The International Dysphagia Diet Standardisation Initiative (IDDSI) Framework
The International Dysphagia Diet Standardisation Initiative (IDDSI) framework was created by a global, multidisciplinary group of experts to address the need for a common terminology for describing modified food textures and drink thicknesses. This standardized approach aims to increase patient safety by reducing the confusion often associated with various national and regional diet terminologies. The framework provides a continuum of eight levels, identified by numbers, text labels, and color codes, spanning both foods and drinks. For liquids, the relevant levels range from 0 to 4, from thin (like water) to extremely thick (like pudding).
Proper assessment by a speech-language pathologist or dietitian is paramount to determine the safest and most enjoyable diet for an individual with swallowing difficulties. The consistency of liquids is particularly important for individuals with dysphagia, as a liquid that is too thin can be aspirated into the lungs, while one that is too thick can leave residue in the throat, also increasing aspiration risk.
Decoding the IDDSI Drink Levels
The IDDSI framework provides clear descriptions and testing methods for each liquid level, with testing ideally conducted at the intended serving temperature.
IDDSI Level 0 (Thin)
These liquids flow like water and can be drunk from any cup or straw. Examples include water, milk, coffee, and tea. The IDDSI Flow Test for Level 0 shows less than 1mL of liquid remaining in a 10mL syringe after 10 seconds.
IDDSI Level 1 (Slightly Thick)
Slightly thicker than water, these liquids flow relatively quickly but require slightly more effort to drink. They can still be consumed through a straw or teat. The IDDSI Flow Test for Level 1 indicates that 1-4mL of liquid remains in the syringe after 10 seconds.
IDDSI Level 2 (Mildly Thick)
Similar to the consistency of nectar, these liquids pour quickly but require some effort to drink from a cup or through a standard straw. The IDDSI Flow Test for Level 2 leaves 4-8mL of liquid in the syringe after 10 seconds.
IDDSI Level 3 (Moderately Thick)
Often compared to honey, moderately thick liquids can be poured but move slowly when shaken. They drip in dollops through the prongs of a fork but are not typically consumed with a standard straw. A minimum of 8mL of liquid should remain in the syringe after 10 seconds during the IDDSI Flow Test.
IDDSI Level 4 (Extremely Thick)
This is the level at what IDDSI level for drinks is the liquid too thick to be poured. These liquids have a pudding or mousse-like consistency. They are cohesive, hold their shape, and cannot be drunk from a cup or sucked through a straw. The IDDSI Flow Test is not applicable for this level, as the liquid does not flow through the syringe. Instead, the Fork Drip Test and Spoon Tilt Test are used to confirm consistency.
Testing Methods for IDDSI Consistency
The IDDSI framework emphasizes practical and accessible testing methods to verify the thickness of liquids and foods.
- IDDSI Flow Test: This uses a 10mL slip-tip syringe to measure the amount of fluid remaining after 10 seconds. It is used for liquid levels 0-3.
- Fork Drip Test: For Levels 3 and 4, this test assesses how the sample behaves on a fork. A Level 4 extremely thick liquid should sit in a mound and not continuously drip through the fork prongs.
- Spoon Tilt Test: This test determines the cohesiveness and stickiness of Levels 4 and 5 foods and liquids. A Level 4 sample should hold its shape on a spoon and fall off in a single lump when tilted or lightly flicked.
Comparison of IDDSI Liquid Levels
| Characteristic | Level 0 (Thin) | Level 1 (Slightly Thick) | Level 2 (Mildly Thick) | Level 3 (Moderately Thick) | Level 4 (Extremely Thick) |
|---|---|---|---|---|---|
| Pours? | Flows like water | Flows easily | Pours quickly | Pours slowly | Cannot be poured |
| Straw Use? | Possible with no effort | Possible | Possible with some effort | Not possible with standard straw | Cannot be used |
| Cup Drinking? | Easy | Sippable with some effort | Sippable with control | Can be drunk with control | Must be spoon-fed |
| Consistency | Water-like | Thicker than water | Nectar-like | Honey-like | Pudding-like |
| IDDSI Flow Test | Less than 1mL remaining | 1-4mL remaining | 4-8mL remaining | Greater than 8mL remaining | Not applicable |
| Testing Method | Flow Test | Flow Test | Flow Test | Flow Test & Fork Drip | Fork Drip & Spoon Tilt |
Nutritional Considerations for Thickened Liquids
While thickened liquids are a vital tool for swallowing safety, they present unique nutritional challenges. Patients on Level 4 extremely thick liquids, in particular, face a higher risk of dehydration and malnutrition. The texture can be unpalatable and may not adequately quench thirst, leading to reduced intake. The increased viscosity can also affect the absorption of certain medications.
To mitigate these risks, a registered dietitian should be involved in the care plan to ensure adequate fluid and nutritional intake. Strategies may include using nutritional supplements thickened to the appropriate level and monitoring intake closely. For some individuals, a healthcare team may determine that a 'free water protocol' is appropriate, allowing unthickened water at specific times for better hydration, under strict supervision. Careful adherence and preparation are crucial, as incorrect mixing can lead to inconsistencies that are dangerous for the patient.
Conclusion
Understanding the IDDSI framework is fundamental for ensuring the safety of individuals with dysphagia. The question of at what IDDSI level for drinks is the liquid too thick to be poured is definitively answered by Level 4, Extremely Thick liquids. This consistency requires spoon-feeding and specialized testing methods, as it does not flow freely. While a critical intervention, extremely thick liquids also present nutritional risks that must be carefully managed in consultation with a healthcare team. By adhering to the standardized IDDSI guidelines and testing protocols, caregivers can provide safer and more effective nutritional support for those with swallowing difficulties. For more information, please visit the official IDDSI website.
Further Reading
- International Dysphagia Diet Standardisation Initiative: https://www.iddsi.org/
Managing Nutrition and Dysphagia
For individuals following a specialized nutrition diet due to dysphagia, working with a speech-language pathologist and dietitian is essential. A customized plan can incorporate a variety of foods and liquids at the appropriate IDDSI level to meet caloric and hydration needs. Examples of meals and snacks might include pureed soups and stews, extremely thick nutritional shakes, and yogurt without fruit pieces. Regular monitoring of weight and hydration status is crucial to prevent complications associated with a restrictive diet.
In addition to modifying textures, ensuring foods are presented attractively and seasoned well can help improve appetite and overall quality of life. Avoiding mixed consistencies, such as soup with chunks, is vital for safety, especially for those on Level 4 diets. As patient needs change, regular reassessment of the prescribed IDDSI levels is necessary to provide the least restrictive, and most enjoyable, diet possible.
