunction did not appear to affect patients' salivary flow.