Salivary Flow Decreases in Healthy Elderly People Independently of Dental Status and Drug Intake

Comprehensive review of dysphagia and technological advances in dysphagia food

As the global population ages, dysphagia is becoming increasingly common among the elderly, posing serious risks such as choking, aspiration pneumonia, and even death. Leveraging advanced technologies to develop specialized food products for those with dysphagia not only serves the economic interests of the elderly food market but also significantly enhances the nutritional health and social satisfaction of this demographic. This review examines the causes and early symptoms of dysphagia, the development of texture-modified foods (TMFs), and the relevant regulations and standards. It also addresses the key factors influencing the swallowing of foods, focusing on rheology and tribology. Most texture-modified foods currently available do not provide an enjoyable eating experience for the elderly or those with dysphagia. The integration of artificial intelligence (AI) and mathematical modeling with food additive manufacturing technology appears promising for improving foods designed for the elderly and those with dysphagia. This paper highlights the critical benefits and potential applications of AI, mathematical modeling, and food additive manufacturing in creating dysphagia-friendly foods and provides a conceptual system for designing diets based on AI for dysphagic foods. AI and mathematical model-based food processing technology enable the food industry to achieve digitalization and large-scale customization, potentially revolutionizing the approach to dietary management in dysphagia.

Characteristics of Salivary Iodine Concentration in Elderly Residents of High-iodine Areas

Salivary iodine is considered a potential indicator for assessing iodine nutrition status. However, there is currently a lack of research data on the characteristics of salivary iodine concentration (SIC) in the elderly population. To evaluate the characteristics of SIC and assess its efficacy in diagnosing thyroid disorders among the elderly population, a cross-sectional study was conducted in a high-iodine area. Spot urine, 24-h urine, saliva, drinking, and cooking water samples were collected from the elderly participants. Iodine concentrations were measured in all these samples. Fasting venous blood samples were obtained to assess thyroid function. The study included 1387 elderly individuals from urban (n = 707) and rural (n = 680) areas. Rural residents showed significantly higher median concentration of cooking water iodine (CWIC) and SIC compared to urban residents (P < 0.001). The median SIC in rural elderly was 2733.3 μg/L versus 860.4 μg/L in urban elderly. SIC demonstrated a significant positive correlation with age (P < 0.001). Multiple linear regression analysis revealed significant positive associations between SIC and drinking water iodine concentration (β = 0.341, 95% CI 0.312-0.370), CWIC (β = 0.393, 95% CI 0.356-0.431), thyroid dysfunction (β = 0.107, 95% CI 0.050-0.164), and goiter (β = 0.236, 95% CI 0.129-0.342). Logistic regression showed that higher SIC levels were associated with increased risk of thyroid dysfunction, with odds ratios ranging from 1.649 to 1.994 for ascending SIC categories. The elderly residents in high-iodine areas, particularly in rural settings, exhibit elevated salivary iodine concentrations that increase with age. These high-iodine levels are significantly associated with an increased risk of thyroid dysfunction.

Impact of aging on the digestive system related to protein digestion in vivo

For the current aging population, protein is an important macronutrient to counteract the development of sarcopenia. Protein digestion is influenced by the capacity of the digestive system. The current evidence is reviewed about the impact of aging on the human digestive system and related to protein digestion in vivo. Aging changes the digestive organs which impacts protein digestion. Dentition decreases and mastication changes, potentially affecting particle size reduction. Stomach gastric acidity is unchanged, gastric emptying is delayed, while total transit time remains unchanged. Production of enzymes by the pancreas is decreased, but any changes in the small intestine remain unresolved. Animal studies showed decreased fecal protein digestion in older compared to young animals. Human studies showed decreased postprandial peripheral plasma appearance of ingested amino acids and increased splanchnic extraction. The findings suggest that the deteriorating digestive system with aging results in decreased protein digestion. Interpretation of the results should be taken with caution because of interindividual differences in the aging process, and because studies on protein digestion in aging humans are scarce. More information is needed on healthy aging and its relation to the digestive tract and protein digestion, several methods including in vitro experiments are valuable in this perspective.

Astringency sensitivity to tannic acid: Effect of ageing and salivary proline-rich protein levels

The link between salivary composition and sensitivity to astringency as a function of age has still not been established. In this work, we propose the hypothesis that ageing leads to changes in the concentration of salivary proline-rich proteins (PRPs), which alters the astringency perception threshold with age. To test this hypothesis, astringency sensitivity to tannic acid and saliva was assessed in 30 elderly people and 24 young people. Basic PRPs (bPRPs) and glycosylated PRPs (gPRPs) were quantified immunochemically via western blot analysis. The results showed that the amounts of bPRPs and gPRPs were similar between the young and elderly groups. However, a positive correlation between the gPRP amount and astringency threshold was observed only in the young group, while a negative correlation between the bPRP amount and astringency threshold was observed only in the elderly group. This finding suggests differences in the contribution of PRP type to astringency perception as a function of age.

The Feel of Speech: Multisystem and Polymodal Somatosensation in Speech Production

PURPOSE

The oral structures such as the tongue and lips have remarkable somatosensory capacities, but understanding the roles of somatosensation in speech production requires a more comprehensive knowledge of somatosensation in the speech production system in its entirety, including the respiratory, laryngeal, and supralaryngeal subsystems. This review was conducted to summarize the system-wide somatosensory information available for speech production.

