Objective: To categorize dysphagic diets according to the food's viscosity, as determined by an objective method.
Design: Description of dysphagic diet in terms of viscosity.
Setting: Food science laboratory at a university hospital.
Specimens: Twenty kinds of foods: 10 commercially available and 10 formulated for a dysphagic diet in a tertiary university hospital, representing a wide range of food viscosities.
Interventions: Not applicable.
Main outcome measures: Viscosity, measured with a viscometer, and a line spread test (LST).
Results: Logarithmic viscosity (centiPoise [cP]) values measured using a viscometer were inversely correlated with the extent of spread (centimeters) on an LST. (Pearson r=-.95, P=.0001). Viscosities and the LST results were 0.9+/-0.1cP and 5.5+/-0.5cm for water, 63.1+/-4.8cP and 3.4+/-0.1cm for the barium solution, 671.0+/-76.9cP and 2.4+/-0.1cm for yogurt, and 10,031+/-728cP and 1cm for pudding.
Conclusions: Dysphagic diets can be categorized according to their viscosities by objective measurements. The LST correlated well with viscometer measurement and is a practical method with which to measure viscosity.