Preprint · Jan 2026
Oral Nutritional Supplements: Efficacy, Indications, and Guidelines
By Hofer V, Riegelnegg M
Malnutrition describes deficiencies, excesses, or imbalances in a person's energy and nutrient intake and can be divided into two main disease groups. The first group includes malnutrition, which encompasses growth retardation, wasting, underweight, and micronutrient deficiencies. The second group includes overweight, obesity, and nutrition-related noncommunicable diseases such as heart disease, stroke, diabetes, and cancer. Undernutrition can be further subdivided into quantitative malnutrition (insufficient energy intake leading to weight loss and wasting) and qualitative malnutrition (micronutrient deficiencies affecting specific physiological functions) [1]. Within the scope of this project, malnutrition refers exclusively to undernutrition and nutrient deficiencies. These can be both a cause and consequence of poor health and lead to metabolic, functional, and physiological deficits with far-reaching consequences: weight loss, loss of body fat and muscle mass, increased mortality and morbidity, as well as higher consumption of healthcare resources [2, 3]. While malnutrition is often associated with famine and food insecurity, it is also a substantial health problem in high-income countries, particularly among elderly people and those with chronic diseases [4]. Disease-related malnutrition may arise from conditions that either increase nutritional requirements (such as cancer, infections, or burns) or impair nutritional intake through long-term illnesses (dementia, chronic obstructive pulmonary disease), mechanical problems (dysphagia, reduced gastric capacity), or behavioural issues (selective eating). Despite these wide-ranging aetiologies, the lack of awareness regarding vulnerable groups' nutritional requirements, combined with societal acceptance of weight loss as a normal part of ageing, results in delayed identification and treatment of this largely preventable condition [2-6]. To address malnutrition and its associated health risks, oral nutritional supplements (ONS) are widely used for prevention and treatment. ONS are commercially manufactured products available in liquid, powder, or solid form, containing carbohydrates, proteins, fats, fibre, vitamins, and minerals. Evidence supports their use across a range of clinical settings, with demonstrated benefits including improved clinical and functional outcomes and enhanced recovery and healing. In clinical practice, ONS are frequently prescribed to patients identified as malnourished or at risk of malnutrition. Their use is not without controversy, however: in some healthcare systems, rapidly rising costs and concerns about inappropriate prescribing have prompted scrutiny of current practice. While ONS may offer limited benefit in certain patient groups, they remain essential for others, underscoring the importance of identifying those most likely to benefit from their use [2, 4, 5]. The right to adequate nutrition is enshrined in the International Declaration on the Human Right to Nutritional Care (Vienna Declaration 2022) [7]. Denying ONS access to malnourished patients could violate fundamental human rights. However, ethical considerations must balance this right with concerns about overuse, inappropriate prescribing, and medicalisation when simpler interventions might suffice [8]. Beyond patient care ethics, ONS require sustainability evaluation. Their environmental impact (resource-intensive production, carbon emissions, and packaging waste) raises questions about healthcare's ecological responsibility. Inappropriate prescribing represents a misuse of resources, a potential violation of patient autonomy, and an avoidable environmental burden [5]. Project aims This project aims to conduct a comprehensive health technology assessment of oral nutritional supplements across different patient populations and clinical indications to support evidence-informed prescribing decisions within the Austrian healthcare system. This project does not aim to evaluate individual clinical indications in detail or to compare the nutritional composition of different ONS products. The scope is limited to orally consumed nutritional supplements and does not include enteral tube feeding. References: [1] Wold Health Organization (WHO). Malnutrition. 2025 [cited 19.02.2026]. Available from: https://www.who.int/news-room/questions-and-answers/item/malnutrition#:~:text=Malnutrition%20refers%20to%20deficiencies%2C%20excesses,stroke%2C%20diabetes%20and%20cancer. [2] American Society for parental and enteral nutrition (ASPEN). Oral Nutrition Supplements: A Practical Tool for Clinicians. 2025 [cited 10.02.2026]. Available from: https://nutritioncare.org/wp-content/uploads/2025/07/MAW-ONS-Practice-Tool-Clinician.pdf. [3] Baldwin C., Smith R., Gibbs M., Weekes C. E. and Emery P. W. Quality of the Evidence Supporting the Role of Oral Nutritional Supplements in the Management of Malnutrition: An Overview of Systematic Reviews and Meta-Analyses. Advances in Nutrition. 2021;12(2):503–522. DOI: https://doi.org/10.1093/advances/nmaa108. [4] Bahat G., Pinar E., Abbasoglu O., Karan M. A., Ozturk S., Barazzoni R., et al. Nutritional care using oral nutritional supplements: 22 questions every clinician Asks—Answered by global experts in a Delphi consensus study. Clinical Nutrition. 2026;57:106552. DOI: https://doi.org/10.1016/j.clnu.2025.106552. [5] NHS and London Procurement Partnership. Scoping the sustainability impact of Oral Nutritional Supplements. [cited 10.02.2026]. Available from: https://www.lpp.nhs.uk/media/586486/nhs-lpp-scoping-the-sustainability-impact-of-oral-nutritional-supplements-v2.pdf. [6] Taylor C. M. and Emmett P. M. Picky eating in children: causes and consequences. Proc Nutr Soc. 2019;78(2):161–169. Epub 20181105. DOI: 10.1017/s0029665118002586. [7] ASPEN E., FELANPE and PENSA,. The International Declaration on the Human Right to Nutritional Care. [cited 10.02.2026]. Available from: https://www.espen.org/files/Vienna-Declaration-2022.pdf. [8] Arbeitsgemeinschaft klinische Ernährung (AKE). Ethische Überlegungen für die Ernährungstherapie. 2024 [cited 10.02.2026]. Available from: https://empfehlungen.ake-nutrition.at/5-probleme-loesen-und-entscheidungen-treffen/5-3-entscheidungen/5-3-1-ethische-ueberlegungen-fuer-die-ernaehrungstherapie/.