ONS is the Preferred Choice Over Milk for Nutritional Support
Oral nutritional supplements (ONS) should be prescribed instead of milk when patients cannot meet their energy and protein requirements through normal food alone, as ONS are specifically formulated as complete, balanced nutritional products designed for medical nutrition therapy. 1
Why ONS is Superior to Milk
Nutritional Completeness and Standardization
ONS are nutritionally complete products containing balanced macro- and micronutrients (protein, carbohydrates, fat, vitamins, minerals) that can serve as a sole source of nutrition if needed, unlike milk which lacks this comprehensive composition. 2, 3
Standard ONS are composed according to European Union regulatory directives for Food for Special Medical Purposes (FSMP), ensuring they meet specific medical nutritional standards that regular milk cannot provide. 2
ONS provide concentrated nutrition in small volumes (typically 400+ kcal and 30+ g protein per day), which is critical for patients with poor appetite who cannot consume large volumes of milk to meet requirements. 2
Evidence-Based Clinical Outcomes
In undernourished or at-risk patients, ONS significantly improve nutritional status, body weight, and reduce mortality—outcomes not demonstrated with milk alone. 2
After orthopedic surgery and hip fractures, ONS reduce complications and unfavorable outcomes, with Grade A evidence supporting their use. 2
In hospitalized older persons, ONS improve dietary intake, body weight, and lower the risk of complications and readmission. 2
Meta-analyses show ONS achieve 78% compliance overall (81% in community settings), with mean intake of 433 kcal/day, demonstrating practical effectiveness. 4
Hierarchical Position in Nutrition Support
ESPEN guidelines establish ONS as the mandatory first step when artificial nutrition is indicated, positioned before tube feeding or parenteral nutrition in the treatment algorithm. 1
ONS should be initiated when patients cannot meet energy needs from normal food alone, providing supplementary intake of up to 600 kcal/day without compromising normal food intake. 1
This hierarchical approach (ONS → Enteral → Parenteral) is supported by Grade A recommendations across multiple ESPEN guidelines. 1
When to Use ONS Instead of Milk
Clear Indications for ONS
Prescribe ONS to undernourished patients when oral nutrition from regular food (including milk) is insufficient for reaching calorie and protein goals. 2
In geriatric patients with malnutrition or at risk, offer ONS when dietary counseling and food fortification (which could include milk) are not sufficient to increase intake and reach nutritional goals. 2
For chronic pancreatitis patients, 80% can be managed with diet and enzyme supplementation, but the remaining 20% require ONS when meals alone are inadequate. 2
Specific Clinical Scenarios
In frail elderly, use ONS to improve or maintain nutritional status (Grade A recommendation). 2
After hospital discharge, older persons with malnutrition should receive ONS to improve intake, body weight, and lower risk of functional decline. 2
In dementia patients with malnutrition risk, ONS improve nutritional status when regular foods (including milk) prove insufficient. 2
For surgical patients at nutritional risk, preoperative ONS reduce complications from 45% to 28% in gastrointestinal surgery. 2
Practical Implementation
Dosing and Duration
ONS should provide at least 400 kcal/day including 30 g or more of protein/day to be effective. 2
Continue ONS for at least one month, as nutritional interventions require time to be effective in older adults who respond more slowly than younger individuals. 2
Monitor body weight, appetite, and clinical status at least monthly during ONS therapy to assess effectiveness and guide continuation. 2
Optimizing Compliance
Adapt ONS type, flavor, texture, and timing of consumption to patient's taste and eating capacities to support compliance. 2
A wide range of ONS styles (milk-based, juice, yogurt, savory), formats (liquid, powder, pudding), and energy densities (1-3 kcal/ml) are available to suit individual preferences. 2
Inform patients about potential benefits to improve motivation, as compliance is crucial for achieving clinical outcomes. 2
Important Caveats
When NOT to Use ONS
Do not use ONS in terminal disease states, including final dementia, where comfort feeding is more appropriate than meeting nutritional requirements. 2
ONS should not be used in dementia patients to correct cognitive impairment or prevent cognitive decline—they are ineffective for these outcomes. 2
Avoid blind supplementation without first attempting dietary counseling and food fortification (the "food first" approach). 5
Potential Concerns with ONS
Most commercial ONS are ultra-processed products that may displace plant-sourced foods and potentially impact gut microbiota diversity when used long-term. 6
Some ONS lack fiber or contain isolated fibers that may contribute to gastrointestinal symptoms and appetite suppression. 6
Cost-effectiveness must be considered, though systematic reviews demonstrate ONS are cost-effective in hospitalized patients. 2
The Bottom Line
Milk is simply a food item, while ONS are medical nutrition products specifically designed, formulated, and clinically validated to treat malnutrition and nutritional risk. 3 When patients cannot meet their nutritional requirements through regular diet (which may include milk as part of normal food intake), ONS provide the concentrated, complete, and standardized nutrition necessary to improve clinical outcomes. 2 The extensive evidence base supporting ONS—including Grade A recommendations for multiple patient populations—does not exist for milk as a therapeutic intervention. 2, 1