"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.