METHOD

The search was conducted with PubMed/Medline and Google Scholar for articles published until November 2023. Numerous search terms were used in conducting the review, which covered the topics of psychophysics, basic and clinical behavioral research, neuroanatomy, and neuroscience.

RESULTS AND CONCLUSIONS

The current understanding of speech somatosensation rests primarily on the two pillars of psychophysics and neuroscience. The confluence of polymodal afferent streams supports the development, maintenance, and refinement of speech production. Receptors are both canonical and noncanonical, with the latter occurring especially in the muscles innervated by the facial nerve. Somatosensory representation in the cortex is disproportionately large and provides for sensory interactions. Speech somatosensory function is robust over the lifespan, with possible declines in advanced aging. The understanding of somatosensation in speech disorders is largely disconnected from research and theory on speech production. A speech somatoscape is proposed as the generalized, system-wide sensation of speech production, with implications for speech development, speech motor control, and speech disorders.

The role of the soft palate dose regarding normal tissue toxicities in older adults with head and neck cancer undergoing definitive radiotherapy

PURPOSE

The number of older adults with head and neck squamous cell carcinoma (HNSCC) is continuously increasing. Older HNSCC patients may be more vulnerable to radiotherapy-related toxicities, so that extrapolation of available normal tissue complication probability (NTCP) models to this population may not be appropriate. Hence, we aimed to investigate the correlation between organ at risk (OAR) doses and chronic toxicities in older patients with HNSCC undergoing definitive radiotherapy.

METHODS

Patients treated with definitive radiotherapy, either alone or with concomitant systemic treatment, between 2009 and 2019 in a large tertiary cancer center were eligible for this analysis. OARs were contoured based on international consensus guidelines, and EQD2 doses using α/ß values of 3 Gy for late effects were calculated based on the radiation treatment plans. Treatment-related toxicities were graded according to Common Terminology Criteria for Adverse Events version 5.0. Logistic regression analyses were carried out, and NTCP models were developed and internally validated using the bootstrapping method.

RESULTS

A total of 180 patients with a median age of 73 years fulfilled the inclusion criteria and were analyzed. Seventy-three patients developed chronic moderate xerostomia (grade 2), 34 moderate dysgeusia (grade 2), and 59 moderate-to-severe (grade 2-3) dysphagia after definitive radiotherapy. The soft palate dose was significantly associated with all analyzed toxicities (xerostomia: OR = 1.028, dysgeusia: OR = 1.022, dysphagia: OR = 1.027) in the multivariable regression. The superior pharyngeal constrictor muscle was also significantly related to chronic dysphagia (OR = 1.030). Consecutively developed and internally validated NTCP models were predictive for the analyzed toxicities (optimism-corrected AUCs after bootstrapping: AUCxerostomia=0.64, AUCdysgeusia=0.60, AUCdysphagia=0.64).

CONCLUSIONS

Our data suggest that the dose to the soft palate is associated with chronic moderate xerostomia, moderate dysgeusia and moderate-to-severe dysphagia in older HNSCC patients undergoing definitive radiotherapy. If validated in external studies, efforts should be undertaken to reduce the soft palate dose in these patients.

From static to semi-dynamic in vitro digestion conditions relevant for the older population: starch and protein digestion of cooked lentils

In the context of adequately feeding the rising older population, lentils have an important potential as sources of (plant-based) protein as well as slowly digestible bio-encapsulated starch and fibre. This study evaluated in vitro digestion of protein and starch in lentils under conditions representing the gastrointestinal tract of older adults. Both static and semi-dynamic simulations were applied to analyze the effect of specific gastrointestinal conditions (healthy versus older adult) on macronutrient digestion patterns. Gastric proteolysis was strongly dependent on applied gastric pH (gradient), leading to a lower extent of protein hydrolysis for simulations relevant for older adults. Fewer and smaller (lower degree of polymerization, DP) bioaccessible peptides were formed during gastric proteolysis under older adult compared to healthy adult conditions. These differences, developed during the in vitro gastric phase, were compensated during small intestinal digestion, yielding similar final proteolysis levels regardless of the applied simulation conditions. In contrast, in the presence of saliva, amylolysis was generally accelerated under older adult conditions. Moreover, the current work highlighted the importance of considering saliva (or salivary amylase) incorporation in simulations where the applied gastric pH (gradient) allows salivary amylase activity. Under both healthy and older adult conditions, in vitro starch hydrolysis bio-encapsulated in cotyledon cells of cooked lentils was attenuated, compared to a white bread reference.

Gemigliptin Improves Salivary Gland Dysfunction in D-Galactose-Injected Aging Rats

Oral dryness is among the most common conditions experienced by the elderly. As saliva plays a crucial role in maintaining oral health and overall quality of life, the condition is increasingly taking its toll on a rapidly growing aging population. D-galactose (D-gal) stimulates their formation, which in turn cause oxidative stress and accelerate age-related decline in physical function. In this study, we observed a reduction in salivary secretion and amylase levels in aged rats injected with D-gal, confirming salivary gland dysfunction. Treatment with gemigliptin increased DPP-4 inhibition and GLP-1 levels in the salivary glands of aging rats and reduced the expression of AGEs and receptors for advanced glycation end products (RAGE). This effect was caused by the presence of additional reactive oxygen species (ROS) in the salivary glands of the examined rats. Gemigliptin's cytoprotective effect reduced amylase and mucin accumulation and increased AQP5 expression, which are important indicators of salivary gland function. In sum, gemigliptin was shown to improve D-gal-induced decline in the salivary gland function of aged rats through its anti-glycation and antioxidant activities. Gemigliptin shows promise as a treatment strategy for patients experiencing decreased salivary function associated with their advancing age.

