Abstract
Loss of appetite in older adults is common and can lead to reduced food intake, increasing the risk of malnutrition, frailty, and mortality. In addition, older adults often experience age-related deterioration in oral processing ability, saliva flow and chewing efficiency, which can further reduce food intake. This observational study investigated individual variations in these factors and their relative influence on food intake and appetite in healthy adults aged ≥ 65 years. After overnight fast, stimulated and unstimulated saliva samples were collected. A breakfast meal was provided, which was video recorded to enable a subsequent behavioural annotation of bites, chews and swallows using the software “ELAN”. Fasting and postprandial blood glucose were measured. Chewing efficiency was assessed using a two-colour chewing gum mixing ability test and the opto-electronic software ViewGum© (version 4.1.2.1). Saliva uptake was assessed using standard test food, and questionnaire data were collected to assess oral health, lifestyle and sensory preferences. Appetite was assessed subjectively using visual analogue scales for three hours after breakfast and objectively through an ad libitum lunch. Preliminary results from 44 participants (median age 72.5 years, BMI 25.6 kg/m2, 22 males) are presented (target sample size of the study is 86 participants). Males were observed to be faster eaters, with larger average bite size and higher saliva uptake values. Faster eaters had a larger ad libitum meal intake and consumed their meal with a larger average bite size, fewer chews per gram, and shorter total oral exposure time. Individuals with a faster eating rate consumed more food and these differences were associated with differences in subjective satiety ratings, postprandial blood glucose and stimulated saliva flow. No differences in chewing performance were observed. This study is the first to explore the association between oral processing and salivary factors with food intake and appetite in older adults. The preliminary results show that variability between individuals can influence food intake, glucose metabolism and post-meal satiety. This study will provide a foundation for better understanding the food needs of older adults and assist in designing appropriate food products for them.
Author Contributions
Conceptualization, L.M. and M.E.C.; methodology, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; software, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; validation, L.M., M.E.C. and D.Z.; formal analysis., L.M., M.E.C. and D.Z.; investigation, L.M., M.E.C. and D.Z.; resources, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; data curation, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; writing—original draft preparation, D.Z.; writing—review and editing, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; visualization, L.M., M.E.C., D.Z., J.W., G.M., C.F. and M.S.; supervision, L.M. and M.E.C.; project administration, L.M., M.E.C. and D.Z.; funding acquisition, L.M., M.E.C., J.W. and G.M. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by UKRI BBSRC FoodBioSystems Doctoral Training Partnership (DTP), grant number BB/T008776/1.
Institutional Review Board Statement
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Committee of University of Reading (UREC 22/29, 22/10/22).
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
The data is available on request from the corresponding author.
Conflicts of Interest
The authors declare no conflicts of interest.
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