Investigating age-related changes in taste and affects on sensory perceptions of oral nutritional supplements

"I see it very much as an end-of-life food" - Barriers to oral nutritional supplement adherence, views from healthy older adults

Malnutrition affects approximately one quarter of UK adults aged 65 years and over. As the global demographic shift continues, malnutrition is expected to increase. Oral nutritional supplements (ONS) are used both to prevent and to treat malnutrition. However, their effectiveness is compromised by poor adherence, and it is not well understood what contributes to this. Therefore, the current research was designed to explore ONS adherence from the parallel perspectives of ONS as a prescribed "medication" and as a food supplement/substitute. Eighteen older adults (13F, 5M; mean age = 73.4 yr; range: 70-80 yr) participated in focus groups (three in-person and one online), to investigate experiences of taking prescribed medications, including dietary supplements, and what should be factors to consider in supporting regular intake of ONS for trial development, as well as any potential improvements to products. Focus group sessions were recorded and then transcribed. Thematic Analysis was applied to the transcripts by the first author, and themes were discussed in depth, using exemplar quotes from participants. Five dominant themes were identified from the data: Disgust, Palatability and Acceptance; End-of-Life Care; Resistance to Medicines; Rituals and Reminders; and Real Food Displacement. Nutritional supplements were characterised as "disgusting", "manufactured", and associated with serious, chronic illness, as well as end-of-life care, in contrast to probiotics which were linked with health and wellness. The sweet taste of ONS was identified as a barrier to intake, given that it is generally associated with a signal to stop eating, and low hunger. As a group, participants tried to "avoid taking medicines", and viewed the need to have them negatively, yet most regularly took prescribed medication and/or vitamin supplements. Participants identified several, rituals and reminders to take medicines, including meal-based, or time-of-day-based prompts (e.g., before, with or after meals). To improve adherence, savoury products were suggested, as well as a more person-centred approach to individual nutritional needs and preferences. Overall, the group discussion mainly identified barriers to intake, but that improving taste, adding to "real food" (not replacing meals), and offering variety of flavour and form (e.g., savoury soups as well as sweet drinks) could be included in future trials to improve appeal and therefore intake. Future work should continue to explore how best to formulate, market and/or prescribe ONS, and how this might vary for malnutrition prevention vs treatment strategies.

Differences in time-intensity sensory profiles of sweet taste intensity of glucose between older and young adults

Background

To understand age-related changes in sweet taste perception in daily life, it is important to understand taste intensity at the suprathreshold level. Previous studies have attempted to characterize the temporal aspects of human taste perception in terms of time-intensity evaluations. The perception of dynamic taste intensity in older adults increases slowly for salty taste; however, there have been no previous studies on time-intensity sensory evaluation of sweet taste in older adults. We hypothesized that older adults perceive sweet taste intensity more slowly than young adults.

Methods

Fifty young and 40 older adults participated in the study and glucose solutions of 0.6 M and 1.5 M were used as stimuli. The study comprised two experiments: (1) a cup tasting test (static taste perception in the mouth), and (2) a time-intensity sensory evaluation, in which the solutions were presented using a custom-made delivery system. The intra-oral device was made to fit each participant's dentition. Further, the level of gag reflex was taken into consideration for each participant in the design of the intra-oral device. A suction tube was placed across the posterior tongue near the throat to remove solution and saliva. The solution delivery system was controlled by an original computer program.

Results

Older adults presented significantly different maximum intensity timing and slope for both concentrations compared with young adults (slope for 1.5 M, p < 0.01; others, p < 0.05). No significant differences were found between the older and young adults for reaction timing and maximum intensity.

Conclusion

We conclude that older adults perceived sweetness more slowly than young adults, and ultimately perceived almost the same intensity as young adults. This is the first reported characterization of the time-intensity profile of sweet taste intensity of glucose in older adults. Using a standardized system enabled us to assess and compare feedback on taste intensities among different age groups in real-time. Based on this, we recommend older adults "savor" to perceive sweet tastes at the same level experienced by young adults.

Brain activity associated with taste stimulation: A mechanism for neuroplastic change?

PURPOSE

Neuroplasticity may be enhanced by increasing brain activation and bloodflow in neural regions relevant to the target behavior. We administered precisely formulated and dosed taste stimuli to determine whether the associated brain activity patterns included areas that underlie swallowing control.

METHODS

Five taste stimuli (unflavored, sour, sweet-sour, lemon, and orange suspensions) were administered in timing-regulated and temperature-controlled 3 mL doses via a customized pump/tubing system to 21 healthy adults during functional magnetic resonance imaging (fMRI). Whole-brain analyses of fMRI data assessed main effects of taste stimulation as well as differential effects of taste profile.

RESULTS

Differences in brain activity associated with taste stimulation overall as well as specific stimulus type were observed in key taste and swallowing regions including the orbitofrontal cortex, insula, cingulate, and pre- and postcentral gyri. Overall, taste stimulation elicited increased activation in swallowing-related brain regions compared to unflavored trials. Different patterns of blood oxygen level-dependent (BOLD) signal were noted by taste profile. For most areas, sweet-sour and sour trials elicited increases in BOLD compared to unflavored trials within that region, whereas lemon and orange trials yielded reductions in BOLD. This was despite identical concentrations of citric acid and sweetener in the lemon, orange, and sweet-sour solutions.

CONCLUSIONS

These results suggest that neural activity in swallowing-relevant regions can be amplified with taste stimuli and may be differentially affected by specific properties within very similar taste profiles. These findings provide critical foundational information for interpreting disparities in previous studies of taste effects on brain activity and swallowing function, defining optimal stimuli to increase brain activity in swallowing-relevant regions, and harnessing taste to enhance neuroplasticity and recovery for persons with swallowing disorders.