Parameters to Consider for Successful Medication Use in Older Adults - an AGePOP Review

Older adults are the main users of medicine and due to their multimorbidity are often faced/confronted with a complex medication management. This review article provides a brief overview on aspects of medication management such as maintaining a stock of the required medicine, understanding and following the instructions for use, coping with the primary and secondary packaging as well as preparation prior to use. The main focus however is on the drug intake itself and provides an overview about the current understanding of real life dosing conditions of older adults and geriatric patients. Furthermore, it elaborates the acceptability of dosage forms, in particular solid oral dosage forms as they represent the majority of dosage forms taken by these patient populations. An improved understanding of the needs of older adults and geriatric patients, their acceptability of various dosage forms and the circumstances under which they manage their medications, will make the design of more patient-centric drug products possible.

Fluoridated milk enhances the mineral density of artificial proximal carious lesions in situ

OBJECTIVE

To compare the mineral density (MD) of non-fluoridated-milk (non-F-milk), fluoridated-milk (F-milk), adjunctive to 1000-ppm-fluoride dentifrice (FD), and 1000-ppm-FD alone of proximal artificial enamel carious lesions (AECL) in high caries-risk patients.

MATERIALS AND METHODS

This double-blind, cross-over in situ study comprised seven high caries-risk volunteers. Orthodontic brackets with one slab of AECL were fixed randomly to each volunteer per phase. The study comprised three experimental periods with a 7-d wash-out period using FD between sessions; (1) A four-week tooth brushing with FD 2×/day by all subjects as a control. The participants were then randomly allocated to (2) drinking 2.5-ppm-F-milk 1×/day or (3) non-F-milk 1×/day, adjunctive to tooth-brushing with FD for 4-weeks. The subjects crossed over from each type of milk and continued the same protocol for another four weeks. After each phase, the MD of each specimen was analyzed using micro-computed tomography (Micro-CT).

RESULTS

The baseline MD was not significantly differences (p = .653). When brushing with FD and drinking F-milk, the MD gain was significantly higher (11.68 ± 2.89%) compared with brushing with FD and drinking non-F-milk (4.59 ± 1.78%) (p = .003) or brushing with FD alone (5.30 ± 2.10%) (p = .003).

CONCLUSIONS

F-milk adjunctive to FD significantly increased MD gain compared with non-F-milk + FD or FD alone.

Designing food for the elderly: the critical impact of food structure

Ageing is an unavoidable progressive process causing many changes of the individual life. However, if faced in an efficient way, living longer in a healthy status could be an opportunity for all. In this context, food consumption and dietary patterns are pivotal factors in promoting active and healthy ageing. The development of food products tailored for the specific needs of the elderly might favour the fulfilment of nutritionally balanced diets, while reducing the consequences of malnutrition. To this aim, the application of a food structure design approach could be particularly profitable, being food structure responsible to the final functionalities of food products. In this narrative review, the physiological changes associated to food consumption occurring during ageing were firstly discussed. Then, the focus shifted to the possible role of food structure in delivering target functionalities, considering food acceptability, digestion of the nutrients, bioactive molecules and probiotic bacteria.

Interactions between Salivary Proteins and Dietary Polyphenols: Potential Consequences on Gastrointestinal Digestive Events

The present review documents the current knowledge and hypotheses on how polyphenols-saliva interactions may modulate the bioaccessibility or bioavailability of nutrients and highlights research prospects in the field. After an updated description of the different classes of dietary polyphenols and their modifications by food processing or digestion, an overview of interactions between salivary proteins and polyphenols (with an emphasis on tannins) is provided. In vitro studies show that the solubility of salivary protein-tannin complexes in gastric conditions depends on the degree of tannin polymerization, while complexes are partly solubilized by bile salts. Salivary proteins-polyphenols interactions may affect digestive processes. For example, polyphenols can bind to and inhibit salivary amylase, with downstream consequences on starch digestion. Some salivary proteins (PRPs) prevent tannin-induced reduced protein digestibility, probably through binding tannins before they interact with digestive proteases. Salivary proteins may also act as scavenger molecules to limit the intestinal uptake of tannins.

Guiding the formulation of soft cereal foods for the elderly population through food oral processing: Challenges and opportunities

As the elderly population is growing steadily, more age-friendly food products that allow them to cover their nutritional needs and are enjoyable need to be designed. Since their oral physiology is considerably altered, the study of Food Oral Processing has become an essential discipline in food development, as it takes into consideration the complex interactions between food structure, oral processing, physiology and perception. Cereals are staple foods in many countries, and their consumption as bakery products is popular among the elderly population. In addition, when fortified with pulse proteins, they can help meet the protein needs of seniors and help fight against sarcopenia. For these reasons, this chapter presents an overview of the various aspects involved in the oral processing and formulation of soft cereal foods, translating them into challenges and opportunities that are of relevance to the design of realistic soft cereal foods targeted for the elderly that are nutritious and sensory appealing. This review focuses on the healthy elderly population and does not intend to cover the needs of the dependent elderly suffering from chronical diseases.

