Clarifying Level 2 Food Consistency: IDDSI vs. NDD
The most important step in defining a Level 2 food consistency is to determine which framework is being referenced. The International Dysphagia Diet Standardisation Initiative (IDDSI) has largely replaced the National Dysphagia Diet (NDD) in clinical practice, standardizing terminology globally. Under IDDSI, Level 2 applies exclusively to mildly thick beverages, while the NDD historically assigned Level 2 to mechanically altered foods. This article focuses on the current IDDSI standard, explaining what mildly thick liquids are and how they are safely prepared for those with swallowing difficulties, or dysphagia.
What are IDDSI Level 2 (Mildly Thick) Liquids?
IDDSI Level 2 liquids are thicker than water but can still be sipped from a cup. They flow at a slower rate than thin liquids, which makes them easier and safer for individuals with poor tongue control or coordination issues to swallow. The thickness is often described as similar to a nectar or a thick milkshake.
Characteristics of IDDSI Level 2 liquids:
- Pourable: They pour quickly from a spoon but slower than thin liquids.
- Sippable: They can be consumed from a cup and require only mild effort to drink from a standard-bore straw.
- Smooth: They must be completely free of lumps.
- Safe: The controlled flow rate helps minimize the risk of choking and aspiration (liquid entering the lungs).
How to Test for IDDSI Level 2 Consistency
To ensure beverages meet the precise requirements for a Level 2 consistency, healthcare professionals and caregivers use the standardized IDDSI Flow Test. This test measures the flow rate of a liquid through a 10 mL syringe over 10 seconds. The procedure is as follows:
- Obtain a 10 mL syringe: Make sure the syringe has a visible milliliter scale and a standard tip.
- Block the tip: Cover the end of the syringe with a finger to prevent spillage.
- Fill with liquid: Pour 10 mL of the beverage to be tested into the syringe.
- Release and time: Release your finger from the tip and let the liquid flow out for exactly 10 seconds.
- Measure the residue: Immediately cover the tip again and measure the amount of liquid remaining in the syringe.
- Interpret the result: A liquid is at a Level 2 (Mildly Thick) consistency if between 4 mL and 8 mL remains in the syringe.
Comparing Different Dysphagia Diet Systems
It is important to understand the distinctions between the current IDDSI framework and the older NDD to avoid confusion and potential harm. The systems use different numbering for their diet levels, and what was once called a Level 2 is now classified differently.
| Feature | IDDSI Framework (Current Standard) | National Dysphagia Diet (Older Standard) |
|---|---|---|
| Level 2 | Mildly Thick Liquids (Nectar-like consistency) | Mechanically Altered Foods (Ground or minced) |
| Equivalents | IDDSI Level 5 corresponds to the texture of the old NDD Level 2 foods. | The concept of 'Mechanically Altered' foods is now covered by IDDSI Level 5 (Minced & Moist) and Level 6 (Soft & Bite-Sized). |
| Testing Method | Objective measurements using the IDDSI Flow Test with a 10 mL syringe. | Based on subjective descriptions and visual assessment. |
| Focus | Standardized, global terminology for food texture and liquid thickness. | Historically defined standards, now largely replaced due to inconsistencies. |
Preparing Level 2 Mildly Thick Liquids
Most liquids need to be artificially thickened to achieve a Level 2 consistency, as few are naturally this thickness. Thickening agents, available as powders or pre-measured packets, are typically used.
Best practices for thickening liquids:
- Follow instructions: Always follow the mixing instructions on the thickener packaging, as the required amount can vary depending on the liquid being thickened.
- Resting time: Allow the mixture to stand for 5–10 minutes after mixing to achieve the correct consistency before serving.
- Test before serving: Use the IDDSI Flow Test to confirm the thickness before serving to ensure patient safety.
- Monitor intake: Ensure adequate hydration, as thickened liquids can decrease overall fluid consumption.
Who needs a Level 2 food consistency?
An individual's need for thickened liquids is determined by a healthcare professional, such as a speech-language pathologist (SLP) or a doctor, after a swallowing assessment. Level 2 liquids are typically recommended for people with dysphagia who have difficulty managing thin or slightly thick liquids due to issues with oral coordination. The slower flow rate provides the person with more time to control the liquid in their mouth and safely swallow.
Conclusion
Understanding the precise definition of a Level 2 food consistency is vital for anyone involved in the care of individuals with dysphagia. The modern IDDSI standard defines Level 2 as "Mildly Thick" liquids, which are specifically formulated and tested to reduce the risk of choking and aspiration. This is a significant distinction from the older NDD framework, where Level 2 referred to "Mechanically Altered" foods. By adhering to the current IDDSI guidelines and using proper testing methods, caregivers and patients can ensure a safe and enjoyable dining experience. Always consult a healthcare provider, such as a speech therapist or dietitian, for personalized recommendations.