Barriers to and Facilitators of the Consumption of Animal-Based Protein-Rich Foods in Older Adults: Re-Analysis with a Focus on Sustainability

Older adults may gain health benefits from the consumption of animal-based protein-rich foods, but environmental pressures suggest advocating some meat and dairy foods over others, and understanding the barriers and facilitators for consuming these different foods would be of value. Existing data on the barriers to and facilitators of the consumption of meat and dairy products were re-analysed for differing effects for white, red, and processed meat consumption and for yoghurt, soft cheese, and hard cheese consumption. White meat consumption was associated with fewer concerns over spoilage and waste and stronger perceptions that meat is convenient (smallest Beta = 0.135, p = 0.01), while red and processed meat consumption were positively associated with liking /taste, appearance, and convenience (smallest Beta = 0.117, p = 0.03). Yoghurt and soft cheese consumption were positively associated with liking/taste and medical concerns, and fewer concerns over ability and habit (smallest Beta = -0.111, p = 0.05), while hard cheese consumption was only associated with liking/taste (Beta = 0.153, p = 0.01). Taken together, these data suggest that enhancing or promoting the enjoyment, taste, visual appeal, and ease-of-consumption of the more sustainable meat and dairy options may be of value in encouraging the consumption of these foods in older adults.

Characterization of Metallic Off-Flavors in Drinking Water: Health, Consumption, and Sensory Perception

Characterization of taste- and flavor-producing metals, namely iron and copper, in drinking water is a multifaceted subject. Both metals are essential nutrients, can be toxic, and are known to produce unpleasant tastes and flavor sensations in drinking water. Ingestion of trace metal contaminants through drinking water is a probable source of human exposure. Biochemical mechanisms of metallic flavor perception have been previously described; however, less is known about how variations in salivary constituents might impact individuals' sensitivities to metallic flavors and beverage consumption behaviors. This research presents findings from in vitro experiments, using artificial human saliva, to better understand the role of salivary lipids and proteins on metallic flavor production as measured by biomarkers of metal-induced oxidative stress. The results indicate that metal-induced lipid oxidation, as measured by thiobarbituric acid reactive substances (TBARS), is dominated by salivary proteins, is slightly inhibited in the presence of salivary nitrite, and is detectable by the TBARS method at and above respective concentrations of 9 µM (0.5 mg/L) and 90 µM (5 mg/L), which are both above the aesthetic standards for iron (0.3 mg/L) and copper (1.0 mg/L) in drinking water. Preliminary study with human subjects indicated that reduction in metallic flavor sensitivity, as measured by the best estimate flavor threshold for ferrous iron among 33 healthy adults aged 19-84 years old (22 females), corresponded with reduced drinking water consumption and increased caloric beverage intake among older subjects (>60 years), as determined by a validated self-reported beverage intake questionnaire. These findings provide insights for further research to examine how salivary constituents can impact humans' sensory abilities in detecting metallic off-flavors in water, and how reduced metallic flavor sensitivity may influence beverage choices and drinking water consumption.

Oral nutritional interventions in frail older people who are malnourished or at risk of malnutrition: a systematic review

BACKGROUND

Malnutrition worsens the health of frail older adults. Current treatments for malnutrition may include prescribed oral nutritional supplements, which are multinutrient products containing macronutrients and micronutrients.

OBJECTIVE

To assess the effectiveness and cost-effectiveness of oral nutritional supplements (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Library, Scopus, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and grey literature were searched from inception to 13 September 2021.

REVIEW METHODS

A systematic review and meta-analysis was conducted to evaluate the effectiveness and cost-effectiveness of oral nutritional supplements in frail older people (aged ≥ 65 years) who are malnourished or at risk of malnutrition (defined as undernutrition as per National Institute for Health and Care Excellence guidelines). Meta-analysis and network meta-analysis were undertaken, where feasible, along with a narrative synthesis. A cost-effectiveness review was reported narratively. A de novo model was developed using effectiveness evidence identified in the systematic review to estimate the cost-effectiveness of oral nutritional supplements.

RESULTS

Eleven studies (n = 822 participants) were included in the effectiveness review, six of which were fully or partly funded by industry. Meta-analyses suggested positive effects of oral nutritional supplements compared with standard care for energy intake (kcal) (standardised mean difference 1.02, 95% confidence interval 0.15 to 1.88; very low quality evidence) and poor mobility (mean difference 0.03, p < 0.00001, 95% confidence interval 0.02 to 0.04; very low quality evidence) but no evidence of an effect for body weight (mean difference 1.31, 95% confidence interval -0.05 to 2.66; very low quality evidence) and body mass index (mean difference 0.54, 95% confidence interval -0.03 to 1.11; very low quality evidence). Pooled results for other outcomes were statistically non-significant. There was mixed narrative evidence regarding the effect of oral nutritional supplements on quality of life. Network meta-analysis could be conducted only for body weight and grip strength; there was evidence of an effect for oral nutritional supplements compared with standard care for body weight only. Study quality was mixed; the randomisation method was typically poorly reported. One economic evaluation, in a care home setting, was included. This was a well-conducted study showing that oral nutritional supplements could be cost-effective. Cost-effectiveness analysis suggested that oral nutritional supplements may only be cost-effective for people with lower body mass index (< 21 kg/m2) using cheaper oral nutritional supplements products that require minimal staff time to administer.

LIMITATIONS

The review scope was narrow in focus as few primary studies used frailty measures (or our proxy criteria). This resulted in only 11 included studies. The small evidence base and varied quality of evidence meant that it was not possible to determine accurate estimates of the effectiveness or cost-effectiveness of oral nutritional supplements. Furthermore, only English-language publications were considered.

CONCLUSIONS

Overall, the review found little evidence of oral nutritional supplements having significant effects on reducing malnutrition or its adverse outcomes in frail older adults.

FUTURE WORK

Future research should focus on independent, high-quality, adequately powered studies to investigate oral nutritional supplements alongside other nutritional interventions, with longer-term follow-up and detailed analysis of determinants, intervention components and cost-effectiveness.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42020170906.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 51. See the NIHR Journals Library website for further project information.