Astringency Sensitivity to Tannic Acid: Effect of Ageing and Saliva

Astringency is an important sensory characteristic of food and beverages containing polyphenols. However, astringency perception in elderly people has not been previously documented. The aim of the present work was to evaluate sensitivity to astringency as a function of age, salivary flow and protein amount. Fifty-four panellists, including 30 elderly people (age = 75 ± 4.2 years) and 24 young people (age = 29.4 ± 3.8 years), participated in this study. Astringency sensitivity was evaluated by the 2-alternative forced choice (2-AFC) procedure using tannic acid solutions. Whole saliva was collected for 5 min before and after the sensory tests. The results showed that the astringency threshold was significantly higher in the elderly group than the young group. No correlation was observed between the salivary protein amount and threshold value. However, a negative correlation between salivary flow and threshold was observed in the young group only. These results showed a difference in oral astringency perception as a function of age. This difference can be linked to salivary properties that differ as a function of age.

A secret of salivary secretions: Multimodal effect of saliva in sensory perception of food

Saliva plays multifunctional roles in oral cavity. Even though its importance for the maintenance of oral health has long been established, the role of saliva in food perception has attracted increasing attention in recent years. We encourage researchers to discover the peculiarity of this biological fluid and aim to combine the data concerning all aspects of the saliva influence on the sensory perception of food. This review presents saliva as a unique material, which modulates food perception due to constant presence of saliva in the mouth and thanks to its composition. Therefore, we highlight the salivary components that contribute to these effects. Moreover, this review is an attempt to structure the effects of saliva on perception of different food categories, where the mechanisms of salivary impact in perception of liquid, semi-solid, and solid foods are revealed. Finally, we emphasize that the large inter-individual variability in salivary composition and secretion appear to contribute to the fact that everyone experiences food in their own way. Therefore, the design of the sensory studies should consider the properties of volunteers' saliva and also carefully monitor the experimental conditions that affect salivary composition and flow rate.

Understanding protein digestion in infants and the elderly: Current in vitro digestion models

The last decades have witnessed a surge of interest in the fate of dietary proteins during gastrointestinal (GI) digestion. Although several in vitro digestion models are available as alternatives to clinical experiments, most of them focus on the digestive conditions of healthy young adults. This study investigates the static/dynamic models used to simulate digestion in infants and the elderly and considers the related in vivo conditions. The in vitro digestive protocols targeting these two groups are summarized, and the challenges associated with the further development of in vitro digestion models are discussed. Static models rely on several factors (e.g., enzyme concentration, pH, reaction time, and rotation speed) to differentiate digestive conditions depending on age. Dynamic models can more accurately simulate the complex digestion process and allow the inclusion of further parameters (sequential secretion of digestive fluids, gradual changes in pH, peristaltic mixing, GI emptying, and the inoculation of luminal microbiota). In the case of infants, age or growth stage clarification and the differentiation of digestive protocols between full-term and preterm infants are required, whereas protocols dealing with various health statuses are required in the case of the elderly, as this group is prone to oral cavity and GI function deterioration.

Relationship among oral health status, bolus formation and food comfortability during consumption of model cheeses in elderly

The aim of this study was to investigate the impact of oral impairment on chewing behaviour, food bolus properties and food comfortability during elderly consumption of model cheeses. Seventy-two elderly persons (aged 66 to 88) was recruited and classified into two groups according to dental status (poor vs. satisfactory). They showed a wide range of salivary flow rates whatever their dental status (stimulated: 0.2-3.8 mL min^-1, resting: 0.1-0.8 mL min^-1). Standardized bites of four model cheeses with an identical composition but different textures (soft, hard, processed and whipped) were tested. The time and number of chewing cycles required to form a bolus were measured. The rheological properties of the bolus were studied, as was saliva moistening. Food comfortability was assessed by means of a questionnaire composed of 5 sections (1-oral comfort, 2-bolus formation, 3-pain, 4-texture and 5-flavour perception). The chewing parameters measured were not modified by the oral health. However, elderly with poor dentition formed harder boluses than elderly with satisfactory dentition. Moreover, for elderly with poor dentition, the quantity of saliva incorporated into the bolus was correlated with the stimulated salivary flow rate, which was not the case for elderly with satisfactory dentition. General oral comfort and its different attributes were poorly associated with the oral health of the elderly. A multifactorial analysis performed on an average cheese showed that food comfortability is independent of changes in the hardness and moistening of the bolus, regardless of dental status. In particular, poor dental status increases the hardness of the bolus without modifying its comfortability.

Food-related oral discomfort: A cross-sectional survey assessing the sensory dimension of oral discomfort in French independently living adults

BACKGROUND

Discomfort encountered during oral processing may cause food avoidance and increase the risk of malnutrition in older adults. The aim of the present survey was to explore the relationships between oral health and the oral discomfort experienced while eating in senior people.

MATERIALS AND METHODS

In a cross-sectional study, oral discomfort was assessed in a sample of 119 independently living participants aged between 35 and 81 years. Statistical analyses were used to identify categorical variables associated with food-related oral discomfort, including age, oral health-related quality of life (OHQoL), saliva secretion, occluding support, oral diseases and denture use.

