The Influence of Liquid Consistency and Food Texture on Swallowing: A Systematic Review Update

Area of Science:

• Otorhinolaryngology
• Speech Pathology
• Clinical Nutrition

Background:

• Diet texture modification is a key intervention for oropharyngeal dysphagia.
• The International Dysphagia Diet Standardisation Initiative (IDDSI) provides a framework for standardizing diet textures.
• Previous reviews have established the impact of diet consistency on swallowing.

Purpose of the Study:

• To synthesize recent evidence (2012-2024) on how liquid consistency and food texture affect human swallowing.
• To update the understanding of swallowing behavior in relation to IDDSI-defined textures.

Main Methods:

• A systematic review adhering to PROSPERO and PRISMA guidelines was conducted.
• Searches across multiple engines identified peer-reviewed studies using IDDSI terminology for quantitative measures.
• Data synthesis focused on swallowing safety, efficiency, and physiologic metrics from 465 eligible studies, with 70 providing IDDSI-mapped data.

Main Results:

• Thicker liquids significantly improved swallowing safety compared to thinner liquids across 25 studies.
• Smaller bolus volumes were associated with reduced residue when using thickened liquids.
• While food textures rarely caused penetration-aspiration, they were linked to increased residue in patient populations.

Conclusions:

• Evidence supports that thicker liquids enhance swallowing safety.
• Diet texture modification should be individualized based on careful patient assessment.
• Further research may be needed to fully elucidate the effects of specific food textures on swallowing physiology.