Promoting Protein Intake in an Ageing Population: Product Design Implications for Protein Fortification

Protein is a macronutrient of interest for an ageing population and intake requirements increase with age. Accordingly, protein is often fortified into products for older adults to help alleviate malnutrition and impede sarcopenia. However, more emphasis needs to be placed upon designing protein-fortified products to ensure suitability for older adults. This study involved a two-stage approach: (1) an initial review of products commonly fortified with protein and (2) two questionnaires for younger and older adults (n = 73; 18-30; 65+) to investigate optimal portion sizes (drinks and cakes) as well as attitudes, consumption habits and preferences towards protein fortification. The initial literature and market review demonstrated protein-fortified products are typically in liquid or snack format; however, there is considerable variability in terms of product types, serving size and protein sources. There were no age-related differences found for ideal cakes portion size whereas there were for liquids. Older adults are typically not consuming protein-fortified products; therefore, more importance should be placed on the consumption moment (breakfast or as snacks between meals) and on cereals, pasta, porridge, cakes, and biscuits. Older adults need increased awareness of, and more education on, the benefits of protein consumption, coupled with products tailored and designed to encourage intake.

Subjective-Physiological Coherence during Food Consumption in Older Adults

BACKGROUND

Subjective-physiological emotional coherence is thought to be associated with enhanced well-being, and a relationship between subjective-physiological emotional coherence and superior nutritional status has been suggested in older populations. However, no study has examined subjective-physiological emotional coherence among older adults while tasting food. Accordingly, the present study compared subjective-physiological emotional coherence during food consumption among older and younger adults.

METHODS

Participants consumed bite-sized gel-type foods with different flavors and provided their subjective ratings of the foods while their physiological responses (facial electromyography (EMG) of the corrugator supercilia, masseter, and suprahyoid, and other autonomic nervous system signals) were simultaneously measured.

RESULTS

Our primary findings were that (1) the ratings of liking, wanting, and valence were negatively correlated with corrugator EMG activity in older and young adult participants; (2) the positive association between masseter EMG activity and ratings of wanting/valence was weaker in the older than in the young adult group; and (3) arousal ratings were negatively correlated with corrugator EMG activity in the older group only.

CONCLUSIONS

These results demonstrate commonalities and differences in subjective-physiological emotional coherence during food intake between older and young adults.

Effectiveness and cost-effectiveness of oral nutritional supplements in frail older people who are malnourished or at risk of malnutrition: a systematic review and meta-analysis

BACKGROUND

Current management of malnutrition can include prescribed oral nutritional supplements (ONS); however, there is uncertainty whether these supplements are effective in people who are older (≥65 years) and frail. We assessed the effectiveness, cost-effectiveness, and adherence and acceptability of ONS in frail older people who are malnourished or at risk of malnutrition.

METHODS

In this systematic review and meta-analysis, five bibliographic databases (MEDLINE, EMBASE, Cochrane Library, Scopus, and CINAHL) and grey literature sources were searched from inception to Sept 13, 2021, to identify studies assessing the effectiveness and cost-effectiveness of ONS (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition. Multiple reviewers independently did study screening, data extraction, and risk of bias assessment. Quality was assessed using version 1.0 of the Cochrane risk of bias tool for randomised controlled trials (RCTs), and the BMJ Drummond checklist was used to assess the quality of the included cost-effectiveness study. A meta-analysis was done for the effectiveness review; for the other reviews, a narrative synthesis approach was used. This systematic review and meta-analysis was registered on PROSPERO, CRD42020170906.

FINDINGS

Of 8492 records retrieved and screened, we included 11 RCTs involving 822 participants, six of which were fully or partly funded by industry. For the majority of the outcomes for which meta-analyses were possible (11/12), Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessments suggested that the evidence was of very low certainty. Results suggested that ONS might have a slightly positive effect on energy (kcal) intake (standardised mean difference 1·02 [95% CI 0·15 to 1·88]; I²=87%; four studies), protein intake (standardised mean difference 1·67 [-0·03 to 3·37; I²=97%; four studies), and mobility (mean difference 0·03 [0·02 to 0·04]; I²=0%; four studies), compared with standard care. Narrative syntheses suggested that the effect of ONS on quality of life, compared with standard care, was mixed. In the identified studies, there was very little information related to active components, determinants, or acceptability of interventions. One economic evaluation, done in a care home setting, showed that ONS could be cost-effective.

INTERPRETATION

We found little evidence of ONS reducing malnutrition or its associated adverse outcomes in older people who are frail. High-quality, non-industry-funded, adequately powered studies reporting on short-term and long-term health outcomes, determinants, and participant characteristics are needed.

FUNDING

UK National Institute of Health and Care Research (NIHR) Health Technology Assessment (NIHR128729).

Effects of visual and aromatic stimulations on the perception of five fundamental tastes

Taste perception is affected by various environmental factors. In the present study, we investigated the effects of visual and aromatic stimulations on stress responses and taste perception. Fourteen young healthy participants were assessed for stress levels and taste intensities under 5 different conditions: normal (no stimuli), watching an action scene, watching a forest scene, sniffing a rosemary aroma, and sniffing a lavender aroma. Compared to participants under the action scene condition, participants under the forest scene or under the rosemary aroma condition showed significantly lower stress levels. Furthermore, the forest scene condition significantly increased the saltiness intensity, whereas the rosemary aroma condition significantly increased the bitterness intensity. A positive or negative correlation was observed between the stress level and taste intensity of sourness and saltiness, respectively. These findings indicate that visual image and aroma have the potential to change taste perception as well as modulate stress conditions.

