This year’s Institute of Food Science (IFST) Spring Conference (SC19) ‘Nutritional Science over Gut Feel’ (University of Birmingham, Birmingham, UK, 4th April 2019) focused on the topic of nutrition, and in particular, considered the role that both the sector and industry plays in identifying, developing and implementing novel scientific and technological solutions aiming to tackle the greatest nutritional challenges facing our community today. The day-long event welcomed speakers from across the food science and nutrition community, discussing a series of thought-provoking talks in sessions held throughout the day on topics including psychology and consumer behaviour, genetic influences on weight loss and GM and gene editing.
The first of the afternoon sessions explored the considerations and challenges associated with the development of palatable foods specifically designed to meet the complex nutritional needs of our ever-growing elderly population, as well as considering how various approaches can be adopted to support healthy ageing and improve overall quality of life for older people.
It is widely accepted that our hunger and desire to eat tends to decline as we age, but why is this? And what implications can this have on our long-term health? A spectrum of interconnecting social, medical, psychological and physical factors have been shown to impact on our food choice as we get older, meaning a holistic approach is required to tackle the rising problem of malnutrition among our elderly population. In fact shockingly, over 40% of those entering care homes in developed countries are already malnourished, with this figure rising steeply on discharge from hospital admissions. This is clearly a problem that needs to be addressed urgently.
What physical changes can make meeting the tailored nutritional requirements of the elderly more of a challenge? Decline in sensory perception is cited as a key malnutrition risk factor, including loss of taste and smell as we age. In particular, age-related increase in the detection threshold for salt in foods mean that meals can taste less flavourful and therefore less appealing, leading to potentially health adverse changes in food preference and choice. This creates a double burden, with older adults more likely to choose fat/sugar laden foods with little nutritional benefit and add extra salt and sugar to other foods to compensate for their reduced perception in taste intensity, in turn increasing the risk of lifestyle related diseases including CVD, CHD, diabetes and some cancers.
This correlation in diminished sensory perception and age appears to be amplified in frail older adults, meaning dependent elderly are particularly vulnerable to malnutrition compared to those living independently, and hence more susceptible to related conditions such as sarcopenia. Oral health problems experienced among some older adults further exacerbate the problem, with the sensation of a dry mouth (xerostomia) caused by a reduction in salivary flow reducing the taste intensity of foods. This, alongside swallowing difficulties and reduced dentition and muscle strength, can make the process of eating a distinctly unpleasant and increasingly laborious task for the elderly.
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Several proposed solutions aiming to combat these issues were discussed; taste enhancement, nutrient fortification and texture optimisation. Although studies have found it hard to demonstrate that texture and flavour modification, such as enhancing the salt content of a meal, directly leads to an increase in intake, an increase in food ‘liking’ has been documented, especially among dependant older adults (Song et al., 2016), and anything that increases the enjoyment experienced by eating is an encouraging result! The addition of umami was briefly discussed, and with its unique ability to enhance flavour without the negative health implications associated with salt, using natural ingredients rich in umami taste compounds could be an exciting venture for the food industry!
Ageing bodies process protein less efficiently, therefore protein requirements are greater for older adults in order to maintain muscle mass and strength, bone health and other essential physiological functions. Fortification of foods targeting the elderly population largely focus on optimising whey protein intake, shown to stimulate muscle protein synthesis to a greater extent than casein. However this has proven to be an unexpectedly difficult task, with protein fortified foods and beverages appearing to worsen the sensation of dry mouth among the elderly. Although the exact mechanisms are still unclear, it is thought that the protein from the food remains in an older adult’s mouth longer after swallowing than younger consumers creating an unpleasant dry feeling; a side effect very unhelpful for trying to encourage food consumption! On a more positive note, research has shown that sensory characteristics of some protein fortified snacks do appear to convincingly replicate those of similar commercial snacks, particularly biscuits – a favourite sweet treat for many- and are therefore more likely to be accepted by consumers, potentially helping to alleviate the risk of malnutrition in the elderly (Tsikritzi et al., 2013). Such findings could go a long way in influencing future reformulation strategies in various food categories.
The take home messages are clear; although we have come a long way in our understanding and approach to tackling malnutrition, more research is undoubtably needed to explore how we may better manipulate textural and taste components of popular foods to not only appeal to the elderly consumer, but simultaneously making it easier for them to meet their unique nutritional requirements. In turn, it seems the food industry have a responsibility to ensure that food products specifically targeted at the elderly population, perhaps with modified packaging design, nutritional content or portion size made available and affordable for all. Innovative research continues in this specialised field of sensory science, and we wait with anticipation for the launch of future nutritionally optimised, palatable products specifically designed for the niche senior market.
Related FSTA example records:
Ageing and taste.
Proceedings of the Nutrition Society Volume: 41 Issue: 4 Pages: 556-565 Published 2012
Aging-related changes in quantity and quality of saliva: where do we stand in our understanding?Journal of Texture Studies Volume: 50 Issue: 1 Pages: 27–35 Published: 2019
FSTA ref.: 2019-07-Ag7565
Association between salivary hypofunction and food consumption in the elderlies. A systematic literature review.
Journal of Nutrition, Health & Aging Volume: 22 Issue: 3 Pages: 407–419 Published: 2018
FSTA ref.: 2018-07-Aj6698
Changes in orosensory perception related to aging and strategies for counteracting its influence on food preferences among older adults.
Trends in Food Science & Technology Volume: 53 2016 Pages: 49–59 Published: 2016
FSTA ref.: 2016-09-Ag8363
Does interindividual variability of saliva affect the release and metabolization of aroma compounds ex vivo?
The particular case of elderly suffering or not from hyposalivation.
Journal of Texture Studies Volume: 50 Issue: 1 Pages: 36–44 Published: 2019
Oral comfort: a new concept to understand elderly people's expectations in terms of food sensory characteristics.
Food Quality and Preference Volume: 70 (Seventh European Conference on Sensory and Consumer Research) Pages: 57–67 Published: 2018
Relationship between sensory perception and frailty in a community-dwelling elderly population.
Journal of Nutrition, Health & Aging Volume: 21 Issue: 6 Pages: 710–714 Published: 2017
Taste loss in the elderly: possible implications for dietary habits.
Critical Reviews in Food Science and Nutrition Volume: 57 Issue: 17 Pages: 3684–3689 Published 2017
The effect of macro- and micro-nutrient fortification of biscuits on their sensory properties and on hedonic liking of older people.
Journal of the Science of Food and Agriculture Volume: 94 Issue: 10 Pages: 2040–2048 Published: 2014