Thickening human milk: the effect of time, temperature, and thickener for infants with dysphagia

The aim of this study was to investigate the effect of time, temperature, and thickener on expressed human milk thickened for infants with dysphagia. Thickening agents included raw oatmeal cereal, commercial thickeners (Gelmix, Purathick), pureed fruits, pureed vegetables, yogurt, and pudding. The International Dysphagia Diet Standardisation Initiative (IDDSI) flow test was used to measure the thickness level across samples at various temperatures (40 °F/4.4 °C, 70 °F/21.1 °C, and 98.6 °F/37 °C) and times (0, 5, 10, and 20 min). Statistical analysis included one-way ANOVA with Tukey post hoc test and multiple linear regression. Fruit purees, particularly banana, achieved the thickest mixtures at all temperatures and maintained a similar thickness over time (20 min). Vegetable puree mixtures were minimally effective at thickening, i.e., between 0 and 1 ml on IDDSI flow test, with exception of squash at 40 °F/4.4 °C. Commercial thickener (Gelmix and Purathick) mixtures continued to thicken over time. The yogurt mixture at 40 °F/4.4 °C thickened initially and thinned slightly over time. The pudding mixture at 40 °F/4.4 °C thickened immediately but quickly became a thin liquid. The raw oatmeal cereal mixtures thinned or thickened over time dependent on the temperature of the human milk (40 °F/4.4 °C mixture thinned over time, while the 70 °F/21.1 °C, and 98.6 °F/37 °C mixtures thickened over time).

Time, temperature, and thickening agents have a significant impact on the thickness level when added to expressed human milk. Certain foods such as fruit purees, squash, yogurt, and raw oatmeal may effectively thicken human milk, and the IDDSI flow test can assess if the mixture maintains a similar thickness level over time. These foods could be considered for older infants with dysphagia. When thickening human milk for infants with dysphagia, close physician and clinician monitoring is recommended given the potential positive and/or negative consequences on oral feeding and overall health.

• Thin liquids can be challenging for infants with dysphagia to safely swallow Human milk is difficult to thicken.

• Pureed fruits and pureed squash thicken human milk effectively at various temperatures and maintain thickness level over 20 minutes. • Pureed fruits and pureed squash thicken human milk effectively at various temperatures and maintain thickness level over 20 Raw oatmeal cereal either thins over time or thickens over time depending on the temperature of the base liquid.