Dysphagia Knowledge Hub — 吞嚥困難知識庫

Oral Nutritional Supplements (ONS) for Dysphagia: Choosing, Thickening and Integrating Into the Care Plan

Dysphagia — difficulty swallowing — does more than create aspiration risk. It silently erodes nutritional status. Patients eat less, tire quickly at mealtimes, and avoid textures that are hard to manage safely. Over weeks, this produces weight loss, muscle wasting, and impaired immune function. Oral Nutritional Supplements (ONS) are a practical first-line intervention: energy- and protein-dense formulas designed to fill the gap between what a patient can eat and what their body needs.

This guide covers ONS selection, IDDSI-compliant thickening, clinical integration, and escalation criteria — practical information for caregivers, speech-language pathologists (SLPs), and dietitians.

Why ONS Are Needed in Dysphagia

Patients with dysphagia face a compounded nutritional challenge:

ONS address all four issues simultaneously: high energy density means less volume is required, and most formulas are nutritionally complete or near-complete.

Types of ONS: Matching the Formula to the Patient

Standard (1.0 kcal/mL)

Best for patients with modest deficits and adequate fluid tolerance. Lower caloric density means larger volumes are required to meet targets — not always practical in dysphagia.

High-Energy (1.5–2.0 kcal/mL)

The most clinically useful category for dysphagia. Compact volume (125–200 mL per serving) with 300–400 kcal delivered. Reduces the burden of large-volume intake. Examples include 1.5 kcal/mL formats (Fortisip Compact, Ensure Plus) and 2.0 kcal/mL concentrates (Resource 2.0, Fresubin 2 kcal).

Disease-Specific Formulas

Indicated when a co-morbidity limits standard formula use:

Select disease-specific formulas only when the underlying condition is active and monitored — the caloric density trade-off must justify the switch.

Key ONS Products: HK and Global Market

Product Energy Density Protein (per 200 mL) Key Notes Availability
Ensure Gold (Abbott) 1.0 kcal/mL ~12 g HMB-enriched; widely available in HK pharmacies HK, global
Ensure Plus (Abbott) 1.5 kcal/mL ~13 g Higher energy; familiar flavours; good palatability HK, global
Fortisip Compact Protein (Nutricia) 2.4 kcal/mL ~18 g / 125 mL Highest caloric concentration; 125 mL bottle reduces volume burden UK, EU, HK (prescription)
Resource 2.0 (Nestlé) 2.0 kcal/mL ~21 g / 237 mL High protein; vanilla and berry; widely stocked in care homes UK, US, HK
Boost High Protein (Nestlé) 1.0 kcal/mL ~15 g Good protein-to-calorie ratio; affordable US, UK
Fresubin 2 kcal (Fresenius Kabi) 2.0 kcal/mL ~20 g / 200 mL Neutral or flavoured; suitable for oral and tube use UK, EU

Note: availability and prescribability vary by territory. In Hong Kong, most products are available OTC or via hospital dietitian referral. In the UK, high-energy ONS are routinely prescribed on the NHS following MUST screening.

IDDSI Compliance: Thickening ONS to the Prescribed Level

Most standard ONS are thin liquids (IDDSI Level 0). Patients prescribed IDDSI Levels 1–4 (slightly thick to extremely thick) must not consume unmodified ONS — aspiration risk applies equally to nutritional supplements as to water.

Which Thickeners Work Best with ONS

Starch-based thickeners (e.g., Resource ThickenUp Classic) may be destabilised by the amylase in saliva over time and can interact with the high-protein matrix of some formulas. Xanthan gum-based thickeners (e.g., Resource ThickenUp Clear, Nutilis Clear, Thick-It Clear) are generally preferred: they are stable in acidic, protein-rich, and hot environments, and maintain clarity.

IDDSI Thickening Guide for ONS

IDDSI Level Description Typical Xanthan Powder Dose (per 200 mL) Flow Test
Level 0 (Thin) No thickener needed 0 g Flows freely through 10 mL syringe in <10 s
Level 1 (Slightly Thick) Very mild resistance ~1.2 g (1 level scoop) Flows through 10 mL syringe in 1–4 s
Level 2 (Mildly Thick) Noticeably thicker than water ~2.4 g (2 scoops) Flows through 10 mL syringe in 4–8 s
Level 3 (Moderately Thick) Pourable but holds shape briefly ~3.5–4.5 g Falls off spoon in thick drops
Level 4 (Extremely Thick) Spoonable; does not flow ~6–8 g Holds shape on spoon; does not pour

Doses are approximate for xanthan gum-based thickener added to a standard 200 mL ONS serving. Always verify with IDDSI flow testing and follow the thickener manufacturer’s guidance — product-specific charts supersede these estimates.

Practical note: mix thickener vigorously for 30–60 seconds, then wait 2–3 minutes before testing and serving. Thickness increases with resting time. Serve promptly — do not allow extended standing as consistency may continue to change.

When to Use ONS: Supplementation, Not Substitution

ONS are most effective — and most appropriate — as between-meal supplements, not meal replacements. The reasoning is physiological: hunger drives engagement with meals, and if ONS are given immediately before or instead of meals, appetite suppression follows, reducing total intake.

Recommended timing: mid-morning (10:00), mid-afternoon (15:00), or evening before bed. These windows avoid peak mealtime hunger while capturing otherwise wasted caloric opportunities.

Exceptions: when the patient cannot tolerate any oral meals (post-surgical, severe fatigue, extreme dysphagia), ONS may temporarily serve as the primary oral nutrition source under dietitian direction. This is a short-term bridge, not a long-term plan.

Palatability and Flavour Fatigue

ONS adherence drops sharply within 4–8 weeks when a single flavour is used daily. Strategies to maintain compliance:

Monitoring Outcomes

Initiate ONS with a clear monitoring protocol. Review at 4 weeks minimum:

If nutritional targets are not being met after 4–6 weeks of optimised ONS use, escalate the review — do not continue an ineffective regimen.

When to Escalate to Enteral Tube Feeding

ONS are not always sufficient. Escalation to nasogastric (NG) or percutaneous endoscopic gastrostomy (PEG) feeding should be considered when:

The decision to escalate involves the multidisciplinary team — dietitian, SLP, physician, and critically, the patient and family. Tube feeding is not a failure; it is a clinical tool appropriate when oral nutrition cannot safely or adequately meet needs.

Summary

ONS are a cornerstone of nutritional management in dysphagia — compact, evidence-based, and adaptable. Selecting the right energy density, thickening to the correct IDDSI level, timing supplementation between meals, and rotating flavours are all modifiable factors that determine whether a patient actually benefits. Pair ONS use with structured monitoring and a clear escalation threshold, and they become a reliable component of a comprehensive dysphagia care plan.

For texture-modified food guidance, see the IDDSI texture levels overview. For malnutrition screening tools, see MUST and MNA in dysphagia care.