What are oral nutritional supplements (ONS)?
Oral nutritional supplements are medical nutrition products taken by mouth to provide additional macro- (energy, protein) and micronutrients (vitamins, minerals) when diet alone is not enough. Unlike standard dietary supplements bought over-the-counter for general wellness, ONS are specifically designed for individuals with increased nutritional needs due to illness, malabsorption, poor appetite, or injury. These products are available in various forms to suit different needs and preferences.
Why are oral nutritional supplements necessary?
ONS are prescribed when an individual's nutritional requirements cannot be met by consuming regular food. This can occur for several reasons, including:
- Disease-related malnutrition: Chronic or acute illnesses often lead to poor appetite and reduced food intake.
- Increased nutritional needs: Conditions like post-surgery recovery, certain cancers, and traumatic injuries increase the body's demand for energy and protein.
- Poor absorption of nutrients: Issues like inflammatory bowel disease (IBD) or short bowel syndrome can prevent the body from absorbing enough nutrients from food.
- Difficulty swallowing (dysphagia): Neurological conditions can make it unsafe to consume regular food and fluids.
- Underweight and weight loss: ONS can help promote weight gain in individuals with a low body mass index (BMI) or those experiencing significant unintentional weight loss.
Who can benefit from oral nutritional supplements?
ONS are a valuable tool for many populations who are malnourished or at risk of malnutrition. These groups include:
- Elderly individuals: Age-related changes, frailty, and chronic diseases can lead to a decline in appetite and food intake.
- Hospitalized patients: Malnutrition is common in hospital settings due to illness and poor appetite.
- Post-operative patients: Recovering from surgery requires extra energy and protein for wound healing.
- Individuals with chronic conditions: People with COPD, heart failure, IBD, and certain cancers may struggle to meet their nutritional needs through diet alone.
- People with swallowing difficulties: Modified-consistency ONS are available for those with dysphagia.
Types of Oral Nutritional Supplements
ONS are available in a variety of styles, formats, and nutritional compositions to match individual requirements and preferences.
Formats:
- Ready-to-drink liquids: These include milkshake-style and juice-style drinks, available in various flavors.
- Powders: Versatile powders can be mixed with milk or water, or added to other foods.
- Puddings and desserts: Offering a different texture, these are suitable for those who prefer a semi-solid option.
- Soups: Savoury-flavoured supplements that can be mildly heated.
Compositions:
- Standard formulas: Provide balanced energy, protein, vitamins, and minerals.
- High-protein formulas: Beneficial for wound healing, post-operative recovery, and cancer patients.
- High-energy/low-volume formulas: Ideal for individuals who cannot tolerate large fluid volumes.
- Fibre-containing formulas: Can help with constipation, but not suitable for those requiring a fibre-free diet.
- Disease-specific formulas: Tailored for conditions like kidney disease or diabetes.
Oral Nutritional Supplements vs. Whole Foods: A Comparison
It is crucial to understand that ONS are a supplement, not a replacement, for whole foods. Whole foods remain the foundation of a healthy diet, but supplements can bridge gaps when needed. Here's a comparison:
| Aspect | Oral Nutritional Supplements (ONS) | Whole Foods (Fruits, Vegetables, etc.) |
|---|---|---|
| Nutrient Source | Concentrated, isolated nutrients (protein, energy, vitamins, minerals). | Natural, synergistic mix of vitamins, minerals, antioxidants, and fibre. |
| Nutrient Bioavailability | Can be highly bioavailable due to specific formulations, but lacks the synergistic effect of whole foods. | Nutrients are more effectively absorbed and utilized by the body when consumed together in their natural state. |
| Convenience | Highly convenient; requires minimal preparation. Comes in ready-to-use liquids, powders, or desserts. | Requires time and effort for shopping, preparation, and cooking. |
| Purpose | To fill specific nutritional gaps and manage malnutrition or disease-related needs. | To provide comprehensive nutrition and support overall health and wellness. |
| Satiety | Can decrease normal food intake if taken close to meals. | Provides fibre and a variety of textures, contributing to a feeling of fullness. |
How to properly use oral nutritional supplements
To get the most benefit and avoid disrupting your regular food intake, follow these guidelines, always under the direction of a healthcare professional like a dietitian.
- Timing is key: Take ONS between meals, after meals, or before bed. Avoid consuming them just before or during a meal, as they can reduce your appetite for regular food.
- Correct dosage: Your doctor or dietitian will determine the appropriate number of servings per day based on your specific needs.
- Variety is important: Taste fatigue is common, so trying different flavours and formats can help maintain compliance. Many brands offer variety packs to sample different options.
- Temperature: Most ready-to-drink supplements taste best when chilled. You can also try gently warming savoury options like soup, but do not boil them, as this can degrade nutrients.
- Creative incorporation: Mix powders into smoothies, yogurts, or other recipes. Freezing juice-based supplements into ice pops can also be a refreshing alternative.
- Storage: Store unopened ONS in a cool, dry place. Once opened, refrigerate and use within 24 hours.
The importance of professional guidance
Because ONS are a medical nutrition strategy, it is vital to use them under the care of a healthcare professional. A registered dietitian can perform a comprehensive nutritional assessment to identify the underlying cause of malnutrition and determine the right type and quantity of supplement. Regular monitoring is necessary to track progress, assess tolerance, and determine when supplementation can be stopped. The aim is always to return to a sufficient oral diet of normal food as soon as clinically appropriate.
Conclusion
Oral nutritional supplements are more than just vitamins; they are a clinically-proven intervention for managing malnutrition and supporting recovery in a wide range of patients. When used correctly and under professional guidance, ONS provide a vital source of concentrated energy and nutrients for individuals unable to meet their needs through diet alone. By understanding what they are, the various types available, and how they complement (rather than replace) whole foods, patients and caregivers can make informed decisions to improve health outcomes and quality of life. For further information and support, consider visiting reputable resources like the Malnutrition Pathway, which offers resources developed by healthcare professionals.
