Développer et évaluer des aliments fortifiés pour permettre aux personnes âgées de répondre à leurs besoins nutritionnels tout en conservant le plaisir de manger

As the body ages, physiological mechanisms deteriorate. To compensate for this decline, nutritional needs may increase in older adults compared to younger adults, particularly in terms of protein intake. At the same time, appetite may decrease with age, leading to reduced food consumption and, consequently, less nutrient intake. This imbalance between nutritional intake and needs leads to undernutrition, a recognised condition in older adults. To prevent undernutrition and its negative consequences, it is crucial for older individuals to meet (or maintain) their nutritional requirements. Therefore, the aim of this thesis is to develop fortified foods and assess whether their consumption can prevent the onset of undernutrition in independent older adults (≥ 70 years) living at home. Food fortification consists in incorporating ingredients of nutritional interest into commonly consumed foods, without increasing the portion to be ingested. The work in this thesis focused on protein and energy fortification.Several approaches were combined. A systematic review of the literature (SLR) documented current knowledge about fortified foods destined for older adults. A study at older adults’ homes validated the feasibility and acceptability of newly developed fortified foods. A laboratory study examined the impact of fortification on the sensory aspects of foods. Finally, a 4-month randomised controlled trial assessed the impact of consuming these fortified foods, whether or not combined with physical activity, on preventing undernutrition.Findings from the SLR highlighted the fact that fortified foods are rarely tested for acceptability within the target population, which can have an impact on compliance. The results of the studies carried out in this thesis also indicate that the older adults are not sufficiently familiar with the nutritional recommendations specific to their age group. Nevertheless, understanding age-related changes is crucial in implementing sustainable dietary modifications in this population. The results also demonstrated that adapted food fortification has been shown to be a feasible strategy to implement at home and to be accepted by independent older adults. The flexibility of this approach, which allows it to be adapted to individual preferences, represents a significant advantage in terms of long-term adoption. In addition, this thesis has shown a positive impact of the consumption of fortified foods in preventing body weight loss in a healthy older population living at home.