RESULTS

Food-related oral discomfort concerned 28.5% of the participants. Within the sample study, the risk of experiencing food-related oral discomfort was increased for participants perceiving average (OR = 7.968, CI 95% = 2.603-24.381, p = .000) or poor OHQoL (OR = 17.109, CI 95% = 4.398-66.552, p = .000) and presenting strictly fewer than 7 occlusal functional units (OFUs) (OR = 3.396, CI 95% = 1.206-9.561, p = .020). Textured foods including fibrous (66.6%), heterogenous (60.6%) and grainy foods (42.4%) were mostly cited as food-related oral discomfort trigger factors. Within the 66-80 years group, participants having 0-6 OFUs were four times more likely to experience oral discomfort related to fibrous foods than participants having more than 7 OFUs (OR = 4.812, CI 95% = 1.192-19.415, p = .024). Within this group, participants having their teeth replaced by denture were also four times more likely to develop oral discomfort related to foods with heterogeneous textures (OR = 4.714, CI 95% = 1.030-21.562, p = .045) and grainy foods (OR = 7.285, CI 95% = 1.308-40.568, p = .023) than non-denture wearers.

CONCLUSION

Poor oral health conditions may generate oral discomfort with foods in the elderly especially with fibrous, heterogenous and grainy textures, and thus affect mealtime experience.

The salivary proteome reflects some traits of dietary habits in diabetic and non-diabetic older adults

PURPOSE

Objective markers of usual diet are of interest as alternative or validating tools in nutritional epidemiology research. The main purpose of the work was to assess whether saliva protein composition can reflect dietary habits in older adults, and how type 2 diabetes impacted on the saliva-diet correlates.

METHODS

214 participants were selected from 2 European cohorts of community-dwelling older adults (3C-Bordeaux and Seniors-ENRICA-2), using a case-control design nested in each cohort. Cases were individuals with type 2 diabetes. Dietary information was obtained using the Mediterranean Diet Adherence Screener (MEDAS). Saliva was successfully obtained from 211 subjects, and its proteome analyzed by liquid chromatography-tandem mass spectrometry.

RESULTS

The relative abundance of 246 saliva proteins was obtained across all participants. The salivary proteome differed depending on the intake level of some food groups (especially vegetables, fruits, sweet snacks and red meat), in a diabetic status- and cohort-specific manner. Gene Set Enrichment Analysis suggested that some biological processes were consistently affected by diet across cohorts, for example enhanced platelet degranulation in high consumers of sweet snacks. Minimal models were then fitted to predict dietary variables by sociodemographic, clinical and salivary proteome variables. For the food group «sweet snacks», selected salivary proteins contributed to the predictive model and improved its performance in the Seniors-ENRICA-2 cohort and when both cohorts were combined.

CONCLUSION

Saliva proteome composition of elderly individuals can reflect some aspects of dietary patterns.

Food perception, lifestyle, nutritional and health status in the older people: Typologies and factors associated with aging well

The aging process is associated with physiological, sensory, psychological, and sociological changes likely to have an impact on food intake and the nutritional status. The present study aimed to explore the heterogeneity of the French older population (>65 years old) using a multidisciplinary approach. More specifically, the study aimed to highlight different typologies (i.e. clusters of individuals with similar characteristics) within the older population. We conducted face-to-face interviews and tests with 559 French older people, recruited from different categories of dependency (at home without help, at home with help, in nursing homes). Clustering analysis highlighted seven clusters. Clusters 1-3 contained 'young' older people (<80) with a good nutritional status; these clusters differed according to food preferences, the desire to have a healthy diet, or interest in food. Clusters 4-7 mainly contained 'old' older people (80+), with an increase in the nutritional risk from cluster 4 to cluster 7. Two of these clusters grouped healthy and active people with a good level of appetite, while the two other clusters were associated with a clear decline in nutritional status, with people suffering from eating difficulties or depression. The results raise the need to develop targeted interventions to tackle malnutrition and implement health promotion strategies among the seniors.

Whey Protein Derived Mouthdrying Found to Relate Directly to Retention Post Consumption but Not to Induced Differences in Salivary Flow Rate

Whey protein is fortified into beverages to provide functional benefits, however, these beverages are considered mouthdrying. To date whey protein derived mouthdrying has not been quantified using a 'physical measure' in parallel with rated perception. Saliva flow could also relate to whey protein derived mouthdrying, however this has not been previously tested as an intervention. Accordingly, volunteers (n = 40) tested mouthdrying in different whey beverages and the sensory profile was evaluated by a trained sensory panel (n = 10). Volunteers also rated mouthdrying combined with collection of saliva samples post beverage consumption to measure retention to the oral cavity. To modulate saliva flow rate, volunteers both chewed on parafilm (to increase saliva flow) and used cotton wool (to remove saliva) before tasting beverages and rating mouthdrying. Both the volunteers and sensory panel rated whey protein beverages (WPB) as significantly more mouthdrying than the control beverage (whey permeate). The significantly higher rating of mouthdrying from the volunteers coincided with significantly higher protein concentration in saliva samples post WPB consumption, supporting mucoadhesion as the mechanism. Modulating saliva flow did not lead to any difference in rated mouthdrying and future work would be beneficial to evaluate further the influence of natural variation in salivary flow rate.

