You can teach an old dog new tricks: olfaction and responses to novel foods by the elderly

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.

Age group determines the acceptability of protein derived off-flavour

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Heat-treatment of protein ingredients can impart sulfurous flavours into beverages.

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Sulfurous flavours negatively impacted consumer acceptance of a dairy beverage.

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Older adults had greater acceptance of sulfurous flavours compared to younger adults.

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Diacetyl reduced the negative impact of these compounds for both age groups.

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Best estimate thresholds give a conservative estimate of off-flavour acceptability.

Many older adults fail to meet their daily protein requirements, potentially due to social, physical and medical factors, including sensory and appetite changes. Additionally, our previous research has identified potential sulfurous off-flavours, originating from heat-treatment of protein ingredients, which could play a role in consumer acceptance. This study aims to determine the hedonic impact of these potential off-flavours when added to a dairy beverage, identify the specific off-flavour concentrations which cause rejection by consumers, and lastly investigate difference in acceptance between older and younger consumers. A rejection threshold (RjT) protocol was used, in combination with Best Estimate Thresholds (BET), whereby sulfurous flavours (dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide), and diacetyl were added to create a range of concentrations. 95 participants (younger n = 49, 18–38 years; older n = 46, 60–79 years) tasted 7 pairs of samples (one blank and one with ascending off-flavour concentration) and selected their preferred samples. Sulfurous flavours negatively impacted consumer acceptance, however, the extent to which they impart a negative effect differs between age groups. Younger adults rejected samples containing low concentrations of sulfurous off-flavours (1.55 ppb), however, older adults rejected samples with concentrations over 3 times higher (5.08 ppb). When combined with sulfurous flavours, diacetyl increased the rejection threshold for both groups. In conclusion, these observations imply that a greater quantity of off-flavour may be present before acceptance is reduced in the older consumer group. Moreover, diacetyl demonstrates partial masking abilities of sulfurous off-flavours, and BET gave a more conservative estimate of acceptability. This knowledge will help guide sensory innovation of high-protein beverages for older consumers to support product acceptance and optimal intake.

Olfaction and Aging: A Review of the Current State of Research and Future Directions

Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.

Olfactory disorders and quality of life--an updated review

Olfactory disorders are common and affect about one-fifth of the general population. The main causes of olfactory loss are post viral upper respiratory infection, nasal/sinus disease, and head trauma and are therefore very frequent among patients in ear, nose, and throat clinics. We have systematically reviewed the impact of quantitative, qualitative, and congenital olfactory disorders on daily life domains as well as on general quality of life and depression. From the extensive body of literature, it can be concluded that loss of the sense of smell leads to disturbances in important areas, mainly in food enjoyment, detecting harmful food and smoke, and to some extent in social situations and working life. Most patients seem to deal well and manage those restrictions. However, a smaller proportion has considerable problems and expresses a noticeable reduction in general quality of life and enhanced depression. The impact of coping strategies is discussed.

Licking microstructure reveals rapid attenuation of neophobia

Many animals hesitate when initially consuming a novel food and increase their consumption of that food between the first and second sessions of access-a process termed attenuation of neophobia (AN). AN has received attention as a model of learning and memory; it has been suggested that plasticity resulting from an association of the novel tastant with "safe outcome" results in a change in the neural response to the tastant during the second session, such that consumption increases. Most studies have reported that AN emerges only an hour or more after the end of the first exposure to the tastant, consistent with what is known of learning-related plasticity. But these studies have typically measured consumption, rather than real-time behavior, and thus the possibility exists that a more rapidly developing AN remains to be discovered. Here, we tested this possibility, examining both consumption and individual lick times in a novel variant of a brief-access task (BAT). When quantified in terms of consumption, data from the BAT accorded well with the results of a classic one-bottle task-both revealed neophobia/AN specific to higher concentrations (for instance, 28mM) of saccharin. An analysis of licking microstructure, however, additionally revealed a real-time correlate of neophobia-an explicit tendency, similarly specific for 28-mM saccharin, to cut short the initial bout of licks in a single trial (compared with water). This relative hesitancy (i.e., the shortness of the first lick bout to 28-mM saccharin compared with water) that constitutes neophobia not only disappeared between sessions but also gradually declined in magnitude across session 1. These data demonstrate that the BAT accurately measures AN, and that aspects of AN-and the processes underlying familiarization-begin within minutes of the very first taste.

Designing new meals for an ageing population

Today's ageing population is an ever-increasing, highly diverse group of people wanting to live a healthy and enjoyable life. Seniors increasingly see the importance of eating healthy and delicious food in a pleasant environment in achieving happiness and well-being. Up until now, the food industry has been rather slow in transforming the wealth of available knowledge regarding the nutritional needs and sensory perception of the ageing into new food products. Based on our own and the published research of others, we discuss here how the design of new meals for an ageing population can be tackled by a consumer-led approach to food product development. After a brief overview of the underlying concepts and practices, a detailed description is given of how this approach could be used in the design of Home Meal Replacements for senior households. This description includes also a comprehensive review of the major determinants of food preference and meal choice behavior in a later age. Finally, relevant implications are derived from the work presented and future trends in the technological development of foods for the ageing highlighted.

Food neophobia and 'picky/fussy' eating in children: a review

Two factors have been shown to contribute to rejection or acceptance of fruits and vegetables: food neophobia and 'picky/fussy' eating. Food neophobia is generally regarded as the reluctance to eat, or the avoidance of, new foods. In contrast, 'picky/fussy' eaters are usually defined as children who consume an inadequate variety of foods through rejection of a substantial amount of foods that are familiar (as well as unfamiliar) to them. Through understanding the variables which influence the development or expression of these factors (including age, personality, gender, social influences and willingness to try foods) we can further understand the similarities and differences between the two. Due to the inter-relationship between 'picky/fussy' eating and food neophobia, some factors, such as pressure to eat, personality factors, parental practices or feeding styles and social influences, will have similar effects on both magnitude and duration of expression of these behaviours. On the other hand, these constructs may be differentially affected by factors such as age, tactile defensiveness, environment and culture. The effects of these variables are discussed within this review. Behavioural interventions, focusing on early life exposure, could be developed to attenuate food neophobia and 'picky/fussy' eating in children, so promoting the ready acceptance and independent choice of fruits and vegetables.

Chemosensory Declines in Older Adults with HIV: Identifying Interventions

Olfactory and gustatory impairments are observed with aging and with HIV infection. Thus, the synergistic effects of aging with HIV infection on olfactory and gustatory declines may be profound. Such declines can jeopardize several areas for an older adult living with HIV such as safety, appetite and malnutrition, cognition, mood, and quality of life. Potential interventions that need to be investigated include hormone replacement therapy, lifestyle changes, medical assessment, and compensation strategies. Nurses are the primary providers of care and education to address sensory alterations of those who have HIV and those who are aging.

Olfactory disorders and their consequences for quality of life

Olfactory disorders are common in the general population, but research into the consequences of these disorders has been lacking. Not until recently, when specific tools for assessing changes in quality of life due to olfactory disorders have become available, have systematic investigations been conducted. In this article we present the most important roles that olfaction plays in humans and review the scientific literature on the consequences of olfactory disorders. This review suggests that quality of life, regarding safety issues and interpersonal relations, as well as eating habits and nutritional intake are severely altered in a large proportion of patients with olfactory disorders.