Factors Affecting Adherence, Intake, and Perceived Palatability of Oral Nutritional Supplements: A Literature Review

Oral nutritional supplements (ONS) are a clinically effective and relatively inexpensive way to supplement the diet of patients with, or at risk of, undernutrition. Good adherence is a primary determinant of the effectiveness of ONS. However adherence can be problematic for those with the greatest clinical need, such as undernourished older adults. This review aimed to appraise the available literature for the factors (contextual, personal and product related) affecting patient adherence and perceived palatability of ONS, identify areas requiring improvement and uncover gaps in the evidence to guide the focus of future research. Contextual factors identified were healthcare staff and the timing of administration. Personal factors included sensory changes and motivation which alter experience of and desire to consume ONS. The product's sensory characteristics determined palatability and intake, but undesirable attributes, such as off-flavours, can stem from nutritional ingredients. The contribution made by aroma to older adults' experience of ONS was a comparatively under-researched area. Further research should address this evidence gap to optimise the flavour, aroma profile and palatability for undernourished older consumers, thereby optimising intake. A combined multidisciplinary effort involving strategic expansion of research, industry development and clinical practice should simultaneously address the factors identified, to provide the best approach to improve adherence.

[A real-world study to evaluate adherence and flavor of a high-protein hypercaloric oral nutritional supplement in patients with malnutrition in a hospital]

AIM

the objective of our real-life study was to evaluate adherence and taste preferences of a hypercaloric and hyperprotein oral nutritional supplement (ONS) in malnourished hospitalized patients.

METHODS

a total of 34 in patients with recent weight loss were included in this study. One flavor (coffe, vanilla or strawberry) was administered each day in a random way to each patient during three consecutive days. In the first three days, patients were asked to fulfill two questionnaires intended to reflect ONS (Renutryl®) tolerance and acceptance. Adherence to the ONS was measured during hospital stay.

RESULTS

the sweet flavor was higher for strawberry (4.54 ± 0.2 points) than for the vanilla flavor (3.13 ± 0.1 points; p < 0.03) and coffee flavor (3.03 ± 0.1 points; p <0.02). When analyzing the total number of patients who took supplements after choosing the flavor, the patients who chose coffee took a total of 13.3 ± 1.1 packages on average during hospitalization (0.91 ± 0.2 per day), the patients who chose strawberry took 13.4 ± 1.3 packages (0.92 ± 0.1 per day), and finally the patients who chose vanilla packages took 8.3 ± 0, 9 packages during admission (0.61 ± 0.1 per day), with significant differences in favor of the strawberry and coffee flavors versus vanilla. The ONS chosen mostly by the patients at hospital discharge was the multiflavor pack (n = 20; 50 %).

CONCLUSIONS

taste preferences for the three flavored ONSs are similar, although adherence was higher during admission to the coffee- and strawberry-flavored ONS. Sweetness may have influenced this finding, especially with the strawberry flavor, with a good tolerance of all three flavors.

Can an Ice-Cream Based Supplement Help Address Malnutrition in Orthogeriatric Patients?

Using a Plan-Do-Study-Act (PDSA) methodology, we describe our first cycle of a project using an ice-cream oral nutritional supplement (ONS ice-cream) to address malnutrition in older patients. A Scandishake-based^® (Nutricia) vanilla flavored ice-cream was developed and piloted on a cohort of orthopedic patients over 3 days. All suitable patients were offered 100 g ice-cream portions (240 kcal/per portion). Acceptability and energy intake were our primary outcomes. Over 3 days, the ONS ice-cream was accepted in 77% (n = 27, median age, 75 years, IQR 12.5) of the times offered. Among these patients the average energy intake per day including the ONS ice-cream was 1006 kcal, a 41% increase in energy intake compared to an initial nutritional survey among the older orthopedic patients (714 kcal, p = 0.010). When surveyed 84% (n = 16) of patients stated they would have the ONS ice-cream again. An ONS ice-cream intervention to improve energy intake in older adults is feasible.

Identification of aroma compounds in a commonly prescribed oral nutritional supplement and associated changes in olfactory abilities with human ageing

Undernutrition is prevalent in the older adult population. Oral nutritional supplements (ONS) are a clinically effective nutritional intervention, however, patient acceptance of ONS can be limited by their palatability. While sensory attributes such as sweetness and mouthfeel have been investigated, the contribution made by aroma to the perceived flavour of ONS has not been studied. Firstly, this research aimed to identify the aroma active compounds within a commonly prescribed ONS using estimated odour activity values (OAV) and gas chromatography olfactometry mass spectrometry (GC-O-MS). Secondly, age related differences in olfactory detection were explored. Eight aroma active compounds were identified within the ONS, including diacetyl (sweet), isoamyl acetate (banana), dimethyl trisulfide (sulfur) and methanethiol (sulfur). When compared with younger adults (n = 24, 18–44 years), older adults (n = 24, 62–80 years) had higher detection thresholds for all aroma compounds and this was significant for isoamyl acetate (sweet, fruity) and methanethiol (sulfur) (p = 0.01 and p = 0.03, respectively). Thus, a decline in olfactory sensitivity was present in the older subjects included in the study, and this reduced detection sensitivity was aroma specific. Thus, older adults’ flavour perception of ONS likely depends on the combined effect of product factors (the aroma profile) along with age related consumer factors (the degree of impairment in perception). This is a fundamental study which will aid future research into how the aroma profile, and associated age related impairments in perception, shape the global perception of ONS for nutritionally at risk older individuals.

Acceptance of oat-based beverages tailored for patients with cancer

Oat-based beverages are a nutritious product with the potential to support increased nutrient intake of patients with cancer. The aim of this research was to evaluate the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer as future vehicles for nutrient delivery. In study 1, three flavors of oat-beverages were well accepted without significant difference in liking among flavors or serving temperature, or between patients with cancer and healthy participants. Patients with cancer more frequently rated the beverages as too sweet compared to healthy participants; flavor intensity was just about right for all participants. In the second study, one of two formulations fortified with protein and fish oil was not different in liking compared to the unfortified chocolate product. Patients associated oat food products with specific oat-based food products and oat health benefits in a free-word association task in the third study. Together, sensory acceptance and the perceived health benefits of oats indicate the potential for oats to be incorporated in fortified and unfortified products tailored for patients with cancer. PRACTICAL APPLICATION: The three studies presented here to assess the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer demonstrate that oats can be incorporated in fortified and unfortified products tailored for patients with cancer. Inadequate nutrition is highly prevalent among oncology patients and there is a lack of available products targeted to improve their nutritional intake. These findings can support product developers and sensory scientists in the development and evaluation of food products acceptable to this population.