Influence of Age and Individual Differences on Mouthfeel Perception of Whey Protein-Fortified Products: A Review

Protein needs are considered to increase with age, with protein consumption being associated with many positive outcomes. Protein-fortified products are often used to improve nutritional status and prevent age-related muscle mass loss in older adults. Accordingly, older adults are commonly provided with products fortified with whey protein; however, such products can cause mouthdrying, limiting consumption and product enjoyment. Currently, the extent to which age and individual differences (e.g., saliva, oral health, food oral processing) influence the perception of whey protein-derived mouthdrying is relatively unclear. Previous research in this area has mainly focused on investigating mouthdrying, without taking into account individual differences that could influence this perception within the target population. Therefore, the main focus of this review is to provide an overview of the relevant individual differences likely to influence mouthfeel perception (specifically mouthdrying) from whey protein-fortified products, thereby enabling the future design of such products to incorporate better the needs of older adults and improve their nutritional status. This review concludes that age and individual differences are likely to influence mouthdrying sensations from whey protein-fortified products. Future research should focus more on the target population and individual differences to maximise the benefits from whey protein fortification.

Relationship between age and sex and the numbers of ingestions and swallows for foods of different textures among healthy adults

BACKGROUND

The number of swallows needed per single ingestion of food is an important index when assisting a patient with dysphagia in eating. While providing meal assistance, the caregiver may assume that one ingestion is completed with one swallow and then may administer the next ingestion even if the individual's mouth still has remaining food from the previous ingestions, increasing the risk for aspiration and choking.

OBJECTIVE

The objective of this pilot study was to clarify the differences in foods ingested and swallowed because of influencing factors such as age and gender among healthy adults.

METHODS

The study enrolled 110 healthy adults (47.4 ± 15.8 years; 57 males, 53 females). The numbers of ingestions and swallows were counted and evaluated by food type (pilaf, 100 g; yogurt 80 g; and sponge cake, 35 g) and participant age and sex and analyzed by least-squares multiple regression analysis.

RESULTS

The mean numbers of ingestion/swallows were pilaf, 12.5 ± 3.2/13.4 ± 4.2; yogurt, 8.8 ± 2.1/10.8 ± 2.1; and sponge cake, 5.8 ± 2.1/7.0 ± 2.1. The mean number of ingestions and swallows for all foods were higher for female participants compared with male participants. Statistical analysis identified sex as a significant influencing factor for the number of ingestion for all foods. For the number of swallows, the significant influencing factors were sex for sponge cake and age for pilaf and yogurt.

CONCLUSION

For the test foods of different textures, sex and age were significant influencing factors for the numbers of ingestions and swallows. Further research is needed to elucidate the problem areas in this pilot study.

Aging and the (Chemical) Senses: Implications for Food Behaviour Amongst Elderly Consumers

The growing aging population are increasingly suffering from the negative health consequences of the age-related decline in their senses, especially their chemical senses. Unfortunately, however, unlike for the higher senses of vision and hearing, there is currently nothing that can be done to bring back the chemical senses once they are lost (or have started their inevitable decline). The evidence suggests that such chemosensory changes can result in a range of maladaptive food behaviours, including the addition of more salt and sugar to food and drink in order to experience the same taste intensity while, at the same time, reducing their overall consumption because food has lost its savour. Here, though, it is also important to stress the importance of the more social aspects of eating and drinking, given the evidence suggesting that a growing number of older individuals are consuming more of their meals alone than ever before. Various solutions have been put forward in order to try to enhance the food experience amongst the elderly, including everything from optimising the product-intrinsic food inputs provided to the remaining functional senses through to a variety of digital interventions. Ultimately, however, the aim has to be to encourage healthier patterns of food consumption amongst this rapidly-growing section of the population by optimising the sensory, nutritional, social, and emotional aspects of eating and drinking. An experimental dinner with the residents of one such home where nostalgic-flavoured healthy ice-creams were served is described.

Differences in oral processing behavior of consumers varying in age, gender and ethnicity lead to changes in bolus properties but only to small differences in dynamic texture perception of sausages

Consumer characteristics such as age, gender and ethnicity influence food oral processing behavior. The aim of this study was to determine the effect of age, gender and ethnicity on consumption time, bolus properties and dynamic sensory perception of sausages. Consumption time, bolus properties (saliva incorporation, particle size distribution and rheological properties) and dynamic texture perception (Temporal Dominance of Sensations, TDS) of sausages were compared between young Dutch, Caucasians (n = 21; 22 ± 2.8 years), young Chinese, Asians (n = 21; 23 ± 1.6 years), and elderly Dutch, Caucasians (n = 22; 70 ± 4.3 years). Elderly Dutch masticated the sausage 22% longer (25.6 s) than young Dutch consumers (21.0 s). Elderly Dutch produced sausage boli that were softer, more adhesive, less cohesive and contained more particles than those of young Dutch adults. Elderly females produced more adhesive and less cohesive sausage bolus than males. Young Chinese females had 75.6% longer consumption time (29.5 s) than young Dutch females (16.8 s). Young Chinese males masticated the sausages in less time (18.8 s) than young Chinese females (29.5 s). Young Chinese produced softer and less cohesive bolus with slightly smaller and more particles than young Dutch. Saliva incorporation and bolus particle size were not affected by age, gender and ethnicity. Mediation analysis revealed that the effect of consumer characteristics such as age, gender and ethnicity on bolus properties was mediated by consumption time. At the beginning and end of consumption time, dynamic texture perception of sausages was similar for all consumer groups and strongly correlated with bolus properties. Differences in dynamic texture perception between consumer groups were observed only during the middle stages of mastication with low dominance rates. We conclude that consumers differing in age, gender and ethnicity vary in oral processing time to produce bolus with textural properties optimized to their needs. Furthermore, consumption time is the underlying mechanism that explains the differences in bolus properties between the consumer groups. While variations in consumption time of sausages lead to considerable differences in bolus properties, it only leads to small differences in dynamic texture perception.

