When to Use Thickened Liquids for Swallowing Difficulties

December 22, 2025 •

3 min read

Dysphagia, or difficulty swallowing, is often managed using thickened liquids, with the International Dysphagia Diet Standardisation Initiative (IDDSI) offering guidance. A 2018 study in the Journal of the American Geriatrics Society, found that roughly 15% of older adults experience swallowing difficulties. This guide explains when to use thickened liquids to improve swallowing safety.

Quick Summary

Thickened liquids help those with dysphagia by slowing liquid flow, which helps with control and lowers aspiration risk. An SLP determines the right thickness, and careful preparation is essential for hydration and safety. Remember to follow medical advice to ensure best results.

Key Points

Medical Guidance: Thickened liquids should only be used when medically necessary, as prescribed by a Speech Pathologist.
Prevent Aspiration: Their main purpose is to slow liquid flow and avoid aspiration.
IDDSI Standardization: IDDSI defines clear levels of thickness.
Monitor Hydration: Watch for signs of dehydration, as some people drink less of thickened liquids.
Choose the Right Thickener: Select a suitable thickening agent and mix it properly.
Avoid Melting Solids: Foods like ice cream must be thickened if consumed.
Medication Impact: Consult a pharmacist about how thickened liquids may affect medications.

Understanding Dysphagia and the Role of Thickened Liquids

Dysphagia, or difficulty swallowing, happens when the muscles or nerves involved in swallowing are weak or uncoordinated. It can stem from conditions like stroke, Parkinson's disease, dementia, or head and neck cancer. Thin liquids can move too fast for those with dysphagia, raising the risk of aspiration. Aspiration occurs when liquids enter the airway, potentially causing aspiration pneumonia. Thickened liquids move more slowly, giving the swallow reflex time to work and protect the airway.

Recognizing the Need for Thickened Liquids: Signs and Symptoms

Identifying signs of swallowing difficulty is the first step toward intervention. While an SLP's assessment is needed for a diagnosis, certain indicators suggest the need for thickened liquids.

Common Indicators of Dysphagia

Coughing or choking while drinking thin liquids
A gurgly voice after drinking
The sensation of liquid getting "stuck" in the throat
Spilling liquid from the mouth
Shortness of breath or labored breathing when drinking
Recurrent respiratory infections or pneumonia

The IDDSI Framework: A Standardized Approach

The IDDSI framework standardizes modified food textures and thickened liquid consistencies. Healthcare providers use this to ensure consistent and safe diet recommendations. The levels are defined by a flow test using a 10ml syringe.

IDDSI Liquid Levels Explained

Level 0 (Thin): Flows like water, no residue after 10 seconds. Examples: water, juice, and coffee.
Level 1 (Slightly Thick): Leaves 1–4 ml in the syringe after 10 seconds. Thicker than water but can be sipped.
Level 2 (Mildly Thick): Leaves 4–8 ml in the syringe after 10 seconds. Similar to nectar or cream soup.
Level 3 (Moderately Thick): Leaves more than 8 ml in the syringe after 10 seconds. Similar to honey.
Level 4 (Extremely Thick): No liquid pours out in 10 seconds; requires a spoon and holds its shape.

Effective Management of Thickened Liquids

Proper management is key to ensuring that thickened liquids are effective and do not lead to complications such as dehydration or poor nutritional intake..

Follow Professional Advice: Always follow the SLP's recommendations for the correct thickness level. This level is based on a swallowing assessment.
Correct Preparation: Use commercial thickeners, following the manufacturer's directions. The amount of thickener can vary depending on the liquid and its temperature.
Avoid Melting Solids: Steer clear of foods that melt into thin liquids, like ice cream, gelatin, and ice cubes, unless thickened.
Hydration is Key: Monitor fluid intake to prevent dehydration, as thickened liquids can be less appealing.
Medication Considerations: Discuss with a pharmacist how to take medications. Thickened liquids can affect absorption.

Comparison of Thickening Agents


Feature	Starch-Based Thickeners (e.g., modified cornstarch)	Gum-Based Thickeners (e.g., xanthan gum)
Texture	Can result in a grainy or starchy texture.	Smoother, less grainy texture.
Thickening Stability	Can thicken further over time.	More consistent over time.
Flavor	May have a starchy flavor, especially in high concentrations.	Generally neutral in flavor.
Clumping	Can clump if not mixed well, especially in cold liquids.	Less prone to clumping.
Cost	Often more affordable.	Can be more expensive.
Best for	Hot liquids; may not be suitable for extended use.	Most types of liquids, for consistent thickness.

Conclusion

Using thickened liquids is a medical decision, advised by an SLP to manage dysphagia and lower aspiration risk. The IDDSI framework offers guidelines for consistency levels, which commercial thickeners can achieve. These liquids need careful preparation and monitoring to ensure proper hydration and patient comfort. Always consult a healthcare professional to determine the appropriate thickness level and to develop a safe and effective dietary plan. For more details on dysphagia management strategies, visit the IDDSI website: www.iddsi.org.

Frequently Asked Questions

Dysphagia is difficulty swallowing, usually due to problems with the muscles or nerves involved.

An SLP determines the correct thickened liquid consistency through a swallowing assessment.

While some household ingredients can thicken liquids, commercial thickeners are standardized for safety and consistency, following frameworks like IDDSI. It is best to use a medical-grade thickener prescribed by your healthcare provider.

Older starch-based thickeners sometimes imparted an unpleasant taste and texture, but modern gum-based thickeners are generally neutral in flavor. Patient acceptance can vary, and flavor perception can be affected by the thickening process.

Yes, they can affect medication absorption. Always consult your doctor or pharmacist.

No. These foods melt into a thin liquid. They can pose an aspiration risk and should be thickened before consumption.

Monitor your intake and ensure all liquids are thickened to the prescribed level.