Texture modification and the use of thickened fluids are well-known strategies used to facilitate swallowing in people with dysphagia. However, some controversy exists around thickeners and their possible negative impact on hydration and medication absorption. This paper considers other properties of food and liquids that may influence swallowing physiology, including:
- Appearance: visible attributes such as colour, shape, size.
- Flavour: combination of taste, smell and trigeminal sensations when tasting bitter, sweet, salty, acidic, umami.
- Texture: - Mechanical attributes such as hardness, cohesiveness, elasticity, adhesiveness.- Geometric attributes including denseness, granularity and conformity. - Surface and body attributes that relate to food sensations in the mouth associated with the moisture and/or fat content in the food.
The authors undertook a systematic review of studies that investigated whether any of the above-mentioned properties were reported to alter swallowing physiology and function in adults with normal swallowing and dysphagia. They analysed 111 independent studies and made the following observations: 70% of studies in the literature were performed on people reporting normal swallowing. Texture and flavour were the main properties that affected swallowing physiology and function. Changes included impact on aspiration/penetration scores, tongue pressures, oral and pharyngeal residue, pharyngeal and upper oesophageal sphincter pressure, and the overall duration of the swallow. This review provides a useful reference for considering modification of food and liquid properties in the clinical management of dysphagia, and highlights the complexity of the topic beyond the use of commercial thickening agents. The authors are clear about the level of evidence, the limitations of the pooled data in this review and the need for individualised treatments when using the insights from the current evidence.