Physiological and oral parameters contribute prediction of retronasal aroma release in an elderly cohort

Malnutrition is a serious problem in the elderly while understanding flavour perception could be a tool for controlling appetite or food choices. To increase our knowledge, we characterised the health and oral physiology (oral volume, swallowing tongue force, number of teeth and salivary flow rate, protein content and antioxidant capacity) of a cohort of 54 community-dwelling French elderly as well as their individual retronasal release of five aroma compounds (2-pentanone, 2-nonanone, 2,3-hexanedione, octanal and linalool) by proton-transfer-reaction mass spectrometry (PTR-MS). In general, large variability across participants was observed in both oral physiological (>40%) and retronasal aroma release (>56%) parameters. Multivariate analyses revealed a relationship between physiological parameters (mostly salivary antioxidant capacity) and retronasal aroma release that explained up to 46% of the variability observed. This study provides new insights to understand retronasal aroma release in the elderly that could contribute to the development of personalised nutrition strategies.

Consistent Effects of Whey Protein Fortification on Consumer Perception and Liking of Solid Food Matrices (Cakes and Biscuits) Regardless of Age and Saliva Flow

Although there are numerous high protein products on the market, they are typically not designed with, or for, older consumers. This is surprising considering that dietary guidelines recognise the need for higher protein intake in later life. Protein fortified products are, however, associated with negative sensory attributes and poor consumer acceptance. This paper investigates the extent of mouthdrying sensations within a high protein solid food matrix, along with the effect of age and saliva flow. Solid models using cakes and biscuits, with or without protein fortification, were investigated. The sensory profile and physical properties were analysed and two volunteer studies (n = 84; n = 70) were carried out using two age groups (18–30; 65+). Volunteers rated individual perception and liking of products, and salivary flow rates (mL/min) were measured. Unstimulated salivary flow rates were significantly lower (p < 0.05) in older adults, although this was not found to influence product perception. Protein fortification of cakes and biscuits significantly increased (p < 0.05) perceived mouthdrying, hardness and “off” flavours, and significantly reduced (p < 0.05) melting rate, moistness and liking compared with the control versions. There is a clear need to address negative sensory attributes associated with protein fortification of cakes and biscuits to ensure product suitability for older adults.

An Investigation of the Influence of Age and Saliva Flow on the Oral Retention of Whey Protein and Its Potential Effect on the Perception and Acceptance of Whey Protein Beverages

Protein fortified products are regularly recommended to older adults to improve nutritional status and limit sarcopenia. However protein fortification can elicit negative sensory attributes such as mouthdrying. Sensitivity to mouthdrying can increase with age, yet the influence of saliva flow and mucoadhesion remain uncertain. Here, two studies tested different whey protein beverages (WPB); 22 healthy younger volunteers completed a pilot and 84 healthy volunteers from two age groups (18-30; 65+) completed the main study. In both studies salivary flow rates (mL/min) were measured and saliva samples were collected at time intervals post beverage consumption to measure mucoadhesion to the oral cavity, where protein concentration was analysed by Bradford Assay. Volunteers rated perception and acceptability of WPBs in the main study. WPB consumption resulted in significantly increased protein concentration (p < 0.0001) in saliva samples compared with a control whey permeate beverage. Older adults had significantly lower unstimulated saliva flow (p = 0.003) and significantly increased protein concentration (p = 0.02) in saliva samples, compared with younger adults. Heating of WPB significantly (p < 0.05) increased mouthdrying and thickness perception and reduced sweetness compared with unheated WPB. Mucoadhesion is concluded to be a true phenomenon in WPBs and increases with age.

Breaking the vicious circle of diet, malnutrition and oral health for the independent elderly

Aging impairs senses, mastication, oral status and function, causing nutritional needs and diet insufficiencies. The present needs of independent older adults suggest that health research and oral health care should shift from reductionist disease management to integral and personal treatment plans, including lifestyle, psychological, nutritional and oral health coaching approaches. Dentists and other medical professionals that work in the field of gerodontology should be educated on the macro and micronutrient needs of the elderly and incorporate certain nutritional plans early in the life of their patients with their approval and cooperation, in order to postpone tooth loss and masticatory impairment. Old recipes such as the Mediterranean diet should be kept as a base for all the elderly and be enriched in a customized interpersonal way from the dentist as well as the medical professional according to the specific needs of one's oral and general health status. In this nonsystematic review paper, the basic aspects of the vicious cycle of nutrition and oral health status are discussed and suggestions of major nutrients' influence and needs for independent elders are reported. Based on the scientific data collected, suggestions are made for the food industry for better quality and dosage of foods for this category of individuals. Such strategies can be a whole new area of interest for the food industry in order to obtain better quality of food packaging for the independent OA with accepted texture, odor, colors, macronutrients and micronutrients' consistency and in specific portions.

