Nutritional Adequacy and Dietary Assessment Approaches in Institutionalised Older Adults Living in Long-Term Care Settings: A Systematic Review (2004–2024)

Background: Adequate nutrition in long-term care (LTC) settings is critical for the health and well-being of institutionalised older adults, yet global evidence consistently reveals significant gaps in dietary provision. Methods: We conducted a systematic review of observational studies published between January 2004 and December 2024 in PubMed and Scopus, following PRISMA 2020 and JBI guidelines. The review assessed whether planned menus and residents’ actual intake met recognised dietary reference values, described dietary assessment methods, and identified common nutrient shortfalls. Results: 34 observational studies from 16 countries were included. The most frequently used assessment methods were weighed food records (50.0%), menu analyses (29.4%), and 24 h recalls or food diaries (20.6%). Among the 25 studies reporting mean daily energy intake, 68.0% documented values between 1250 and 1800 kcal/day, and 73.5% indicated intakes below established reference values. Additionally, 11 studies (32.4%) found that residents consumed less than 75% of the energy planned in menus. Protein intake was below 60 g/day or 0.83 g/kg body weight/day in 41.2% of studies. Across 22 studies assessing micronutrients, recurrent inadequacies included vitamin D (61.8%), calcium (55.9%), folate (50.0%), zinc (41.2%), and fibre (47.1%). In studies quantifying planned–served–consumed stages, actual intake represented approximately 64.0–87.0% of planned energy and protein. Conclusions: Nutrition in LTC settings frequently falls short of meeting the energy and nutrient requirements of institutionalised older adults. Persistent inadequacies in energy, protein, and key micronutrients were observed across studies, alongside substantial variability in dietary assessment methods and reference frameworks, limiting comparability of findings.