The relation between stimulated salivary flow and the temporal consumption experience of a liquid oral nutritional supplement

Use of oral nutritional supplements (ONS) in undernourished patients has proven clinical benefits, but this can be hampered by low adherence due to poor experience of palatability. Many patients, particularly older patients, experience hyposalivation which can cause taste changes and reduce the enjoyment of foods. The aim of this study was to investigate differences in the temporal consumption experience (comprising sensory perception, in-mouth aroma release and subjective appetite) of a clinically relevant portion of ONS, for groups differing in saliva flow rates (SFR). The SFR (mL/min) of thirty healthy individuals was measured on three occasions. This data was used to categorise individuals into three groups using quartile analysis: low flow (LF) (0.3–0.6 mL/min, n = 5), medium flow (MF) (0.7–1.2 mL/min, n = 16) and high flow (HF) (1.3–1.8 mL/min, n = 9). Over the consumption of eight 15 mL sips of ONS, individuals rated their sensory perception and subjective appetite perception using line scales. Additionally, in-mouth aroma release was measured for each sip, using atmospheric pressure chemical ionisation (APCI). Compared with the MF and HF group, the LF group reported a significantly greater increase of mouth-drying over increased sips (p = 0.02). The LF group also experienced significantly higher aftertaste perception (p < 0.001), and more intense in-mouth aroma release (p = 0.015), compared with the HF group. These findings occurred concurrently with relatively lower hunger sensations in the LF and MF group. Many patients who are prescribed ONS likely experience reduced salivary flow rates. The unique sensory experiences of these individuals should be considered in order to optimise palatability and nutritional intake.

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A full portion of ONS was evaluated by three groups differing in saliva flow rates.

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A sensory profiling method captured perceptual differences over repeated sips.

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Mouth-drying built up most significantly for the low saliva flow group.

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Intensity of aftertaste and aroma release was highest in the low saliva flow group.

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Sensorial intensity of ONS may be associated with greater feelings of satiation.

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.

Nutrition and gastroenterological support in end of life care

Malnutrition and the broad spectrum of cancer cachexia frequently occur in patients with malignant disease of all tumour stages and impact on survival and quality of life of patients. Structured screening for the risk of malnutrition with validated tools and nutritional assessment are the prerequisite for adequate nutritional support in cancer patients. In patients receiving tumour directed therapy, the patients diet should meet the requirements to give optimal support, while later on comfort feeding is part of symptom focused palliation. The basis of nutritional support in a malnourished patient is nutritional counselling, and nutritional support can be offered within a step-up approach meeting the patient's needs. A combination of nutritional support with interventions targeting metabolic changes and physical exercise is suggested to treat cancer cachexia.

The provision of recipes and single-use herb/spice packets to increase egg and protein intake in community-dwelling older adults: a randomised controlled trial

OBJECTIVE

This study investigated the impact of recipe and single-use herb/spice packet provision on egg intake and protein intake in community-dwelling individuals aged over 55 years.

DESIGN

Using a randomised-controlled intervention design, 100 older adults were randomised to receive (n 53) or not receive (n 47) high-protein egg-based recipes and herb/spice packets through the post for 12 weeks, from June to December 2016. Egg intake, protein intake, adverse events, lean body mass and functional measures of lean body mass were measured at baseline, after the 12 weeks and after a further 12 weeks.

SETTING

Bournemouth, UK.

PARTICIPANTS

Community-dwelling older adults.

RESULTS

Intention-to-treat data were analysed using regression, controlling for various demographic and lifestyle characteristics. Ninety-three individuals (intervention, n 50; control, n 43) completed assessments at all three time points. Egg intakes increased by end of intervention in both groups (mean: 4-5 eggs/month). After a further 12 weeks, higher egg intakes were sustained in the intervention group, while egg intakes in the control group returned to baseline levels (between-group difference: β = -0·124, P = 0·047). No differences were found in other measures (largest β = -0·106, P = 0·12).

CONCLUSIONS

The provision of high-protein egg-based recipes and single-use herb/spice packets over 12 weeks increased egg intakes up to 12 weeks after end of intervention. Other factors may explain increased egg intakes during the intervention, but the sustained effects most plausibly result directly from recipe provision. Limited effects in other measures suggest that the recipes may have replaced as opposed to added to existing protein intakes.

Beliefs about inevitable decline among home-living older adults at risk of malnutrition: a qualitative study

BACKGROUND

Approximately 14% of free-living adults aged ≥65 years are at risk of malnutrition. Malnutrition screen and treat interventions in primary care are few, show mixed results, and the advice given is not always accepted and followed. We need to better understand the experiences and contexts of older adults when aiming to develop interventions that are engaging, optimally persuasive and relevant.

METHODS

Using the Person-based Approach, we carried out 23 semi-structured interviews with purposively selected adults ≥65 years with chronic health or social conditions associated with malnutrition risk. Thematic analysis informed the development of key principles to guide planned intervention development.

RESULTS

We found that individuals' beliefs about an inevitable decline in appetite and eating in older age compound the many and varied physical and physiological barriers that they experience. Also, we found that expectations of decline in appetite and physical ability may encourage resignation, reduce self-efficacy to overcome barriers, and reduce motivation to address weight loss and/or recognise it as an issue that needs to be addressed. Fear of loss of independence may also reduce the likelihood of asking general practitioners for advice.