Oral processing and comfort perception of soft cereal foods fortified with pulse proteins in the elderly with different oral health status

This study investigated the oral processing and bolus formation mechanisms of two soft cereal products fortified with pulse proteins, sponge-cake (FSC) and brioche (FB), in the elderly population, and their relationship with the perception of oral comfort. Twenty subjects aged 65 and over participated in the study. They were classified in two groups according to dental status (poor vs. satisfactory) and presented varying stimulated salivary flow rate (SSF). Bolus properties (hydration ratio, apparent viscosity and particle size) were characterized after three chewing stages. Results showed that subjects with a poor dental status (DS) had a longer chewing duration for FB, while individuals with a higher SSF had a shorter duration for FSC. Compared to FSC, more saliva was added to the FB boli, and the viscosity and particle size of FB bolus were also higher. Based on the bolus particle size evolution during chewing, FB was considered to be more difficult to fragment than FSC, this latter showing a dramatic particle size reduction from the beginning of chewing. From the viscosity data, a model was used to represent the variations of the bolus structure index during chewing and a coefficient of interaction of saliva with food was defined. For both products, the perception of comfort depended more on the DS than on SSF. Bolus apparent viscosity was related to the perception of oral comfort in FSC, while the chewing duration and the bolus particle size at the beginning of chewing contributed to explain oral comfort in FB. Finally, the comparison of these results with those obtained previoulsy with standard (i.e. non enriched) sponge cake and brioche suggested that the proposed protein fortification did not challenge the oral comfort perception by the elderly.

Longitudinal analysis of the salivary metabolome of breast-fed and formula-fed infants over the first year of life

INTRODUCTION

The salivary metabolome has been increasingly studied over the past ten years due to the potential of saliva as a non-invasive source of biomarkers. However, although saliva has been studied in relation to various diseases, its dynamic evolution during life is not known. This is particularly true for the first months of life. Infancy is indeed a critical period during which numerous behavioural and physiological events occur, such as dietary transitions and tooth eruption, which can lead to important biological modifications in the oral cavity.

OBJECTIVES

The aim of this work was therefore to study the evolution of the salivary metabolome during the first months of life by ¹H NMR.

METHODS

Saliva of 32 infants with different milk feeding histories (breast vs formula) was collected at 6 stages, including 3 months old, 15 days before the onset of complementary feeding (CF), approximately 15 days after the onset of CF, approximately 21 days after the onset of CF and at approximately 11 and 15 months, and analysed.

RESULTS

The longitudinal analysis showed a significant modification of the profiles of 18 metabolites over time; 14 presented an increase in abundance whereas 4 presented a decrease. These modifications seemed to be linked, for the most part, to an increase in oral microbial metabolism. Milk feeding history during the first months of life had no effect on metabolites.

CONCLUSION

This work shows that the salivary metabolome should be considered when studying the changes occurring during infancy.

Relating oral physiology and anatomy of consumers varying in age, gender and ethnicity to food oral processing behavior

The aim of this study was to link parameters describing oral physiology and anatomy of consumers varying in age, gender and ethnicity to food oral processing behavior. Three groups of healthy consumers were compared: Dutch, Caucasian adults (18-30 yrs, n =32), Chinese, Asian adults (18-30 yrs, n =32) and Dutch, Caucasian older adults (65-85 yrs, n =32). Mastication performance, salivary flow rate (stimulated and unstimulated) and dental status were quantified to characterize oral physiology. Volume of oral cavity, tongue dimensions, facial anthropometry, height and weight were quantified to characterize anatomy. Oral processing behavior of three solid foods (carrot, cheese and sausage) was quantified by video recordings and eating rate (g/s), average consumption time (s), chews per bite (-) and average bite size (g) were determined. Dutch, Caucasian older adults had smaller volume of oral cavity, lower number of teeth and larger head width compared to Dutch, Caucasian adults. Chinese, Asian adults showed significantly higher mastication performance and larger head width compared to Dutch, Caucasian consumers, while dental status did not significantly differ between groups. Males had significantly larger volumes of oral cavity and larger head height and width compared to females. Dutch, Caucasian adults had a shorter average consumption time (s), less chews per bite and consumed the three foods with higher eating rate (g/s) compared to Dutch, Caucasian older adults. Chinese, Asian adults had a significantly longer average consumption time (s), more chews per bite, smaller average bite size (g) and lower eating rate (g/s) compared to Dutch, Caucasian adults. Twenty-one significant relationships were found between oral physiological and anatomical parameters and oral processing behavior. Body weight resulted in the largest β-values, indicating to be the anatomical parameter of largest influence on oral processing behavior. We conclude that only few oral physiological and anatomical parameters related with food oral processing behavior. We suggest that other factors, including cultural factors contribute to variation in food oral processing behavior between different consumer groups more than saliva flow, volume of oral cavity, mastication performance and dental status.

Considerations for the Development of Innovative Foods to Improve Nutrition in Older Adults

The population of older adults is growing globally. This increase has led to an accumulation of chronic illnesses, so-called age-related diseases. Diet and nutrition are considered the main drivers of the global burden of diseases, and this situation applies especially to this population segment. It relates directly to the development of coronary heart disease, hypertension, some types of cancer, and type 2 diabetes, among other diseases, while age-associated changes in body composition (bone and muscle mass, fat, sarcopenia) constitute risk factors for functional limitations affecting health status and the quality of life. Older adults present eating and swallowing problems, dry mouth, taste loss, and anorexia among other problems causing “anorexia of aging” that affects their nutritional status. The strategies to overcome these situations are described in this study. The impact of oral food processing on nutrition is discussed, as well as approaches to improve food acceptance through the design of innovative foods. These foods should supply a growing demand as this group represents an increasing segment of the consumer market globally, whose needs must be fulfilled.