CONCLUSIONS

The key findings identified include a sense of resignation, multiple different barriers to eating and a need for independence, each underpinned by the expectation of a decline in older adulthood. Interventions need to address misperceptions about the inevitability of decline, highlight how and why diet recommendations are somewhat different from recommendations for the general population, and suggest easy ways to increase food intake that address common barriers.

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.

Recent progress in the use of functional foods for older adults: A narrative review

The number and proportion of older adults are increasing globally, and it is predicted that in 2020, there will be 723 million people worldwide aged 66 and older. In recent decades, numerous studies showed that healthy eating is positively associated with better nutritional status and quality of life, and the decreased incidence of noncommunicable diseases. As older adults become health conscious, the demand for foods and beverages rich in nutrients and bioactive compounds has increased. The increased demand for healthy food stimulated a recent rapid increase in designing, producing, and marketing functional foods to prevent or correct nutrient deficiencies and to improve the nutritional status of older adults. These functional products contain and/or are enriched with dietary fiber; omega-3 polyunsaturated fatty acids; phytoestrogens; polyphenols; carotenoids such as alpha- and beta-carotene; lutein and zeaxanthin; pre-, pro-, and synbiotics; and plant sterols and stanols. A limited number of publications have thoroughly addressed the effect of functional foods on the nutritional status of older adults. The goal of this review was to review existing recent research on the role of functional foods in healthy and active aging.

The Psychology of Nutrition with Advancing Age: Focus on Food Neophobia

Many factors impact on eating behaviour and nutritional status in older adults. Strategies can be suggested to combat the impact of these factors, including the development of novel food products, but food neophobia ("the reluctance to eat and/or avoidance of novel foods") may be a barrier to the acceptance of these foods/products. This work aimed to investigate associations between food neophobia, physical disadvantage, and demographic characteristics in adults over 55 years old. Cross-sectional data from 377 older adults was analysed for relationships between food neophobia scores and physical disadvantage (denture wearing, help with food shopping and/or preparing, and risk of sarcopenia), controlling for age group, gender, living status, education, and employment level. Initial analyses demonstrated higher food neophobia scores in association with denture wearing (Beta = 0.186, p = 0.001). However, when demographic characteristics were also considered, food neophobia scores were no longer related to denture wearing (Beta = 0.069, p = 0.226) but instead were related to a higher age, living alone, and a shorter education (smallest Beta = -0.104, p = 0.048). Food neophobia may thus act as a barrier to the consumption of novel foods/products in those who are of higher age, are living alone, and have a shorter education.

Quantifying Sweet Taste Liker Phenotypes: Time for Some Consistency in the Classification Criteria

Taste hedonics is a well-documented driver of food consumption. The role of sweetness in directing ingestive behavior is largely rooted in biology. One can then intuit that individual differences in sweet-liking may constitute an indicator of variations in the susceptibility to diet-related health outcomes. Despite half a century of research on sweet-liking, the best method to identify the distinct responses to sweet taste is still debated. To help resolve this issue, liking and intensity ratings for eight sucrose solutions ranging from 0 to 1 M were collected from 148 young adults (29% men). Hierarchical cluster analysis (HCA) revealed three response patterns: a sweet-liker (SL) phenotype characterized by a rise in liking as concentration increased, an inverted U-shaped phenotype with maximum liking at 0.25 M, and a sweet-disliker (SD) phenotype characterized by a decline in liking as a function of concentration. Based on sensitivity and specificity analyses, present data suggest the clearest discrimination between phenotypes is seen with 1.0 M sucrose, where a liking rating between -15 and +15 on a -50/+50 scale reliably distinguished individuals with an inverted U-shaped response from the SLs and the SDs. If the efficacy of this approach is confirmed in other populations, the discrimination criteria identified here can serve as the basis for a standard method for classifying sweet taste liker phenotypes in adults.

Practical multimodal care for cancer cachexia

PURPOSE OF REVIEW

Cancer cachexia is common and reduces function, treatment tolerability and quality of life. Given its multifaceted pathophysiology a multimodal approach to cachexia management is advocated for, but can be difficult to realise in practice. We use a case-based approach to highlight practical approaches to the multimodal management of cachexia for patients across the cancer trajectory.

RECENT FINDINGS

Four cases with lung cancer spanning surgical resection, radical chemoradiotherapy, palliative chemotherapy and no anticancer treatment are presented. We propose multimodal care approaches that incorporate nutritional support, exercise, and anti-inflammatory agents, on a background of personalized oncology care and family-centred education. Collectively, the cases reveal that multimodal care is part of everyone's remit, often focuses on supported self-management, and demands buy-in from the patient and their family. Once operationalized, multimodal care approaches can be tested pragmatically, including alongside emerging pharmacological cachexia treatments.

SUMMARY

We demonstrate that multimodal care for cancer cachexia can be achieved using simple treatments and without a dedicated team of specialists. The sharing of advice between health professionals can help build collective confidence and expertise, moving towards a position in which every team member feels they can contribute towards multimodal care.

Effect of Age and Severity of Facial Palsy on Taste Thresholds in Bell's Palsy Patients

Background and Objectives

To investigate whether taste thresholds, as determined by electrogustometry (EGM) and chemical taste tests, differ by age and the severity of facial palsy in patients with Bell's palsy.

Subjects and Methods

This study included 29 patients diagnosed with Bell's palsy between January 2014 and May 2015 in our hospital. Patients were assorted into age groups and by severity of facial palsy, as determined by House-Brackmann Scale, and their taste thresholds were assessed by EGM and chemical taste tests.

Results

EGM showed that taste thresholds at four locations on the tongue and one location on the central soft palate, 1 cm from the palatine uvula, were significantly higher in Bell's palsy patients than in controls (p<0.05). In contrast, chemical taste tests showed no significant differences in taste thresholds between the two groups (p>0.05). The severity of facial palsy did not affect taste thresholds, as determined by both EGM and chemical taste tests (p>0.05). The overall mean electrical taste thresholds on EGM were higher in younger Bell's palsy patients than in healthy subjects, with the difference at the back-right area of the tongue differing significantly (p<0.05). In older individuals, however, no significant differences in taste thresholds were observed between Bell's palsy patients and healthy subjects (p>0.05).

Conclusions

Electrical taste thresholds were higher in Bell's palsy patients than in controls. These differences were observed in younger, but not in older, individuals.

Recalled taste intensity, liking and habitual intake of commonly consumed foods

Taste intensity and quality affect the liking of foods, and determine food choice and consumption. We aimed to 1) classify commonly consumed foods based on recalled taste intensity for bitter, sweet, salty, sour, and fatty taste, and 2) examine the associations among recalled taste intensity, liking, and habitual consumption of foods. In Stage 1, 62 Canadian adults recalled the taste intensity of 120 common foods. Their responses were used to identify sets of 20-25 foods classified as strongly bitter, sweet, salty, sour or fatty-tasting. In Stage 2, 287 U.S. adults validated these selections, and let us reduce them to sets of 11-13 foods. Ratings of recalled taste intensity were consistent across age, sex and overweight status, with the exceptions that sweet, bitter and fatty-tasting foods were rated as more intense by women than by men. The recalled intensity ratings of the most bitter, salty and fatty foods (but not sour or sweet foods) were inversely correlated with liking and intake. The negative correlation between fatty taste intensity and fatty food liking was stronger among normal weight than among overweight participants. Our results suggest that the recalled taste intensity of foods is associated with food liking and habitual consumption, but the strength of these relationships varies by taste. The food lists based on taste intensity ratings provide a resource to efficiently calculate indices of exposure to the different tastes in future studies.

The palatability of oral nutritional supplements: before, during, and after chemotherapy

Purpose

Oral nutritional supplements (ONS) are commonly prescribed to malnourished patients to improve their nutritional status. Taste and smell changes in patients with cancer can affect the palatability of ONS. The present study investigated: (1) the palatability of six ONS in testicular cancer patients before, during the first two cycles, and after chemotherapy; (2) the relation between the palatability and taste and smell function; (3) the metallic taste of these ONS.

Methods

Twenty-one testicular cancer patients undergoing first-line cisplatin-based chemotherapy participated. Two milk-based (vanilla; strawberry), two juice-based (apple; orange), and two yoghurt-based (vanilla-lemon; peach-orange) ONS were tested. A questionnaire was used to assess the palatability of ONS and to which extent the attribute ‘metallic’ was applicable. Taste and smell function were measured using taste strips and ‘Sniffin’ Sticks’, respectively.

Results

The palatability of ONS was highly variable among patients. The milk-based strawberry ONS was preferred most before, during, and after chemotherapy. The liking of the milk-based vanilla ONS tended to decrease over time (p = 0.053), whereas the liking of the other ONS remained stable. A higher smell threshold and a lower sour taste threshold were correlated to a decreased liking of the milk-based vanilla ONS. The two juice-based ONS tended to taste more metallic during than before chemotherapy.

Conclusion

Health care professionals and patients should be aware that the palatability of ONS can change over time. Regular structured contact between health care professionals and patients regarding the choice of ONS seems warranted.

Electronic supplementary material

The online version of this article (doi:10.1007/s00520-016-3263-6) contains supplementary material, which is available to authorized users.

Barriers to and Facilitators of the Consumption of Animal-Based Protein-Rich Foods in Older Adults

Protein intakes in the older population can be lower than recommended for good health, and while reasons for low protein intakes can be provided, little work has attempted to investigate these reasons in relation to actual intakes, and so identify those of likely greatest impact when designing interventions. Questionnaires assessing: usual consumption of meat, fish, eggs and dairy products; agreement/disagreement with reasons for the consumption/non-consumption of these foods; and several demographic and lifestyle characteristics; were sent to 1000 UK community-dwelling adults aged 65 years and over. In total, 351 returned questionnaires, representative of the UK older population for gender and age, were suitable for analysis. Different factors were important for consumption of the four food groups, but similarities were also found. These similarities likely reflect issues of particular concern to both the consumption of animal-based protein-rich foods and the consumption of these foods by older adults. Taken together, these findings suggest intakes to be explained by, and thus that strategies for increasing consumption should focus on: increasing liking/tastiness; improving convenience and the effort required for food preparation and consumption; minimizing spoilage and wastage; and improving perceptions of affordability or value for money; freshness; and the healthiness of protein-rich foods.

Retronasal aroma allows feature extraction from taste of a traditional Japanese confection

Background

Common foods consist of several taste qualities. Consumers perceive intensity of a particular taste quality after noticing it among other taste qualities when they eat common foods. We supposed that while one is eating the facility for noticing a taste quality present in a common food will differ among taste qualities which compose the common food. We, therefore, proposed a new measurement scale for food perception named ‘noticeability’. Furthermore, we found that consumers’ food perceptions to common foods were modified by retronasal aroma. In this study, in order to examine whether retronasal aroma affects the relationship between noticeability and perceived intensity for taste, we evaluated participants for noticeability and perceived intensity of five fundamental taste qualities (sweetness, saltiness, sourness, bitterness, and umami) under open and closed nostril conditions using one of the most popular traditional Japanese confections called ‘yokan’.

Results

The taste quality showed that the highest noticeability and perceived intensity among five fundamental taste qualities for yokan was sweetness, independent of the nostril condition. For sweetness, a significant decrease of correlation between noticeability and perceived intensity was observed in response to retronasal aroma. On the other hand, for umami, correlation between noticeability and perceived intensity significantly increased with retronasal aroma.

Conclusions

As the retronasal aroma of yokan allowed feature extraction from taste by Japanese consumers, we reconfirmed that consumers’ food perceptions were modified by the retronasal aroma of a common food.

The effect of barium on perceptions of taste intensity and palatability

Barium may affect the perception of taste intensity and palatability. Such differences are important considerations in the selection of dysphagia assessment strategies and interpretation of results. Eighty healthy women grouped by age (younger, older) and genetic taste status (supertaster, nontaster) rated intensity and palatability for seven tastants prepared in deionized water with and without 40 % w/v barium: noncarbonated and carbonated water, diluted ethanol, and high concentrations of citric acid (sour), sodium chloride (salty), caffeine (bitter), and sucrose (sweet). Mixed-model analyses explored the effects of barium, taster status, and age on perceived taste intensity and acceptability of stimuli. Barium was associated with lower taste intensity ratings for sweet, salty, and bitter tastants, higher taste intensity in carbonated water, and lower palatability in water, sweet, sour, and carbonated water. Older subjects reported lower palatability (all barium samples, sour) and higher taste intensity scores (ethanol, sweet, sour) compared to younger subjects. Supertasters reported higher taste intensity (ethanol, sweet, sour, salty, bitter) and lower palatability (ethanol, salty, bitter) than nontasters. Refusal rates were highest for younger subjects and supertasters, and for barium (regardless of tastant), bitter, and ethanol. Barium suppressed the perceived intensity of some tastes and reduced palatability. These effects are more pronounced in older subjects and supertasters, but younger supertasters are least likely to tolerate trials of barium and strong tastant solutions.

Taste intensity in the Beaver Dam Offspring Study

OBJECTIVES/HYPOTHESIS

To determine the distribution of the perceived intensity of salt, sweet, sour, and bitter in a large population and to investigate factors associated with perceived taste intensity.

STUDY DESIGN

Cross-sectional population.

METHODS

Subjects (n = 2,374; mean age, 48.8 years) were participants in the Beaver Dam Offspring Study examined during 2005 to 2008. Perceived taste intensity was measured using paper disks and a general labeled magnitude scale. Multiple linear regression was performed.

RESULTS

Mean intensity ratings were: salt = 27.2 (standard deviation [SD] = 18.5), sweet = 20.4 (SD = 15.0), sour = 35.7 (SD = 21.4), and bitter = 49.6 (SD = 23.3). Females and those with less than a college degree education rated tastes stronger. With adjustment for age, sex, and education, stronger perceived sour and bitter intensities were related to current smoking (sour: B = 2.8, 95% confidence interval [CI], 0.4 to 5.2; bitter: B = 2.8, 95% CI, 0.3 to 5.4) and lipid-lowering medications (sour: B = 5.1, 95% CI, 2.5 to 7.6; bitter: B = 3.2, 95% CI, 0.6 to 5.8). Alcohol consumption in the past year was related to weaker salt (B = -2.8, 95% CI, -5.3 to -0.3) and sweet intensity ratings (B = -2.3, 95% CI, -4.3 to -0.3), whereas olfactory impairment was associated with higher sweet ratings (B = 4.7, 95% CI, 1.4 to 7.9).

CONCLUSIONS

Perceived intensities were strongest for bitter and weakest for sweet. Sex and education were associated with each taste, whereas age did not demonstrate a consistent relationship. Associations with other factors differed by tastants, with current smoking and alcohol consumption being related to some tastes.

Ageing and taste

Taste perception has been studied frequently in young and older adult groups. This paper systematically reviews these studies to determine the effect of ageing on taste perception and establish the reported extent of sensory decline. Five databases were searched from 1900 to April 2012. Articles relating to healthy ageing in human subjects were included, reviewed and rated (Downs and Black scoring system). Sixty-nine studies investigated the effect of ageing on taste perception; forty examined detection thresholds of which twenty-three provided sufficient data for meta-analysis, eighteen reported identification thresholds and twenty-five considered supra-threshold intensity perception. Researchers investigating detection thresholds considered between one and thirteen taste compounds per paper. Overall, the consensus was that taste detection thresholds increased with age (Hedges’ g = 0·91, P < 0·001), across all taste modalities. Identification thresholds were reported to be higher for older adults in seventeen out of eighteen studies. Sixteen out of twenty-five studies reported perception of taste intensity at supra-threshold levels to be significantly lower for older adults. However, six out of nine studies concerning sucrose found perceived intensity of sweet taste not to diminish with age. The findings of this systematic review suggest taste perception declines during the healthy ageing process, although the extent of decline varies between studies. Overall, the studies reviewed had low Downs and Black scores (mean 16 (SD 2)) highlighting the need for more robust large scale and longitudinal studies monitoring the impact of ageing on the sensory system, and how this influences the perception of foods and beverages.

Development of a telemedical monitoring concept for the care of malnourished geriatric home-dwelling patients: a pilot study

Elderly patients are at high risk of malnutrition and sarcopenia, promoting further morbidity which in turn decreases quality of life and increases the claiming of medical services and associated costs. Early and sustained administration of oral nutritional supplements has been shown to improve the nutritional status with robust clinical benefit. Many patients however, poorly adhere to prescribed supplements, so consistent monitoring is needed. Clinical monitoring usually ends with the discharge rendering the continuation of nutritional supplement therapy in the patient's home problematic. We developed a telemedicine based health care concept for intensive home monitoring. In a first randomized controlled prospective study we analyzed the feasibility of this innovative approach. The intervention group received oral nutritional supplements and telemedical monitoring with daily assessment of body weight, number of taken oral energy supplements and state of health. The control group received usual care. 13 patients were included in each group, eight patients of the intervention group left the study prematurely, five patients were closely monitored and used the devices for a mean 67 ± 63.5 days. Follow up data of body weight and BMI showed no relevant differences between both groups. The results and experiences gained in this pilot study demonstrate that telemedical systems provide encouraging new options to enable an intensive monitoring of malnourished patients. A continuous intensive therapy monitoring of this patient group however, is a particular challenge. Albeit possibilities, limitations and useful parameters were identified, which will be used to improve the conception in an ongoing prospective randomized trial.